Presentation on theme: "Update of the National Energy Code for Buildings"— Presentation transcript:
1 Update of the National Energy Code for Buildings
2 Recent history of the Energy Code development in Canada OutlineRecent history of the Energy Code development in CanadaNational Energy Code for Buildings (NECB) 2011Impetus for updating the 1997 Model National Energy Code for BuildingsApproach used in NECB and detailsThis presentation will focus on two main areas:a history of the development of national energy codes for constructionSecond, I’ll be talking about the National Energy Code for Buildings (NECB) 2011 which is an update of the Model National Energy Code for Buildings (MNECB) 1997the reasons why the decision was made to update the MNECB, and a discussion on the approach and basic philosophy used in the update, its framework, and an overview of its technical aspects
3 Model National Energy Code for Buildings 1997 HistoryModel National Energy Code for Buildings 1997Prescriptive approach: building envelope, HVAC, service water heating, lighting, electrical powerEngineering approach: performance “Performance Compliance for Buildings”reference and proposed building modelingModel National Energy Code for Houses (MNECH) published in 1997The Model National Energy Code for Buildings (MNECB) was published in 1997.The basis of the document was the prescriptive provisions found in various parts of the code dealing with building envelope, HVAC, service water heating, lighting and electrical power. The building envelope part allowed for some prescriptive trade-offs between building envelope components.Since the publication of the previous Energy Measures, modeling methodology and tools had dramatically progressed, so that the MNECB 1997 contained a Part dealing with a whole building engineering approach on how to perform the modeling. Most of the provisions and guidelines related to this were published in a separate document entitled "Performance Compliance for Buildings“, published in In this procedure, the energy use of the proposed building is determined in accordance with the modeling approach. This is then compared to the energy used by the same building but designed to the prescriptive requirements (the reference building). The energy used by the proposed building cannot exceed that used by the reference building.The scope of the MNECB 1997 generally addressed all buildings except for Part 9 housing. A separate energy code for Part 9 housing was published at the same time, the Model National Energy Code for Houses 1997.
4 Total life-cycle costing History (cont’d)Total life-cycle costingDifferent construction requirements for different energy sourcesRegional variations in energy costsNot widely adoptedThe requirements in both energy codes were established using total life-cycle costing. This costing involved different values depending on the principle energy source. This resulted in a variation of total energy used by buildings that have different energy sources, all other design considerations being the same. Also, the costing took regional energy cost variations into account and so requirements could vary from one region to another even if the climatic considerations were identical.Although the MNECB 1997 was not widely adopted by the provinces and territories (in fact, only one province referenced the document), a number of government, utility, and private sector programs used the MNECB as a complement to incentive programs and to establish a baseline for new energy-efficient building design. These programs include NRCan’s Commercial Building Incentive Program (CBIP), utilities programs in BC, Manitoba, Ontario and Quebec and LEED-Canada.Based on the lack of adoption of the MNECB by the provinces and territories, work on the energy codes was suspended until..
5 Decision to UpdateJune 2005 Canadian Commission on Building and Fire Codes (CCBFC) meetingNRCan presentation and request for updateMotion“Moved … and seconded … that CCBFC supports, as a first phase, the work on the technical basis for the development of the revisions to the MNECB as a progeny document on condition that the necessary support and funding for the project is provided from NRCan and/or others.”At the June 2005 meeting of the CCBFC, NRCan requested that the CCBFC update the MNECB 1997 based on declining energy resources available to Canadians and the high levels of demand on energy by buildings. The CCBFC agreed to a first phase that required that provincial/territorial support from the building construction departments be demonstrated and that the project be funded by NRCan and/or others. The actual motion that was approved is shown on the slide.
