Heat pump the brand name Freon, a trademark of DuPont. Its manufacture is now banned or severely restricted by the Montreal Protocol of August 1987 because of the damage that CFCs cause to the ozone layer if released into the atmosphere. One widely adopted replacement refrigerant is the hydrofluorocarbon (HFC) known as R-134a (1,1,1,2-tetrafluoroethane). Heat pumps using R-134a replaced R-12 (dichlorodifluoromethane) and have similar thermodynamic properties but with insignificant ozone depletion potential and a somewhat lower global warming potential. Other substances such as liquid R-717 ammonia are widely used in large-scale systems, or occasionally the less corrosive but more flammable propane or
Montreal flood of 1987 Montreal flood of 1987 The Montreal flood of 1987 happened on July 14 of that year when a series of strong thunderstorms crossed the island of Montreal, Canada, between the noon hour and 2:30 p.m. Over of rain fell during this very short period of time. The sewer systems were overwhelmed by the deluge and the city was paralyzed by the flooded roads. Autoroute 15, a sunken highway also known as the Decarie Expressway, soon filled with water, trapping motorists. Some 350,000 houses lost electricity, and tens of thousands had flooded basements. Two people died, one in a submerged car