Method for fire proofing cable duct and ground drain with a cylindrical insert with thermally expanding cladding

摘要

A method for fire proofing a ground drain or cable duct etc. has a cylindrical insert (5) with an outer cladding (4) which expands under high temperatures, or through burning, e.g. vermicular graphite. The cylinder can be plastic moulded and is held in the cable duct by an outer flange (6). During a fire the plastic cylinder and support flange can melt while the cladding is activated to expand and form a gas tight closure for the duct. The system can be retrofitted to existing ducts.