Indoor airPLUS Construction Specifications

• About the Indoor airPLUS Construction Specifications
• How to Qualify a Home for the Indoor airPLUS Label
• Terms Used in This Document
• Indoor airPLUS Verification Checklist
• Indoor airPLUS Construction Specifications
  
  
  1. Moisture Control
     
     
     • Water-Managed Site and Foundation
     • Water-Managed Wall Assemblies
     • Water-Managed Roof Assemblies
     • Interior Water Management
        
  2. Radon Control
  3. Pest Barriers

4. HVAC Systems
   
   
   • Heating and Cooling Equipment
   • Ventilation
   • Air Cleaning and Filtration
   • Dehumidification
      
5. Combustion Pollutant Control
   
   
   • Combustion Source Controls
   • Attached Garage Location
      
6. Low Emission Materials
7. Home Commissioning

• Abbreviations
• References
• Climate Zones Map

• Slope patio slabs, walks and driveways a minimum of ¼ in. per ft. away from house, tamp back-fill to prevent settling, AND slope the final grade away from the foundation at a rate of ½ in. per ft. over a minimum distance of 10 ft. Where setbacks limit space to less than 10 ft., provide swales or drains designed to carry water away from the foundation. Back-fill tamping is not required if proper drainage can be achieved using non-settling compact soils, as determined by a certified hydrologist, soil scientist, or engineer.
   
• Install protected drain tile at the footings of basement and crawlspace walls, level or sloped to discharge to outside grade (daylight) or to a sump pump. The top of each drain tile pipe must always be below the bottom of the concrete slab or crawlspace floor. Each pipe shall be surrounded with at least 6 inches of ½ to ¾ in. washed or clean gravel. The gravel layer shall be fully wrapped with fabric cloth to prevent fouling of the drain tile. If a drain tile discharges to daylight and radon-resistant features are required (see Specification 2.1), install a check valve at the drain tile outfall.
   
• Install a drain or sump in basement and crawlspace floors, discharging to daylight at least 10 ft. outside the foundation or into an approved sewer system. Floor drains are not required for slab-on-grade foundations.

Beneath concrete slabs, including basement floors:

• Install a 4 in. layer of ½ in. diameter or greater clean aggregate, covered with 6 mil (or thicker) polyethylene sheeting, overlapped 6 to 12 in. at the seams, and in direct contact with the concrete slab above; OR
   
• Install a 4 in. uniform layer of sand, overlain with a layer or strips of geotextile drainage matting installed according to the manufacturer’s instructions, and covered with polyethylene sheeting overlapped 6 to 12 in. at the seams.

Crawlspace floors:

• Cover crawlspace floors with a concrete slab over 6 mil (or thicker) polyethylene sheeting overlapped 6 to 12 in. at the seams; OR
   
• Cover crawlspace floors with 6 mil polyethylene (10 mil recommended) sheeting, overlapped 6 to 12 in. and sealed or taped at the seams and penetrations. The sheeting shall be attached to walls and piers with adhesive and furring strips.

Exceptions:

• In areas of free-draining soils — identified as Group 1 by a certified hydrologist, soil scientist, or engineer through a site visit — a gravel layer or geotextile matting is not required under concrete slabs.
   
• Polyethylene sheeting is not required in Dry (B) climates, as defined by IECC Figure 301.1, unless the sheeting is required for radon resistance (see Specification 2.1).

• Poured concrete, concrete masonry, and insulated concrete forms (ICFs) shall be finished with a damp-proof coating; AND
   
• Wood-framed walls shall be finished with trowel-on mastic and polyethylene, or with other waterproofing demonstrated to be equivalent.

Exceptions:
Houses without below-grade walls.

• Insulate crawlspace and basement perimeter walls according to IRC Table N1102.1 or IECC Table 402.1.1 (also see Specification 1.12); AND
   
• Seal crawlspace and basement perimeter walls to prevent outside air infiltration; AND
   
• Provide conditioned air at a rate not less than 1 cfm per 50 s.f. of horizontal floor area. If radon-resistant features are required (see Specification 2.1), do not install exhaust ventilation, as described in IRC section R408.3.2.1.

