Steel Corrosion Protection + Fire Protection

[zlindauer]

I am working on a building at a water treatment facility. The roof is framed with steel joists and deck. The steel is required to be protected from both fire and corrosion, since there will be corrosive off-gassing from the processes taking place in the building.

Currently the architect is calling out a cementitious fireproofing for the roof joists. Will this provide a suitable corrosion protection? What is the best way to achieve both corrosion resistance and fire protection for structural steel?

I realize now that this building would be better off with a concrete roof, but that ship has sailed.

Thank You!

 

[hokie66]

A high performance coating system should be used for the structural steel and joists. Probably hot dipped galvanizing followed by organic topcoats. Suggest you consult with a major coating supplier like Porter or Carboline. Don't try to make the fireproofing material do the job of corrosion protection.

The deck is more difficult. Maybe stainless steel deck?

 

[Ron]

Agree with hokie66...the fireproofing will not protect from corrosion. Cementitious fireproofing is better for this than the fibrous fireproofing, but it is still low density, absorptive material...so if the environment will be humid, then look for separate corrosion protection then fireproofing.

ps...intumescent coatings won't solve the whole problem, but might be something to consider for the deck.

 

[zlindauer]

Thanks for the input.

Is there a problem with the fireproofing adhering to the steel if I coat it for corrosion protection? I've always specified that steel to receive fireproofing shouldn't be primed and painted...

 

[Ron]

zlin...some coatings will allow cementitious adhesion (galvanizing, for instance)...others will not. If adhesion is a problem, use lath to keep fireproofing intact.