Feb 2008

Protection Against Exterior Fire Exposure

When it comes to determining the adequacy of fire protection for your building, it is also necessary to consider the potential fire exposure that may exist from an adjacent building and/or adjacent outdoor combustible storage.

In modern industrial parks, clear space between buildings and/or outdoor storage is usually sufficient to protect against an exposure fire. However, in some large cities and heavily populated industrial areas, land may be at a premium and the exposure potential can be significant.

Building Exposure

If the exposing building is of combustible construction, lacking in an adequate sprinkler system or in close proximity to your building, action may be needed to protect your building from a potential fire in the exposing building.

The calculation process needed to determine adequacy of exposure protection for a specific building are beyond the scope of this writing. Some of the data needed includes:

  • Construction details of the exposed and the exposing building including percent of wall openings, size of the exposing wall.
  • Occupancy classification of the exposing building.
  • Aspect ratio of the exposing wall (length/height) or height/length).
  • Adequacy of the sprinkler system in the exposing building.

In conjunction with several tables and formulae in FM Global Data Sheet 1-20, “Protection Against Exterior Fire Exposure,” the above information will result in recommended protection (if any) that is needed for your building.

Depending upon the depth of the exposure potential, improvements to the exposed building can include:

  • Protection of any openings such as windows and/or loading dock doors.
  • Construction of a fire resistive wall for the exposed portion of the building.
  • The installation of outside automatic sprinklers, usually located at the top of the exposed wall.

If the exposed building is multistory and the construction, protection, occupancy and proximity of the exposing building is such that it creates a significant hazard, protection of the exposed wall in the multistory building may be needed for several stories above the roof of the exposing building.

Outdoor Yard Storage

Determining exposure protection to a building from yard storage is similar to determining the exposure potential that may exist from an adjacent building.

In addition to considering details of the exposed building as mentioned above such as building construction and wall openings, other items to consider when determining the hazard from yard storage include:

  • Commodity classification of the storage. Is it scrap metal or wood pallets?
  • Area covered by the storage.
  • Is outside protection (such as fire hydrants) present

Solutions may be the possible relocation of the yard storage, or, as discussed above, making modifications to the exposed building wall.

Risk Logic can help in determining the potential exposure hazard that may exist to a building by collecting all the necessary data for both the exposed building and the potential exposure.