6 Decision to Update February 2007 CCBFC meeting Building Energy Codes Collaborative (BECC)business planP/T supportfunding from NRCanFebruary 2007 CCBFC meeting“Moved by …, seconded by …, that the updating of the MNECB as a progeny document based on the BECC business plan be approved, subject to:the process to develop the document would follow the policies and procedures of the Commissionthe work would not compromise the capacity to complete the current and ongoing priorities of the coordinated codes development system”The Building Energy Codes Collaborative (BECC) was established. BECC was a provincial-territorial-federal committee supported by the Council of Energy Ministers, the Assistant Deputy Minister Steering Committee on Energy Efficiency and NRCan with a mandate of pursuing the update of the MNECB as a stand-alone document. The BECC put together a business plan that contained letters of support for addressing energy requirements for buildings in a code from both the energy and building construction provincial/territorial ministries, as well as a commitment of funding from NRCan.BECC presented this business plan at the February 2007 meeting of the CCBFC. The CCBFC agreed to update the MNECB 1997 on the conditions that it follow the code development process established by the CCBFC and that the work not compromise the work being undertaken on the other model code documents. The actual motion that was approved is shown on the slide.
7 First meeting in December 2007 Task groups NECB 2011Standing Committee on Energy Efficiency in Buildings (SC-EEB) formed in 2007First meeting in December 2007Task groupsBuilding EnvelopeHVAC and Service Water HeatingLighting and PowerPerformance ComplianceCode ConsolidationThe Standing Committee on Energy Efficiency in Buildings (SCEEB) was established in 2007 to complete the technical update of the document. The first meeting of the SCEEB was held in December 2007, and the work is proceeding on an accelerated basis that is scheduled to produce the National Energy Code for Buildings (NECB) in 2011.The bulk of the work is being addressed by task groups of the SCEEB. They are the Task Groups on building envelope, HVAC and service water heating, lighting and electrical power, building energy performance compliance, and code consolidation. The task groups are responsible for specific Parts of the Code. In addition, the task group on code consolidation, which is comprised of the chairs of the other task groups and of the SCEEB, is overseeing the development of all the other task groups to ensure that there is consistency in the approach and to provide overall guidance.
8 Energy used by the building Paths of compliance NECB 2011Objective-basedEnergy used by the buildingPaths of compliancePrescriptive pathTrade-off path (within the Part)Performance pathSimple payback approachThe NECB 2011 will be in objective-based format as are the National Building, Plumbing and Fire Codes.The NECB 2011 will have a pure energy objective in that it will address energy used by the building and will not codify factors and costs related to energy source and local variations. The provisions will, of course, vary depending on climate zone as determined by heating degree days.It will have three compliance paths: a prescriptive path, a trade-off path that allows for trade-off within a part only, and a performance path.Costs will not be codified, though cost analysis, using a simple payback approach, will be conducted to support the technical changes.
9 Task Group on Building Envelope Maximum overall thermal transmittances (U-values) will not differ for different assembly constructionThermal requirements categorized by climate zone, defined by heating degree days – six Canadian climate zonesThermal requirements will be fuel source neutralLimitation on the fenestration and door to wall ratio in the prescriptive pathAir barrier requirements are being introduced for building envelope assembliesNow, let's get into some of the finer details of what you will see in the NECB We’ll start with the work of the Task Group on Building Envelope, whose mandate it is to update Part 3 – Building Envelope of the MNECB 1997.- Air leakage requirements are being introduced for building envelope assemblies- The overall thermal transmittances (U-values) will not differ for different types of assembly construction. In other words, there will be one U-value for roofs one for opaque walls, etc.The thermal requirements will be given by climate zone for six Canadian climate zones.(Zone 4: , Zone 5: , Zone 6: , Zone 7a: , Zone 7b: , Zone 8: 7000 and above)The thermal requirements will be fuel source neutral
10 Task Group on Building Envelope (cont’d) Existing ProvisionsTable A (1)Prescriptive Requirements – Above-ground Building AssembliesForming Part of Sentence (1)Assembly DescriptionPrincipal Heating SourceElectricity, OtherOil, Propane, Heat PumpNatural GasMaximum Overall Thermal Transmittance (U-value), W/m2 ºCRoofsType I - attic-type roofs0.1400.200Type II - parallel-chord trusses and joist-type roofs0.230Type III - all other roofs (e.g., concrete decks with rigid insulation)0.2900.4100.470Walls0.3300.4800.550FloorsType I- parallel-chord trusses and joist-type floors0.220Type II- all other floors (e.g., concrete slabs with rigid insulation)Here is an example of the existing provisions in MNECB 1997 for maximum overall thermal transmittance for above-ground components. As you can see, there are three different roof types and two different floor types, each with different U-values depending on the principal heating source.In the MNECB 1997, more insulation is required if the roof was an attic-type roof. More insulation is required for an attic in a building heated by electricity compared to one heated with natural gas.
