Building Envelope and Air Barrier Testing

Transcription

1 Building Envelope and Air Barrier Testing BUILD. CONNECT. ACHIEVE. Ed Simpson, CCP, CPMM TESTCOMM, LLC 0 WEBINAR SERIES 2015

2 AIA Quality Assurance The Building Commissioning Association is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. 1

3 Course Description The Air Barrier is an integral part of the building envelope and, according to the IECC and WSEC is an element that must be tested for proper installation and performance. Identifying and understanding how elements and assemblies that make up the building envelope interact; the critical part that the air barrier plays in the building envelope, along with understanding the testing process and responsibilities of the various parties involved in the design, construction and testing, will help deliver a quality building for the Owner and make commissioning of the envelope system much easier for the whole building commissioning authority. 2

4 Learning Objectives Participants will be able to: Identify primary elements and assemblies that make up the air barrier and building envelope in new construction. Identify code requirements and standards that dictate air barrier testing Identify air barrier design elements that enhance building performance, provide occupant comfort and safety, and provide energy savings for the Owner. Identify responsibilities of Architects, Engineers, Contractors, the testing agency and Commissioning Authority for air barrier testing. Identify proper testing techniques so witnessing and validating the air barrier test can be properly accomplished 3

5 Building Enclosure and Air Barrier- Are They The Same? Building enclosure-that thing between the inside and outside of the building that separates conditioned space from the outside environment may include the Air Barrier and other elements, such as façade, vapor barrier, insulation, fenestration (windows and doors), etc., but often used synonymously. 4

6 Air Barrier Testing is not- Full Building Enclosure Commissioning Vapor Barrier testing and commissioning Thermal transferrance testing Sound transferrance testing Beware- codes and specifications often use Air Barrier testing and Building Envelope commissioning interchangeably- Know the difference between all of the activities. 5

7 What s the Dif? Building Envelope- separates the inside from the outside and may include vapor and air barrier elements Air Barrier separates conditioned and unconditioned spaces, either at the building envelope or within a building. Examples: Warehouse building with offices and unheated storage space- air barrier would normally include office space only. Hotel with unheated garage space underneath- Air barrier would consist of hotel space only Bank Branch with unheated attic space- Air barrier would consist of the heated space on main floor only. Air Barriers can also separate conditioned spaces within a building. Hospital with isolation rooms- difference in positive and negative pressures or different uses can require an air barrier 6

8 UNCONDITIONED CONDITIONED UNCONDITIONED 7

9 So, What s this thing called an Air Barrier? Air barriers are a system of assemblies, products, components and details that, when properly installed, prevent or limit the leakage or transport of air and air infiltration into and out of the building envelope or conditioned spaces within a building. An effective air barrier must: Be fully bonded and fully adhered to the substrate to transfer positive and negative wind or air pressure loads to the substrate Provide continuous coverage across varying substrates to assure uninterrupted air barrier protection Feature integrated details across the entire conditioned space Deliver waterproof performance to assure long term durability Offer flexibility in design for varying wall configurations and climatic conditions Not to be confused with the vapor barrier, which may be an element of the building envelope assembly. 8

10 Air Barrier vs. Vapor Barrier- don t get confused Air Barrier- used to stop the movement of air in and out of the conditioned space (water vapor can also be transported by air) Vapor Barrier- used to stop the movement of water vapor through the assembly. VB are installed on the warm side of the insulation in a building assembly. Vapor barrier position determined based on climatic conditions-in warm climates it will be on the exterior; in cold climates- interior Same materials may be used for both vapor and air barriers In warm climates, may be the same component 9

11 Why do we test Air Barriers in Buildings? Continuous air barriers increase energy efficiency, allow for more precise control of building interior conditions and extend building durability. Heating and cooling loss through air barriers result in poor mechanical system operation and additional energy to condition the building. This adds up to additional costs for the owner and can result in premature failure of equipment Uncontrolled air leakage can allow environmental allergens/ pollutants and other airborne contaminants into the building. In heating zones, leakage can cause condensation, ice dams, and failure of building cladding systems. In cooling zones, exterior, warm, moist air can cause condensation on inside and promote mold growth. Properly applied air barriers can prevent the infiltration of moisture laden air through the envelope. Rain and other forms of precipitation can penetrate the building envelope. A properly designed air barrier (exterior) can also provide the primary drainage plane to shed the precipitation. 10

