Update of theNational Energy Code

for Buildings

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Outline

Recent history of the Energy Code development in Canada

National Energy Code for Buildings (NECB) 2011• Impetus for updating the 1997 Model National

Energy Code for Buildings

• Approach used in NECB and details

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History

Model National Energy Code for Buildings 1997

Prescriptive approach: building envelope, HVAC, service water heating, lighting, electrical power

Engineering approach: performance “Performance Compliance for Buildings”• reference and proposed building modeling

Model National Energy Code for Houses (MNECH) published in 1997

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History (cont’d)

Total life-cycle costing

Different construction requirements for different energy sources

Regional variations in energy costs

Not widely adopted

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Decision to Update

June 2005 Canadian Commission on Building and Fire Codes (CCBFC) meeting• NRCan presentation and request for update

Motion• “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.”

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Decision to Update

Building Energy Codes Collaborative (BECC)• business plan

• P/T support

• funding from NRCan

February 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 Commission

– the work would not compromise the capacity to complete the current and ongoing priorities of the coordinated codes development system”

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NECB 2011

Standing Committee on Energy Efficiency in Buildings (SC-EEB) formed in 2007

First meeting in December 2007

Task groups• Building Envelope

• HVAC and Service Water Heating

• Lighting and Power

• Performance Compliance

• Code Consolidation

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NECB 2011

Objective-based

Energy used by the building

Paths of compliance• Prescriptive path

• Trade-off path (within the Part)

• Performance path

Simple payback approach

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Task Group on Building Envelope

Maximum overall thermal transmittances (U-values) will not differ for different assembly construction

Thermal requirements categorized by climate zone, defined by heating degree days – six Canadian climate zones

Thermal requirements will be fuel source neutral Limitation on the fenestration and

door to wall ratio in the prescriptive path

Air barrier requirements are being introduced for building envelope assemblies

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Task Group on Building Envelope (cont’d)

Existing ProvisionsTable A-3.3.1.1.(1)

Prescriptive Requirements – Above-ground Building AssembliesForming Part of Sentence 3.3.1.1.(1)

Assembly Description

Principal Heating Source

Electricity, OtherOil, Propane, Heat Pump

Natural Gas

Maximum Overall Thermal Transmittance (U-value), W/m2 ºC

Roofs Type I - attic-type roofs 0.140 0.200 0.200Type II - parallel-chord trusses and joist-type roofs

0.230 0.230 0.230

Type III - all other roofs (e.g., concrete decks with rigid insulation)

0.290 0.410 0.470

Walls 0.330 0.480 0.550Floors

Type I - parallel-chord trusses and joist-type floors

0.220 0.220 0.220

Type II - all other floors (e.g., concrete slabs with rigid insulation)

0.290 0.410 0.470

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Task Group on Building Envelope (cont’d)

Proposed ApproachHeating Degree-Days of Building Location(1), Celsius degree-daysZone 4: < 3000

Zone 5: 3000 to 3999

Zone 6: 4000 to 4999

Zone 7A: 5000 to 5999

Zone 7B: 6000 to 6999

Zone 8: ≥ to 7000

Maximum Overall Thermal Transmittance (W/m2K)In Contact With the GroundWalls 0.568 0.379 0.284 0.284 0.284 0.210Roofs 0.568 0.379 0.284 0.284 0.284 0.210Floors 1 0.757

for 1.2 m0.757 for 1.2 m

0.757 for 1.2 m

0.757 for 1.2 m

0.757 for 1.2 m

0.379 full area

Above-Ground ComponentWalls 0.315 0.278 0.247 0.210 0.210 0.183Roofs 0.227 0.183 0.183 0.162 0.162 0.142Floors 0.227 0.183 0.183 0.162 0.162 0.142Fenestration 2 2.4 2.2 2.2 2.2 2.2 1.6Doors 3 2.4 2.2 2.2 2.2 2.2 1.6

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

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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 < 4000

FDWR ≤ (2.590 X 10-8)∙HDD2 – (3.516 X 10-4)∙HDD + 1.392, for 4000 ≤ HDD ≤ 7000

FDWR = 0.20 for HDD > 7000

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Task Group on Building Envelope (cont’d)

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Task Group on Building Envelope (cont’d)

Building envelope trade-off compliance path• Scaled down version of the full performance path,

considering only building envelope elements

• Demonstration that the building envelope will not use more energy than it would if all components were to comply with the prescriptive path

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Task Group on Lighting and Electrical Power

Lighting

Lighting requirements are generally being harmonized with ASHRAE 90.1 2010

Additional requirements for automatic control devices, including automatic daylighting controls

Lighting power allowances for building exteriors will be introduced for more exterior lighting applications

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Task Group on Lighting and Electrical Power (cont’d)

Lighting (cont’d)

Lighting Power Density (LPD) tables updated

Lighting Power DensitiesUsing the Building Area Method

Building Area Type W/m2

Automotive facility 9.79

Convention center 11.30

Courthouse 11.51

Dining: bar lounge/leisure 10.87

Dining: cafeteria/fast food 10.01

Dining: family 10.11

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Task Group on Lighting and Electrical Power (cont’d)

Lighting (cont’d)

LPD tables updated

Lighting Power Densities Using the Building MethodBuilding Type(1) Lighting Power Density

(W/m2)

Automotive facility 8.8

Convention centre 11.6

Courthouse 11.3

Dining: bar lounge/leisure 10.7

Dining: cafeteria/fast food 9.7

Dining: family 9.6

Dormitory 6.6

Exercise centre 9.5

Fire station 7.6

Gymnasium 10.8

Health-care clinic 9.4

Hospital 13.0

… …

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Task Group on Lighting and Electrical Power (cont’d)

Lighting (cont’d)

New lighting trade-off compliance path• for interior lighting only

• quantify the impact of daylighting/daylight dependent and other controls

• compare the overall lighting energy use of a building to a prescriptive baseline

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Task Group on Lighting and Electrical Power (cont’d)

Electrical Power

Few technical changes are proposed

New voltage drop requirements for feeder conductors and branch circuit conductors

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Task Group on HVAC and Service Water Heating

For prescriptive path, values for efficiency ratings, insulation thicknesses, etc., are being updated

New requirements• maximum temperature set

points for vestibules• more requirements for when

cooling is installed• more requirements for heat recovery systems

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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 pipes

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Task Group on HVAC and Service Water Heating (cont’d)

Trade-off Path for HVAC (similar for SWH)

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1

2

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1

2

321

321

iiiiii

iiiiii

BaVBaV

ToVToVTOIHVAC

where i - counter for number of components included, as per Article 5.3.2.2, for the given HVAC system α1i - constant weighting factor to link the component efficiency variations of component i to system efficiency variations as per Article 5.2.3.10α2i - first order weighting factor to link the component efficiency variations of component i to system efficiency variations as per Article 5.2.3.10α3i - second order weighting factor to link the component efficiency variations of component i to system efficiency variations as per Article 5.2.3.10ToVi - Specified value of component i for the proposed building as per Article 5.3.2.5BaVi - Base value specified for component i the reference building as per Article 5.3.2.6

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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 guide

Criteria/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 NECB

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NECB 2011

Public review of the proposed changes will take place in the fall of 2010

www.nationalcodes.ca

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NECB 2011

Questions?

www.nrc-cnrc.gc.ca/irc