BBE 533: MAINTENANCE MANAGEMENT PAUL M.SYAGGA,PhD MARCH 2010

BBE 533: MAINTENANCE MANAGEMENT PAUL M.SYAGGA,PhD MARCH 2010
UNIVERSITY OF NAIROBI DEPARTMENT OF REAL ESTATE AND CONSTRUCTION MANAGEMENT BBE 533: MAINTENANCE MANAGEMENT PAUL M.SYAGGA,PhD MARCH 2010

COURSE OUTLINE FOR BLE 533: MAINTENANCE MANAGEMENT.
1.Principles of maintenance management What is maintenance? Facilities management Nature and types of maintenance 2.Economics of building maintenance Determinants of maintenance Design and maintenance Life cycle costing Service life prediction 3.Maintenance management process Condition assessment for maintenance Prioritization for maintenance Resource requirements for maintenance Execution of maintenance works

COURSE OUTLINE FOR BLE 533: MAINTENANCE MANAGEMENT.
4.Building failures diagnosis and avoidance Causes of defects in buildings Defects in foundations Defects in floors and floor finishes Defects in walls and wall finishes Defects in roofs and roof coverings Defects in plumbing and electrical systems Grounds maintenance 5.Conservation of historical monuments Need for conservation of monuments Procedures in conservation of monuments Laws relating to conservations of monuments in Kenya

1.Principles of maintenance management
1.1.What is maintenance? The following terms that are often used in property industry in relation maintenance need to be defined to avoid confusion. Maintenance : refers to work undertaken in order to keep or restore a facility/property to an acceptable standard. To keep means to maintain to the same or nearly the same physical and functioning level as original. To restore means to put back to the same or nearly the same original physical and functioning level Acceptable standard means that physical and functioning level which sustains the utility and value of the utility/property. This is because there is no absolute standard which is satisfactory in all cases all the time. ii Maintenance management: refers to activities undertaken to make sure that capital investments are protected as well as ensuring acceptable working environment for users, depending on the quality of investment and costs in use. iii Asset management: refers to the process of creating register of assets,and conserving the assets for the operations of the organisation.Thus creation of data base and property maintenance are components of asset management.

1.Principles of maintenance management contd.
iv Property management: refers to process directed at maintaining the value of property as a resource and includes: Overseeing physical maintenance Rental assessment and collection Enforcement of lease covenants Advise on whether to maintain,rehabilitate or redevelop v Conservation: refers to the preservation of facilities including their maintenance so that they may continue serving their useful purpose as well as retaining their historical and cultural features for posterity. vi. Facilities managementy.A new concept in property industry that embraces a wide range of property and user-related functions.It is the active management and co-ordination of non-core building services (buildings,fittings and furniture,plant and equipment,IT,etc) together with associated human resources necessary to assist an organisation achieve its strategic objectives.

1.2.Facilities management Facility management is an interdisciplinary field primarily devoted to the maintenance and care of commercial or institutional buildings, such as hotels, resorts, schools, office complexes, sports arenas or convention centers. Duties may include the care of air conditioning, electric power, plumbing and lighting systems; cleaning; decoration; groundskeeping and security. Some or all of these duties can be assisted by computer programs. These duties can be thought of as non-core or support services, because they are not the primary business (taken in the broadest sense of the word) of the owner organization The term facility management is similar to property management although not exactly the same.While both manage the day to day operations of a facility/property such as cleaning, maintenance and security, similar to Janitors, one must not confuse it with such a title. The property manager has an expanded role which includes leasing and marketing activities whereas the facility manager role focuses on existing tenants who usually are owner occupants. An important feature of facility management is that it takes account of human needs of its tenants in the use of buildings and other constructed facilities. These softer factors complement the harder factors associated with the maintenance and care of engineering services installations.The term "end-user satisfaction" is often used both as a goal and a measure of performance in facilities management.

The discipline of facility management and the role of facility managers in particular are evolving to the extent that many managers have to operate at two levels: strategic-tactical and operational. In the former case, owners need to be informed about the potential impact of their decisions on the provision of space and services. In the latter, it is the role of a facility manager to ensure proper operation of all aspects of a building to create an optimal environment for the occupants to function. This is accomplished by managing some of the following activities. i)Environmental Health and Safety: Building Cleanliness;Waste Removal;Occupational Health and Safety;Hazardous Material compliance,etc. ii)Mechanical Systems Maintenance including preventive and predictive maintenance of: HVAC/R (Heating, Ventilating, Air conditioning and Refrigeration) to regulate Indoor Air Quality and Temperature Control; and Elevator Maintenance

iii)Power Systems maintenance including Normal power such as Electrical Substations and Switchgear Emergency power systems such as Uninterruptible power supply (UPS) systems, and Standby generators iv)Building Systems including Building Automation Systems (BAS),Building Monitoring systems (monitoring capabilities only) and Security and Locks. v)Life/Safety Systems that include Sprinkler systems,Smoke/fire detection systems,Fire Extinguishers; Signage and Evacuation Plans. vi)Space Management including Office Space Layout and Furniture Placement and Systems In summary typical functions of Facilities Management which can either be outsourced or carried out by a combinationcan of in-house and outsourcing can be summed up as Facility acquisition whether through development,purchase or lease Strategic facility space planning,particularly space allocation for people and equipment Support services such a office administration Facility operations and maintenance,in particular to achieve equipment availability as well as ,health and safety of users.Thus maintenance though would seem as merely one of the activities of facilities management,it is indeed a major and critical activity performed during the operational phase of a building’s life cycle, which normally extends over many decades. References International Facility Management Association British Institute of Facilities Management Journal of Facilities Management

1.3.Nature and types of maintenance 1.3.1.Purpose of maintenance: primary purpose of maintenance is to preserve, keep or restore a facility/property to its initial state to the extent practicable or to an acceptable standard so that: It remains in a state that is neither dangerous nor injurious to the health of the occupants i.e. it must maintain health and safety standards for public health It continues to provide functional utility for which it was intended: as a factory, mosque, hospital, state house, etc) It retains the value of investment as a capital asset thus continuing to provide adequate return on investment It presents good appearance: preserving the character of the neighbourhood and enhancing the self-esteem of both owner and occupants, i.e. the way we look is not very different from what we are.

1.3.2.Maintenace activities There are basically three activities that constitute maintenance works namely: Servicing:day to day routine chores that maintain cleanliness and order Rectification: making good faults arising from design, unsuitable materials or poor construction Replacement: restoring some worn out materials or components due to wear and tear or incorrect use A fourth type of activity often confused with maintenance are any works of a capital nature carried out to improve on the original design or as major overhaul to the original design and specification such as modifications,alterations,renovations,which are improvements to a facility,rather than maintenance.Such works add more than retain the original design.

1.3.3.Types of maintenance The three maintenance activities usually categorised by the manner in which the works are executed namely: Planned preventive maintenance: work organised and carried out with forethought and intended to reduce the probability of failure or performance degradation namely: Scheduled maintenance at pre-determined intervals Condition-based maintenance based on continuous monitoring Running maintenance carried out when machine is in service Preventive shut-down maintenance, when factory closes down for maintenance ii Planned corrective maintenance:work organised and carried out after a failure has occurred i.e. advance provision is made in form of labour and spares so that work is carried out through: Corrective shut-down maintenance carried out after failure but for which expenditure provision had been made Emergency corrective maintenance to avoid serious consequences. Unplanned/emergency/breakdown maintenance: ad-hoc maintenance as a result of unseen or damage due to external sources. It may also described as “wait and see “ maintenance

2.Economic of maintenance .
2.1.Determinants of maintenance While there may be no absolute standard for all facilities all the time largely on account of economic and social considerations, there ,however, some standards are universally applicable such as structural stability or public health concerns.Thus what is injurious or dangerous to the safety and health of occupants/users of a building or facility should not be in doubt. However,considerations for upholding investment value, preserving character of the neighbourhood or enhancing esteem of owners and occupants, could perhaps be subject to varying interpretations. Therefore the determinants of maintenance standards or factors which influence decisions on how to maintain a facility, are complex and sometimes conflicting, and in particular they include the following: Design factors(acts of omission/commission during design and construction) Statutory requirements User requiremets/Type of user Value considerations Budgetary constraints

2.Economics of maintenance contd.
2.1.2.Influence of design on maintenance Any building/facility is designed to satisfy the functional requirements for utility, aesthetics, and user-friendliness. However, the need for maintenance arises either from normal wear and tear or defects of omissions/commissions during design, choice of construction materials/components, construction phase, and the use/abuse during occupation. Informed design should draw a balance between functional requirements and the overall financial commitments(initial and maintenance costs) throughout the life cyle of the building/facility. There exists an inverse relationship between initial costs(purchase/construction) and future maintenance costs, so that a reduction in future maintenance costs may be obtained by increasing initial costs and vice-versa. The problem is to determine the optimal model for the inter-relationship of initial and future costs of a development project at the design stage. A technique often used in this determination is called life-cyle costing. See figure on “Effects of early design decisions on building life-cycle costs” in Syagga and Aligula(1999) page 50.

2.1.2.Statutory requirements Some legislation may prescribe standards of safety or hygiene to achieved in the management of assets notably, lifts and fire equipment, preservation of monuments or structural safety of buildings. For example: Antiquities and Monuments Act(1983) prescribe that no person is allowed to destroy, alter or deface monuments or do any work that would impair the preservation of monuments, nor extend or modify the external of the monument. Public Health Act requires that buildings are constructed and maintained in such a manner that they are neither injurious nor dangerous to health of dwellers; nor dilapidated/ defective as to be unsafe. Registered Lands Act(1963)(section55), states that “to keep a building in repair”,shall in the absence of express provision to the contrary mean “in such a state of repairs in which a prudent owner might reasonably be expected to keep his property due allowance being made for age, character and locality of the building at the commencement of the lease” Other pieces of legislation that make reference to property maintenance include Occupational Safety and Health Act(2007),Local Government Act(Revised 1998),Sectional Properties Act(1987),laws relating to landlords and tenants,etc .

