ASHRAE 90.1 and NECB 2011 Envelope Compliancevancouver.csc-dcc.ca/img/content/VanChapter/Presentations/cgl - CSC... · 11/20/2014 1 November 19, 2014 Envelope Compliance ASHRAE 90.1

11/20/2014

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November 19, 2014

Envelope Compliance

ASHRAE 90.1 and NECB 2011

OVERVIEW

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� Code requirements and the Standards

� Broad overview of the Standards

� ASHRAE 90.1 prescriptive path and mandatory provisions for Envelope

� NECB prescriptive path and mandatory requirements for Envelope

� Summary comparison of the prescriptive path and mandatory provisions / requirements and what it means in the BC building context

� Looking at accounting for thermal bridging in specifications

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BCBC 2012

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VANCOUVER BUILDING BY-LAW

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STANDARDS IN CODES

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ASHRAE 90.1 2004 – Previous BCBC

ASHRAE 90.1 2007 – Previous VBBL

ASHRAE 90.1 2010 & NECB 2011 –

Current BCBC and VBBL

ASHRAE 90.1 OVERVIEW

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WHO ARE THEY?

American Society of Heating Refrigeration and Air-conditioning

Engineers

WHAT IS THE STANDARD?

First addition developed in 1970

In 1999 the standard was put into continuous maintenance

Applies to all commercial buildings and MURBS greater than 3 stories.

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ALTERNATIVE PATHS FOR

COMPLIANCE

ALTERNATIVE PATHS FOR

COMPLIANCE

Prescriptive

Trade-off

Energy cost budget

PRESCRIPTIVE PATH (OR TRADE-OFF) REQUIRE THAT ALL PARTS OF THE

STANDARD BE MET:

PRESCRIPTIVE PATH (OR TRADE-OFF) REQUIRE THAT ALL PARTS OF THE

STANDARD BE MET:

Part 5 - Building envelope

Part 6 - Heating, ventilating and air-conditioning

Part 7 - Service water heating

Part 8 - Power

Part 9 - Lighting

Part 10 - Other equipmentMandatory

Provisions


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ASHRAE 2004 Baseline

ASHRAE 2007Increased BE requirements

ASHRAE 2010No major changes in BE requirements

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NECB OVERVIEW

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� Developed by Natural Resources Canada & the National Research Council for Canada

� What is the Standard?

� Last version was in 1997 (MNECB)

� Design intent was to be roughly equivalent

to ASHRAE 90.1 2010

� Applies to new buildings (except part 9),

additions to existing building, but silent on

renovations

� Before now, not referenced in BCBC or VBBL

� MNECB is referenced in LEED

NECB OVERVIEW

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� Prescriptive

� Trade-off (simple or detailed)

� Energy simulation (building energy compliance)

ALTERNATIVE PATHS FOR COMPLIANCE

� Part 3 – Building envelope

� Part 4 – Lighting

� Part 5 – Heating, ventilating and air-conditioning systems

� Part 6 – Service water heating systems

� Part 7 – Electrical power systems and motors

PRESCRIPTIVE PATH (OR TRADE-OFF) REQUIRE THAT ALL

PARTS OF THE STANDARD BE MET:

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ZONES AND HEATING DEGREE DAYS (HDD)

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ASHRAE 90.1 Climate zones for BC

ZONES AND HEATING DEGREE DAYS (HDD)

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ASHRAE 90.1 2010

BUILDING ENVELOPE

ASHRAE 90.1- BUILDING ENVELOPE

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THIS MEANS THAT THE

BUILDING SHOULD BE

DESIGNED TO MEET

THESE PROVISIONS:

5.4.1 Insulation

5.4.2 Fenestration and Doors

5.4.3 Air leakage

ASHRAE 90.1- MANDATORY PROVISIONS

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ARCHITECTURAL DRAWINGS

5.8.1.3 Loose-Fill Insulation

Limitation. Open-blown

or poured loose-fill insulation shall

not be used in attic roof spaces

when the slope of the ceiling is

more than three in twelve.

