Lessons Learned from British Columbia

Adoption and Compliance with Energy Codes: ASHRAE 90.1 and NECB

Graham Finch, MASc, P.EngPrincipal, Building Science Research Engineer RDH Building Engineering Ltd.Vancouver, BC

RCIC 2013 Edmonton – May 1, 2013

Presentation Outline

Energy Efficiency Requirements for Part 3 Buildings in BC

Enforcement & Compliance

ASHRAE 90.1 Overview & Lessons Learned

NECB 2011 Similarities & Differences

In the Past:

City of Vancouver (VBBL 2007), ASHRAE 90.1-2007

• ASHRAE in code for more than a decade

• Enforcement boosted in past few years (checklists)

Rest of BC (BCBC 2006), ASHRAE 90.1-2004

• ASHRAE added in 2008

• Enforcement up to the authority having jurisdiction (AHJ)

Window Performance – BC Energy Efficiency Act (2009)

LEED – ASHRAE 90.1-2007 PRM or MNECB 1997

Upcoming:

City of Vancouver (VBBL 2013), ASHRAE 90.1-2010 or NECB 2011

Rest of BC (BCBC 2012+), ASHRAE 90.1-2010 or NECB 2011

Window Performance – BC Energy Efficiency Act & Within Code

Overview of Energy Efficiency Requirements in BC

City of Vancouver released new building permit & occupancy documentation process to improve compliance with ASHRAE 90.1

Checklists signed off by each registered professional (mechanical, electrical, enclosure/architect) and coordinating professional

Effective R-values on drawings/ “Insulation schedules”

Energy model outputs

Enforcement & Compliance

ASHRAE 90.1 “Energy Standard for Buildings Except Low-Rise Residential Buildings”

Compliance involves meeting energy efficiency requirements in all sections:

5 – Building Envelope (Enclosure)

6 – Heating, Ventilating, and Air Conditioning

7 – Service Water Heating

8 – Power

9 – Lighting

10 – Other Equipment

ASHRAE 90.1 Overview

Alternate compliance options within each section

Prescriptive

Trade-offs

Energy Simulation

Involves several disciplines with professional engineers coordinating their efforts plus one coordinating professional taking overall responsibility

Chosen compliance path has implications for building design

ASHRAE 90.1 Overview

Mandatory Provisions (Section 5.4)Insulation

• Protection, Rating, Labeling, Installation

Fenestration & Doors• NFRC certification, airtightness, labels

Air Leakage• “continuous air barrier”, prescriptive sealing, Vestibules, weather seals

Prescriptive Compliance Path (Section 5.5)

All components must meet prescriptive tables, maximum 40% glazing area

Building Envelope Trade-off Compliance Path (Section 5.6)

Trade-off enclosure components using ASHRAE ENVStd software

Energy Cost Budget (ECB) Path (Section 11)

Whole building energy cost simulation & tradeoffs ($ not kWh)

ASHRAE 90.1 Building Enclosure Compliance

Compliance pathway is heavily influenced by building enclosure design :

Window to wall ratio

• Maximum 40% for Prescriptive Option

• No limit for BE Trade-off option or ECB

Minimum assembly and component R-values

• Prescriptive Option - difficult to comply with thermal bridging

• BE Trade-off Option – detailed area weighted U-value calculations input into ENVStd software

• Energy Cost Budget (ECB) - detailed area weighted U-value calculations input into energy model

Changes to design during tendering and construction can erode final compliance – need for “factor of safety”

ASHRAE 90.1 Building Enclosure Compliance

All building envelope assemblies (including details) must meet Table 5.5 thermal requirements (by climate zone)

Opaque Walls/Roof: Assembly Maximum U-value (Minimum effective R-value) or Insulation Minimum R-value (nominal insulation)

Windows/Doors/Skylights: Maximum U-value and SHGC restrictions

Maximum of 40% window to wall ratio

Maximum of 5% skylight to roof ratio

Basic area take-offs only necessary to verify window-wall ratio (and skylight to roof ratio)

Can be difficult to comply with for many common building designs

Prescriptive Building Envelope Option

Two alternate ways to meet prescriptive requirementsAssembly Maximum U-value (Minimum R-value)

• Accounts for all materials in assembly including air-films

• Easiest method to comply with and greatest flexibility in design

Insulation Minimum R-value

• Prescriptive rated R-value of installed insulation (nominal minimum)

• Many assemblies prescriptively require continuous insulation (ci)

Prescriptive Building Envelope R-value Tables

Only screws/nails are considered “fasteners” (or adhesives)

Where any continuous or discontinuous framing (girts, studs, clips, brick ties, shelf angles, slab edges) penetrate through the insulation – it is not considered c.i.

