2015 iecc –whole building air leakage...
TRANSCRIPT
©September 2012www.becx.comwww.pieglobal.com
2015 IECC – Whole Building Air
Leakage Compliance
• Presented by:
Jeffrey Crowe, PEProject Manager
©September 2012www.becx.comwww.pieglobal.com
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
©September 2012www.becx.comwww.pieglobal.com
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
©September 2012www.becx.comwww.pieglobal.com
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.
©September 2012www.becx.comwww.pieglobal.com
Energy and Operating Costs
Image courtesy U.S. Energy Information Administration
©September 2012www.becx.comwww.pieglobal.com
Energy and Operating Costs
Image courtesy Buildings Energy Data Book http://buildingsdatabook.eren.doe.gov
©September 2012www.becx.comwww.pieglobal.com
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
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)
What about AB materials at the roof?
• Fully adhered roof membranes (TPO, EPDM, Modified, Built-up, etc.)
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
• 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 Assembly #2
AB Assembly #1
These look a little different than standard
details…
Compliance Options Comparison
• 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?
• 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
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
Testing revealed that windows
were performing well and not a
substantial source of air leakage.
Case Study – SICU Rooms
Rooms were significantly
leaky, even when compared
against conservative results!