Standard procedure for running cables was to have a slot in the floor of the telephone closet and run the polyethylene cables from floor to floor. I believe what changed this was the major fire in 1975 at The World Trade Center in New York City. A fire started at night on one of the floors and spread to the closet and ignited the cables. Cables burned from the 9th to the 19th floors causing over $2 million in damages. Alarms were delayed because the Trade Center did not have to comply with NYC building codes. There were no sprinklers and smoke detectors only in the air conditioning ducts,which did not activate because the ac was shut down for the night. I' m sure Arthur and Sam remember this fire.