{HEAD ~ The couplings} are mounted in {TAIL ~ the floor} of the structure and are constructed and secured in the floor such as to prevent fire and smoke from passing around the couplings between the couplings and the floor 
are mounted in
{ HEAD ~ The couplings } are mounted in { TAIL ~ the floor } of the structure and are constructed and secured in the floor such as to prevent fire and smoke from passing around the couplings between the couplings and the floor
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH