Fire Protection for Structural Steel
August 4, 2009
Structural steel needs to be protected from fire so it does not reach temperatures, which would compromise its strength and possibly lead to collapse. The steel members in a building are protected from fire by several methods. These include gypsum board, which has chemically bound water that boils off during a fire, spray-applied fire resistant materials (SFRM), such as sprayed cementatious which absorbs energy, and intumescent products, which when heated expand to many times their original thickness and form a char layer.
These fire protection products can become damaged during renovation or during normal wear and tear. According to John Mammoser, a consultant with Rolf, Jensen & Associates, when repairing the damage, attention should be paid to material compatibility. For example, old and new SFRM are compatible but new intumescent materials might not be compatible over old intumescent on the same piece of steel due to different chemistry.
To aid the repair process, facility executives should be sure to know what material has been applied in their facility and also the building code at the time of original construction, since current regulations might just require that repairs maintain the original fire rating. The manufacturer of the existing fire protection product can provide ideas for how to patch it.