Can quick-opening structures be used for manholes that are at normal pressure but pose extreme hazards? ?
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Can quick-opening designs be used for manholes on equipment that operates at atmospheric pressure but poses extreme hazards? ? (Other conditions are not considered.) Please share your opinions, or cite relevant standards.
It is best not to use quick-opening manholes.
The standards for quick-opening manholes do not specify any restrictions regarding the types of media that can be used. However, if the equipment involves extremely hazardous media, whether it is a pressure vessel at normal pressure or one under pressure, the design and manufacturing requirements are very strict. According to HG/T20583, the pressure class of the flanges used for connecting such vessels must be no less than 2.0 MPa, and the flanges must be long-neck butt-welded flanges. Therefore, quick-opening manholes cannot be used, as they do not meet the minimum requirements for extremely tall medium-pressure vessels.
Absolutely not; for media that pose a high level of risk, there are specific requirements regarding design pressure, flange structure, and the type of sealing surface.
It is mainly considered from a safety perspective; whether it is safe or not has nothing to do with quick-opening features. If the manhole is safe enough, then using a method that is relatively quick to open is also acceptable, and ordinary bolts can be replaced with quick-opening bolts.
Long-neck butt welding and quick-opening seem to be two different concepts
Thank you to all those who responded. I was wondering if there are any relevant standards that stipulate that quick-opening manholes must not be used under normal pressure or in situations involving extreme hazards.
Hehe, I mean the standard requirement is a long-neck flange, while the quick-opening type uses a flat-welded flange; the flange type doesn’t meet the requirements
My understanding is that if the medium is a gas or a volatile liquid, the pressure rating of the manhole should be high; however, if the medium is not volatile and the gas at the surface is non-toxic, a quick-opening manhole can be used.