scope:

This standard sets the performance requirements of rack storage flue spacers in regards to their ability to maintain a 6 in. (76 mm) wide transverse flue space within a rack structure. All requirements in this standard shall be met in order for these products to be eligible to receive FM Approvals certification.

This standard is intended to evaluate only those hazards investigated and is not intended to determine the suitability for all end use conditions of these products. Conditions under which these products are used vary widely. For example, these materials may be subjected to environments, storage arrangements, and fuel loadings not anticipated by this standard.

This standard does not address the issue of rack storage flue spacers during natural hazard events such as seismic occurrences.

Approval criteria shall include, but are not limited to, performance requirements, marking requirements, an examination of manufacturing facilities, an audit of quality assurance procedures, and a follow-up program.

Purpose

This standard states Approval requirements for rack storage flue spacers. Rack storage of combustible commodities creates a substantial hazard and potential for large fires should ignition occur in the storage area due to several issues such as large amounts of fuel that can be concentrated in racks, uninhibited airflow throughout a stable rack array, and the potential for shielding of commodity from overhead sprinklers. While solid shelves may inhibit vertical fire growth, they at the same time promote horizontal fire spread and can prevent sprinkler water from penetrating down through a rack to the fire area. They also limit the pre-wetting of combustibles. Lack of adequate flue spaces within rack storage arrangements can allow a fire to grow uncontrolled by impeding sprinkler water flow down to the seat of the fire and promoting fire spread to combustibles on adjacent shelves. The generated heat can cause excessive numbers of sprinkler heads to activate which will deplete the fire protection water supply while the fire continues to grow. Once the fire breaks out of the area of origin, it could be too large in intensity for the sprinkler systems to be effective. Presence of inadequate flue spaces within a rack storage arrangement may be considered a fire hazard and, if not properly addressed, may require special protection such as in-rack sprinklers for potential fire situations.