October 30, 2006—As the performance characteristics of strawbale construction are more critically defined through accredited laboratory facilities, it is becoming increasingly viable in mainstream contexts, according to BuildingGreen.com.
New tests of two strawbale wall assemblies under ASTM E119-05a to establish firewall ratings continue that trend: separate one- and two-hour ratings were achieved. A two-hour firewall is required for many applicationssuch as schools and other institutional or commercial buildings—while most residential firewalls require a one-hour rating.
The protocol for ASTM E119-05a, Fire Tests of Building Construction and Materials, involves heating one side of an assembly to a defined time-temperature curve reaching approximately 1,850°F (1,010°C) in 120 minutes, then spraying it with a moving stream of water to test the wall’s post-fire coherence and stability.
In 1993, two other bale wall assemblies were tested to ASTM E-119 standards, though a final report was never produced. An unplastered subject survived for 34 minutes before burn-through at a joint between bales; a second subject plastered with gypsum on the burn side and cement stucco on the other survived the two-hour test with an exterior temperature rise averaging less than 10°F (6°C) over the face.
Details of the tests, including specific assembly details and data points, may be acquired at the Web site of the Ecological Building Network and the Development Center for Appropriate Technology.
Source: BuildingGreen.com