Note: Continuous insulation is not necessarily a mandatory requirement for prescriptive compliance (high enough R-values can be achieved without true ci)

Continuous Insulation (ci)

Nominal R-values = Rated R-values of insulation which do not include impacts of how they are installed

For example R-20 batt insulation or R-10 foam insulation

Effective R-values or Real R-values = Calculated R-values of assemblies/details which include impacts of installation and thermal bridges

For example nominal R-20 batts within steel studs becoming ~R-9 effective, or in wood studs ~R-15

Nominal vs Effective R-values

Thermal bridging occurs when a more conductive material (e.g. aluminum, steel, concrete, wood etc.) provides a path for heat to flow such that it bypasses a less conductive material (insulation)

The bypassing “bridging” of the less conductive material significantly reduces its effectiveness as an insulator

Examples:

Wood framing (studs, plates) in insulated wall

Steel framing in insulated wall

Conductive cladding attachments through insulation (metal girts, clips, anchors, screws etc)

Concrete slab edge (balcony, exposed slab edge) through a wall

Window frames and windows themselves

Thermal Bridging

Effective R-values account for thermal bridges and represent actual heat flow through enclosure assemblies and details

Heat flow finds the path of least resistance

Disproportionate amount of heat flow occurs through thermal bridges

Often adding more/thicker insulation can’t help

Required for almost all energy and building code calculations

Energy code compliance has historically focused on assembly R-values – however more importance is being placed on details and interfaces & whole building impacts of thermal bridges

Why Thermal Bridging is Important

ASHRAE/NECB/NBC Climate Zone Divisions

• >7000 HDD

• 6000 to 6999 HDD

• 5000 to 5999 HDD

• 4000 to 4999 HDD

• 3000 to 3999 HDD

• < 3000 HDD

Wall, Roof & Window Requirements for Alberta (Part 3)

ClimateZone

Wall – Above Grade: Minimum R-value (IP)

Roof – Flat or Sloped: Minimum R-value (IP)

Window: Max. U-value (IP)

8 31.0 40.0 0.28

7B 27.0 35.0 0.39

7A 27.0 35.0 0.39

6 23.0 31.0 0.39

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ZoneWall (Mass, Wood, Steel): Min R-value

Roof (Attic,Cathedral/Flat): Min R-value

Window (Alum, PVC/FG):Max. U-value

8 19.2, 27.8, 27.0 47.6, 20.8 0.45, 0.35

7B 14.1, 19.6, 23.8 37.0, 20.8 0.45, 0.35

7A 14.1, 19.6, 23.8 37.0, 20.8 0.45, 0.35

6 12.5, 19.6, 15.6 37,0, 20.8 0.55, 0.35

*7A/7B combined in ASHRAE 90.1

Wall, Roof & Window Requirements for Alberta (Part 9)

ClimateZone

Wall - Above Grade: Minimum R-value (IP)

Roof –Flat/Cathedral: Minimum R-value (IP)

Roof –Attic: Minimum R-value (IP)

Window: Max. U-value (IP) / Min. ER

8 21.9 28.5 59.2 0.25 / 29

7B 21.9 28.5 59.2 0.25 / 29

7A 17.5 28.5 59.2 0.28 / 25

6 17.5 26.5 49.2 0.28 / 25

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ClimateZone

Wall - Above Grade: Minimum R-value (IP)

Roof –Flat/Cathedral: Minimum R-value (IP)

Roof –Attic: Minimum R-value (IP)

