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 Metro, buses and suburban train service were stopped. The basement of an elderly care hospital in the Saint-Henri neighbourhood was flooded and 240 patients were left without electricity, food, and health services for a while. Most home insurance claims were declined unless the insured was specifically covered by a clause concerning flood. However, the car owners were covered. The Quebec government promised monetary help but only 20 to 40% of the expected C$40 million was ever distributed. Court cases against the municipal authorities, including a class action, were rejected as the flood was considered in legal terms an "Act