... B1 Grade-noncombustible, GB8624-2006, Germany Grade DIN4102, B Grade (have passed the test of National Firefight Supervise Test ... as middle fireproof and protective layer of the fireproof roller shutter.Main product: ceramic fiber fabric, silicate fiber felt.Thickness ... B1 Grade-noncombustible, GB8624-2006, Germany Grade DIN4102, B Grade (have passed the test of National Firefight Supervise Test ...