Small Filter Plenums

DOE-STD-1066-99

14.3.2 Final Filter Plenums Located in Separate Building

14.3.2.1 Separate buildings which house filter plenums should be of minimum 2-hour

fire rated construction when located less than 5 feet (1.5 meters) from an

adjacent building.

14.3.2.2 Filter plenum housing should be a minimum of 1-hour fire rated construction

when located more than 5 feet (1.5 meters), but not more than 20 feet (6.1

meters) from an adjacent building.

14.3.2.3 Filter plenum housing located greater than 20 feet (6.1 meters) from an

adjacent noncombustible building may be of unprotected noncombustible

construction provided that no unprotected openings occur in the adjacent

building.

14.3.2.4 Filter plenum housings need not be fire-rated or separated from an adjacent

building if the adjacent building wall is of minimum 2-hour fire-rated

construction with no unprotected openings.

14.3.3 Filter Plenums Located Near Combustible/Flammable Liquids

Filter plenums located near combustible or flammable liquid storage buildings or tanks should

be located not less than 50 feet away from the buildings or tanks and be housed in minimum

2-hour fire rated construction.

14.3.4 Small Filter Plenums

Small filter plenums that serve as a final filter and have a leading surface area of 16 square

feet (1.4 square meters) or less need not be separated by fire rated construction from other

parts of a building or be located in a separate fire rated enclosure if the filter plenum is

located in a building provided with an automatic fire sprinkler system, designed and installed

in accordance with NFPA 13, and the filter plenum is provided with an automatic water spray

system as described herein.

14.3.5 Existing Plenums

Plenums that have already been built and are in service before issuance of these guidelines

are not required to be upgraded with a fire-rated enclosure or minimum separation distance

unless there is a significant hazard that endangers building occupants, the public, or the

environment, as determined by an FHA per DOE Orders or is required by the AHJ.

14.4 Protection of Openings in Fire Rated Construction

Fire protection features should be designed to maintain the integrity of containment systems

as reflected in the SAR.

14.4.1 Ratings for Doors

14.4.1.1 Door openings into 2-hour rated filter plenum housings should be

1 1/2-hour minimum fire-rated.