Thank you both for your input.
The NFPA has standards for firefighting equipment. Although accessories like the knee pads are not explicitly covered in the standards many firefighters will be weary of anything that is less than the standard for the rest of their gear.
NFPA 1971: STANDARD ON...
I am a firefighter developing a product for personal protective equipment. The piece I am creating is a knee pad with a plastic impact shell and foam padding. I have very little knowledge on the vast variety of plastics available. There are limitations to what I can use. The plastic needs to be...