CHAPTER 4 BUILDING TRANSPORTATION SYSTEM

BUILDING TRANSPORTATION SYSTEM is the system for conveying people in buildings The mechanical transportation of people and goods is an energy-using service that needs the designer’s attention at the earliest stage of building design. System includes: Elevators, Escalators and Walkalators

ELEVATORS (LIFTS) Elevator (Lifts) is a vertical transport equipment that efficiently moves people or goods between floors (levels, decks) of a building, vessel or other structure Two basic types: Hydraulic-lifting platform is pushed upward/downward by plunges Traction-Electric lifts

ELEVATORS (LIFTS) Passanger lifts are provided for buildings of over three (3) storeys, or less if wheelchair movement is needed. Minimum standard is one lift for each four storeys, with a maximum walking distance of 45m between workstation and lift lobby. Prestige requirement require higher standards (depends on the rent earning potential)

ELEVATORS (LIFTS) Peak demand for lift service is assessed from the building size, shape, height and population. 25% of the population require transportation during a 5 min peak period. Congestion at peak travel times is minimized by arranging the lifts lobbies in a cul-de-sac of (2 lift doors on either side of a walkway, rather than in a line of four doors along one wall). Construction specifications of lifts are given in BS 5655: 1989 and BS Code of Practice 407:1972 Car speed for various travel distance (see table 1) Table 1: Design lift car speed Floors Car speed (m/s) 4 9 15 Over 15 0.75 2 3 5-7

ELEVATORS (LIFTS) _Hydraulic Lifting platform is pushed upward/downward by plunges (ram) Liquid (oil/high pressure water) is forced into or withdrawn to create movement. A pump is used to control the liquid Suitable for moderate car speed and fairly short travel (e.g. hospital) Speed range between 0.12m/s and 1m/s with maximum height 21m. Machine room are usually located at the lowest level. Types: Direct acting (holed) Suspended (hole less)

ELEVATORS (LIFTS) _Hydraulic Direct Acting- single cylinder that bored into the ground with the cylinder having a depth that reaches the height of the plunger. Direct Acting

ELEVATORS (LIFTS) _Hydraulic Suspended- required on or two rams to suit the load and located in the shaft (not in the ground hole). Utilizing the telescopic format to extend the plunges upward. Suspended type

ELEVATORS (LIFTS) _Hydraulic Advantages Eliminating rooftop structure ( power pack at low level) Small machine room & can be located at some distance from the shaft Load imposed on the shaft is far more less ----offering structural cost economies No brake or gear necessary No pulleys of driving sheave No counterweight and a larger lift car can sometime be used for a given well size Extremely accurate floor levelling can be achieved Acceleration and travel is very smooth Simplification of shaft’s structural design

ELEVATORS (LIFTS) _Electric Principle components- lifting platform, lifting machinery, counterweight cables. Gearless ascend (upward movement) heights for gearless are limited by technology feasibility & cost limitation the net ascent distance will be limited by factors of mechanical performance capabilities some commercially available gearless elevators can move up at rates more than the speed suggested in the table 2 Geared location of gear between motor & drive sheave small motor provide gear reduction ratio (efficient & comfort) employed for medium speed & medium height application used in buildings with greater height & greater lifting capacity

ELEVATORS (LIFTS) _Electric Table 2: Electric Lift Specifications HEIGHT OF ACENT Ft(m) NUMBER OF STOPS SPEED Ft/min (m/s) LIFTING CAPACITY Lbs (kg) Geared To 300 (90) 30 300-500 (1.5-2.5) 2000-4000 (900-1800) Gearless To 500-750+ (150-230+) 30-80 500-1200+ (2.5-6.0+)

ELEVATORS (LIFTS) _Electric Principles of Operation Roping Arrangements Single wrap traction -geared machines or -gearless (lower speed) Double-wrap traction -the use of diversion puller increases the risk of rope slip -Double-wrap pulley reduces the frictional area of rope with the diving sheave -used on high speed and heavily loaded elevators.

ELEVATORS (LIFTS) _Electric Roping-Type A -used with geared machines at lower car speeds -halves the load on the sheave and allows the use of high-speed motors -disadvantage: the length of the rope is 3 times of the single-wrap system Roping –Type B -used for heavy goods elevators, where it is required to reduce the motor power and pressure -acting upon the bearings

ELEVATORS (LIFTS) _Electric Size depends on the size & speed of car, type of door Pit must permits over travel & water tight with proper drainage Buffer sits to the base (spring /oil) to reduce impact Allowing air to escape below & above moving car to prevent air pressure building + smoke vent with unobstructed openings No other services should accommodate shaft Constructed of reinforced concrete / brickwork ---sufficient strength to carry load & superimposed loads Fire resistant ---< one hour

ELEVATORS (LIFTS) _Electric Lift Doors Two sets of doors are required at lift entrances; 1. Car doors fitted to the lift car 2. Landing doors fitted to the lift shaft enclosure (open metalwork enclosures are no longer allowed) Landing doors must be made of solid incombustible materials ---reduce fire risk & ensure safety of passengers Landing doors must have no means by which an authorized person can open them from a landing Door may be of the following type 1. two-leaf side opening 2. Two leaf centre opening 3. Single-leaf side opening