2.Economics of maintenance contd..
Basic user requirements These include the provision of shelter from weather and provision of acceptable indoor environmental conditions. These may be realized through the three levels of care: basic level, intermediate, and intensive/highest level of care. However, sometimes user requirements go beyond what was originally designed, in which case they call for improvements rather than maintenance, as for instance, new facilities are added. User requirements will also depend on the type of facility and status symbol, such that maintaining a classroom is relatively less demanding than maintaining a hospital ward, a presidential suite in a hotel or the state house grounds.Similarly,maintenance level of a life support equipment is certainly higher than any other equipment in a hospital. The concept of duty of care: Like a hospital patient a building or other facility requires varying levels of attention through out its economic life, notably basic care: cleaning/servicing, intermediate level of care:inspections and repairs, and intensive care:replacements/renewals of components. The needs can be determined at the design stage,then subsequently monitored and re-appraised regularly when the building is in use, and appropriate level of attention given so that the building can continue to fulfill its functions. The concept of duty of care marries in well with planned preventive maintenance See figure on “Levels of maintenance in the context of duty of care”

2.1.4.Value considerations Properties that are tradeable in the market require some minimum level of maintenance for them to attract market value. The optimum level of expenditure on maintenance should be that which gives maximum return, i.e. point at which marginal increase in maintenance expenditure equals marginal value(dv/dm=1). For properties which do not trade in the market the marginal value is synonymous with utility/functional value. The appearance of a building must be acceptable in terms of culture,religion,defence or status. The way things look is not irrelevant to the way things work: how they look is how they should look. The concept of obsolescence. Abuilding or other facility has three types of life:the physical life; the functional life; and the economic life that need to be preserved so as to avoid negative/reducing effect called depreciation. Depreciation on physical life of a building arising from wear and tear or physical impact is called physical depreciation Depreciation on the functional life of a building, arising from errors/omissions in design(room sizes,ceiling heights,facilities/amenities) is called functional obsolescence., and is regarde as curable obsolescence.Works carried out to achieve desired standards are called improvements or rehabilitation. The depreciation/loss in value arising from conditions external to facility that affect its character/degree of utilisation, hence less demand (presence of a nuisance,outmigration,economic downturn)is called economic obsolesence, and regarded as incurable obsolescence. It cannot be corrected through maintenance,except by demolition or change of user. Obsolescence sometimes in depreciation when it precipitates physical deteroriation because when demand falls property gets neglected and suffers severe physical deteroriation leading to demolition

The present value concept: Economic obsolescence is incurable,but physical and functional obsolescence can be cured through maintenance and rehabilitation, respectively.Rehabilitation involves conversion and modernisation beyond the routine maintenance. However,with time it may be necessary to consider whether to continue to maintain,rehabilitate or demolish a building or facility. The decision is normally made in favour of higher present value of proposed development. The comparison is made between modernisation and replacement with a new facility on the same site, with both values being discounted to the present value. Present Value,Y is denoted by Y=1/(1+i)^n, where”I” represents the interest/discount rate, and “n” represents period by which the rehabilitation/redevelopment will be realised/mature.

2.1.5.Budgetary constraints In industry,the responsibility of maintenance is to ensure that the facilities/equipment used in production are operating at the required level of productive efficiency and are available when required. Thus inadequate maintenance would not only lead to costly repairs but to lost production as well. Optimum equipment availability is achieved when the total sum of maintenance costs(preventive + corrective) is at minimum. When less preventive maintenance is applied breakdown maintenance increases and equipment availability reduces.It is therefore possible to reduce breakdown costs and increase equipment availability by increasing preventive maintenance upto a point when the sum of the two is at minimum, and that becomes the optimal point. Thus equipment availability(operating level of efficiency when required) may determine how much maintenance is necessary and what to spend on the same, this being where the total sum of the two is at minimum.

2.2.Life cycle costing Life cycle costing is a tool to be used in the decision-making process, the objective being to ensure the best value for money over the economic lifespan of the asset with the time value of money being taken into account. It is comparative evaluation of time-phased costs(total/whole life costs) and revenues attributable to a project/asset/component over a specified project life.The total /whole life cycle cost of the asset is the sum of initial acquisition costs and subsequent running costs of an asset over its operating life. It is also known as whole life-cycle costing,cost-in use,engineering economics,cost-benefit study or terotechnology. The process contains parallel and inter-related phases namely: Establish the objective and justification for the project Identify the life-cycle/total/whole costs likely to occur in the life of the project Formulate assumptions to be employed in the analysis(lifespan,discount rates,frequency/incidence of life costs,etc Rank the alternative cost scenario using any comparative methods of analysis including NPV,IRR, Annual Equivalent(AE),Payback period,etc. Subject the results to further sensitivity analysis to the various cost factors so as to rationalise acceptable alternative See Fig on Key Decisions in the Whole Life-cycle costing Process of a building facility.

2.3.Service life prediction 2.3.1.Need for service life prediction The need for “Sustainable Construction” necessarily imposes inherent requirements for specified levels of durability of building materials and components and it is understood that these can only be entrenched within the construction sector through standardization. Standards,including practices and guidelines for predicting service life would support the performance approach by facilitating evaluation of long-term performance(durability performance) of both new and traditional materials and components in their intended service environments. Service life prediction is a requisite tool for helping assess long-term environmental effects,for maintenance management of infrastructure systems,or indeed for maintenance of building envelop systems,envelope components and related materials. Increasingly building material and component manufacturers are seeking sytematic methods to assess the likely risk of premature deteroriation of existing products given specific climatic effects,or the most vulnerable exposure conditions of new products in specified systems. Ability to predict the service life of building materials,components,and systems is needed to improve the selection processes.Because durability is a vague term,evaluation of durability using existing standards does not give adequate service life information.

2.3.2.Durability testing and service life testing compared. In Kenya both the Kenya Bureau of Standards and the Materials Branch of the Ministry of Roads and Public Works undertake durability tests on building materials with respect to the following parameters/attributes. Dimensional measurement Compressive strength Water-absorption and moisture content Density Weathering Rupture Fire resistance Thermal conductivity Noise attenuation

One needs to note ,however,that the above typical standard durability tests cannot provide useful service life information because: Each standard is developed as a screening test and employs a single arbitrary set of severe conditions intended to cause the same mode of failure as that expected in service, and The relationship between the laboratory exposure conditions and expected service conditions is not known. What is really needed is an approach that yields information about the individual and combined effects on service life of differences in material,processing,design,exposure and application variables. In contrast to the typical durability test, service life prediction requires definition of one or more failure criteria,characterisation of service conditions,determination of rates of degradative reactions in many specimens under conditions which can be related to those expected in service,and calculations of times of failure and their distribution. Because a reliability approach is clearly preferred,service life prediction tends to be data-intensive both in the amount of data that should be collected and that which should be available in databases. A standard durability test can usually be performed by a technician with little supervision,whereas service life prediction requires experiments planned,supervised,and analysed by a materials specialist.As a result,a service life prediction standard is different from a typical durability standard. The problems of service life prediction tend to increase in difficulty with the number of materials in a building component,largely because of the increased number of interfaces between dissimilar materials; the difficulties increase even more with systems consisting of many components.

Service life prediction standards There are currently a number of ISO standards on service life prediction based on the works of ASTM,RILEM,CIB and others namely: ISO(2000) :Part 1 on General Principles describes the general principles and procedures that apply to design,when planning service life of buildings and constructed assets.It is important that the design stage includes systematic consideration of local conditions to ensure,with a high degree of probability,that the service life will be no less than the design life.The standard is applicable to both new constructions and the refurbishment of existing structures. ISO(2001a) : Part 2 on Service Life Prediction Procedures describes methodology/procedure that facilitates service life predictions on building components. ISO(2002) :Part 3 on Performance Audits and Reviews is concerned with ensuring the effective implementation of service life planning.It describes the approach and procedures to be applied to pre-briefing,briefing,design,and construction,and where required,the life care management and disposal of buildings and constructed assets to provide a reasonable assurance that measures necessary to achieve a satisfactory performance over time will be implemented. ASTM = American Siciety for Testing and Materials RILEM = International Union of Testing and Research Laboratories for Materials and Structures CIB = International Council for Building Research Studies and Documentation

The above standards are procedural and premised on the assumption that for each building component or product there is a reference service life(RSLC) that can be adjusted by factors(environmental load,material quality,wormanship,and other related factors)describing deviations from the reference situation to the actual building conditions.This permits reaching an adjusted service life estimate(ESLC) for the component or product that is then used in estimating the service life of the building or the component. One key concern is the determination of what the Reference Service Life(RSLC) of a product or component is prior to using the factor method. The RSLC is the service life that a building or component would expect or is predicted to have(ESLC) in a certain set(reference set) of in-use conditions.Thus ESLC=RSLC*A*B*C…(factors); for which A,B,C….=/<1(equal to or less than 1). This factorial approach(“factor method”) need further development and refinement as regards the factors,the theoretical calculation methods,and the reference life data to be used. It is in effect a method by which to transfer knowledge on service life from a known reference condition to a project specific condition and is typically used in engineering design.

2.3.4.Methods for the development of RSLC The development of RSLC is guided by two fundamental questions namely: What standards are required(what are the aspects/factors of durability and performance)? How are these standards to be determined/established? Requisite RSLC standards Determination of mechanical and environmental loads(in laboratory tests and in real service,real and simulated) to which materials or components are likely to be subjected Characterisation(macro,micro and surface) of materials and components Identification of degradation of kinetics of materials and components (in different environments and at different locations in the specimen,taking size effects,surface effects,and effects of flaws into account) Identification and expression of performance requirements and performance criteria for materials and components Organization and representation of computerized knowledge of materials and components.

Approaches to determination of RSLC The current primary approaches and methods for evaluating the service life of a building component include the following six methods, which also describe their main usage: 1) Methods based on a probabilistic approach (Sierres et al. 1985); these are currently used, for example, as the basis for standards and guidelines regarding structural design calculations. 2) Statistical approaches (Brandt and Wittchen 1999) that may be used when data on several equivalent building components are available. (3) Comparisons between long-term and short-term exposure tests (Jernberg et al. 2004), typically a standard practice for the treatment of the results derived from laboratory and in-service tests. (4) Feedback from practice, which is considered a standard practice for the diagnosis of a building component failure. (5) Factorial method for service-life estimation,for which there exist several formulations and associated research, is synthesized i)Relating to or being an instrument whose sound is modified or augmented by a synthesizer. Ii)Relating to or being compositions or a composition performed on synthesizers or synthesized instruments. in Jernberg et al. (2004). This method is commonly used for the assessment of the service life of in-service building components and in-service buildings. The factor method is a standard method given in ISO (3) (6) Methods based on possibility theory (data fusion) as detailed in Lair (2000) and Jernberg et al. (2004).

