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IECC BUILDING CODE ENERGY EFFICIENCY & AIR TIGHTNESS TESTING (2018 IECC SECTION 406)
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Third Party Energy Efficiency Inspection Services Energy Rating Index ERI (IRC,IBC & IECC Protocol)
BUILDING LEAKAGE (DUCT & ENVELOPE )
Leaky houses have their own set of problems ranging from drafts, blistering paint, ice dams and frozen pipes to a house that won’t adequately heat or cool. While in the past airsealing efforts concentrated on the easy to find air leaks around windows and door, we now know that the most important leaks in a house are the hard to find leaks in the attic, crawlspace, attached garage and other framing connections. These hidden leaks are responsible for most of the air leakage in typical houses, and are often the cause of performance and durability problems.
And whether a house is tight or loose, nothing will cause it to deteriorate faster than moisture migration and condensation in attics, ceiling and other building cavities. Vapor barriers will stop moisture diffusion, but most moisture problems in buildings are a result of uncontrolled air leakage through the building envelope. And the way most vapor barriers are installed, they do little or nothing to stop uncontrolled air leakage. In many buildings, moisture problems are made worse by the common use of hot tubs, whirlpools and saunas.
BUILDING CODE AIR TIGHTNESS PROTOCOL
2018 I-Code references: IRC N1102.4.1.2, IECC R402.4.1.2
This testing is a mandatory requirement (all residential energy code compliance paths) for new attached (SFA) and detached single family dwellings. SFA dwellings include duplexes, triplexes, townhomes and row-houses where each dwelling unit extends from foundation to roof or ceiling.
Testing Protocol
• A multi-point air tightness test shall be conducted based on the ANSI/Residential Energy Services Network (ANSI/RESNET)/ICC 380 or RESNET Standard 800, Section 802, Procedures For Building Enclosure Air Tightness Testing.
• A multi-point air tightness test shall be conducted, per Section 802.6. Compliance requirement The building air change rate at 50 Pascal test pressure (ACH50) shall not exceed 3.0 ACH50 for either gas or electric heated homes.
Submittal requirement
Output from blower-door testing / analysis software showing, at minimum, the following information:
• Building address
• Date of test
• Technician and company conducting the test
• Building volume (cubic feet)
• Building leakage rate at 50 Pascal test pressure (corrected CFM50)
• Percent uncertainty in the corrected CFM50, at the 95% confidence level (+/- 5%)* • Building air change rate at 50 Pascal test pressure (ACH50 = CFM50 x 60 / Volume) The Tester must be identified on the software report. This information may be hand-written on the software output.
* If uncertainty exceeds this limit, use Section 802.8.1 to calculate “Adjusted CFM50.” Calculate “Adjusted ACH50” = (Adjusted CFM50 x 60)/Volume and write this value on software report.
BLOWER DOOR TESTING
The easiest way to measure building airtightness is with a diagnostic tool called a blower door. The blower door consists of a powerful, calibrated fan that is temporarily sealed into an exterior doorway.
The fan blows air out of the house to create a slight pressure difference between inside and outside. This pressure difference forces air through all holes and penetrations in the building envelope. Blower door tests are typically performed at a pressure difference of 50 Pa (0.2 inches of water column).
By simultaneously measuring the air flow through the fan and its effect on the air pressure in the building, the blower door system measures the airtightness of the entire building envelope. The tighter the building (e.g. fewer holes), the less air you need from the blower door fan to create a change in building pressure.