SPECIFICATIONS

5.8.1.7.3 Insulation materials in

ground contact shall have a water

absorption rate no greater than

0.3% when tested in accordance

with ASTM C272.

5.4.1 Insulation (refers to 5.8.1) - Examples

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SPECIFICATIONS

5.8.2.4 U-factor.

U-factors shall be

determined in

accordance with NFRC

100. U-factors for

skylights shall be

determined for a slope

of 20 degrees above

the horizontal.

SPECIFICATIONS

5.8.2.5 Solar Heat Gain

Coefficient. SHGC for the

overall fenestration area

shall be determined in

accordance with

NFRC 200.

5.4.2 Fenestration and Doors (refers to 5.8.2) - Examples

SPECIFICATIONS

5.8.2.6 Visible

Transmittance.

VT shall be

determined

in accordance with

NFRC 200. VT shall

be verified and

certified by the

manufacturer.


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5.4.3.1.2 Air Barrier Installation The following areas of the continuous air barrier in

the building envelope shall be wrapped, sealed, caulked, gasketed, or taped in an

approved manner to minimize air leakage:

a. Joints around fenestration and door frames (both manufactured and site-built).

b. Junctions between walls and floors, between walls at building corners, between

walls and roofs or ceilings.

c. Penetrations through the air barrier in building envelope roofs, walls, and floors.

d. Building assemblies used as ducts or plenums.

e. Joints, seams, connections between planes, and other

changes in air barrier materials.

5.4.3 Air Leakage - Examples

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SPECIFICATIONS

5.4.3.1.3 Acceptable Materials and Assemblies.

[…] a. Materials that have an air permeance not exceeding 0.004 cfm/ft2 under a pressure

differential of 0.3 in. w.g. (1.57psf) when tested in accordance with ASTM E 2178. […]:

1. Plywood—minimum 3/8 in. […]

3. Extruded polystyrene insulation board—minimum ½ in. […]

5. Exterior gypsum sheathing or interior gypsum board—minimum 1/2 in. […]

9. Fully adhered single-ply roof membrane […]

11. Cast-in-place and precast concrete.

13. Closed cell 2 lb/ft3 nominal density spray polyurethane foam—minimum 1 in.

b. Assemblies of materials and components (sealants, tapes, etc.) that have an average air

leakage not to exceed 0.04 cfm/ft2 under a pressure differential of 0.3 in. w.g. (1.57psf)

when tested in accordance with ASTM E 2357, ASTM E 1677, ASTM E 1680 or ASTM E283

[…]



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5.4.3 Air Leakage - ExamplesGlazing Product

ASHRAE 90.1 - 2010 NAFS-08

(R, LC and CW)

NAFS-08

(AW perf. class)

cfm / ft² at 1.57 psf cfm / ft² at 1.57 psf cfm / ft² at 6.24 psf

Glazed Swing and

Entrance Doors

1.0 Not part of NAFS Not part of NAFS

Curtain wall and

Storefront


Unit Skylights 0.3

(or 0.5 at 6.24 psf)

0.3 0.3 for sliding seals

0.1 for compression seals

0.04 for fixed

Non-Swing Opaque

Doors

0.4 0.3 * Excludes site built and

steel doors

0.3 for sliding seals

0.1 for compression seals* Excludes site built and steel doors

Other products, such

as fixed and operable

windows

0.2

(or 0.3 at 6.24 psf)

0.3 0.3 for sliding seals


0.04 for fixed

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5.4.3.4 Vestibules […]

a. Building entrances with revolving doors.

b. Doors not intended to be used as a building entrance.

c. Doors opening directly from a dwelling unit. […]

f. Building entrances in buildings located in climate zone 4, 5, 6, 7, or 8 that

are less than 1000 ft2 in area.

g. Doors that open directly from a space that is less than 3000 ft2 in area and

is separate from the building entrance.