The probabilistic approaches are well adapted when the studied phenomenon is well known; that is to say, when enough information is available to define the relevant probability law and its parameters. Several probability laws are well known and well fitted to the more common degradation phenomena of classical materials in civil engineering. However, the definition of the probability law and its parameters is difficult when a complex building component is studied and when no or only a small amount of information is available, which is the usual case in the construction domain. The statistical approaches are well adapted when sufficient observations of a specific building component are available, such that a coherent sample can be done and statistical principles can be applied. However, even if in some civil engineering domains such statistics exist (for example, road, dams, and railways), this is not a current practice in the building domain. The first four methods and approaches have two primary similarities: i) They proceed to a direct assessment of service life, that is to say, the service life of a building component can be determined from the use of probability functions, statistics, tests results or inspection results relevant to this specific building component. For example, if considering a statistical approach, the service life of a window unit can be deduced from the observation of the behaviour or response of the unit over time of a set of similar window units. (ii) It is difficult to transpose/transfer their results to other related inservice environments and to other building components. For example, the results of an accelerated short-term exposure test of a rubber component subjected to ultraviolet radiation cannot be used to evaluate the service life of this same type of rubber component when exposed to freeze-thaw conditions

The fifth method (factorial method) proposes a direct assessment of service life and permits taking into account the specific effect of each in-service condition. However, a significant drawback of this method is the subjective manner in which the factor values are estimated. The last method (data fusion) for determining the service life of building components, proposed by Lair (2000), allows a direct assessment of the component. Hence, the main focus is to further develop this method for other types of data (service life, probability, and performance data) and at other geometrical levels (material, element, and building component). If the primary objective is to be able to assess the in-service service life of all geometrical entities (from materials to building) considering all their possible degradation scenarios and functions (as mechanical resistance, thermal isolation or esthetical function,...). Among existing approaches, the approach based on possibility theory is the only one to allow this objective to be reached.

Steps in the determination of RSLC The proposed methodology allows one to duduce the service life of building components, i.e., the time to reach the multi-performance profile that corresponds to the failure of the building component.The methodology is comprised of four primary steps: i) Undertaking a system analysis to provide an overview of the functioning of the building component, which is indispensable to complete an FMEA. ii) Identification of all possible degradation scenarios of the building components as well as their causes and consequences using failure mode and effects analysis(FMEA). iii)Collection and preparation of RSLC data (service life, probability, and performance) associated with the degradation scenarios,transformation of this data into a fuzzy-set format, and assessment of its quality; . iv)Service-life assessment.

System analysis A system analysis requires modeling the behaviour of the building component when subjected to environmental stresses (climatic and usage) over its in-service stage. It is from this stage that a "functional model" of the building component of interest can be developed; such a model provides a means to link actions causing deterioration to that of loss in functional performance and is a prerequisite for carrying out the FMEA . The first step of this analysis is to build an organisational model. This requires assessing the mechanical, physical, and chemical characteristics of the individual elements of which the building component is comprised and the respective geometrical scales in which these elements are constituted, and then determining the interrelation among all elements. In a second step, the environmental stresses that may cause degradation of the building component are characterized; this step includes first determining the environments to which the building component may be subjected. For example, establishing the environments that exist on the interior and exterior surface of a wall. Then, the environmental agents that may cause degradation of the building component are identified (e.g., snow, wind, solar radiation, etc.). The final step is to develop a "functional model" based on the identification of performance functions that are characteristic of the building component and its elements. This permits an understanding of the building component behaviour in terms of its functional performance when subjected to the previously defined stresses.

2. Failure mode and effects analysis(FMEA) The purpose for completing the FMEA is to obtain as complete a list as possible of degradation scenarios or chains of degradation that could damage the building component during the in-service stage. The FMEA is a risk analysis method, developed during the 1970s and still being used in different industrial fields, such as the spatial, nuclear, and medical fields (Dyadem Press 2003). The application of this method to the building field was initiated by Lair (2000), who modified the chaining of the analysis that now allows the analysis to benefit from the results of FMEA. The first step in applying the principles of FMEA consists of defining the potential degradation modes, the causes (stresses, incompatibilities between materials, errors during building construction), and the consequences for each function, component. The second step consists of determining the degradation scenarios in an iterative .The iterative principle, from step i (step i = 0: beginning of the in-service stage) to step i+ 1, aims to determine if the degradation consequences at step i could be the cause of degradation at step i + 1.

3.Collection and preparation of RSLC data The collection and preparation of data(service life, probability, and performance related) is an important step in the methodology that is summarized here.All available data useful to the service-life assessment and that may be derived from different sources of information are collected and organised in the following manner: service life of each set of scenarios, each single scenario, and each single phenomenon that have been identified from the previous step of the methodology; the probability of occurrence of each set of scenarios, each single scenario, and each phenomenon, which have been determined in order to deduce the most probable scenarios to be considered for the service-life assessment; performance versus degradation functions of each pair, {phenomenon; function}, that have been identified from the FMEA and that allow deducing the multiperformance profile of the building component from the knowledge of the degradation states of its elements. Given that these data may be obtained from several sources, they may be heterogeneous, imprecise, uncertain, and incomplete in nature. It is for this reason that the quality of each piece of data must also be evaluated.If the quality of the data at the objective point is not sufficient, then it is necessary to obtain available data at other points.

4. Service-life assessment The set of principle outputs of this last step of the service-life assessment methodology include the following: (i) to assess the service life of the entire set of scenarios of the building component, without considering their probability of occurrence; (ii) to assess the probability of occurrence of each scenario to retain only the more probable ones in the pursuit of the methodology; (iii) to deduce the multi-performance profile at a specified time in the life of the building from the duration of the retained scenarios, based on the outputs derived from the performance versus degradation functions. Finally, the service life of the building component is obtained when the multiperformance profile corresponds to the failure profile; that is to say, when the performance level of one function or a combination of functions reaches its failure threshold. This approach is rather similar to the life-cycle optimization that uses a probabilistic approach ,except that: (i) an approach based on possibility theory is proposed; (ii) all the possible degradation scenarios of the consider entity (material, element, building component) are taken into account; (iii) several types of functions, such as mechanical resistance with thermal and acoustical isolations, are managed together.

2.Economics of maintenance contd
References: Durability of Building Materials and Components by Seda and Levitan,1980 Durability of Building Materials and Components by Baker P.J et al,1990 Guidelines on Durability in Buildings by Canadian Standards Association,1994 Guide to Durability of Buildings, and Building Elements,Products and Components by British Standards Institution,1992. ISO 15686(1,2,3&8) on Building and Constructed Assets Failure mode and effects analysis in the cladding industry(Layzell J. P.1997), International Conference on Building Envelope Systems and Technology, ICBEST’ 97, Bath, UK (April 1997), pp Durability assessment of building systems(Lair, J. and J-F. Le Teno,1999), in: Durability of Building Materials and Components 8, M. A. Lacasse and D. J. Vanier, Eds., Proceedings of the 8th International Conference on the Durability of Building Materials and Components, Vancouver, Canada (June), pp Failure Mode Effects and Criticality Analysis (FMEA) – a tool for risk analysis and maintenance planning(Lair, J.,2003)).Report submitted to the CIB W80/RILEM 175-SLM Service Life Methodologies, February, CSTB France.

3.Maintenance management process
Condition assessment for maintenance Prioritization for maintenance Resource requirements for maintenance Execution of maintenance works

3.1.Condition assessment for maintenance Effective building maintenance requires the following information in order to retain or restore the same to the desired condition,which in turn primarily determine the cost and timing of maintenance work. Applicable condition standards:acceptable standards for each category of building The condition of the building fabric,elements,etc The frequency of failures The type and extent of maintenance work required The risks associated with postponement of the required maintenance work The quality of the building fabric or elements for use.

3.Maintenance management process contd.
3.1.1.Condition standards Queensland Department of Public Works in Australia for instance,uses the following five levels of rating to determine maintenance standards for each building or equipment: Level 5:best possible condition for buildings/equipment with highly sensitive functions(operating theatres, steam plant and medical gas in hospitals) or high profile buildings(parliament or state house,etc) Level 4: good operational and aesthetic condition for good public presentation and high reliability and functionality such as five star hotels,embassies,banks; or water treatment plants, standby generators in hotels and hospitals Level 3: reasonable condition to meet operational requirements, such as school buildings or lifts. Level 2: minimum condition to meet minimum operational and safety and health requirements only, such as car ports, storage facilities; garden irrigation systems,etc Level 1:holding condition for dormant assets to be maintained at minimum to meet statutory requirements pending disposal/ demolition.

3.1.2.Condition and risk assessment The quantification of maintenance demand is governed by the need to define the gap between current and the desired condition.The process takes the following steps: Assessment of defects: diagnose the defect and ist causes Assessment of remedial action:based on the diagnosis of the defect and cause,proposals should be made for appropriate remedial action Assessment of consequential events if remedial action is delayed:deferred remedial action may lead to further deteroriation and consequential damage to the property Assessment of the impact consequential event:impact/seriousness of the consequential event/damage as a result of remedial action being deferred Assessment of the probability of the consequential event occuring:what are the chances that damage may result? Assessment of frequency of failures:interval between failures,despite remedial action or regular maintenace.This helps in strategic planning process and effective allocation of resources Assessment of maintenance required:this is not the same as building condition because similar buildings under different conditions could require different degrees of maintenance,and similarly,different buildings under different conditions could have different maintenance needs.

Rating/assessment of the impact of consequential events The impact of consequential events if work is postponed may be described in five categories namely: Catastrophic : postponement may lead to loss of life,structural collapse or exposure to life threatening situations,so that remedial works must be treated as emergency and executed immediately. Serious:may lead to collapse of major sections with potential health, safety and life risks.Remedial works must be done as soon as possible within 3 to 6 months. Moderate: substantial detrimental impact on assets/sorrounding assets with potential exposure to health and safety risks,or failure of asset.Work to be done within 12 months. Limited: limited detrimental impact on the asset/sorrounding assets with limited potential exposure to health and safety risks or failure.Remedial works should be carried out within 24 months. Negligible:very little detrimental impact on the condition of the asset/soorounding assets. Remedial work can be deferred for more than 5 years.

Probability of consequential events occurring The likelihood of consequential event occurring can also be measured on a probability scale so as help in prioritisation of the works a s follows: Almost certain: it is almost 100% sure(>90%) that the event will occur Likely:the chance of event occurring is about 80%(>70<90%) Average: there is about 50% chance that the event will occur(>30<70%) Unlikely:there is about 20% chance like the scattered thunder showers Highly unlikely: less than 10% chance,e.g. snow in Nairobi.