11 Task Group on Building Envelope (cont’d) Proposed ApproachHeating Degree-Days of Building Location(1), Celsius degree-daysZone 4: < 3000Zone 5: to 3999Zone 6: to 4999Zone 7A: to 5999Zone 7B: to 6999Zone 8: ≥ to 7000Maximum Overall Thermal Transmittance (W/m2K)In Contact With the GroundWalls0.5680.3790.2840.210RoofsFloors 1for 1.2 mfull areaAbove-Ground Component0.3150.2780.2470.1830.2270.1620.142FloorsFenestration 188.8.131.52Doors 3In the proposed approach, there is one maximum overall U-value for each assembly types (roof, wall, floor) regardless of the principal heating fuel.Table 1. Proposed Thermal Requirements for the NECB 2011Notes to Table 1:1 – floors in contact with the ground with imbedded heating cables or heating or cooling pipes require full area insulation in all heating-degree day categories2 - exception of overall thermal transmittance of 3.4 W/m2K for skylights not exceeding 2% of gross roof area3 - exception of overall thermal transmittance of 4.4 W/m2K for doors not exceeding 2% of gross wall area
12 Task Group on Building Envelope (cont’d) The maximum allowable total vertical fenestration and door area to gross wall area (FDWR) will vary by climate zone:FDWR = 0.40 for HDD < FDWR ≤ (2.590 X 10-8)∙HDD2 – (3.516 X 10-4)∙HDD , for 4000 ≤ HDD ≤ FDWR = 0.20 for HDD > 7000
14 Task Group on Building Envelope (cont’d) Building envelope trade-off compliance pathScaled down version of the full performance path, considering only building envelope elementsDemonstration that the building envelope will not use more energy than it would if all components were to comply with the prescriptive path
15 Task Group on Lighting and Electrical Power Lighting requirements are generally being harmonized with ASHRAEAdditional requirements for automatic control devices, including automatic daylighting controlsLighting power allowances for building exteriors will be introduced for more exterior lighting applicationsNext, looking at the work of the Task Group on Lighting and Electrical Power whose mandate is to update Part 4 (lighting) and Part 7 (electrical power) of the MNECB 1997.To give you a sense of some of the changes coming forward for the lighting part there will be:- a general harmonization of lighting requirements in the NECB with the proposed lighting requirements of ASHRAE 90.1 / 2010- additional requirements for automatic control devices- requirements for more exterior lighting applications
16 Task Group on Lighting and Electrical Power (cont’d) Lighting (cont’d)Lighting Power Density (LPD) tables updatedLighting Power DensitiesUsing the Building Area MethodBuilding Area Type W/m2Automotive facility 9.79Convention center 11.30Courthouse 11.51Dining: bar lounge/leisure 10.87Dining: cafeteria/fast food 10.01Dining: family 10.11The lighting power density tables will be updated.The table shown is an excerpt from the lighting power density tables in the MNECB 1997.
17 Task Group on Lighting and Electrical Power (cont’d) Lighting (cont’d)LPD tables updatedLighting Power Densities Using the Building MethodBuilding Type(1)Lighting Power Density (W/m2)Automotive facility8.8Convention centre11.6Courthouse11.3Dining: bar lounge/leisure10.7Dining: cafeteria/fast food9.7Dining: family9.6Dormitory6.6Exercise centre9.5Fire station7.6Gymnasium10.8Health-care clinic9.4Hospital13.0…The new lighting power densities (LPDs) were determined by updating the lighting models that form the basis for the LPDs.Based on the illumination requirements for the space type, the lighting equipment combinations are considered and the required power for each of those combinations is determined . The model conducts multiple simulations to arrive at the lighting power densities for each of the space types.
