Use aerial support in truss-roof operations

Use aerial support in truss-roof operations

Lance C. Peeples


Webster Groves, Missouri

I would like to comment on Bob Pressler`s “Operations on Peaked-Roof Structures” (The Truck Company, July 1995), in which he states, “Cut the hole as close to the ridge pole as possible. In lightweight truss houses, cutting as high up as possible is best.” Except for this statement, the article is excellent.

In my opinion, the author fails to stress the inherent danger involved in opening truss roofs–i.e., if fire has involved the attic to the degree that vertical ventilation is indicated, then collapse of the truss assembly should be assumed to be imminent. If the roof`s collapse is assumed to be imminent, then the firefighter assigned to open the roof must be independently supported by an aerial device.

Chief John Mittendorf (retired) of the Los Angeles City (CA) Fire Department previously has reported that unprotected lightweight truss assemblies failed in 90 seconds in test fires conducted by his department. (“Lightweight Construction Tests Open Fire Service Eyes to Special Hazards,” Western Fire Journal, Jan. 1982, 23.)

In a September 1992 letter to the editor (Fire Engineering, page 40), Chief Vincent Dunn of the City of New York (NY) Fire Department suggested the following standard operating procedure for all truss-roof building fires:

1. Make an exterior size-up.

–If the fire is beyond the control of an initial attack hoseline, then set up an exterior attack.

–If no smoke or only minor smoke is showing, then enter and make an interior size-up of the fire (see No. 2 below).

2. Make an interior size-up.

–If it is a fire involving the contents of the building, then use standard operating procedure–extinguish with an interior attack hoseline.

–If it is a structure fire involving the truss structure itself (any type), then evacuate the building and use an exterior attack on the fire and protect exposures.

While it may be necessary to commit interior attack lines to private dwellings with truss roofs to facilitate a primary search, the members operating within the structure may be afforded some small degree of protection from collapse by interior partitions. Members operating on the truss roof are in severe danger and should be independently supported by an aerial device.

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