3.2.Prioritization for maintenance When funds are not enough to carry out all required works some works may be postponed to the next period that funds are available. The process of assessing the urgency of the required maintenance and ranking the work is called prioritising maintenance work. The process should be unbiased,objective and take into account as many factors as possible which affect the importance and urgency of the required maintenance works. 3.2.1.Factors determiningin priority rating The following factors affect/determine the urgency of required maintenance actions: Risk associated with postponement The condition of the asset The frequency of failure Relative importance of facility/space/element relative to others Required maintenance action(complexity of the works: replace, repair, service, repaint,remove,clean,etc) Required quantity of work

3.2.2.Priority rating system A more unbiased and objective method is to weigh and rank the priorities according to their urgency as follows: Identify technical factors affecting the required urgency of required work Allocate a weight to each factor according to its impact on the urgency of the required maintenance work Calculate and rank the cumulative weight of all factors affecting the urgency of the required work for each asset/element. The highest weight is ranked first so that priority 1 is most urgent The following equation can be used to calculate the priority weight: P=f(Pr+Pc+Pb+Pf+Ps+Pa)*Cest Where P= priority weight;Pr=risk factor;Pc=condition factor;Pb=frequency of failures factor;Pf=facility factor;Ps=section factor;Pa=action factor; and Cest=estimated cost required

3.3.Resource requirements for maintenance Maintenance works can be undertaken in-house or outsourced or a combination of both. Whatever the case, it is necessary that the following cost items are used to determine the financial annual estimates for maintenance: a)Material budget: costing is spread over the various trades in proportion to estimated volume of material usage per trade or activity. b)Plant and equipment budget: based on purchase, hire and the maintenance c)Manpower budget: Based on estimates of workload on routine maintenance, workload on repairs, work content and resultant productive standard hours(PSH) per job, and effective performance(EP) of the labour force for each trade(productive standard hours/gross hours worked*100). Based on above, labour required can be calculated as: N=j*wc*100/ep+sc Where N=number of persons; j =estimated number of jobs; wc=work content per job; ep=effective performance; sc= % of sickness/leave Total cost of labour force= (Basic wage*N)+% for overhead and other costs(usually being ,1/3 of basic wage). d) Where work is outsourced, it may be based on term contracts with agreed annual rates for labour, materials and equipment, particularly for routine maintenance. For major repair works, bills of quantities may be prepared as needs arise.

3.4.Execution of maintenance works 3.4.1.Programming To obtain best possible results with cost effectiveness the work should be programmed according to content, urgency, etc and then translated into weekly and monthly schedule and upgraded regularly. The following should be considered: Jobs should be pre-inspected by supervisor so that jobs are allocated to those who can do them best Plants, tools, equipment and materials must be available at work place when required Transport must be available to convey operatives to the sites without delay The operative must spend maximum amount of time during working hours on productive activities The supervisor must be available to give assistance and advice to operatives when required A weekly record of accomplishment should be kept and made available to the management

3.4.2.Performance improvement a) Repairs and maintenance are generally labour intensive,oftenscattered and difficult tosupervise.It is therefore essential to achieve good labour relations with the operatives,and set realistic targets rather than to wield a big stick to the operatives.Thus the supervisor must work with the people, get on with the people and inspire them. b) The management on the other hand,should understand the objectives of the organisation,decide on the target requirements, and monitor the performance achieved in both production and costs. c) The maintenance manager should call a weekly meeting of his management team comprising of appropriate senior staff so as to evaluate the achievements for the week; consider proposals for improvements; and decide on wayforward for the coming week to overcome problems which have been identified as affecting performance. d) Performances monitoring should consider the following in actions to be taken: i)monthly expenditure on labour ,transport and materials against approved budget ; ii)effective performance :lost time,unmeasured work,non-productive work iii)cost effectiveness: depends on effective performance and materials costs iv)work programmes: monitored and compared with objectives v)technical inspections against inspection schedules.

3.4.3.Maintenance management system(MMS) With advancement in technology, property industry has developed building management system(BMS) for the control of various activities within a building. A building management system is a computer-based system that links the various systems in a building such as lighting control, air conditioning, access control, public address systems, smoke and fire alarms. This allows intelligence responses to threats or failures to be coordinated across different services. Various commercial software packages for building management exist such as ARCHIBUS/FM software which is a system of integrated modules with all aspects relevant in the management of a facility: asset register, property leases, security, space occupancy, and maintenance. Maintenance management system(MMS) is a computer-based system that can be operated separately or as part of a building management system that automates repetitive tasks and structures maintenance flow to suit virtually every operation.

3.4.4.Tasks included in the MMS Typical automated tasks handled by computerised maintenance management system includes the following activities: Asset register Equipment history Resource allocation Work order control Preventive maintenance Corrective maintenance Failure reports Purchasing and inventory control Supplier tracking Maintenance cost analysis Comprehensive management reporting

4.Maintenance and conservation of monuments
Need for conservation of monuments Procedures in conservation of monuments Laws relating to conservations of monuments in Kenya

4. Maintenance and conservation of monuments
4.1. Definitions: The objects around us which are products of former actions of people both living and dead are the historical benchmark of time.They give one a sense of his/her position in time and space and hence provide a basis for evaluation of our own self. A people’s pride in their historic and cultural heritage is what creates the need for any conservation programme. A monument is any building or structure, below or above the surface of the land, preserved for its historical importance, or built to remind people of great events of personalities. Conservation is therefore the professional care of monuments, in order that they may continue existing, serving a useful purpose. It refers to all acts that prolong the cultural and natural heritage of monuments, including their maintenance in a good state of repair, and maintaining other features such as characteristics of activities which take place within the buildings.

4.Conservation of historical monuments contd.
4.2.Objectives of conservation The principal objectives of conservation of monuments are: To awaken the interests of the people in their common architectural and important times in history. Artefacts from the past provide material evidence of the past was like. To protect and enhance buildings and areas of architectural or historical interests to maintain historical continuity and establish a sense of security in the face of social changes To ensure a living role of ancient buildings in the contemporary society. Well informed conservationists will apply their knowledge of past design as a basis for criticism and improvement in the design and construction of new structures. To conserve the character of buildings and historic facilities as national assets

Maintenance and conservation of monuments contd.
4.3.Ethics of conservation Conservation involves making interventions at various scales and levels of intensity which are determined by the physical conditions, causes of deteroriation and anticipated future environment of the cultural property under consideration. Whatever intervention is proposed it should conform to the following conditions in order not to negate the real purpose of conservation: The condition of the monument before any intervention and all methods and materials used during treatment must be fully documented Historic evidence must not be destroyed, falsified or removed Any intervention must be the minimum necessary Any intervention must be governed by unswerving respect for the aesthetic, historical and physical integrity of cultural property.

4. Maintenance and conservation of monuments contd.
4.4. Conservation interventions The starting point in conservation is to take an inventory of all historic and cultural property in the land, to serve as the basis for deciding the form of intervention. The following interventions ,subject to the rules of consrvation ethics may be applied individually or in combination as appropriate: Consolidation : physical addition of other material to ensure continued stability of the structure Prevention: protection of property by controlling environmental agents of degradation Preservation/maintenance: undertaking repairs to prevent further decay Rehabilitation: modernisation/alteration, and retaining the original use Restoration: reviving original structure thro’ replacement of missing parts Reproduction: copying any missing/existing artefacts so as to maintain their harmony Reconstruction : damage by fire or war can be reconstructed relying on accurate documentation/evidence so as to be in harmony with the design of the original structure.

4.5.Role of maintenance and rehabilitation in conservation Maintenance in the case of monuments refers to the doing of any act which may be necessary for the purpose of maintaining /protecting a monument or a protected area or of securing convenient access thereto, including fencing,covering,repairing,restoring and cleaning a monument. While arguments continue on appropriate combination of preventive, corrective and unplanned maintenance, the latter two forms,are executed when the facility has “broken down”. Given the nature of monuments it will be extremely difficult to reconstruct them without destroying original texture or omitting some details.Thus where possible historical structures should not be left in disrepair to a point where they need corrective maintenance, but should be constantly kept in good shape. Both corrective and unplanned maintenance by their operations are unsuitable for maintenance of monuments.Preventive maintenance is most suitable for conservation of monuments because it will not require the structure to break down in the first instance so as to carry out curative measures

Rehabilitation is not the same thing as refurbishment. Rehabilitation refers to activities carried out to correct major defects in a facility without adaptive alteration so as to preserve original shape, style and texture. As a consequence rehabilitation has social, cultural and economic advantages since the monuments retain their identity, cause less human upheaval and political friction; utilise existing infrastructure and services, avoid demolition costs and utilise existing capital. physical decay. Refurbishment on the other hand is economically motivated and involves modifications, extensions and restyling of structure to suit changing needs or revised use. It has nothing to do with maintenance nor is conservation its primary objective. An existing building once refurbished should be equally as efficient in its new role as a purpose designed building would be.

4.6.Conservation of monuments in Kenya While conservation of monuments in a country like Britain dates back to 1882,in Kenya conservation of monuments is a recent phenomenon dating back to the enactment of Antiquities and Monuments Act(1983) and National Museums Act(1983). Antiquities and Monuments Act(1983) was enacted for purposes of protection and preservation of monuments, acquisition of monuments and repair and maintenance of monuments. The Act empowers the Minister in charge of heritage to declare structures approved to be monuments by publication in the Kenya gazette. The Act requires that every monument whether placed under public or private ownership must be protected and properly maintained. No person is allowed to destroy, remove any items from monuments, alter or deface monuments or do any work that would impair the preservation of monument Where an owner entrusted with the care of the monument fails to maintain it, the Minister will notify the same of the negligence, and failing to take action within reasonable time allows the Minister to order the work to be done at the expense of the owner. Where a monument in private hands is in danger of being destroyed /fall into decay, the Minister may require the owner to sell it/lease it to the Government within 2 months, failing which allows the Minister to invoke the provisions of Land Acquisition Act to compulsorily acquire the property.

4.7.Acquisition of monuments Under the National Museums Act, the National Museums of Kenya Board is authorized to prepare a list of structures worthy of consideration as monuments to the Minister for approval and gazettment. The custody of the monuments may be vested in public or private management as the case may be. The Government, however, through the Board can purchase, lease or accept a gift or bequest of monuments Although some monuments are owned by individuals, most of the monuments are in the custody of the National Museums of Kenya Board(including Lamu Island and Mombasa Old Town). Other public institutions that manage monuments include Ministry of Public Works(Uhuru Gardens),Ministry of Health(Karen Blixen),City Council of Nairobi(Macmillan Library),Kenya Commercial Bank(Kipande House),Ministry of Justice(High Court). The monuments under the Board are funded by appropriations in aid from GOK through the ministry in charge of heritage. Some conservation grants also come from development partners. However, the Board obtains less than 10% of the Ministry’s budget, of which less than 25% is devoted to conservation works. As a result only corrective maintenance is undertaken at the expense of preventive maintenance.

