有限空间概念:有限空间,是指封闭或者部分封闭,与外界相对隔离,出入口较为狭窄,作业人员不能长时间在内工作,自然通风不良,易造成有毒有害、易燃易爆物质积聚或者氧含量不足的空间。常见的有限空间:密闭设备:如船舱、贮罐、车载槽罐、反应塔(釜)、冷藏箱、压力容器、管道、烟道、锅炉等;地下有限空间:如地下管道、地下室、地下仓库、地下工程、暗沟、隧道、涵洞、地坑、废井、地窖、污水池(井)、沼气池、化粪池、下水道等;地上有限空间:如储藏室、酒糟池、发酵池、垃圾 Limited space concept: limited space, refers to the closed or partially closed, relatively isolated from the outside world, the entrance is more narrow, the operator can not work for a long time, poor natural ventilation, easy to cause toxic and harmful, flammable and explosive material accumulation or oxygen content Insufficient space. Common limited space: airtight equipment: such as cabin, tank, car tank, reactor (reactor), freezers, pressure vessels, pipes, flue, boilers, etc .; underground limited space: such as underground pipelines, basement, underground warehouse , Underground works, undergrowth, tunnels, culverts, pit, waste wells, cellars, cesspools (wells), digesters, septic tanks, sewers, etc .; limited space on the ground: such as storage rooms, distiller’s grains, fermentation tanks, garbage