2015 IECC Whole Building Air Leakage Compliance

Transcription

1 2015 IECC Whole Building Air Leakage Compliance Presented by: Jeffrey Crowe, PE Project Manager September 2012

2 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 2012

3 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 2012

4 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 (CO 2 ) 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 2012

5 Energy and Operating Costs Image courtesy U.S. Energy Information Administration September 2012

6 Energy and Operating Costs Image courtesy Buildings Energy Data Book September 2012

7 Percent Annual Energy Savings due to improved building air tightness (Modeling results from Annex 46) 50% 45% Energy Savings 40% 35% 30% 25% 20% 0.4 cfm/ft cfm/ft cfm/ft2 15% 10% 5% 0% 1A 2A 2B 3A 3B 3C 4A 4B 4C 5A 5B 6A 6B 7A 8A Climate Zone Source Leakage Rate at 0.3 in w.g. (75 Pa) cfm/ft 2 Baseline 1.0 ASHRAE Std requirement for air sealing 0.40 Current Army requirement for air sealing 0.25 Proposed requirement for air sealing September 2012

8 What about Occupant Comfort? First year natural gas consumption was relatively low Electrical use was relatively high Numerous occupant comfort complaints

9 Leakage Location Matters

10 Repairs to CreateContinuous Air Barrier (But only in accessible areas above ceiling grid)

11 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 winter electric usage decreased due to reduced electric reheat in winter; increased natural gas usage for overall heating cost savings summer electrical usage did not increase, even during the hottest summer on record!

12 Summary -Why Air Barriers? Energy conservation Reduce heating and cooling loads EPACT 2005 / EISA % reduction over ASHRAE 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

13 2015 IECC Requirements Three Options for Compliance 1. Materials (C ) 2. Assemblies (C ) 3. Whole Building (C402.5)

14 Option #1 -Air Barrier Materials Air Permeance cfm/ft² at 1.57 psf

15 Self-Adhering Bituminous Membrane

16 Precast & Cast-in-place Concrete

17 Spray Polyurethane Foam (SPF)

18 Non-Perforated Building Wraps

19 Fluid-Applied Waterproofing

20 Insulated Metal Panels (IMPs)

21 Exterior / Interior Gypsum Sheathing

22 What about AB materials at the roof? Fully adhered roof membranes (TPO, EPDM, Modified, Built-up, etc.)

23 And steep slope roofing Fully Adhered Butyl or Modified Asphalt Underlayments

24 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

25 Option #2 -Air Barrier Assemblies Air Leakage 0.04 cfm/ft² at 1.57 psf Collection of air barrier materials and air barrier components assembled together in a specific manner More than air permeance! Testing per ASTM E 2357

26 Assembly Testing Conditions

27 Option #3 -Air Barrier Systems Air Leakage Pa, Testing per ASTM E 779

28 Compliance Options Summary Big Picture Materials Assemblies Systems ASTM E 2178 ASTM E 2357 ASTM E 779 Materials: cfm/ft 1.57 psf Assemblies: 0.04 cfm/ft 1.57 psf Whole Bldg: 0.40 cfm/ft 1.57 psf Pa or other (0.15, 0.25, etc.) Comparison: Fenestrations/Curtain Wall Curtain wall: 0.06 cfm/ft 300 Pa Residential: 0.3 cfm/ft 300 Pa Commercial: 0.3 cfm/ft Pa Three Options, but what is the most useful metric?

29 Compliance Options Comparison AB Material #2 AB Material #1 What s missing here?

30 Compliance Options Comparison AB Assembly #2 AB Assembly #1 These look a little different than standard details

31 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?

32 Whole Building Air Leakage Testing Prep Measures

33 Building Testing in Closed Condition

34 Fan Capacity Requirements Allowable leakage is 0.40 cfm/ft² of the building envelope. Passing fan capacity must be supplied to project Ex: 100,000ft 2 envelope x 0.40 cfm/ft 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)

35 Equipment Layout/Setup Fans set up at exterior doors Fans located at points to ensure nearly uniform pressure at the building

36 Test Data & Reporting

37 Test Data & Reporting

38 When is the building tested?

39 2015 IECC -How does it compare? Jurisdiction Source Requirement cfm/ ft 2 at 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 /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 in 2 Pa /100ft Germany Passive House Std 0.6 1/h at 50 Pa 0.11 How else can we appreciate these numbers?

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

41 Case Study SICU Rooms Background: 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

42 Case Study SICU Rooms 1 st step ASTM E 783 testing at windows

43 Case Study SICU Rooms Testing revealed that windows were performing well and not a substantial source of air leakage.

44 Case Study SICU Rooms 2 nd step Room Air Leakage Testing

45 Case Study SICU Rooms

46 Case Study SICU Rooms Rooms were significantly leaky, even when compared against conservative results!

47 Case Study SICU Rooms

48 Case Study SICU Rooms

49 Questions?