... fireproof board for tunnel use 1.100% non-asbestos 2.Excellent bending strength 3.Low water absorption Mgo fireproof board for ... tunnel use Materials:vermiculite, go, Mgcl2, perlite, fiberglass cloth etc ... to use for construction Fireproof time:2 hours (single fireproof board) Usage:Tunnel ,subway and other public places need high ...