2015 iecc –whole building air leakage compliance...air tightness (modeling results from annex 46)...

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2015 IECC – Whole Building Air

Leakage Compliance

• Presented by:

Jeffrey Crowe, PEProject Manager


Learning Objectives

• Understand 2015 International Energy Code Council (IECC) whole building

air leakage requirements and compliance options

• Recognize air leakage requirements and how they compare to other

standards

• Learn how a whole building air leakage test is performed

• Appreciate how whole building air leakage principles can be applied to

microclimates


Agenda

• Why Air Leakage?

• 2015 IECC Language

– Compliance Options

• Materials

• Assemblies

• System

• Whole Building Air Leakage Testing

• Test Summary

• Leakage Rates & Existing Codes

• Microclimate Testing


Energy and Operating Costs• Residential and commercial buildings account for

almost 39 percent of total U.S. energy consumption and 38 percent of U.S. carbon dioxide (CO2) emissions

• Building envelope loads:

– Commercial: 34 percent for energy used on site

– Residential: 52 percent of energy used on site

• The building envelope serves as a thermal barrier and plays an important role in determining the amount of energy necessary to maintain a comfortable indoor environment relative to the outside environment.


Energy and Operating Costs

Image courtesy U.S. Energy Information Administration


Energy and Operating Costs

Image courtesy Buildings Energy Data Book http://buildingsdatabook.eren.doe.gov


Percent Annual Energy Savings due to improved building air tightness (Modeling results from Annex 46)

Source Leakage Rate at 0.3 in w.g. (75 Pa)

cfm/ft2

Baseline 1.0

ASHRAE Std 189.1 requirement for air sealing 0.40

Current Army requirement for air sealing 0.25

Proposed requirement for air sealing 0.15

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

1A 2A 2B 3A 3B 3C 4A 4B 4C 5A 5B 6A 6B 7A 8A

Climate Zone

En

erg

y S

av

ing

s

0.4 cfm/ft2

0.25 cfm/ft2

0.15 cfm/ft2

What about Occupant Comfort?

• First year natural gas consumption was relatively low

• Electrical use was relatively high

• Numerous occupant comfort complaints

Leakage Location Matters

Repairs to Create Continuous Air Barrier(But only in accessible areas above ceiling grid)

Repair Results

• Building Air leakage Test-out – Air leakage reduced from 0.43

cfm/ft² to 0.26 cfm/ft². – A 41% reduction!

• Reduced comfort complaints & space heaters

• Discovered / repaired return air imbalances in building which were adding to the stack effect.

• 2012 winter electric usage decreaseddue to reduced electric reheat in winter; increased natural gas usage for overall heating cost savings.

• 2012 summer electrical usage did not increase, even during the hottest summer on record!

Summary - Why Air Barriers?

• Energy conservation– Reduce heating and cooling loads– EPACT 2005 / EISA 2007

• 30% reduction over ASHRAE 90.1-2004 by 2012

• Net zero by 2030 (Executive Order 13514)

• Mechanical System Sizing/Operation– Designing / Modeling Infiltration Loads

• Moisture and mold control– Water vapor transport via air movement – Very costly to remediate– Politically volatile

• Pollutant transport (IAQ)– Example: Warehouse facilities - Fumes

• Microclimate Conditioning• Sound/acoustics

2015 IECC Requirements

Three Options for Compliance1. Materials (C402.5.1.2.1)2. Assemblies (C402.5.1.2.2)3. Whole Building (C402.5)

Air Permeance ≤ 0.004 cfm/ft² at 1.57 psf

Option #1 - Air Barrier Materials

Self-Adhering Bituminous Membrane

Precast & Cast-in-place Concrete

Spray Polyurethane Foam (SPF)

Non-Perforated Building Wraps

Fluid-Applied Waterproofing

Insulated Metal Panels (IMPs)

Exterior / Interior Gypsum Sheathing

What about AB materials at the roof?

• Fully adhered roof membranes (TPO, EPDM, Modified, Built-up, etc.)

