NFPA 90A 2002 Revision and Raised Floor Air Distribution

The previous version of NFPA 90A, the 1999 Edition, did not address air diffusers designed for raised floor applications. The standard test method for NFPA compliance was NFPA 255, the NFPA equivalent to ASTM E84, also called the “tunnel test”. This test required a 24 foot sample of product to be tested in a fire tunnel and was not applicable for discrete devices, such as the access floor diffusers.

Titus worked with members of the Technical Committee on Air Conditioning for NFPA 90A to have changes added to reflect the growing need access floor diffusers to meet the standard. The standard was updated and the new 2002 version went into effect on August 8, 2002.

NFPA 90A

The previous version of NFPA 90A required that products used in a raised floor plenum meet NFPA 255, the tunnel test. In the tunnel test, a 20” by 24 foot sample of the product is placed in a 25 foot long tunnel. A fire is started on one end of the tunnel. The flame and smoke spread is measured as it moves down the length of the tunnel.

The flame and smoke spread is compared to a known sample and given a rating. Typical results would be stated as 25 foot flame spread and 50 foot smoke spread, or 25/50. Under the old version of NFPA 90A, a product had to meet 25/50 to be used in a raised floor plenum.

Effective August 8, 2002, the NFPA 90A, 2002 Edition added UL 2043 as the test method for air diffusers designed for raised floor applications. Under section 4.3.10.6.5.6 of the 2002 Edition,

“…discrete products, shall be permitted in the raised floor plenum where listed as having a maximum peak optical density of 0.5 or less, an average optical density of 0.15 or less, and a peak heat release rate of 100 kW or less when tested in accordance with UL 2043, Standard for Safety Fire Test for Heat and Visible Smoke Release for Discrete Products and Their Accessories Installed in Air- Handling Spaces.”

UL 2043

UL 2043 is the Fire Test for Heat and Visible Smoke Release for Discrete Products and Their Accessories Installed in Air-Handling Spaces. The test has been used for speakers and lighting used in ceiling plenums for many years under section 4.3.10.2.6.5, the ceiling cavity section of NFPA 90A.

UL 2043 tests the product over an open flame for ten minutes and determines for the rate of heat release and optical density of the smoke. The standard requires that the peak rate of heat release to be 100kW or less, the peak normalized optical density to be 0.50 or less, and the average normalized optical density to be 0.15 or less.

The addition of UL 2043 to the NFPA 90A raised floor section provides a method to test discrete products, such as access floor diffusers, for fire / smoke compliance to NFPA 90A.