Exceptions:

• Homes built in areas designated as flood zones (conditioned crawlspaces are not recommended for use in flood zones).
   
• Raised pier foundation with no walls.
   
• Dry climates, as defined by IECC Figure 301.1.
   
• Marine climates, as defined by IECC Figure 301.1, if no air handler or return ducts are installed in the crawlspace.

Note:
In each of the preceding exceptions, floors above unconditioned spaces shall be insulated to the IECC-specified R-value and sealed to prevent air infiltration.

• Monolithic weather-resistant barriers (i.e., house wrap), shingled at horizontal joints and sealed or taped at all joints; OR
   
• Weather-resistant sheathings (e.g., faced rigid insulation), fully taped at all “butt” joints; OR
   
• Lapped shingle-style building paper or felt.

Note:
Include weep holes for masonry veneer and weep screed for stucco cladding systems, according to the manufacturer’s specifications.

Exception:
Dry climates, as shown in IECC Figure 301.1.

Exception:
Dry climates, as shown in IECC Figure 301.1.

Exception:
Climate Zones 1 to 4, as shown in IECC Figure 301.1.

• Install water-resistant hard-surface flooring in kitchens, bathrooms, entryways, laundry areas, and utility rooms. Do not install wall-to-wall carpet adjacent to toilets and bathing fixtures (i.e., tubs and showers).
   
• Install moisture-resistant backing material (i.e., cement board or the equivalent, but not paper-faced wall board) behind tub and shower enclosures.
   
• Install all condensate discharge according to IRC section M1411.3.
   
• Insulate piping installed in exterior walls.

Advisory:
Lumber should not exceed 18% moisture content.

• Capillary break installed according to Specification 1.2; AND
   
• A 3 or 4 in. diameter gas-tight vertical vent pipe, clearly labeled “Radon Pipe” or “Radon System,” connected to an open T-fitting in the aggregate layer (or connected to geotextile drainage matting according to the manufacturer’s instructions) beneath the polyethylene sheeting, extending up through the conditioned spaces and terminating a minimum of 12 in. above the roof opening. For crawlspaces, install at least 5 ft. of horizontal perforated drain tile on either side of the T-fitting, attached to the vertical radon vent pipe beneath the sheeting and running parallel to the long dimension of the house; AND
   
• Radon fan installed in the attic (i.e., an active system) OR an electrical receptacle installed in an accessible attic location near the radon vent pipe (i.e., a passive system) to facilitate future fan installation if needed; AND
   
• Foundation air sealing with polyurethane caulk or the equivalent at all slab openings, penetrations, and control or expansion joints. Sump covers also shall be air sealed (e.g., mechanically attached with full gasket seal or equivalent.)

Exception:
The Indoor airPLUS Construction Specifications recommend, but do not require, radon-resistant features for homes built in EPA Radon Zones 2 and 3 unless required by local building codes (see Advisory 1).

Advisories:

1. Elevated levels of radon have been found in homes built in all three zones on EPA’s Map of Radon Zones. Consult your state’s radon coordinator for current information about radon in your area. Go to www.epa.gov/radon/whereyoulive.html and click on your state for contact information.
    
2. If soil or groundwater contamination is suspected on or near the building site (e.g., former industrial sites), volatile contaminants or breakdown products may pose an IAQ risk through soil gas intrusion. In such cases, EPA recommends radon-resistant features consistent with Specification 2.1, which can prevent the intrusion of soil vapor into a house. See the EPA Vapor Intrusion Primer or ASTM E2600 for more information, or consult your state or tribal Brownfield voluntary cleanup program or environmental regulatory agency for information on the risks of vapor intrusion in your area.

Advisory:
The U.S. Surgeon General and EPA recommend that all homes (including homes built in Radon Zone 3) be tested for radon. Refer interested buyers to www.epa.gov/radon for more information.