4.8.Criteria for listing of monuments The National Museums of Kenya Board prepares the list of possible monuments to the Minister for consideration. If accepted, the Minister will publish notice in the Kenya Gazette and give the public one moth for objections. If objections are successful the Minister will withdraw the notice, but objection are unsuccessful the notice stands. The Minister is not bound to give reasons for refusing recommendations from the Board or objections on the gazette notice. In the listing for monuments the Board may take the following criteria into account: Well designed/well built Fine examples of an architectural style Given importance by their setting A way of life/process that is no longer practised Strongly associated with an important historical development/figure Very unusual

4.9.Other environmental conservation laws and regulations in Kenya 4.9.1.Aspects of environmental laws Besides the conservation of monuments there are several other laws and regulations concerning environmental conservation in Kenya namely: Laws relating to protection and use of land(Agriculture Act,Physical Planning Act) Laws relating to protection and use of natural resources(Forest Act,Water Act,Mining Act,Grass Fires Act,Wildlife(Consevation and Management Act) Laws relating to use and maintenance of the built environment(Public health Act,Local Government act,Occupational Safety and Health Act,Landlord and Tenant Act) The law relating to supervision and co-ordination of the various enviromental management activities/all matters relating to the environment(The Environmental Management and Co-ordination Act,1999).

4.9.2.Need for consolidated legal and institutional framework for environmental management The various laws on environmental conservation have not been adequately enforced by the relevant authorities due to a number of reasons namely: Weak administrative structures Gaps/overlaps in the institutional responsibilities Absence of provisions on standards Inadequate deterrents and incentives Preference for short-term gains at expense of more sustainable alternatives in policy making/planning Low levels of participation/awareness among majority population Poverty which promotes unsustainable use of resources

4.9.3.National Environment Management Authority(NEMA) As a result of weaknesses in environmental management,Parliament in the year 200 enacted the Environment Management and Co-ordination Act(1999) which established the National Environment Management Authority(NEMA) to among other things: Exercise supervision and co-ordination over all matters relating to the environment, Identify types of projects and programmes, plans and policies for which environmental audit/monitoring must be conducted, Monitor and assess activities, in order to ensure that the environment is not degraded by such activities,environmental management objectives are adhered to, and adequate early warning on impending environmental emergencies is given, and Be the principal instrument of Government in the implementation of all policies relating to the environment

4.9.4.Environment impact assessment(EIA) Environment Impact Assessment(EIA) is a method used to identify a project’s probable impacts on the environment, so that short-term development benefits do not take precedence at the expense of natural environment. EIA is carried out early in the project cycle(feasibility stage) to bring together a wide range of environmental ,social and economic considerations of a project before investment. Monitoring is carried during and after implementation to ensure conformity with EIA recommendations NEMA has identified among others the following projects for mandatory EAI to ensure that development does not take place at the expense of environment: Urban development Transportation and electrical infrastructure Forestry and mining Dams, rivers and water courses Large-scale agriculture and irrigation Processing and manufacturing industries Major developments in biotechnology Management of hydrocarbons,etc.

4.9.5.Environmental restoration orders,easements orders and conservation orders NEMA may issue and serve on any person an environmental restoration order requiring that person whose activities are contrary to good environmental management to restore the environment to original state, and pay compensation to other persons whose environment/livelihood has been harmed by the action. The same orders may be given by a court of competent jurisdisdiction A court may on application under the Act grant an environmental easement order .i.e. the imposition of obligation in respect of the use of the burdened land to facilitate the conservation and enhancement of the benefitted environment.Any person whose existing interest in the burdened land will be restricted by the order will be compensated by the applicant granted the easement. A court may on application under the Act grant an environmental conservation order on burdened land so as to amomng other things preserve open space,preserve scenic beauty, or restrict agricultural activity on the burdened land

5.Building failures diagnosis and avoidance
5.1. Causes of defects in buildings The diagnosis of defects in buildings can be compared with crime detection because one starts with symptoms and proceeds to build the evidence by careful investigation,eliminating the red herrings in the process to diagnose the probable cause of the fault. This process requires a sound knowledge of both building construction and the chemistry of building materials As much data as possible should be collected from the following sources: a visual inspection of the defect and the surrounding area site tests laboratory examination of samples of materials building drawings and specifications used in construction interviews and discussions with design team, contractors, managers and users of the buildings

5.Building failures diagnosis and avoidance contd.
The majority of defects in buildings result from the following: The application of forces greater than the building and its components can withstand The effects of materials (gases, liquids or solids) The effect of biological agents (fungi, termites, rodents, man, etc) Changes in climatic conditions (temperature, sunlight, moisture). Acts of omission and commission namely:Far too often the defects occur because the designer has not provided for sufficient safeguards to accommodate the likely changes in the building and components. Both the design details as well as materials chosen could have been inappropriate for the conditions to which they will be subjected. Better informed design and choice of materials could lead to considerable reduction in the number of defects that occur in buildings. Poor workmanship,especially non-compliance with instructions given in the specifications is also responsible for occurrence of defects. The lack of maintenance, or incorrect maintenance also leads to a reduction in effective life of a material far below that which should be achieved. The morphological changes in buildings and components The above causes may lead to the following changes in the building and its components: Changes in the composition or condition of materials used in construction so that they become susceptible to applied forces. These changes may result from fire; effects of gas, liquids and solids; biological agents; climate; etc. Changes in the building structure (cracks, deflection, collapse). These may be caused by applied forces; fire; climatic conditions; etc, Changes in shape, size or weight which may arise from applied physical forces;effects of gases, liquids or solids; effects of changes of climate. Changes in appearance, including colour. These may be caused by wear and tear;fire; effects of gases, solids; effects of changes in climate (temperature of sunlight).

5.Building failures diagnosis and avoidance
Causes of defects in buildings Defects in foundations Defects in floors and floor finishes Defects in walls and wall finishes Defects in roofs and roof coverings Defects in plumbing and electrical systems Grounds maintenance

5.2.Defects in foundations. Site conditions Soil conditions have an important influence on foundation design and subsequent behaviour of buildings. Site investigations should therefore take place before carrying out new building works including alterations and extensions. Low-lying sites may be liable to flood so it is important to know the highest recorded flood levels so as to keep all excavation work above ground level. Some clays contain sulphates and these may cause corrosion of buried concrete, iron and steel.Where presence of sulphates is suspected the ground water should be analysed. Soils with larger particles such as sand expel water out fast when under load and soon settle after the load is applied. By contrast, clays offer resistance to water expulsion, and settlement can continue for years after construction. Settlement problems Cracking is fairly common in dwellings due to settlements arising from the following causes: Inadequate foundations Low-bearing or shrinkable clay soil Presence of large trees near the buildings Mining subsidence

Shrinkable Soils: The greatest problems occur when shrinkable soils have dried excessively through the removal of moisture by nearby growing vegetation. Such is likely to be greatest at the corners of foundations. As the ground falls away, the weight of the building pushes the the suspended parts of the foundation down and the walls in that vicinity crack. Cracking is predominantly diagonal and follows the vertical and horizontal mortar joints in masonry work The cracks are widest at the top corners of the building and decrease as they approach ground level. Door and window frames also distort due to the deformation of the walls, leading to their sticking or jamming In severe cases service pipes may fracture, walls may bulge and floors may slope noticeably. Presence of trees: When trees are cut down before building, long term swelling of clay soils can be substantial and can take place over several years. The upward forces on foundations can cause severe stresses at the corners of the building or may act centrally. In the former case cracking patterns are usually similar to those already mentioned but with important difference that crack width is greatest near the foundation level and becomes narrower at the higher levels consent of the local authority as well as that of the owner of the property from which support is required. Subsidence: When subsidence occurs due to mining operations (Keyohole, Komarock, Githurai, etc) the building tilts towards the advancing workings and random forms of cracking generally occur.

5.2.3.Remedial measures for settled buildings Remedial measures are generally difficult and expensive. Therefore the first need is for adequate site reconnaissance. Where the soil is of firm shrinkable clay, it is necessary to take the foundation down to a depth which should eliminate significant ground movements. Several Types of foundations can be used in these circumstances and choice is likely to be dictated by financial considerations. Where damage has occurred much care should he taken in deciding whether repairs are necessary, and if so the form they should take. For less severe damages, it may be sufficient to reduce further movements by surrounding the building with a relatively impervious apron of precast slabs or in situ concrete to a suitable width. The ground should be allowed to absorb moisture before cracks in the building are repaired.

5.Building failures diagnosis and avoidance contd
For severe damage the most common remedy for differential movements in buildings is through underpinning of foundations.Ransom,(1987) provides the following classification of visible damage and the related repair treatment: Very slight/slight:Fine cracks, not greater than 5mm wide, usually not visible in externally.Some slight sticking of doors and windows possible. Such cracks can be easily filled. Moderate: Cracks may be typically from 5-15mm. Doors and windows will stick.Service pipes may fracture.General weather- tightness may be impaired. External masonry may need reappointing. Some local replacement may be necessary. Severe/very severe:Cracks may be typically from 15-25mm in width.Walls are likely to lean or bulge Beams may lose their bearing. Doors and window frames will distort and glass is likely to break Service pipes are likely to be disrupted. Walls may require shoring.External repair work will be necessary involving partial or complete rebuilding

Underpinning. Before any underpinning is done the building should be carefully examined and any urgent repairs carried out. The thickness and the structural condition of walls to be underpinned should receive special consideration, as well as the nature of the ground under the existing foundations. In case of movements associated with drying action of tree roots, it is usual to cut the roots and kill the stump before underpinning. The wall to be underpinned should first be supported with flying or raking shores Loads reduced as far as practicable Holes excavated alongside under the existing foundations to a suitable depth with satisfactory safe bearing capacity. A single hole could be sunk if settlement is confined to one corner, or the whole building could be underpinned if foundations are entirely on unstable ground. The foundations and walling are constructed under existing foundations, whether strip concrete, reinforced concrete beams and piers, etc. The top of the new walling has to be pinned up to the underside of the existing foundation by ramming into the gap 25mm dry cement mortar, manufactured keying blocks of dense concrete or concrete 'legs' using a mallet or club hammer.

Shoring Shoring may be needed to give temporary support to walls and floors during alteration work, demolition work or underpinning, or where a structure has become unsafe. Without adequate shoring the building could collapse. Shoring is usually of timber or steals frames and may take a number of different forms namely: Raking shores. Usually used to provide temporary support to a wall which has become defective and unsafe, or as a precautionary measure while alteration work is being undertaken. Flying shores. These are used to provide support between buildings, where an intervening building has been demolished, or across a narrow street or alley. The consent of the local authority as well as that of the owner of the of the property from which support is required. Dead shores. The purpose of dead shores is to support dead and superimposed loads of a building, mainly while alteration and repair work in progress. At the same time it is generally necessary to strut existing floors and roofs to relieve the walls of their weight.