ASHRAE 90.1 PRESCRIPTIVE METHOD

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THE PRESCRIPTIVE

METHOD CAN ONLY BE

USED IF:

The vertical

fenestration ≤ 40%

of Gross wall Area

The skylight

fenestration ≤ 5%

of gross roof area

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ASHRAE 90.1 - OPAQUE AREAS

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� For conditioned spaces the exterior building envelope shall comply with, to either: the residential or the non-residential requirements in the tables

� For semi-heated spaces the semi-exterior building envelope needs to comply with the requirements in the tables

ASHRAE 90.1 - PRESCRIPTIVE OPAQUE AREAS

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THE TABLES CONTAINING THE THERMAL PERFORMANCE

REQUIREMENTS ARE PROVIDED IN THE STANDARD, BY CLIMATIC

ZONES, AND LOOK LIKE THIS:

For all opaque elements (except doors) compliance should be

demonstrated by the following methods:

� Maximum U-factors, C-factors or F-factors for the entire assembly

� Minimum rated R values of insulation

Exception: For multiple assemblies within a single class of

construction for a single conditioning space, weighted average can

be used.

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ASHRAE 90.1 PRESCRIPTIVE OPAQUE AREAS

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Components

Zone 5

Non-Residential Residential Semi-Heated

U factor R value U factor R value U factor R value

Roof - insulation above

deck

0.048

(R20.8)

20.0c.i. 0.048

(R20.8)

20.0c.i. 0.119

(R8.4)

7.6c.i.

Roof - Attic 0.027

(R37.0)

38.0 0.027

(R37.0)

38.0 0.053

(R18.9)

19.0

Walls - Mass 0.090

(R11.1)

11.4c.i. 0.080

(R12.5)

13.3c.i. 0.151

(R6.6)

5.7c.i.

Walls - Steel framed 0.064

(R15.6)

13.0+7.5c.i. 0.064

(R15.6)

13.0+7.5c.i. 0.124

(R8.1)

13.0

Walls - Wood framed 0.064

(R15.6)

13.0+3.8c.i. 0.051

(R19.6)

13.0+7.5c.i. 0.089

(R11.2)

13.0

ASHRAE 90.1 PRESCRIPTIVE - OPAQUE AREAS

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SO THAT MEANS:

� If there is more than nails or screws going through the insulation, it is not continuous

� If there are studs, girts, clips, even brick ties they need to be accounted for.

�This can be done by calculating the effective U (or R) values of these assemblies

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NOMINAL R VALUES

Rated R values which do not

take into account framing or

other element interrupting

the insulation

Calculated R

values which

allows for the

impact of

thermal bridges

EFFECTIVE R VALUESvs.


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Zone 4&5 = 0.064

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29Zone 5 = 0.051Zone 4 = 0.064

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Components

Residential R-values

R values

Zone 4 Zone 5 Zone 6 Zone 7 Zone 8

Roof - insulation

above deck

20.0c.i. 20.0c.i. 20.0c.i. 20.0c.i. 20.0c.i.

Roof - Attic 38.0 38.0 38.0 38.0 49.0

Walls - Mass 11.4c.i. 13.3c.i. 15.2c.i. 15.2c.i. 25.0c.i.

Walls - Steel framed 13.0+7.5c.i. 13.0+7.5c.i. 13.0+7.5c.i. 13.0+15.6c.i. 13.0+18.8c.i.

Walls - Wood

framed

13.0+3.8c.i. 13.0+7.5c.i. 13.0+7.5c.i. 13.0+7.5c.i. 13.0+15.6c.i.


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ASHRAE 90.1 PRESCRIPTIVE - FENESTRATION

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Windows <40% of gross wall area and Skylights <5% gross roof areaWindows <40% of gross wall area and Skylights <5% gross roof area

All fenestration compliance shall be demonstrated through meeting:

• U factor no greater than the prescriptive requirements

• SHGC no greater than the prescriptive requirements

If there are multiple assemblies, compliance shall be based on an area-weighted average U-factor or SHGC (for a single space-conditioning and within a single class of construction).