Advisories:

1. Additional precautions should be taken in areas of “Heavy” termite infestation probability (as identified by IRC Figure 301.2[6]) as follows:
   
   
   • Foundation walls should be solid concrete or masonry with a top course of solid block, bond beam, or concrete-filled block; AND
   • Interior concrete slabs should be constructed with 6 x 6 in. welded wire fabric or the equivalent, and concrete walls should be constructed with reinforcing rods to reduce cracking; AND
   • Sill plates should be made of preservative-treated wood.
      
2. The following additional precautions should be taken in areas of “Very Heavy” termite infestation probability (as identified by IRC Figure 301.2[6]) i.e., Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina, and parts of California and Texas:
   
   Below-grade:
   
   
   • Foam plastic insulation should not be installed on the exterior face of below-grade foundation walls or under slabs.
      
   Above-grade:
   
   
   • Foam plastic insulation installed on the exterior of above-grade foundation walls should be kept a minimum of 6 in. above the final grade and any landscape bedding materials, and should be covered with moisture-resistant, pest-proof material (e.g., fiber cement board or galvanized insect screen at the bottom-edge of openings).
   • Foam plastic insulation applied to the interior side of conditioned crawlspace walls should be kept a minimum of 3 in. below the sill plate.

• Documentation of design load calculations (i.e., load calculation worksheet or software report), AND
   
• System design documentation (i.e., sizing calculations and equipment performance information), AND
   
• Verification that outdoor and indoor coils match in accordance with the AHRI Directory of Certified Product Performance. For more information, see www.ahridirectory.org

• Design verified by appropriate documentation (i.e., duct-sizing worksheet or annotated layout), AND
   
• Duct system verified to meet the following additional requirements:
  
  
  • Seams in the HVAC cabinet, plenum, and adjacent ductwork shall be sealed with mastic systems, tape that meets the applicable requirements of UL 181A or UL 181B, or gasket systems.
  • Building cavities shall not be used as part of the forced air supply or return systems.
     
• Duct openings shall either be covered during construction or vacuumed out thoroughly prior to installing registers, grilles, and diffusers (see Specification 7.1).

Performance Test Alternative:

• Room-by-room airflows balanced and verified within +/-20% of calculated room airflows to meet design loads (see Specification 4.1), except for baths, closets, and pantries, AND
   
• Duct system TOTAL leakage test no greater than 6 cfm per 100 s.f. of floor area (or 9% design fan flow), measured at 25 Pa, with duct boots and air handler in place, according to ASTM E1554, ASHRAE 152, or other RESNET-approved method.

Note:
Ducts and equipment may be located in framing spaces or building cavities adjacent to garage walls or ceilings if they are separated from the garage space with a continuous air barrier (see ENERGY STAR Thermal Bypass Checklist Guide).

Performance Test Alternative:
Measured pressure differential no greater than 3 Pa (0.012 in. w.c.) between closed rooms and adjacent spaces that have a return.

• Whole house mechanical ventilation system & controls shall be installed to deliver the prescribed outdoor air ventilation rate (ASHRAE 62.2 section 4), including ventilation restrictions in ASHRAE 62.2 section 4.5 (e.g., not greater than 7.5 cfm/100 s.f. in “Warm-Humid” climates as defined by IECC Figure 301.1); AND
   
• Transfer air (i.e., air from adjacent dwelling units or other spaces such as garages, crawlspaces, or attics) shall not be used to meet ventilation requirements (ASHRAE 62.2 section 6.1); AND
   
• Outdoor air inlets shall be located a minimum of 10 ft. from contaminant sources (ASHRAE 62.2 section 6.8); AND
   
• Airflow shall be tested to meet rated fan airflow (at 0.25 in. w.c.) OR verify duct(s) sized according to the requirements of ASHRAE 62.2 Table 7.1 and the manufacturer’s design criteria (ASHRAE 62.2 section 7.3).

Note:
Outdoor air ducts connected to the return side of an air handler shall be permitted as supply ventilation only if the manufacturers’ requirements for return air temperature are met (e.g., most manufacturers recommend a minimum of 60 °F air flow across furnace heat exchangers).

