Material, Steel or Other Equivalent : Any noncombustible construction that has structural and thermal integrity properties equivalent to steel at the end of the applicable exposure to the standard fire test
NFPA 301 Code for Safety to Life from Fire on Merchant Vessels, 2001 ed. https://www.nfpa.org/Assets/files/AboutTheCodes/30 1/301-A2012-ROP.pdf, (Code: Life Sfty from Fr on Merchant Vssl - Amer) {291 NFC}