Intumescent coating type in Plenum space of semi-conductor clean room

I am looking for a appropriate intumescent coating (2 hr) types for the plenum space of semi-conductor clean room, and roof structure (trusses) above the plenum. The plenum has more than 20 CFM/CF/minute air flow with temperature/humidity controled. And the roof structure space do not have controled temperature/humidity. It's located in central Texas, so uncontroled space will have 120 °F and 85% humidity. I am looking at epoxy base or solvent base ones. Chemical resistance would be premium - lots of chemicals (solvent, acid, etc.) are used.