Window: Max. U-value (IP) / Min. ER

8 17.5 28.5 59.2 0.25 / 29

7B 17.5 28.5 59.2 0.25 / 29

7A 16.9 28.5 49.2 0.28 / 25

6 16.9 26.5 49.2 0.28 / 25

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For Comparison to NBC 2010 (2012 Update) Section 9.36

Excerpt from 90.1-2010 Table 5.5-7 (Edmonton, AB)

Building Enclosure Component

Climate Zone 7 – Residential Buildings

Minimum Assembly R-value

ft2 ⋅°F⋅ h/Btu

Minimum InsulationR-value

ft2 ⋅°F⋅ h/BtuRoof – Insulation Above Deck R-20.8 R-20 c.i.Roof – Attic R-37.0 R-38Above Grade Wall – Wood-Frame R-19.6 R-13 + 7.5 c.i.Above Grade Wall – Steel Frame R-23.8 R-13 + 15.6 c.i.Above Grade Wall – Mass R-14.1 R-15.2 c.i.Below Grade Wall – Concrete R-10.9 R-10.0 c.i.Windows Maximum Window U-value Btu/h∙ft2∙°F

Non Metal Frame (Vinyl, Fibreglass and Wood)

U-0.35 (no SHGC requirement)

Metal Framed Windows (Aluminum, Window Wall)

U-0.45 (no SHGC requirement)

Metal frames (Curtainwall & Storefront)

U-0.40 (no SHGC requirement)

* c.i. = continuous insulation

Window-wall ratios >40%

Curtain-wall or window-wall spandrel panels

Balconies & exposed slab edge projections

Mass concrete walls with interior insulation

Roof parapet, overhang details, canopies

Insulation placed between steel studs or z-girts

Best suited for simple buildings

Common Difficulties in Meeting Prescriptive Compliance

Structural Stud Framing in Taller Multi-Unit Residential Buildings

Common Difficulties in Meeting Prescriptive Compliance

Spandrel Panels

Common Difficulties in Meeting Prescriptive Compliance

verticals

Cladding Attachment through Exterior Insulation – Minimize Thermal Bridging

Solutions for Meeting Prescriptive Compliance

Alternate Cladding Support Comparison

Cast-in-Place Concrete Balcony & Slab Edge Thermal Breaks

Solutions for Meeting Prescriptive Compliance

Allows for greater flexibility in architectural design

Common path for Multi-Unit Residential Buildings where more complex enclosure designs are utilized

Necessary where window-wall ratios exceed 40% and enclosure assemblies/details may not meet minimum prescriptive requirements

Requires determination of effective thermal performance of all enclosure assemblies, details, and components

Trade-offs made between any enclosure component (i.e. between walls and windows, or walls and roofs etc.)

Building Envelope Trade-off Option

Compliance is assessed by calculation of Envelope Performance Factor (EPF) calculated using ASHRAE EnvStdsoftware

EPF approximates the total heating and cooling energy associated with a single square foot of surface. A lower EPF is better than a high EPF

Overall U-value of building enclosure driving factor in EPF plus day-lighting and solar-heat gain through windows

Proposed building enclosure is compared to a minimally prescriptively compliant baseline building enclosure

Baseline building construction is identical except that all building enclosure assemblies meet maximum U-value (minimum R-value) requirements within each class of construction and a 40% window-wall ratio is assumed

Building Envelope Trade-off Option

Step 1: Identify Building “Spaces”

Step 2: Define “Surfaces” within each Space

Step 3: Coordinate Surfaces & Assemblies

Step 4: Summarize Windows/Doors for each surface

Step 5: Summarize Data and Calculate Areas

Step 6: Enter Data and run EnvStd Program

Building Envelope Trade-off Option Process

Wall and Roof Areas and U-values input into ENVStdSoftware by construction type, orientation and occupancy