12 Aren t buildings airtight enough already? Simple answer- NO! (according to Department of Energy) In cooler climates, estimated that air leakage is responsible for up to 43% of heating loads in buildings. According to a NEBB survey, in sample of 203 commercial buildings, the average measured air leakage was 1.55 CFM per SF of above grade surface when tested at 0.3 w.g pressure difference. AB SF= H x W of envelope surface, including roof and floor area. Example- H=16 W= 100 for all 4 sides, roof = 100x100, floor 100x100= 6400 SF wall surface SF Roof/floor = SF total x 1.55 CFM Leakage potential = 40,920 CFM air loss in building (the size of a medium/ large sized air handling unit) That means that you would have to supply 40,900 CFM MORE heating and cooling = $ on bottom line over life of the building 11

13 Codes, Regulations and Guidelines, Oh My! 12

14 Lot sa folks tell us what to do IECC define procedures in energy code USACE guidelines to be used for government facilities under their purview NIBS Guideline Exterior Enclosure Technical Requirements for the Commissioning Process AABA- American Air Barrier Association- procedures and guides ASHRAE/IESNA Energy Standards for Buildings ASHRAE Energy Standards for Buildings ASTM E779 - Standard Test Method for Determining Air Leakage Rate by Fan Pressurization ASTM E1185- Standard Practices for Air Leakage Site Detection in Building Envelopes and Air Barrier Systems Seattle Energy Code (Seattle area only) Local Building Code Official option Project Specifications in Division 1 and Division 7 13

15 14 Some requirements for ABT/ BET IECC Requirement has been in effect since 2006 code, originally for buildings 5 stories and above, now for all commercial and multi-family buildings. Target air leakage is 0.40 CFM/ft2 or less at dp of 0.3 w.g (75 pascals) Requires that testing be performed by fan pressurization, depressurization or both Includes requirements for inspection of building envelope before testing Design review includes exterior details such as window, insulation, building wrap, caulking, flashings, etc. by knowledgeable consultant. LEED v4 Enhanced Commissioning Building Envelope testing can be used to get enhanced points along with continuous building monitoring Gov t Agencies (USACE, VA, NAVFAC, GSA,etc.) require air barrier or BET. State codes may require some form of AB verification (CA,CT,DC,GA,IL,MD,MA,MN,MS,NY,OR,RI,WA all have codes that incorporate Air barrier requirements )

16 Enough code stuff-what does it really say? All air barrier penetrations must be sealed, caulked, or gasketed so air doesn t leak Window air leakage must meet requirements in the code table Doors and openings sealed or weather-stripped to meet code, with some exceptions Air intakes, exhaust openings, stairways and shaft vents must have dampers Cargo doors (think loading docks, roll up doors) must have weather seals All building entrances shall have vestibules- doors in and out must have self closing devices and designed so interior and exterior doors are not open at the same time Recessed lighting in the building envelope sealed to limit air movement between inside and outside sealed or gasketed between housing and wall or ceiling. 15

17 What if it doesn t pass? Depends on the jurisdiction you are in some jurisdictions have mandatory provisions, some offer a get out of jail free card. WA State example: Compliance shall be demonstrated by performing a whole building test of the completed building and documenting the results of the test. A final certificate of occupancy shall not be issued for the building or portion thereof, until the building official determines the building, or portion thereof, has been tested in accordance with the WSEC. Get out of jail free card- If the building fails the first test, do practical remedial steps and retest. If the building official says you did what you could, and it still doesn t pass, he can issue the COO. CA example: CA energy Code (Title 24) does not address pass/ fail Cal Green Code- says testing has to be verified by third party Gov t Agencies (USACE/VA, etc.): Spelled out in separate guides or in construction specifications 16

18 Allowable AB Leakage Rates in USA EXAMPLES: USACE/NAVFAC/VA 0.25 CFM/SF IgCC 0.25 CFM/SF IECC-2012/ CFM/SF ASHRAE CFM/SF GSA P CFM/SF ASHRAE CFM/SF Remember, buildings are not static, they are living structures and because of envelope expansion and contraction due to weather conditions, the building breathes. The leakage allowance accounts for this differential. 17

19 Air Barrier Construction 18

20 Ways Air Can Penetrate the Air Barrier and Building Envelope In general, there are two ways for air to penetrate a building- 1) Through cracks or joints, or other openings in the barrier/envelope 2) Through the construction materials (ex.- cinder block walls, filled, open cell styrofoam forms) 19

21 Air is Sneaky- THINK- where can air go in or out Joints around manufactured or site built fenestration and door frames Junctions between walls and foundations, between walls at building corners, between walls and structural floors or roofs, and between walls and roof or roof panels. Openings at penetrations of utility services through envelope Building assemblies used as ducts or plenums Through semi-permeable materials (CMU, Open Cell Styrofoam) Joints, seams and penetrations of vapor retarders Recessed lighting fixtures 20