The SHGC can be reduced using a multiplier when a permanent projection provides shading for the window

ASHRAE 90.1 PRESCRIPTIVE - FENESTRATION

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Components

Zone 5

Residential Non-Residential Semi-Heated

U factor SHGC U factor SHGC U factor SHGC

Non-Metal Framing 0.35

0.40 for

all

0.35

0.40 for

all

1.20

0.40 for

all

Metal Framing (curtain

wall and storefront)0.45 0.45 1.20

Metal Framing (entrance

doors)0.80 0.80 1.20

Metal Framing (operable

and fixed windows, non-

entrance doors) 0.55 0.55 1.20

Skylight (glass,

without curb)

0-2%0.69

0.490.69

0.491.36

NR

2-5% 0.39 0.39 NR

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NECB 2011

BUILDING ENVELOPE

NECB

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NECB - MANDATORY PROVISIONS

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NO SPECIFIC

MANDATORY

PROVISIONS

But more specific than ASHRAE on how to deal with effect of structural members that may

partially and completely penetrate the envelope

In the prescriptive requirements, we find that :

Insulation should be installed in a manner that avoids affecting its R value (convection, wetting, etc.).

Insulation value required depends on zone, assembly (wall, roof or floor) and location (above or below grade or spaces heated to different temperature)

Air leakage should be controlled, including at fenestration and doors, which have limits of air leakage allowable

A vestibule is likely required

NECB - PRESCRIPTIVE METHOD

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THE PRESCRIPTIVE

METHOD CAN ONLY

BE USED IF:

FDWR ≤ 0.40 for HDD < 4000

FDWR ≤(2000- 0.2*HDD)3000

for 4000 ≤ HDD ≤ 7000

FDWR ≤ 0.20 for HDD > 7000

The skylight fenestration ≤ 5% of gross roof area

&

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NECB - THERMAL BRIDGING

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THERMAL BRIDGING

CREATED BY

STRUCTURAL

MEMBERS

The thermal bridging effect of closely spaced repetitive structural members (e.g. studs) and of ancillary members (e.g. sill and plates) should be

taken into account.

The thermal bridging of major structural elements that are parallel to the building envelope can be ignored, provided that they do not increase the thermal transmittance to more than twice than

permitted.

The thermal bridging of major structural elements that must penetrate the building envelope need

not be taken into account, provided that the sum of the areas is less than 2% of the above ground

building envelope.

Service equipment, shelf angle, ties and associate fasteners as well as minor

structural members need not be taken into account!!!

NECB PRESCRIPTIVE INSULATION

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The prescriptive method requires:

W

4xW W

4xW

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NECB PRESCRIPTIVE AIR LEAKAGE

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5.4.3 Air Leakage - ExamplesGlazing Product

NECB 2011 NAFS-08

(R, LC and CW)

NAFS-08

(AW perf. class)

L/s m² at 75 Pa L/s m² at 75 Pa L/s m² at 300 Pa

Curtain wall 0.20 Not part of NAFS Not part of NAFS

Fixed Windows and

Skylights

0.20 0.20 0.20

Operable Windows ,

Skylights & Doors

0.50 1.5 for A2 rating

0.50 for A3 rating

1.5 for A2 / 0.5 for A3 for

sliding seals


Main Entry Door if

<2% of wall area

5.0 1.5 for A2 rating

0.50 for A3 rating

1.5 for A2 / 0.5 for A3 for

sliding seals


Revolving Doors and

Automatic Sliders


NECB PRESCRIPTIVE WALLS ABOVE GRADE

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Assemblies

Any Occupancy

R values (effective)


Walls 18 20.4 23 27 31

Roofs 25 31 31 35 40

Floors 25 31 31 35 40

Walls - mass 11.4

Walls - steel framed 15.6

Walls - wood framed 19.6

� No difference between residential

and non-residential

� No difference between the different

type of construction

Roofs - insulation above 20.8

Roofs - attic 37.0

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NECB PRESCRIPTIVE FENESTRATION AND DOORS

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ComponentsU values (effective)