And steep slope roofing…

• Fully Adhered Butyl or Modified Asphalt Underlayments

What are NOT Air Barrier Materials?• Expanded polystyrene rigid foam (EPS)

• Building paper and asphalt felt (15#, 30#)

• Spray foam (open cell, low density)

• Some mechanically attached building wraps (check air permeance)

• Perlite board

• Fiberboard

• Fiberglass and cellulose insulation

Option #2 - Air Barrier Assemblies

• Collection of air barrier materials and air barrier components assembled together in a specific manner

• More than air permeance!

• Testing per ASTM E 2357

Air Leakage ≤ 0.04 cfm/ft² at 1.57 psf

Assembly Testing Conditions

Option #3 - Air Barrier Systems

Air Leakage ≤ 0.40 cfm/ft² @ 75 Pa,

Testing per ASTM E 779

• Materials: 0.004 cfm/ft2 @ 1.57 psf

• Assemblies: 0.04 cfm/ft2 @ 1.57 psf

• Whole Bldg: 0.40 cfm/ft2 @ 1.57 psf Pa or other (0.15, 0.25, etc.)

• Comparison: Fenestrations/Curtain Wall– Curtain wall: 0.06 cfm/ft2 @ 300 Pa

– Residential: 0.3 cfm/ft2 @ 300 Pa

– Commercial: 0.3 cfm/ft2 @300 Pa

• Big Picture

Materials � Assemblies � Systems

ASTM E 779ASTM E 2357ASTM E 2178

Compliance Options Summary

Three Options, but what is the most useful metric?

Compliance Options Comparison

AB Material #1

AB Material #2

What’s missing here?


AB Assembly #2

AB Assembly #1

These look a little different than standard

details…


• Whole building air tightness is

the most useful metric!– Provides actual measurement of building

envelope performance

– Allows for location of leaks that may inform

occupant comfort

– Generally improves quality of overall product

So how is testing accomplished?

Whole Building Air Leakage Testing

Prep Measures

Building Testing in “Closed” Condition

• Allowable leakage is 0.40 cfm/ft² of the building envelope.

• “Passing” fan capacity must be supplied to project– Ex: 100,000ft2 envelope x 0.40 cfm/ft2@75 Pa = 40,000

cfm “passing”– Residential blower doors: ~4,000 cfm– High power fans: ~8,000 cfm– Portable truck mount: ~50,000 cfm

• One way and bottleneck limitation with single fan

• Uniformity of interior pressure must be verified throughout building, bias pressures for wind, etc.

• Test to 75-Pa in both directions (pressurization & depressurization)

Fan Capacity Requirements

Equipment Layout/Setup

• Fans set up at exterior doors

• Fans located at points to ensure nearly uniform pressure at the building

Test Data & Reporting

When is the building tested?

2015 IECC - How does it compare?Jurisdiction Source Requirement cfm/ ft2at 75Pa

USA 2015 IECC 0.40 cfm/ft² at 75 Pa 0.40

UK TS-1Commercial

Best Practice

5 m3/h/m2 at 50 Pa 0.36

Germany DIN 4108-2 1.5 1/h at 50 Pa 0.28

USACE/ City of

Fort Collins

Test Protocol / Local

Code Amendments

0.25 cfm/ft² at 75 Pa 0.25

UK TS-1Commercial Tight 2 m3/h/m2 at 50 Pa 0.14

CAN R-2000 1 in2 EqLA @10 Pa /100ft2 0.13

Germany Passive House Std 0.6 1/h at 50 Pa 0.11

How else can we appreciate these numbers?

Microclimate Testing

Differential pressures frequently occur within hospital zones. ERs, ORs, SICU rooms, etc.

Case Study – SICU RoomsBackground:• SICU rooms were not consistently maintaining a negative pressure

• Windows and rooms were suspected to be contributing to pressure

fluctuations

• Window and room air leakage testing requested by client

Case Study – SICU Rooms

1st step – ASTM E 783 testing at windows


Testing revealed that windows

were performing well and not a

substantial source of air leakage.

Case Study – SICU Rooms2nd step – Room Air Leakage

Testing


Rooms were significantly

leaky, even when compared

against conservative results!

Questions?

2015 iecc –whole building air leakage compliance...air tightness (modeling results from annex 46)...

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