Rigid foams behave differently from one another during a fire, as shown in testing under ASTM E84, Standard Test Method for Surface
Burning Characteristics of Building Materials. As the rcs data evaluated samples are mounted in the ceiling position, this test is not indicative of performance in wall assemblies, but as acknowledged in Section “
Decentralized sound masking
in the mid-1970s to address the problem of large zone size.
Rather than place sound generation, volume, and frequency control in a central location, the electronics required for
these functions are integrated into ‘master’ loudspeakers,
which are distributed throughout the facility—hence the ‘decentralized’ name.
Each ‘master’ is connected to up to two ‘satellite’ loudspeakers, which repeat its settings. Therefore,
a decentralized system’s zones are only one to
three about goldman sachs 10,000 small businesses loudspeakers in size (i.e. 30 to 62 m2 [225 to 675 sf]). This distributed design inherently controls ‘phasing.’ Additionally,
because each small zone offers fine volume control, local variations can be addressed, allowing more consistent and effective masking levels to be achieved across a facility.
However, there are still limits to the adjustments that can be made
with respect to frequency, which, in turn, impacts performance.
The purpose of this test method is to determine the relative burning behavior of the material by observing the flame spread along the specimen.”
Polyiso insulations are available in both Class A (flame spread <25) and Class B (flame spread <75),
while most EPS and XPS products are
Class A. EPS and XPS have ASTM E84 values <25 because trust review they melt and no longer remain in the test position. (See “Fire Resistance Properties of
Polyiso Foam Plastic Insulation Used in Wall Assemblies” at This is acknowledged in ASTM E84 S
flame spread indices that do not relate directly to indices obtained by testing materials that remain in place.