This standard applies to general-purpose overhead conveyors that are pulled by detachable chains and continuously transport items along space-enclosed lines. Its working environment temperature is -20~+45℃. The allowable working environment temperature of the trolley, chain and track is -20~+180℃, and the allowed working environment temperature of the horizontal slewing device is -20~+100℃. When the environmental conditions exceed the above range, the supply and demand parties shall negotiate and make special orders.