短语词组短語firedamp emission 沼氣泄出firedamp limit 瓦斯極限含量allowable firedamp 容許瓦斯氣量firedamp layer [鑛業]瓦斯積聚層;瓦斯層firedamp pool 沼氣池firedamp alarm 沼氣警報firedamp indicator 沼氣檢定器;瓦斯指示器firedamp accumulation 瓦斯積聚firedamp migration [鑛業]瓦斯遷移 返回 firedamp