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