Pipe Explosion

By Paul c Date 01-30-2004 01:05

I am investigating an explosion in an enclosed welded tube pipe. The pipe was 40 ft long and 2" diameter. When penitrated it exploded with fire, maybe ignited by the drill or hot metel fragments. Have you ever heard of such an incident before? Are there any articles for safty or how this could occur?

By andy

Date 01-30-2004 12:30

Paul -

I think there have been a few of these types of incidents but not many seem to be well documented. They appear to be connected with the accumulation of hydrogen gas in the bore of the pipe above the lower explosive limit. The souce of the gas varies. On some nuclear stations the hydrogen can result from the radiolysis of water, but for conventional plant simple corrosion can be a cause.

One similar incident on a site in my organisation was put down to corroison in a hollow sealed pipe support and grinding caused a quick flash-off. The cause has not been explained in detail but sampling revealed concentrations of hydrogen >10% of the lower explosion limit in many supports with some containign concentrations of >100% of the LEL (>4% hydrogen).

Unfortuntaly I don't have any further details and your information is not sufficient to enable a further discussion but the fact that you mention that it is enclosed suggests that it may be a similar mechanism.

Hope this is useful

Andy

By Bill A

Date 01-30-2004 14:02

We can probably point you in the right direction if you supply the following details:
pipe wall thickness
steel grade or specification or properties (particularly toughness, if known)
temperature of the pipe at the time of failure
what was inside the pipe and at what pressure
confirm that it was penetrated by a drill bit and not by a torch cut