Re: I fully agree with those of New Yorkers
Francis wrote:- I'm not an expert in explosions but I witnessed explosions in smaller steam pipes due to the injection of cold water..
- I'm not an expert in vibration but I've seen pipes vibrate, and therefore transmitting the vibration to their physical supports, because of the pressure going off. Just like a squirming water hose left on..
I think Francis is close to the truth here. The steam pipe is reported to have failed, not because it was old or defective, but rather as a result of a phenomenon called "water hammer". It is almost always the result of human error in bringing a shutdown steamline back into operation. Water hammer, or a repeated collapse and restoration of the steam cloud or bubble in a pipe section or container, occurs when steam is rapidly introduced into a pipe or container which contains cooled liquid condensate (water). This results in rapid, hammer-like variations in pressure, almost always exceeding the strength of the pipe attachments and/or the pipe or container itself. There is a great deal of stored energy in steam, and once the pipe ruptured an explosive release of energy occurred, ending only when the source was finally shut off.
The right way to introduce steam is to isolate the assumed empty pipe or container, open all the drain valves, and very slowly introduce live steam. This will drive any liquid out the drains - a process that can take 30 - 60 minutes in a large system.. When the drain flow is entirely steam (no liquid) then it is safe to close the drains and introduce normal steam flow.
There very likely was asbestos insulation around the old pipe. However the release, with all the attendant moisture and steam, almost certainly prevented any significant release of airborne asbestos filaments - the only vector that causes significant human hazards. Moreover the mesothelioma risk associated with asbestos occurs primarily with heavy smokers - the combination of the two factors raises the risk over a thousand - fold over either factor alone.