As I explained to Bird a couple of days ago (which obviously never made
it to Shelly's server), the system is normally sealed against intrusion.

D

Normally.

We had to pig an oilfield pipe line one time. For those who don't know,
a pig is a vinyl coated bullet cone shaped wad that is shot down a
pipeline under pressure to make sure the line is clear before it is
sealed or put into use. On one end, a "trap" of expanded metal is put
on to catch any high velocity refuse, and to make the discharge come out
in a T fashion rather than straight out.

Job ends one afternoon, and pipe end pig cap protector left off. Nutria
(google it) love tunnels, and an estimated four of them went into the
open end of the pipe. Next morning, pressure cap is placed on end of
pipe, and 15,000 psi pump attached. Pipe is something extra heavy, so
very heavy pressure is used to "PIG" the line. A mixture of seawater
and nitrogen at a 7000 PSI pressure.

The nutria (never determined how many) made the 2+ mile trip in less
than .5 seconds, and hit the expanded metal chamber on the catching end.

It was very easy to see the personnel who were anywhere near the
terminus, as well as any vehicles. Red spray was the description.

Joke of the day to anyone wearing red was, "Hey, did you save any of
that for lunch." Somewhat the consistency of pulled pork with a little
swamp grass mixed in.

Only a couple of injuries from puncture wounds caused by high velocity
bone shards.

Pigging was always an exciting activity.

Steve