Window/door areas entered within each of the assemblies

Output from ENVStdshows Pass/Fail & No. of EPF Points

Building Envelope Trade-off Option

Assessing Reasons for Non-Compliance

Lower EPF is better

Current Design

Proposed Base Margin % Difference

Roof 981 1011 30 -3%

Skylight 0 0 0

Exterior Walls and Windows 6552 5753 -799 14%

Floor 873 779 -95 12%

Slab 0 0 0

Below Grade Wall 0 0 0

Daylighting Potential 3478 4140 663 -16%

Total 11884 11683 -201 1.7%

FAILS

Component Area UxA % of Heat Loss

Windows 10,884 4,898 55.7%

Doors 1,093 492 5.6%

Wall EW1 8,479 1,495 17.0%

Wall EW2 894 147 1.7%

Wall EW3 168 26 0.3%

Curb and slab edge details 1,585 652 7.4%

Floor and Soffit Areas 7,466 622 7.1%

Roof and Deck Areas 7,474 460 5.2%

TOTAL 38,043 8,791

Overall Effective U-Value 0.23

Overall Effective R-Value 4.33

Impact of Window to Wall Ratio on Overall Performance

Value of High Performance Windows on ASHRAE Compliance

ASHRAE, Maximum 40% Glazing Area

Non-Compliant

Compliant

1. Allows for Higher Window-Wall Ratios

Improve Enclosure R-value

Whole building energy simulation considers building envelope plus HVAC, DHW, lighting and power.

Trade-offs allowed between BE and mechanical systems

Energy cost ($) of proposed building compared to baseline building (with minimally compliant enclosure and baseline HVAC system)

Used where building envelope performance cannot meet BE Trade-off or prescriptive requirements

Requires detailed building envelope R-value calculations for energy model input – same level of detail as required for BE Trade-off with overall R-values

ECB energy model is different the LEED PRM energy model

Energy Cost Budget Option

Energy Cost Budget – depends on $ savings, not necessarily energy

Bigger benefit to addressing higher cost fuel (often electricity) rather than higher energy use (ie gas heating)

Common approach for compliance for buildings undergoing LEED or other energy modeling

Mechanical systems often make-up for poor enclosure choices – not great from long-term or passive approach

Allows for most flexibility in design, higher window to wall ratio, more thermal bridging (to a point)

Trends with Energy Cost Budget Option

ASHRAE Mandatory Provisions Checklist

City of Vancouver Submission Checklist

“Insulation Schedule” and Effective R-values on Drawings

Comparison of actual vs prescriptive R-values

Energy Modeling outputs

Compliance Documentation

National Energy Code of Canada for Buildings (NECB) 2011 replaces MNECB 1997

Similar compliance paths to ASHRAE 90.1 – Prescriptive, Trade-offs, and Energy Modeling

3 – Building Envelope4 – Lighting5 – HVAC6 – Service Water Heating7 – Electrical Power Systems and Motors8 – Building Energy Performance Compliance Path

Building Envelope: Maximum window to wall ratio from 40% (HDD <4000) down to 20% (HDD >7000)

Energy Consumption vs Energy Cost

NECB 2011 Similarities & Differences

ASHRAE 90.1-2010 vs NECB 2011

ClimateZone

Wall – Above Grade: Minimum R-value (IP)

Roof – Flat or Sloped: Minimum R-value (IP)

Window: Max. U-value (IP)

8 31.0 40.0 0.28

7B 27.0 35.0 0.39

7A 27.0 35.0 0.39

6 23.0 31.0 0.39

NEC

B 2

01

1

ASH

RA

E 9

0.1

-20

10

–R

esi

de

nti

al B

uild

ing Climate

ZoneWall (Mass, Wood, Steel): Min R-value

Roof (Attic,Cathedral/Flat): Min R-value

Window (Alum, PVC/FG):Max. U-value

8 19.2, 27.8, 27.0 47.6, 20.8 0.45, 0.35

7B 14.1, 19.6, 23.8 37.0, 20.8 0.45, 0.35

7A 14.1, 19.6, 23.8 37.0, 20.8 0.45, 0.35

6 12.5, 19.6, 15.6 37,0, 20.8 0.55, 0.35

*7A/7B combined in ASHRAE 90.1

Builder Insight Bulletins & Building Enclosure Design Guides

www.hpo.bc.ca

City of Vancouver Checklists

ASHRAE 90.1 User Guides

NECB 2011 Presentations

For More Information & Assistance

Graham Finch, MASc, P.Enggfinch@rdhbe.com604-873-1181

Discussion