A fire transmission prevention system for use in a drainage system to prevent the transmission of {HEAD ~ smoke} and {TAIL ~ fire} through the drainage system 
A fire transmission prevention system for use in a drainage system to prevent the transmission of { HEAD ~ smoke } and { TAIL ~ fire } through the drainage system
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH