ASTM E 2357: Air Leakage Testing for the Real World

Diagram of specimen wall for testing air barrier assembly performance, as specified in ASTM E 2357.

The standard also defines a specific test procedure. The wall specimen is mounted in a well-sealed test chamber with an air supply that allows application and measurement of both positive and negative air pressure differentials across the wall structure in three stages:

• Sustained Load - 600 Pa (12.5 psf), equivalent to a 70 mph wind speed for 1 hour.
• 2000 Cyclic Loads - 800 Pa (16.7 psf), equivalent to an 81 mph wind speed for 3 seconds each.
• Wind Gusts - 1200 Pa (25 psf), equivalent to a 99 mph wind speed for 3 seconds.

These stages are intended to simulate air pressures typically experienced by buildings, including: stack pressure (difference in pressure between the bottom and top of the air column), wind pressure (creating positive pressure on one side of the building and negative pressure on the other), and fan pressure (created by HVAC or fan systems within the building).

Following each stage, the air leakage rate-or air permeance-of the wall assembly Is measured at pressure differentials of 25, 50, 75, 100, 150, 250 and 300 Pa; the calculated leakage at 75Pa is reported. Air barrier deflection is then measured. To comply with the International Energy Conservation Code (IECC), the air barrier assembly may not exhibit air permeance greater than 0.2 liters per second/square meter at 75 Pa pressure (0.04 cfm/ft. at 1.57 lb/ft).

Compliance

ASTM E 2357 has been adopted by the Air Barrier Association of America (ABAA) as a key element of its acceptance criteria. As noted, the data generated by this standard test method is important to verify an air barrier assembly's compliance with the IECC, a critical consideration given today's focus on energy efficiency.

Have questions about building envelope testing?