Which is better, a breathing manhole or an emergency vent manhole cover?
Thread Content
The structure of the breathing manhole cover and the emergency venting manhole cover differs slightly. Has anyone used a breathing manhole? What are the advantages of this breathing manhole over the emergency vent manhole cover?
The manhole cover is of the purely gravity-type; it does not close automatically once opened, as it is after all a last-line of defense meant for emergency pressure relief. The breathing manhole will reset automatically; it is generally used for normal breathing protection. Since there is a high demand for it, people simply borrow such manholes. There’s not much difference, I think they’re just two similar things.
What does \"borrowing a manhole\" mean? Does it involve creating a manhole on the top of the tank and then installing a breathing manhole? Also, is the breathing manhole more expensive or the manhole cover?