ELEVATORS (LIFTS) Location Considerations Location of building entrances ---should be located in the central area, or if not, should be centralized Grouping ---better group than spread, reduces installation cost Staircase location ---demand of lift reduced if passengers pass stairs first before lift Departmental stores ---easily seen & accessible to encourage visits to upper floors Hospitals ---bed lifts required near operating theatres Lobbies ---desirable & large enough to allow traffic visible from entrance hall

ELEVATORS (LIFTS) Number of Lifts The number & size of lifts must be related to following: 1. Population of the building 2. Type of building occupancy 3. The starting & finishing times of population 4. Number of floor and heights 5. Position of building in relation to public transport services. Population When clear figure is unobtainable Estimation 1.Net floor area 2. Population density per sq meter. Example: General office building population density of one person per 10m² of net floor volume

ELEVATORS (LIFTS) Round Trip Time The time in sec taken by a single lift to travel from the ground floor to the top floor, including stops, and return to the ground floor. Flow rate A percentage of the total population requiring lift service during a 5 min peak period Survey (10% -25%) will require lifts during 5 min peak demand hour If no info available ---assume 12% for speculative buildings & 17% for unified buildings

ELEVATORS (LIFTS) Interval (s) Expressed in seconds & represents the round trip of one car dived by the number of cars in a common group system Provides a criterion for measuring the quality of service Average waiting time; theory = ½ of the interval time, practice = ¾ of interval time

ELEVATORS (LIFTS) Example A 15 storey office block has a net floor area above ground level of 8000m². Assuming starting times ad a population density of one person per 10m² of net floor area, calculate the flow rate and from tables, find lift speed, number and capacity of lift. Check the quality of service form the table.

Flow rate Flow rate – allowing 17% of population from total building occupants 8000m2/10m2 ×17/100 =136 persons during 5 min peak demand period Travel and speed Assuming floor height of 3.3m, the lift travel = 14 ×3.3=46.2m. From table 2, the nearest travel for offices is 45m which requires speed of 2.5m/s. (Ground floor is not included) Table 2 Table 1

Table 3 Table 4 Number and capacity of lift From table 1, for 24-passenger cars may be installed having a handling capacity of 137 and interval of 41s Table 3 Quality of service Refer table 1 (green box) interval=41s From table 3 - interval 41s ---satisfactory - calculate the waiting time 31s (3/4 x interval) From table 4 15 storeys/ 4 lift = 3.75 storeys/lift ---satifactory Table 4

ESCALATOR Continuous conveyors designed for moving large numbers of people quickly and efficiently from one floor to another. Staircases that could move upward or downward operate continuously during hours of occupancy Mostly deployed in pairs Supporting lift services For example; basement to ground floor where traffic is light; to avoid the need for lift to serve low demand

ESCALATOR 1. Bottom; step return idler sprockets, step chain safety switches & curves sections of the rack 2. Centre; carries all straight track sections which connect the upper & lower curved sections 3. Top; driving motor, driving sprockets, electrical controller and emergency breaks bottom top centre

ESCALATOR-component

ESCALATOR Escalator vs Elevators Advantages Travel between floors occur much rapidly in lifts traveling vertically in medium / high-rise building are more practical in elevators Elevator assemblies occupy less space Enable movement by wheelchair-bound, stretcher (in case of an emergency) Advantages Could be reversible to suit traffic at peak times Not like lift ----no waiting time Continuous operation---moves people more A device to communicate/highlight what is present at the next floor

ESCALATOR Capacity Step width between 600mm ~ 1.2m Carrying capacity depends on speed & width of thread Ex ; 1m will allow 2 people to stand side by side,1.2m for air terminals & railway stations to allow passenger to pass easily when carrying luggage,2m for departmental store with heavy traffic

ESCALATOR Location Easily seen area to maximize usage Example; in departmental stores, escalators are located to be possible to see over a wide area of the floors so as to encourage sales Arrangement Many arrangements may be used depending upon the standard of service required and cost

Multiple parallel Crisscross layout Parallel Layout

ESCALATOR Guidelines for design 1.Estimating how many escalators may be needed. Speed & width (human buffer zone) -----speed----Capacity 2. Placement locations for escalators. Building use-----function 3. Placement format for escalators • Ways to organize and stack escalators ----parallel, criss-cross, stacked & in-line • These are distinguished by their basic layout of overall system, pathway between units, traverse direction, upward / downward 4. Sizing issues for placing escalators Major dimensions for scalators;Incline angle (max 30), horizontal lengths (heights between floors), overall width, opening in floor, headroom between units

WALKALATORS/MOVING WALKWAY A moving walkway or moving sidewalk (colloquially sometimes travelator, horizontal escalator, walkalator, autowalk, movator) is a slow moving conveyor mechanism that transports people, across a horizontal or inclined plane, over a short distance. Moving walkways can be used by standing or walking on them. They are often installed in pairs, one for each direction.

WALKALATORS/MOVING WALKWAY Types: High speed Widely used in airports, tunnels allowing for a large number of passengers, (up to 10,000 per hour), whereas the transportation zone was narrower and fast moving. Required additional safety procedure (holding to the side rail and shopping cart/baby carriage/suitcase is not allowed) Inclined An inclined moving walkway is used in airports and supermarkets to move people to another floor with the convenience of an elevator (namely, that people can take along their suitcase trolley or shopping cart, or baby carriage) and the capacity of an escalator.

End of Chapter 4