18 Task Group on Lighting and Electrical Power (cont’d) Lighting (cont’d)New lighting trade-off compliance pathfor interior lighting onlyquantify the impact of daylighting/daylight dependent and other controlscompare the overall lighting energy use of a building to a prescriptive baselineA simple trade-off compliance path will be introduced in the lighting part of the NECB This trade-off path allows the user to quantify the impact of daylighting / daylight dependent control and other controls on the energy use, in order to compare it to the overall lighting energy use of a building defined by the prescriptive path within the NECB. This gives the lighting designer more flexibility in applying the LPDs.
19 Task Group on Lighting and Electrical Power (cont’d) Few technical changes are proposedNew voltage drop requirements for feeder conductors and branch circuit conductors
20 Task Group on HVAC and Service Water Heating For prescriptive path, values for efficiency ratings, insulation thicknesses, etc., are being updatedNew requirementsmaximum temperature set points for vestibulesmore requirements for when cooling is installedmore requirements for heat recovery systemsNext we’ll look at the work of the Task Group on HVAC and Service Water Heating whose mandate is to update Part 5 (HVAC) and Part 6 (Service Water Heating) of the MNECB 1997.To give you a sense of some of the changes coming forward for the HVAC and Service Water Heating parts:- The efficiency ratings of HVAC and Service Water Heating equipment and the minimum pipe insulation thicknesses are being updated in the prescriptive paths.New requirements for maximum temperature set points for vestibules;New requirements when cooling is to be installedMore requirements for heat recovery systems, andNew requirements for solar thermal service water heating equipment, where installed.
21 Task Group on HVAC and Service Water Heating (cont’d) New HVAC and service water heating trade-off compliance paths that consider system efficiencies as opposed to individual component efficiencies – would include losses through the ducts and pipesThe HVAC and service water heating parts are also proposing the introduction of a new “simple” trade-off path (I.e. within the Parts only) A methodology has been established to calculate the system efficiencies as opposed to individual component efficiencies. This methodology, for example, takes into account system losses through the ducts and pipes. Compliance for the overall system will be shown when the weighted sum of the individual component efficiencies is not exceeded and provided certain limitations are met. .With respect to both the trade-off path and performance path, there will be some limitations imposed on the HVAC and service water heating equipment. For instance, regardless of the compliance path chosen, the minimum levels in National and provincial energy efficiency acts will be maintained.
22 Task Group on HVAC and Service Water Heating (cont’d) Trade-off Path for HVAC (similar for SWH)wherei - counter for number of components included, as per Article , for the given HVAC systemα1i - constant weighting factor to link the component efficiency variations of component i to system efficiency variations as per Articleα2i - first order weighting factor to link the component efficiency variations of component i to system efficiency variations as per Articleα3i - second order weighting factor to link the component efficiency variations of component i to system efficiency variations as per ArticleToVi - Specified value of component i for the proposed building as per ArticleBaVi - Base value specified for component i the reference building as per ArticleThis table demonstrates what the proposed new trade-off path could look like. The overall system efficiency would be based on the component efficiencies and how each one was weighted for it’s effect on the overall efficiency. The methodology behind a trade-off tool included over 20,000 modeling computations to determine the weight factors.
23 Task Group on Building Performance Compliance Contents of the supplement “Performance Compliance for Buildings” is being shifted to either the Code, the explanatory appendix to the Code, or a proposed users guideCriteria/systems that are in the proposed building will be included in the reference building (e.g., cooling)The goal is to base compliance on building energy targets – for a subsequent version of the NECBNext we’ll look at the work of the TG on Building Energy Performance Compliance whose mandate is to update Part 8 of the MNECB 1997.The requirements within the supplement “Performance Compliance for Buildings” will be moved to within the body of the code, into the appendix of the code or into a proposed user’s guide for the NECB, which should be available shortly after the Code is published.The ultimate performance goal of the National Energy Code for Buildings is to establish an energy target or budget based on class of building, and could take the form of energy used per square meter of building floor area or per cubic meter of building. The modeling procedure of the performance compliance path would then produce an energy usage that could be compared against the energy target. This was not achievable for the 2011 version but will be the goal for the subsequent edition.
24 NECB 2011Public review of the proposed changes will take place in the fall of 2010A public review of the proposed changes to the Model National Energy Code for Buildings will take place in the fall of 2010.Additional information on the code development process and the National Energy Code for Buildings can be found at the Canadian Codes Centre website: