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Energy efficiency Requirements for Part 3 Buildings in BC. The measures of enforcement and compliance, with an overview and lessons learned regarding ASHRAE 90.1 as well as, the similarities and difference in the NECB 2011.
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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
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
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
Wit
ho
ut
a H
RV
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
Wit
h a
HR
V
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