5.3.Defects in ground floor concrete Failures in floor slabs may be attributed to chemical attack in the hardcore or poor compaction of the hardcore, as well as concrete shrinkage on drying. Soluble sulphates present in hardcore or in ground water can attack the set cement in concrete, the severity of attack depending on the type of sulphate present and the level of the water table. This will manifest itself initially by lifting of the floor and binding of doors, followed by cracks and some movement of the external walls near the dpc level usually shown by a slight extrusion of the dpc. Floor slabs may settle and crack if hardcore thickness is excessive, as may occur on sloping site, or where deep trench-fill has been used for foundations. This makes thorough compaction difficult. The solid slab will drop and crack particularly towards the edges under which the depth of hardcore is greatest. Concrete floors often shrink on drying which causes cracks and tends to exert stress at the interface between it and floor screeds and finishes. The other failure arises from the inability of concrete to present a surface, which allows ready bonding of superimposed finishes. Remedial measures: Sulphate attack may be avoided or greatly reduced in severity by using materials which are usually free from soluble sulphates (coarse sand, gravel, crushed, clean concrete rubble, quarry waste); by placing concrete of low permeability; by using sulphate resistant cement To avoid failure hardcore should be well compacted, and where thickness of hardcore exceeds 600mm, a suspended floor rather than a solid floor should be used. If the concrete has lifted and is badly cracked remove all concrete floor and the hardcore, then providing a polythene sheeting on the ground before placing sulphate free hardcore, and then concrete made with sound aggregate. If the concrete has only slightly lifted it may be possible to cut through it around its perimeter and fill the gap with a compressible material (fibreboard, expanded polystyrene)

5.4.Defects in suspended reinforced concrete floors Suspended reinforced concrete floors usually deflect slightly and cause little trouble in so doing. Occasionally greater deflection may occur, leading to cracking at the base of partitions because they have failed to provide support for them. A number of factors may be responsible for the deflections on suspended re floors: Drying shrinkage of the concrete due to properties of cement and aggregate, and water/cement ratio. Inadequate design Poor workmanship including early removal of formwork, overloading with materials during construction process Movements of peripheral or intermediate supports Superimposed loads higher than those for which the floor was designed Remedial work: The replacement of a floor is an expensive and troublesome operation and should therefore only be undertaken if there is a risk of structural failure.

5.5.Defects in floor screeds Constructional problems in floor screeds arise from; inadequacies of the mix of the concrete base and the screed; poor texture of the surface of the base concrete; too long an interval between casting the base concrete and the screed; an inadequate curing process for the screed; too large an area of the screed laid in one operation; and too thick a screed. If the bond with the base is poor, and shrinkage stresses are high, the screed will crack, with a tendency to curl at the edges of the cracks. If the screed is tapped it will sound hollow. Similarly, finishes applied over the screed such as tiles and sheet coverings are also likely to crack and split, and ultimately, lose their adhesion to the screed Remedial work: the extent of the work will depend on the state of the damage. If the screed is weak it will be best to take it all up and relay ^ If cracked but lifted slightly, it may be sufficient to grind one side down to the level of the other Between these two extremes it may be possible to cut out and patch.

5.6.Defects in granolithic concrete and terrazzo Granolithic concrete consists of aggregates specially selected to provide the surface hardness and texture required for use in factory floors. The problems that have occurred with granolithic are similar to those with screeds (shrinkage cracking, poor bond to the base, and dusting of the surface). Terrazzo consists of a mix of cement and a decorative aggregate, usually marble and laid on a concrete screed. The failures include cracking and crazing, and lack of a good bond to the screed. Surface crazing may be increased by too rapid drying and too rich a mix. Remedial measures: Crazing and cracking may mar the decorative appearance of both granolithic concrete and terrazzo but are usually tolerated since the repair particularly for terrazzo is likely to be an expensive and specialized operation. In cases of severe damage it will be necessary to remove the finish and relay.

5.7. Defects in plastic sheets and tiles Sheet and tile flooring are made from thermoplastic binders(PVC) are applied mostly to concrete screeds. Common failures are that the sheet or tile becomes loosened and their edges lift; and adhesive becomes detached from the concrete surface and may ooze through the joints. These defects arise from: water either from the concrete base, or excessive water from cleaning and spillage which have affected adhesion to the concrete base. tiles were not properly stuck to the base and may become displaced. Remedial work: Determine the source of water and eliminate its presence in the future Floor cleaning should be restricted to wet mopping to restrict excessive quantities of water If the sheet or tile is stained and edges damaged they should be replaced

5.8.Defects in timber flooring The most serious defect that is likely to occur in a suspended timber ground floor is an outbreak of dry rot. Joists to upper floors are rarely attacked by dry rot but outbreaks can occur in damp cupboards or other enclosed spaces or through leaks in rainwater, waste or service pipes. More common problems in upper floors are sagging and springiness resulting from overloading, inadequate size of joists or lack of strutting. Herringbone strutting should be provided to all floors with spans exceeding 3m to stiffen the joists. A common defect with wood-block flooring is due to expansion of the blocks through uptake of moisture leading to lifting and arching from the concrete base. Though lifting may occur anywhere, it is common at the perimeter of the floor. It is therefore necessary to provide a compression joint around the perimeter of the floor. Another common defect is unevenness resulting from unequal wear, which is normally cured by sanding, while loose blocks are reset in adhesive, and damaged ones removed. Remedial measures Remedial measures Timber finishes to solid floors; whether of board, strip, block or mosaic, need to be kept from becoming damp. Any sources of damp penetration must be dealt with. Most common cause of moisture penetration in is through failure to provide an adequate dpm. A less common defect is that caused by using timber at too high an initial moisture content. Timber in contact with a concrete base needs to be protected by a damp-proof layer. Remove all infected timber and treat infected masonry Improve ventilation by providing air-bricks to give at least 3000mm squared of open area per metre run of external wall.

5.9.Defects in walls Defects in walls are essentially of two types namely: Inadequate protection against moisture protection/dampness Cracking and spalling of the walling materials Dampness in walls Dampness in walls may occur in the following areas: More or less permanent dampness showing more clearly on the internal wall surface from ground level up to a height of 750mm,but may be higher in severe cases, or if the outer face is covered with non-porous finish. The decorations may be damp, blistered or dicoloured, or, if dry, may have been pushed off the wall by a film of salts which will often be seen as a fluffy crystalline growth. The skirting board may be rotted and if the floor is suspended timber floor it may be weak near the wall. Damp patches, variable in size and position, appear on the inner face of external walls exposed to deriving rain. The damp areas appear after rain and may take some days to dry out, often leaving a stain or followed by the appearance of efflorescence on or under the decorations Dampness appears on the internal plasterwork of the upper parts of the external walls of a flat-roofed building having parapets, appearing initially at the junction of the walls and the ceiling, and may spread down the wall or ceiling A localized damp area on the internal plasterwork with evidence of mould growth of efflorescence around the edges of the area; and externally the wall will also be wet with evidence of algal growth of efflorescence

5.9.2.Causes of dampness in walls include the following: Moisture penetration from the ground Rain penetration. Water enters many buildings as a result of rainfall, either directly through defects in the roof or walls or indirectly by absorption. Generally the rain will penetrate solid masonry, which is not rendered, usually directly through cracks in the mortar, and between mortar and brick or block. Construction water. Considerable quantities of water used in the construction of a building may not dry out by the time the building is occupied. There may be a redistribution of water content to produce wet areas, particularly on the underside of concrete floors and impervious finishes such as paintwork. Condensation arising from water vapour that gets in touch with cold surfaces; while some materials have the property of absorbing moisture from the air. Occupational. Water may be present in the building from leaking pipes; tanks and cisterns; cleaning Remedial measures: If the dampness is due to absence of DPC in masonry work(usually fairly continuous and roughly horizontal),it may be feasible to cut a slot in the wall and insert a DPC or to inject a chemical damproofmg system. Inadequate laps in flexible DPCs can also lead to moisture penetration. Laps should be at least 100mm and the DPC laid on a full mortar bed and also fully covered with mortar above to prevent damage. It is not uncommon for the DPC in the walls to be bridged by pointing, or rendering over it. This should be prevented by projecting the DPC through the external face and by stopping any rendering short of it. Repoint defective joints and make them watertight against penetrating rain Condensation is prevented by better ventilation (air vents, extract fans, etc) Repair and replacement of leaking pipes/cisterns will remove source of occupational water Remove damaged plaster as it may continue to contain salts which will continue to damage decorations

5.9.3.Cracking and spalling in walls
Load-bearing masonry walls can crack and their surfaces may spall. Cracks in the external walls of buildings, whether visible from outside or inside lead to more complaints than other defects, since to many people appearance of cracks means the building is becoming unsafe. Cracking is associated with movements which may arise from: Moisture changes in masonry units. Many building materials expand and contract when they take up or lose moisture. This movement is always not wholly reversible, depending on the degree of wetting and drying. It is the irreversible rather than reversible movements that cause serious damage to walls. Temperature changes Roof movement Chemical attack Physical attack Reinforced concrete walls are liable to cracking followed by spalling (falling off) when steel reinforcement that is not adequately protected with thick cover of good quality concrete rusts. The rusting is accompanied by expansion, which leads to cracking of overlying concrete. When blockwork or brickwork panels between reinforced concrete columns expand due to moisture movement or thermal movement but the expansion is restrained by columns, the panels may bow outwards resulting in tensile cracking, which cuts the blockwork or brickwork vertically. Besides cracks caused by various reasons, walls are often subject to surface disintegration particularly those made of clay bricks. The surface of the bricks crumbles away gradually so that eventually the brick faces become recessed or larger pieces flake off. Excessive salt content in bricks may not only cause the surface of the bricks to disintegrate but may force an applied rendering off the wall.