• Provide local mechanical exhaust ventilation to the outdoors in each bathroom and kitchen, meeting ASHRAE 62.2 section 5 requirements. In addition, all bathroom ventilation fans shall be ENERGY STAR qualified unless multiple bathrooms are exhausted with a multi-port fan.
   
• Conventional clothes dryers shall be vented to the outdoors. Electric condensing dryers are not vented and shall be plumbed to a drain according to the manufacturer’s instructions.
   
• If a central vacuum system is installed, the system shall be vented outdoors at least 10 ft. from the ventilation system air inlets (see Specification 4.5), or the power/filtration unit shall be installed in the garage according to the manufacturer’s instructions.

• HVAC filters shall be rated MERV 8 or higher according to ASHRAE 52.2 (at approximately 295 fpm).
   
• There shall be no visible bypass between the filter and the filter rack.
   
• The filter access panel shall include gasket material or comparable sealing mechanism to prevent air leakage, and it shall fit snugly against the exposed edge of the installed filter when closed to prevent bypass.
   
• No air-cleaning equipment designed to produce ozone (i.e., ozone generators) shall be installed.

Advisory:
Filters perform best when the filter rack design includes the following features, which are also included in some manufacturers’ filter media boxes:

• Flexible, air-tight (e.g., closed-cell foam) gasket material on the surface that contacts the air-leaving (downstream) side of the filter, AND
• Friction fit or spring clips installed on the upstream side of the filter to hold it firmly in place.

• Additional dehumidification system(s), OR
   
• A central HVAC system equipped with additional controls to operate in dehumidification mode.

Exception:
Climate Zones 4-8, 3B, 3C, and the portions of 3A and 2B above the white line as shown by IECC Figure 301.1.

Advisory:
Although not required to meet this specification, independent dehumidification is recommended in Climate Zones 4A and 3A above the white line as shown in IECC Figure 301.1.

• Gas-fired furnaces/boilers shall be direct vented, except in Climate Zones 1-3 as shown in IECC Figure 301.1.
   
• Oil-fired furnaces/boilers shall be power vented or direct vented, except in Climate Zones 1-3 as shown in IECC Figure 301.1.
   
• Combustion water heaters shall be power vented or direct vented.
   
• No unvented combustion space-heating appliances shall be permitted.

Exception:
Houses with no combustion heating equipment located in conditioned spaces.

Note:
Unfinished basements and crawlspaces (except raised pier foundations with no walls) and attached garages that are air-sealed to the outside and intended for use as work space or living space, are considered “conditioned spaces” for the purpose of this requirement.

• Masonry fireplaces are not permitted, with the exception of “masonry heaters” as defined by ASTM E1602 and section 2112.1 of the International Building Code (i.e., fireplaces engineered to store and release substantial portions of heat generated from a rapid burn).
   
• Factory-built, wood-burning fireplaces shall meet the certification requirements of UL 127 and emission limits found in the EPA Standard for New Residential Wood Heaters.
Natural gas and propane fireplaces shall be power vented or direct vented, as defined by NFPA 54, section 3.3.108, have a permanently affixed glass front or gasketed door, and comply with ANSI Z21.88/CSA 2.33.
 
• Wood stove and fireplace inserts as defined in section 3.8 of UL 1482 shall meet the certification requirements of that standard, and they shall meet the emission requirements of the EPA Standards for New Residential Wood Heaters and WAC 173-433-100 (3).
   
• Pellet stoves shall meet the requirements of ASTM E1509.
   
• Decorative gas logs as defined in K.1.11 of NFPA 54 (National Fuel Gas Code) are not permitted.
   
• Unvented combustion space-heating appliances are not permitted.

Advisory:
To minimize the potential for spillage or back-drafting, fireplaces and fuel-burning appliances located in conditioned spaces should be installed in compliance with ASHRAE 62.2 (section 6.4) or by conducting a Worst Case Depressurization Combustion Air Zone (CAZ) Test according to an established protocol.

• Prohibiting smoking in indoor common areas, specified explicitly in building rental/lease agreements or condo/co-op association covenants and restrictions, AND
   
• Locating designated outdoor smoking areas a minimum of 25 ft. from entries, outdoor air intakes, and operable windows, AND
   
• Minimizing uncontrolled pathways for ETS transfer between individual dwelling units by sealing penetrations in the walls, ceilings, and floors of dwelling units, sealing vertical chases adjacent to dwelling units, and applying weather stripping to all doors in dwelling units leading to common hallways.

• Common walls and ceilings between attached garages and living spaces shall be visually inspected to ensure they are air-sealed before insulation is installed.
   
• All connecting doors between living spaces and attached garages shall include an automatic closer, and they shall be installed with gasket material or be made substantially air-tight with weather stripping.

Advisory:
ENERGY STAR qualified fans are highly recommended.

• Structural plywood and OSB shall be certified compliant with PS1 or PS2, as appropriate, and shall be made with moisture-resistant adhesives as indicated by “Exposure 1” or “Exterior” on the American Plywood Association (APA) trademark.
   
• Hardwood plywood shall be certified compliant with the formaldehyde emissions requirements of ANSI/HPVA HP-1-2004 and U.S. HUD Title 24, Part 3280, OR certified compliant with CA Title 17.
   
• Particleboard and MDF shall be certified compliant with the formaldehyde emissions requirements of ANSI A208.1 and A208.2, respectively, and U.S. HUD Title 24, Part 3280, OR certified compliant with EPPS CPA 3-08 by the CPA Grademark certification program, OR certified compliant with CA Title 17.
   
• Cabinetry shall be made with component materials that are certified to comply with all the appropriate standards above OR shall be registered brands or produced in registered plants certified under KCMA’s Environmental Stewardship Certification Program (ESP 01-06).

Note:
In California, composite wood products shall be certified compliant with CA Title 17 as appropriate.

• Green Seal Standard GS-11, OR
   
• Greenguard Certification for Paints and Coatings, OR
   
• Scientific Certification Systems (SCS) Standard EC-10.2-2007, Indoor Advantage Gold, OR
   
• Master Painters Institute (MPI) Green Performance Standards GPS-1 or GPS-2, OR
   
• A third-party low-emitting product list based on CA Section 01350, e.g., the CHPS List at www.chps.net/manual/lem_table.htm

• Inspect ductwork before installing registers, grilles, and diffusers to verify it is dry and substantially free of dust or debris, and that there are no disconnects or visible air gaps between boots and framed openings. If duct openings were not covered during construction, thoroughly vacuum out each opening prior to installing registers, grilles, and diffusers.
   
• Inspect air-handling equipment and verify that heat exchangers/coils are free of dust caused by construction activities (e.g., drywall, floor sanding) AND the filter is new, clts specified MERV rating (see Specification 4.7). After installation of registers, grilles, and diffusers, verify detectable airflow from each supply outlet.
   
• Verify the HVAC contractor has documented measured airflow or pressure drop across the cooling coil or heat exchanger within +/- 15% of system design airflow, or the manufacturer-specified operating range, tested according to ASTM E1554, ASHRAE 152, or an equivalent method.
   
• Verify the HVAC contractor has documented the installation and testing of proper refrigerant charge. This requirement may be met by any of the following methods according to ACCA 5 QI-2007:
  
  
  • Superheat method test measurement within 5% of the manufacturer-recommended charge, OR
  • Subcooling method test measurement within 3% of the manufacturer-recommended charge, OR
  • Other equivalent method/tolerance approved by the equipment manufacturer.

Note:
If weather conditions do not meet required test conditions, verify that the builder or contractor has arranged for future testing.

• A copy of the Indoor airPLUS verification checklist or other written documentation indicating compliance with all required measures from the Indoor airPLUS construction specifications, signed by an official representative of the builder, AND
   
• HVAC, duct, and ventilation system design documentation (i.e., airflow requirements) or performance test results (i.e., measured cfm) required by Specifications 4.1, 4.2, and 4.5, respectively, and a description of the ventilation system (i.e., system type, components, and controls), AND
   
• Operations and maintenance instruction manuals for all installed equipment and systems addressed by Indoor airPLUS requirements, including HVAC systems and accessories, combustion appliances, and radon system literature and test kit instructions.