All Fenestration 0.42 0.39 0.39 0.39 0.28

All Doors 0.42 0.39 0.39 0.39 0.28

� No difference between residential and non-residential

� No difference between the different type of assemblies

� No SHGC requirements

� Exceptions: � Skylights that represent < 2% of gross roof area can have a

thermal transmittance of no more than 0.60

� Doors that represent < 2% of gross wall area can have a

thermal transmittance of no more than 0.77

Non-metal 0.35

Metal framing (CW) 0.45

Metal framing (others) 0.55

Entrance doors 0.80

Skylights 0.58

NECB - PRESCRIPTIVE METHOD

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CONCLUSION REGARDING THE STANDARDS

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� Wood frame is well suited for prescriptive but:

� New standards will generally require exterior insulation to meet the

max U-factor with 2x6 residential

� Only zone 4 in ASHRAE (but not in NEBC) could do without exterior

insulation in residential

� For non-combustible buildings, the prescriptive method is not a likely

candidate

� This is especially true for exposed concrete towers and buildings with

high window/wall ratio

� Exterior insulated assemblies may meet it but structure penetrating

through (balcony slabs, parapet, etc.) need to be taken into account

� Mandatory provisions go beyond the U-value requirements

� These need to be met to comply with the prescriptive path

� Provisions need to be incorporated in specifications and drawings

� Other Paths

� Restrictions of prescriptive paths often lead to trade-off or energy

modeling approaches

COMPARISON OF BOTH STANDARDS

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ASHRAE 90.1 2010 NECB 2011

Mandatory

requirements

Yes, for all methods Not for energy modeling

Prescriptive

requirements

Generally less

demanding R values

Stringent, specific

• Framing Take into account Take into account

• Structure Not clear Specific (if this then…)

• Cladding attachments Take into account Some can be ignored

• Service penetrations Ignore Specific (if this then…)

• Walls More categories Less categories

• Fenestration & doors More categories Less categories

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MORE ON SPANDRELS

COMMON CONSTRUCTION

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Lab Measurement

OPAQUE WALL ASSEMBLIES

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ASHRAE 90.1-2010 NECB 2011

U -Value R-Value U-Value R-Value

IP U-0.064 R-15.6 U-0.056 R-18.0

SI U-0.364 R-2.75 U-0.315 R-3.17

Prescriptive Thermal Performance Targets for Spandrels

Assuming R15.1 Spray Foam

WINDOW WALL SPANDREL

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No Spray Foam

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WINDOW WALL SPANDREL WITH SLAB BYPASS

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No Spray Foam

Assuming R15.1 Spray Foam

WINDOW WALL SPANDREL

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ASHRAE 90.1

R-15.6

E.g. Window Wall Spandrel

R-7.1

NECB

R-18.0

E.g. Spandrel + Slab Bypass + 3” SPF

R-4.4

E.g. Spandrel + 3” SPF

R-9.8

E.g. Spandrel + Slab Bypass

R-3.8

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3.4

4.24.8 5.0

7.4

8.2

8.8 9.1

0

1

2

3

4

5

6

7

8

9

10

0 5 10 15 20 25 30

Sp

an

dre

l S

ecti

on

R V

alu

e

Back Pan Insulation

Detail 22 (Air in Stud Cavity) Detail 23 (Spray Foam in Stud Cavity)

CURTAIN WALL SPANDREL AREAS

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SPANDRELS AND SPECS

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Food for Thought…

� Because spandrel panels are part of a glazing system, they get lumped

into Division 8 in the specifications, but… spandrel performance is often

missing from the spec!

� The effective U-value target should be specified for spandrels

� Condensation resistance / limits on surface temperatures should also

be specified based on design conditions of project

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THANK YOU

CATHERINE LEMIEUX, P.ENG.

[email protected]

604.454.0402

Documents

ASHRAE 90.1 and NECB 2011 Envelope Compliancevancouver.csc-dcc.ca/img/content/VanChapter/Presentations/cgl - CSC... · 11/20/2014 1 November 19, 2014 Envelope Compliance ASHRAE 90.1