22 Typical Air Barrier Assemblies/Components-NW In Walls Gyp Board Vapor Barrier Insulation Curtain Walls Fenestration Flashings Sealants/Coatings In Roofs Membranes/ Air or Vapor Barrier Curbs Flashings Sealants and Coatings In Floors Air or Vapor Barrier Insulation Images courtesy of NEBB 21

23 CONSTRUCTION DETAILS MATTER 22

24 APPLICATION INSTRUCTIONS ARE IMPORTANT 23

25 EXAMPLES OF AIR BARRIER MATERIALS 24

26 TEAM MEMBER RESPONSIBILITIES, OR WHO DOES WHAT TO GIT-ER-DONE! 25

27 It Starts With The Owner s OPR and BOD The Owner, through the OPR should specify what is to be included in the air barrier designation. This is especially important where the air barrier is not at the building enclosure (i.e. hospital isolation rooms, buildings with unconditioned spaces, etc.) BOD should provide details on how the air barrier requirements are to be met, including proposed materials for sealing envelope, proposed methods for sealing joints, transitions, etc. between assemblies and elements of air barrier and method of testing to be used in the process. 26

28 Design Team Responsibilities 27 o Arch- Show, detail and specify the air barrier in the construction documents o Arch- Build quality control in the front end so you aren t fixing at the back end ME- takes fresh air requirements into consideration when designing systems and sequences of operation (code required DOAS air handling units) ME - include items like low leakage dampers, minimum penetrations thru the air barrier EE -keeping air barrier penetrations to a minimum, specifying exterior luminaires that have sealing gaskets and may already be rated for leakage.

29 28 General Contractor Since the air barrier testing can occur at any time during the construction schedule when it is determined the air barrier is complete, the GC has many hats to wear. Advance planning- Construction document review, selection of trades, submittal review, required mock up s, field testing, Air Barrier QA/QC, air barrier pretest, troubleshooting, and final testing. Coordinate subcontractor work involving the air barrier system Other support requirements specified in Division 01 and 7 specifications.

30 Air Barrier Test Technician/ BE Consultant Do a pre-test meeting and review all requirements for testing. Provide all test equipment and technical expertise Inspect preparations before testing Conduct test and infrared scan of building Assist in identifying and eliminating sources of air leakage before, during, and after testing Re-test if necessary Prepare a report for the Owner and Building Official 29

31 BECxA- What am I looking at? 30

32 Some other things to look for- Sealing around utility/ mechanical penetrations Sealing around exterior recessed lighting Roof membrane overlap of parapets and flashings Proper flashings at roof penetrations and curbs Caulking and sealing fenestration and transitions Weather stripping and sealing at doors Compare details to actual construction- is it done per plan details and manufacturer s instructions? 31

33 Do we have issues? 32

34 33

35 34

36 35

37 36

38 Air Barrier Testing with Blower Door 37

39 Basic Air Barrier Testing Equipment 38

40 BASIC TEST PROCEDURE EXPLAINED Verify building is ready for testing Setup test equipment Pressurize building and record results Infrared Scan, if necessary, for evaluation De-pressurize building Infrared Scan, if necessary, for evaluation Verify calculations/ results of test If building fails, identify issues or areas that need remediation Prepare report for Owner/ contractor Re-test, if necessary 39

41 Air exfiltration under 0.3 pressure 40

42 41

43 Air Infiltration under 0.3 negative pressure Negative pressurization can detect issues that don t show up under positive pressurization 42

44 So, What did we learn today? 1. Air Barrier Testing is important for energy conservation, indoor air quality and comfort for the occupants of a building. 2. Building envelope, air barrier and vapor barrier are used interchangeably, but are different animals 3. Air is sneaky can get in and out in many ways 4. Lots of ways to skin the cat- or building- to prevent energy losses through the BE/AB 5. Codes/ standards address the issue of air barriers and building envelope testing 6. No two projects are the same. Many people responsible for steps from OPR and design through final testing and occupancy. Time spent on planning, coordination, communication and training can make things easier. 7. Testing agency has multiple methods to perform testing, but it takes COOPERATION and KNOWLEDGE to pull it off. Its Not Magic! 43

45 Questions? Fragen sie bitte? Вопросы? Quel question? Domande? 问题吗? Preguntas? 44

46 Thank You Ed Simpson, CCP, CPMM, LEED AP 45 WEBINAR SERIES