2013 Building Energy Efficiency Standards Staff Workshop · 17/8/2011 · 2013 Building Energy Efficiency Standards Staff Workshop ... ASHRAE 90.1, ASHRAE 189 ... ASHRAE Handbook

C A L I F O R N I A E N E R G Y C O M M I S S I O N

2013 Building Energy Efficiency Standards Staff Workshop

David W. WareCalifornia Energy Commission

August 17, 2011

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C A L I F O R N I A E N E R G Y C O M M I S S I O N

Nonresidential Air Infiltration Standard

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• PurposeReduce infiltration & exfiltration through envelopeo Infiltration increases heating & cooling energyo Exfiltration increases fan, heating & cooling energy

• ResearchInfiltration contributes to >40% of office building heating loadsAverage air leakage rate of 203 sampled buildings was 1.55 cfm/ft2 @ 0.3” w.g.

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Examples of Air Infiltration Standards

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• State & local jurisdiction adoptionsFL, WI, WA, MA, MN, Seattle

• National reference standards & codesASHRAE 90.1, ASHRAE 189IECCIgCCArmy Core of Engineers

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National Air Infiltration Standard

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IECC Climate Zones

Air Barrier Requirements:CZs 4-6

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National Air Infiltration Standard

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• IECC 2012, Section 502.4.1 air barrier requirement

Building infiltration target of ≤ 0.40 cfm/ft2 at a pressure differential of 0.3” w.g.o can be met through: (1) choice of materials, (2)

assembly testing, (3) building performance testing

IECC & ASHRAE air infiltration requirement not applicable to climate zones 1-3 (which encompass majority of CA climate zones)

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Nonresidential Air Infiltration Analysis

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• How much is infiltration reduced when the HVAC system is running and pressurizing the space?

Benefits of reduced air leakage usually associated with heating loadsNACM presently assumes 100%2009 PNNL study suggests 75%o Drivers affecting air infiltration:

Building height (stack effect)Wind speed (pressure differences)Temperature

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Nonresidential Air Infiltration Analysis

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• Stack effect to be modeled in accordance with ASHRAE Handbook - Fundamentals – 2009, Chapter 16, Equation 38

• 1, 3, and 12 story office buildings analyzed

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

‐50 0 50 100 150

Infil

trat

ion

(cfm

/ft²)

Outdoor Temperature (°F)

Stack Effect Infiltration by Floor - Baseline

1

1P

2

2P

3

3P

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

‐50 0 50 100 150

Infil

trat

ion

(cfm

/ft²)

Outdoor Temperature (°F)

Stack Effect Infiltration by Floor - Proposed

1

1P

2

2P

3

3P

C A L I F O R N I A E N E R G Y C O M M I S S I O N

Nonresidential Air Infiltration Analysis

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1. Run energy models to determine potential value of energy savings using 2013 LCC methodology

– 6 representative climate zones

2. Compare modeled energy savings to existing estimates of the cost to comply with: ≤ 0.40 cfm/ft2 at 0.3” w.g.

3. Conduct additional measure cost and feasibility research if necessary

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Nonresidential Air Infiltration Analysis

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C A L I F O R N I A E N E R G Y C O M M I S S I O N

Nonresidential Air Infiltration Analysis

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-1.0%

0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

6.0%

7.0%

3 7 9 13 14 16

Perc

ent T

DV

Sav

ings

Climate Zone

Air Leakage TDV Savings

LO

RT

WH

0.0%

0.5%

1.0%

1.5%

2.0%

2.5%

3.0%

LO RT WH

Perc

ent T

DV

Sav

ings

Building Type

Average Air Leakage TDV Savings

LO

RT

WH

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Nonresidential Air Infiltration Requirement

• Refine analysis and cost effectiveness • Air infiltration/air barrier requirement may

be dependent on:– Climate zone– Building height– Building type

• Air barrier compliance alternatives– Materials– Assemblies– Building testing 11

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Nonresidential Air Infiltration Requirement

• Limit air leakage by continuous air barrier• Air barrier compliance alternatives

– Materials: ASTM E2178 – Standard Test Method for Air Permeance of Building Materials

– Assemblies: ASTM E2357 – Standard Test Method for Determining Air Leakage of Air Barrier Assemblies

– Building testing: Air leakage ≤ 0.40 cfm/ft2 at a pressure differential of 0.3” w.g.

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ASTM E2178 Product Materials Building Performance Testing

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Nonresidential Air Infiltration Standard

• Questions?• Comments?

Contact: David W. [email protected]

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