Outdoor Railroad Bridge FRP Repair Fire Protection

[blaxabbath]

We are designing an FRP repair to be installed on the underside of a wood beam for a timber bridge (about 6LF in the middle of the beam for flexural strengthening, so very small but over MANY beams). The bridge is out in a rural area so I have discussed with the owner possibly installing some form of fire protection to (1) provide a mechanical flame barrier over the FRP, and (2) insulate the FRP system (specifically the epoxy). The thinking behind this is that brush fires often pass under these bridges and, even when they get a little charred, the bridges are designed to stay in service and we want the repair to be as 'durable' against heat when the bridge is exposed to the passing fires.

I've been researching different boards and wraps but my biggest hurdle has been getting my messages returned from manufactures (guess they'd rather use their energy chasing work after the project is spec'd). Most of the boards I am finding are for industrial environments (temps up over 1300F) and are overkill for what we need. Some of the wraps are lower grade but cumbersome to install.

Does anyone have experience working with such constraints and could offer some thoughts?

 

[b1ueshift]

It seems you need something weather proof, but most fire rated products aren't designed for outdoor use.

Maybe you could use intumescent paint.

 

[chicopee]

Intumescent fire retardants and fire resistant coatings are available for wood products.