On Sat, Dec 24, 2011 at 11:22:14AM -0500, Skip Gundlach wrote:
> ═
> On Sat, Dec 24, 2011 at 11:06 AM, Ben Okopnik <[email protected]> wrote:
>
> Now that PEX is available at the average hardware store, I can't see any
> reason to ever use anything else on a boat. Manufacturers should have
> been doing it for the past 20 years.
>
> Pex sanitation???
Nope - PEX potable water hose. Although there's excellent PEX sanitation
hose, too, at much lower cost than that "marine" san hose.
> Sounds great - but I'm not going to take out what I have put
> in :{))
[laugh] No, wouldn't be much point in that.
> Meanwhile, as to shattering on impact, I invite you to go purchase a couple of
> couplings and a stick of 1.5" pipe, make up the joints, and then take a hammer
> (sledge, too, if you want) to it and report the progress :{))═ (or, at least,
> my attempts to prove the fragility of S40, let alone S80, 1.5" pipe, have worn
> me out without success)
According to OSHA, it's easy to do - just run compressed air through it.
Then, it explodes like a bomb.
http://www.osha.gov/dts/hib/hib_data/hib19880520.html
Quote:
-----------------------------------------------------------------
When PVC piping explodes, plastic shrapnel pieces are thrown in all
directions.
"We're seeing more incidents of explosive failure, and we're citing more
employers for using PVC air system piping," said Paul Merrill, senior
safety inspector in L&I's Spokane office.
"It's probably just a matter of time before someone gets seriously
injured in one of these explosions unless everyone pays more attention
to the manufacturer's warnings," Merrill said.
Last year, a section of PVC pipe being used for compressed air exploded
27 feet above a warehouse floor. A fragment of the pipe flew 60 feet and
embedded itself in a roll of paper. Fortunately, nobody was in the area
at the time.
A PVC pipe explosion in a new plant in Selah broke an employee's nose
and cut his face.
PVC piping buried 3 feet underground at a Yakima manufacturing plant
exploded, opening up a crater approximately 4 feet deep by 3 feet
across.
-----------------------------------------------------------------
In fact, ANSI/ASME prohibit above-ground installation for PVC except
where "...the above ground portion of the plastic service line is
completely enclosed in a conduit or casing of sufficient strength to
provide protection from external damage and deterioration."
Not that we're talking about putting compressed air through the stuff,
but we are talking about how things fail when they do fail - and PVC is
quite frangible when stressed. PEX and regular hose aren't. Maybe my
engineering mindset plus my live-aboard experience lead me into being a
bit too conservative in design, but - all else being held equal - I'd
rather use a material that "fails soft" when I can.
Ben
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