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