Remedial measures: Repair the cracks either by repointing the mortar joints or by cutting out and replacing cracked masonry. Cracking of walls caused by spread of roofs occurs mainly through the weakening of structural roof members with time, or substitution of heavier roof tiles for those originally specified. As the roof spreads it moves the top few courses of the wall masonry outwards slightly, resulting in horizontal cracks in the plaster below the eaves. It may be necessary to rebuild the roof and top few courses. Cracking can also be caused by the movement of flat concrete roofs .As the roof moves outwards it pushes the few top courses of masonry with cracks near to the corners of the building and at the junction of roof with walls. Cracks will also appear in mortar joints. This movement could be minimised by inserting a flexible DPC, or the wall and roof be designed to act together. Where cracks are horizontal and at the wall/roof junction a coving may hide them, or decorating with lining paper and wallpaper. Sulphate attack on mortars can be prevented by ensuring that the walls do not get wet and stay unduly wetted; and by use of bricks with low soluble sulphates; and use of sulphate resisting OPC in the mortar. After eliminating the source of wetness repointing will be necessary, as will be rendering the damaged plaster

5.10.Defects in roofs Problems with flat roofs In many tropical countries flat roofs perform so badly that costly conversion works are often implemented to provide new alternative pitched roofs. But it is always not possible or desirable to construct pitched roofs high rise and wide span buildings on grounds of cost, aesthetics, utility and structural reasons In such cases flat roofs still provide the most practical alternative. Flat roofs are often considered the most vulnerable element to climatic degradation in buildings. Flat roofs are generally designed to slope up to 10 degrees pitch providing falls between 1 in 40 and 1 in 100(usually 1 in 80).However, variations in construction accuracy, settlement, and thermal and moisture movement lead to lower finished falls. Local areas of the roof too can deviate markedly from overall falls, particularly around features like roof drains. Local ponding rather than shedding of rainwater then occurs, which in turn can lead to further local deflections, more ponding and slower drying. Ponding may also occur due to blockage of drainage system arising from the presence of debris or tree leaves or birds nesting. Although flat roof covering materials like asphalt and bitumen are said to be impermeable, persistent ponding at the same place cause gradual deterioration of the bituminous felt. Moisture generated within the building condenses and falls back or construction water is trapped which afterwards drips out Sometimes the covering material (asphalt, bitumen) may begin to deteriorate and cause roof leakage due to failure to allow for the differential moisture and thermal movement to which flat roof is prone; adverse effects of solar radiation; blistering effect caused by pressure of entrapped moisture or air; inadequate detailing at parapets and projections; mechanical damage. Remedial measures If a decision is made to use a flat roof then the designed falls should be achieved by sloping the structure rather than by forming them by a screed or in the insulation. Further defects will also be avoided by regular inspection and maintenance. Where ponding has caused roof leakage it will be necessary to relay the roof or provide new covering over the whole area.

5.11.Problems with pitched roofs Pitched roofs have the tendency to sag or spread. The structural timbers may have become bowed due to long-term loading, beetle attack or corrosion of nails and other forms of fixing. Sagging roofs may be supported using struts, or be wholly replaced Covering materials for pitched roofs such as galvanised corrugated iron sheets may rust; asbestos cement sheets may crack, while tiles may slip. High temperatures and humidity tend to accelerate the corrosion of iron sheets. There may be need to paint the sheets to reduce or delay the rate of corrosion The cracks that occur in asbestos sheets are either due to improper fixing or the corrosion of the fixings. Such cracks are seen radiating from the fixings. Other cracks may be seen along the tops of ridges, particularly where asbestos has been painted on one side. Paint applied to one face only of the sheets prevents access of air to that face and carbonation, restricting subsequent shrinkage to the opposite side. The differential changes in size may result in the sheet bowing and eventually cracking. Under the circumstances the sheets have to be replaced. The tiles may slip from the roof if the battens have become seriously weakened by fungus or beetle attack. Tiles may also slip if their nibs have become disintegrated due to crystallisation of salts on the underside of the tiles. This occurs mainly in clay tiles, which have been underfired.

5.12.Defects in doors and windows The causes of defects in doors and windows will depend on materials used, exposure and use. In case of timber doors and window frames, they distort due to fluctuation in moisture content thus causing changes in the dimensions of the constituent parts of the frame. The opening lights may distort and fail to open or close For door frames distortion results in out-of-squareness so that the door tends to bind against the frame. Timber on windows and doors often decay due to dry rot, or wet rot and insect attack. Dry rot fungus grows on timber, which has been moist for a long period, resulting in loss of strength, and the timber crumbles readily. The remedy is to use well-seasoned timber, which may also be treated with preservatives Wet rot grows on timber that is both moist and wet, i.e. timber that is in contact wet materials or exposed to rain. The decayed timber is dark in colour. Timber decay due to insect attack arises from woodworm or larvae hatched in the surface crevices of timber by certain insects. The worms eat the sapwood and reduce timber strength in the process. Other insects such as termites directly feed on timber. Timber should therefore be properly treated to reduce incidence of attack. Corrosion of metals used in window and door furniture may be caused by atmospheric pollution, chemical attack or bimetallic corrosion. Atmospheric pollution results in rusting of iron or formation of green patina on copper materials Chemical attack also results in corrosion of unprotected metal.

5.13.Defects in plasterwork The main function of rendering is to help to exclude rainwater. If rendering becomes cracked, rainwater will penetrate and cannot readily re-evaporate. Also if water enters, frost damage, or expansion of brickwork mortar (sulphate attack) may produce extensive cracking or detachment. If a good bond to the wall is not achieved, rendering may become detached. If render coats are too rich or too wet, have too much fine sand, they crack, water penetrates and failure may follow. Loss of adhesion is common in renderings applied to saturated walls. Following are common plastering defects. Cracking : Fine hair cracks on the finished plaster: may arise due to application of final coat before initial shrinkage of under-coats is complete. These are difficult to repair and may be concealed with wall paper. Clearly defined cracks following a definite line, which may arise due to thermal or settlement movement. These should normally be cut out and filled. Plaster joints between structural columns and internal walls may crack due to differential movement between column and wall. The defect can be avoided by forming a groove in the plaster at the juncture, or by making a cut in the plaster and masking it with a cover strip fixed at one edge only. Loss of adhesion: due to inadequate mechanical key, dirty surfaces, or application of top coat while undercoat is still green. The remedy is usually to strip and replaster to ensure a proper bond Dry out: Plaster dries before setting so that plaster surface is soft and dry with very fine cracks. The only remedy is to strip and replaster Efflorescence: soluble salts brought to the face of the plaster as building dries out.

Remedial measures The remedy is to dry brush the surface as the salts appear, and delay decoration until structure is thoroughly dry. If this is not practicable then use a porous paint suitable for early decoration. Mould growth: will develop if dampness is present. Scrap off any existing mould and decoration and replaster. Flaking and peeling of final coat: due to persistent moisture penetration through the background. Remedy is to strip defective plaster and provide positive barrier to dampness Irregularity of surface texture: due to uneven trowelling or marked differences in suction of backgrounds, particularly if the mortar has a different suction from that of the masonry wall. The remedy is to lay or point in mortar similar in character to masonry or apply an additional coat of plaster Popping or blowing: particles in the background or plaster expand after the plaster coat has set. Where the holes are small they can be filled by brushing with thick slurry of plastic paint. Larger holes are filled by normal patching techniques. 4 Recurrent surface dampness: strip the plaster and provide an impervious barrier Rust staining: this arises from application of unsuitable plaster to metal lathing or plaster in contact with corrodible ferrous metal in persistently damp conditions. The remedy is to strip plaster and replaster and paint ends of metal lathing.

5.14.Defects in building services Building services can be defined as those systems and their components whichprovideplumbing, sewerage, heating , ventilation, air conditioning, lighting, power, vertical transport, fire protection, and special services such as public address or oxygen to a building.The design of these systems and their components requires many skills and close co-operation between the design team, client and maintenance team to ensure that installations are economic,durable and main tenable. All services should be readily accessible and adequate working space should be provided to enable maintenance and repair work to be carried out conveniently and economically. Drainage Common failures include blocked drains/pipes; leakage from drains/pipes; leaking joints. Failures are caused by inappropriate specification: incorrect gradient or pipe size; incorrect junction design; unnecessary bends; drains inadequately protected; use of pipes subject to photo-oxidation without suitable protection from solar radiation. poor installation: change of gradient or backfall during laying; incorrect jointing techniques; incorrect connections; rubble allowed into system; pipe expansion not allowed for; gutters undersized; downpipes poorly fixed, mispositioned relative to gullies; not accessible for cleaning. Storage and handling: pipes scratched or fractured by rough handling; pipes softened by solvents; pipes stacked so as to become distorted Remedies: Foul drains should be designed and laid in a manner that they carry water and solids to the sewer without blockage Plastic pipes must be handled and stored so that they are not damaged ^ Plastic pipes must be accurately aligned, fully supported and have leak-proof joints S Exposed plastic pipes should be of a material that is adequately durable in sunlight or that can be made so by appropriate protection. All water draining from a roof should be conducted without spillage to its below-ground drainage system. If gutters are undersized or if downpipes are blocked or displaced, water spillage can saturate walls and can lead internal dampness and to early deterioration of walls.

Water supply Common failures include: Storage cisterns: if warning pipe bores are too small, or pipes sag or have inadequate slope, cisterns may overflow causing both internal and external damage Ball valves: defective ball valves so that water drips or flows out of the flow pipe;sometimes the cistern or tank fails to fill.Most common failures affecting ball valves are perforated floats, eroded seating, defective washers or the presence of grit. Hot and cold water systems: loss of supply through blocked pipes; damage to building fabric and furnishings following a bust pipe; risk of explosion of heating system. Leaking joints: joints may leak due to expansion and contraction under extreme weather conditions; bimetallic corrosion occurring when dissimilar metals have been used to make the joint (copper vs steel); chemical action of fluxes etc used in making joints which may cause the pipe to be perforated. Fittings :include baths,lavatory basins,sinks and water closets.Defects include blockage,inadequate flushing,perforated float,etc. Remedial measures: Warning pipes should be of sufficient bore and slope to minimise the risk that the cistern will overflow. The pipe material should be rigid and should be suitable for both service and excess temperatures. The pipe should be located to take account of the risk of accidental or deliberate damage Stored water temperature in unvented hot water systems must not exceed 100 degrees centigrade at any time Clean ball valve to remove grit; replace washers; and intall new seating.

Electrical services Power systems up to the service position remain the property of the electricity board.From thereon the wiring becomes the responsibility of the consumer. Common failures: Cable overheating: All electric cables give off heat in use dependent on the load they carry. The heat emitted by any cable operating within its design loading is normally safely dissipated. Sometimes, however, the normal heat dissipation from a cable is impeded by thermal insulation or because the temperature of its environment is raised by other heat sources. Consequent overheating of the cable may damage its insulation with risk of short circuit or fire. Cables in power circuits, which may be loaded to the full capacity, are more at risk than those in lighting circuits. Damaged sheathing: if the wrong technique is used in removing the outer sheathing of plastics- covered flat twin cable, the insulation of the live conductor may be imperceptibly cut. In the presence of even a small quantity of moisture, tracking and acing can then be initiated between the live conductor and the bare earth conductor. Once this has occurred a permanent conducting path is formed and arcing may continue intermittently even in the dry. Molten copper at very high temperatures can be violently discharged; the heat generated can be a fire risk. Remedies: Cables must not be prevented from dissipating, adequately, the heat generated by their designed loading Cable sheathing must not be stripped or trimmed in a manner that may damage the insulation of the conductors. Lamps and fittings not only have to be replaced, but should also be cleaned at regular intervals.The frequency of replacement will depend on the burning hours per year, but as a guide, tubes that work 100 hours per week may need to be replaced every 12 months, while those that work for a quarter of this time should only need to be replaced every 4 years

5.15.Specialised Services. There are many types of specialist service which may be installed in a single building and for which there will be need for maintenance.Such maintenance needs may be governed by statutory regulations or manufacturers' specifications.These specialist intallations are often maintained through maintenance contracts with intallers, suppliers or specialist companies,and include the following : Communication systems, including telephones; alarm systems; intercom devices and public address systems for conference facilities Vertical transport systems, including all systems for lifting people and goods such as lifts, escalators, hoists and cranes. Air-conditioning equipment.In addition to heating and refrigeration plant and, in some cases, equipment for humidity control. Fire-fighting equipment. Lifts * These are maintained under service contracts, usually for periods of 5 years. There are basically three types of service contracts for lifts: Inspect and Report Service Contract consisting of regular inspection of the elevator and equipment only and does not require service contractor to carry out any works. A written report is submitted drawing attention of owner to any defects noted. Paint, Oil and Grease Service Contract, which makes provision for regular examination, lubrication, cleaning and making adjustments in the machine and accessories as appropriate. All Inclusive Service Contract in which the contractor undertakes to keep the elevator in a proper condition(See sample of Lift Maintenance Agreement by Otis Elevator Company Ltd) Contract prices should be fixed for one year based on material costs and existing wage agreements ruling at the date of the agreement,being the base month.In the event of any alterations in either national or local wage agreements or other substantial variation in material cost the contract price is subject to pro-rata variation.

Air-conditioning equipment. The maintenance of air-conditioning plant must be carried out in accordance with the planned machinery maintenance instructions and time frequency as laid down by the suppliers and manufacturers. The maintenance and service agreement must conform to the occupational and health safety requirements under the relevant legislation(Public Health Act,Factories Act,Kenya Bureau of Standards,etc). The schedule of equipment to serviced and maintained include: Centrifugal chiller Cooling tower Reciprocating compressor Condenser water pumps Chilled water pumps Air compressors Airconditioning distribution boards Shop fan oil units Fire fighting equipment The service and maintenance of the equipment must comply strictly with the standards set by manufactures as well the relevant legis!ation(Fire Act,Kenya Bureau of Standards,etc.). Details of service may include: Complete examination of Fire Extinguishers and checking for correct operation Fixing tags to equipment that was serviced to show date of inspection and date when next service is due Any equipment found faulty or not repairable at the time of the service will be noted. References: Miles and Syagga,1987 Eldridge,J,1976 Seely,I(1976) BRE,1991

5.16.Grounds maintenance Introduction. The care of the grounds is an important aspect of property management Well kept grounds improve property's appearance and image, help increase or, at least maintain its value and create a sense of pride among residents and tenants. Maintenance of the grounds can either be carried out by hiring the services of a contractor to carry out the work, or through the use of in-house staff to carry out this work. Sometimes a combination of the two is used. The method adopted is dependent on the size of the property, budgetary considerations and the availability, capability and cost of in-house personnel and equipment as opposed to a contractor's performance. The experience of many property owners is that it is less expensive and less troublesome to rely on a contractor for this service. However, public institutions in Kenya such as public universities, colleges, among others use direct labour, while international agencies such as embassies and United Nations agencies use contract labour. Given the importance of grounds maintenance to real property, it is important to develop a checklist to ensure that all work is performed properly. A comprehensive grounds maintenance management plan which indicates all tasks necessary for comprehensive grounds care is essential. Such a plan should specify who is responsible for which task, the frequency thereof and any other such pertinent information as may be required Grounds maintenance includes several activities but these can basically be grouped under the two categories of lawn care and ornamented plant care.

Lawn Care This includes tasks such as lawn mowing, leaf collection, application of herbicides, fungicides, and insecticides, among others. Mowing and Trimming. Mowing can be defined as the cutting of turf grass on lawns so as to retain them at a specific height above ground and keep them looking tidy. Trimming on the other hand refers to any other cutting of grass done between the mowing periods and this is done especially in cases where there has been some unexpected rainfall, which causes rapid growth of the grass. These two activities can either be done by contract or through an in-house arrangement, but regardless of which method is selected, the main concern is always the determination of the frequency of carrying out the mowing and trimming activities. Mowing should be undertaken when the grass is between mm while trimming is done when the grass has grown too fast and the next mowing session is still a few days away. The mowing of the lawns should be done once a month using lawn mowers and the frequency of trimming is subject to the amount of precipitation received and it is done using slashers. Costing and apportionment of funds is based on what the contractors quote, while in the case of in-house maintenance, no specific amount is set aside for this activity.

Edging: Edging refers to a re-definition of the edges of lawns by making clear-cut boundary destinations on the grounds that indicate the extent of the lawns. Edging can be done mechanically or manually with a mechanical edging giving better results. Edging should be carried out on all accessible sidewalks, curbs and patios and an arrangement should be made for removal of debris. Edging should be done at least once a month or even more frequently especially in the rainy seasons. In the former case edging was done in-house while in the latter case it was done by a contractor. In both cases, however, the people carrying out the edging ensured that the debris was removed. Leaf Collection and Removal: Leaf collection as an activity involves the removal of fallen leaves, flowers or any other part of the plants to keep the area neat. In the case of lawns the frequency of leaf collection is dependent on a variety of factors including the climate of an area, and the type of grass and the "look" that the owner wants to achieve during different seasons. Regardless of whether the maintenance work is contracted or in-house, the average frequency should be once every month using manual equipment such as rakes, debris pans, and pavement brooms. A more frequent collection would be necessary depending on the season and accumulation of leaves.

Soil Analysis: Soil analysis is a process carried out to identify any deficiencies of nutrients, air or any other component of the soil so as to come up with a suitable solution to alleviate the situation and this could range from fertiliser application to increased water supply. This will help to ensure that the soil is able to support proper plant growth.. It is therefore important that appropriate advice is obtained regularly from agronomists. Fertilization: Fertilization is the process of supplying any nutrients to the soil which are either totally absent or are in insufficient quantities. Proper fertilization is especially essential to the health of turf grass and it is important to know that what is termed, as 'proper fertilization' in one area may not be proper to the same plants in another area. The amount of fertiliser to be applied is dependent on factors such as soil type, moisture availability, type of plant, length of growing season and type of fertiliser being used, among other factors.lt is therefore necessary to regularly consult specialists to advise on the need for soil fertilization. Herbicides, Fungicides, and Insecticide Application: Every living thing has its own enemies, which interfere with its survival. Plants such as grasses are no exception and can suffer from the detrimental effects of weeds, fungi and insects or pests. To reduce the effect of these, frequent application of herbicides, fungicides and insecticides, respectively can help to alleviate the situation. All these chemicals can be applied on a preventive or curative basis, either to deter any possible attack or they can be applied to get rid of the unwanted substances when an attack has already occurred. It is recommended that herbicides and pesticides are sprayed onto the lawns once every three months and that property owners regularly consult specialists for advice.

Aeration: This is basically a process of increasing the amount of air in the soil. This activity is dependent on the particular type of grass or plant being handled. Aeration is done using various specialised equipment such as rollers, drums and/or piston-type aeration. Specification of when aeration should be done especially in heavy traffic areas is essential. Due to its specialist nature of activity, aeration should best be left in the hands of contractors and specialists to determine the needs. Dethatching: Dethatching is removal of excessive plant build-up so as to ensure that each plant has sufficient exposure to sunlight and nutrients from the soil for it to grow properly. Dethatching should be limited to the seasons in which grass is growing rapidly and it should be performed in such a manner that the grass will recover in two weeks.Dethatching should be done once every 6 weeks in the rainy season and once every 12 weeks in the drier seasons and it is carried out together with weed removal as deemed necessary. Overseeding: This is an activity carried out in management-designated areas where blends of mixtures are used to achieve the desired quality of grass. It is essential that this process is preceded by dethatching when the thatch build up exceeds 12 mm thickness.

5.Building failures diagnosis and avoidance contd
Ornamental Plant Care Included under this are activities similar to the lawn care but are here applied to the care of ornamental tree, shrubs, and flowerbeds. If not handled with care it is an area in which property owners can make significant investments. It is, therefore, important to ensure that the owners deal only with a firm that has successful experience in handling this type of work. As in the case of lawn care the following activities are essential to ornamental plant care: Application of herbicides to all ornamental trees, shrubs, and flowerbeds is essential. Application of fertiliser is necessary. A soil analysis to determine the need to use any special fertilisers required to correct nutrient deficiencies is essential. Edging of all ornamental trees, shrubs, and flower beds for clear definition of boundaries, weeding of all beds, turning of existing mulch and application of new mulch so that all beds are neat and attractive and contain no more than 75 mm of total mulch is necessary. It is also essential to ensure that water basins around plants are large enough to accommodate the amount of water required to establish moisture through the major root zones. Edging should be done at least once every two months and be accompanied by application of mulch as deemed necessary. Pruning of all shrubs and ornamental trees in order to maintain neat appearance as well as ensuring that only the strong branches of plants are left to promote general stability of the plant should be undertaken regularly. Pruning cuts should therefore be made to lateral branches or buds or flush with the trunk. The seals should be usedappropriately. Particular care should be taken with shrub pruning to ensure that shrubs are not clipped into balled or boxed forms unless such is required by the design. A preventive insect and disease control plan should be carried out for all ornamental trees, shrubs, and flowers. This plan involves identification of the insects and diseases to which these plants are susceptible, materials required helping prevent insect and disease problems, amount and costs of such materials and their application. Watering of the lawns and ornamental plant beds is done, in most of the institutions surveyed, at least every morning between 7.30 a.m. and 9.00 a.m. depending on the amount of precipitation received. For instance, no watering is done when there are heavy rains while watering may be done twice a day during a very hot season. References: Syagga and Aligula,1999

BBE 533: MAINTENANCE MANAGEMENT PAUL M.SYAGGA,PhD MARCH 2010

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BBE 533: MAINTENANCE MANAGEMENT PAUL M.SYAGGA,PhD MARCH 2010

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