NFPA 318

Standard for the Protection of Cleanrooms 2015 Edition

Origin and Development of NFPA 318

The committee on Cleanrooms was formed in 1988 and held its first meeting during May of that year. The Committee was organized into chapter subcommittees that separately prepared indi­vidual chapters and related appendix material for review by the full Committee at meetings held October 1988, March 1989, September 1989, March 1990, September 1990 and June 1991.

The standard was submitted and adopted at the Fall Meeting in Montreal, in1991. The 1992 edition was the first edition of this standard.

The 2015 edition has been completely reorganized in an effort to make the standard more user friendly.

ATS FXP™ complies with the following paragraphs of NFPA 318: Interior automatic sprinklers shall not be required where ducts are approved for use without internal automatic sprinklers.

9.3.4 Exhaust ducts penetrating fire resistance–rated construction shall be contained in an enclosure of equivalent fire-resistive construction. Fire resistance construction and enclosures with equivalent fire- resistive construction shall extend 1.8m(6 ft) or a distance equivalent to two times the duct diameter, whichever is greater, on either side of the rated construction.

9.3.5 Fire dampers shall not be installed in exhaust ducts.

9.3.6* Exhaust duct systems shall be constructed of noncombustible materials, an approved or listed duct system for use
without internal sprinklers, or protected with sprinklers in accordance with Chapter 11. Ductwork directly connected to equipment that does not process flammable or combustible liquids or flammable gases, and where the equipment is constructed of noncombustible materials or materials listed as meeting the requirements ofANSI/UL2360 orANSI/FM 4910, shall be permitted to be completed using ductwork that is constructed of materials listed as meeting the requirements of ANSI/UL 2360 or ANSI/FM 4910, provided the hook-up duct does not exceed 16.4 ft (5 m) and is connected directly to a duct that complies with 9.3.6. Ductwork meeting the requirements of shall not require internal sprinklers.

9.3.8 The interior and exterior surface of nonmetallic exhaust ducts shall have a flame spread index of 25 or less, and the exterior surface of nonmetallic exhaust ducts shall have a smoke-developed index of 25 or less when the interior or exterior of the duct is exposed to fire when tested in accordance with ASTM E 84, Standard Test Method for Surface Burning Characteristics of Building Materials, or ANSI/UL 723, Standard for Test for Surface Burning Characteristics of Burning Materials.

Reprinted with permission from NFPA 318, Protection of Cleanrooms, Copyright© 2000, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire Protection Association, on the referenced subject which is represented only by the standard in its entirety.


Factory Mutual, NBS PS 15-69, ASTM, NFPA, SMACNA


ATS 4922 FireSafe™ Duct is listed in the “FM Approvals Guide” for installation without internal sprinkler protection and for use inside cleanrooms. This listing is based on horizontal and vertical fire tests performed on
the duct to the FM 4922 Standard where criteria to meet the standard is as follows:

Also, ATS FXP™ meets the test protocol for SPI and FPI (smoke and flame propagation indices) according to FM 4910
Standard for Cleanroom Materials.
If the product you are considering is FM 4910 approved but NOT FM 4922-approved, FM’s written position is as

NFPA 318 – Protection of Cleanrooms

ATS 4922 FireSafe™ Duct meets the NFPA 318 as follows:

ATS also meets the following standards for manufacturing fiberglass reinforced plastic duct/pipe:

The Significance of the NBS PS 15-69 Standard

The NBS PS 15-69, although now a defunct standard, is still a good guide for sound practices for composite manufacture. ATS FXPTM ducts meet or exceed requirements by NBS PS 15-69 for physical strength and quality. (Note: NBS PS 15-69 standard does not concern itself with fire safety.)