Raised storage floors - Fire resistance exemptions

Raised free-standing floors supported by racking are frequently erected for storage purposes and whether they are considered as a gallery or as a floor forming a storey the provisions for fire resistance for elements of structure apply. In the case of automated storage systems where people do not normally frequent any of the raised storage tiers it is not necessary to provide the storage structure with fire resistance. Where people frequent the storage tiers in the course of their normal use, the provisions for fire resistance for the raised storage floor and its supporting structure may be dispensed with where the number of persons likely to be on the raised floor at any one time is low (and does not include members of the public) and the raised floor – (a) is within a single storey building or compartment and is structurally free-standing; (b) consists of only one tier with the space both above and below used only for storage purposes; (c) is not more than 20 m in both width and length and does not exceed one half of the floor area of the space in which it is situated. However, these limits should not apply where the building is fitted throughout with an automatic sprinkler system in accordance with Section 8 complying with the relevant recommendations of BS 5306-2 or BS EN 12845 in respect of occupancy rating and additional requirements for life safety; (d) is served by a stair or stairs to comply with the relevant maximum travel distance given in Table 2.3 and at least one stair discharges within 4.5 m of an exit from the building or compartment; (e) has a surface classification on the underside not lower than Class 3 (National class) or Class D-s3,d2 (European class) (see paragraphs 3.4 and 3.7); and (f) is designed and constructed so that any persons on the floor will be readily aware of a fire starting on the lower level. Design and construction features include the use of perforations in the floor, leaving a space between the floor and the walls of the space housing it and automatic fire detection and alarm systems. However, where either the length or width of a raised storage floor is greater than 10 m an automatic fire detection and fire alarm system to BS 5839-1 of at least Category L5 standard with a smoke detector or detectors located to give warning of a fire below the floor should be provided.