[time-nuts] OT Euro/US plumbing was 14 tpi UNS die

Chuck Harris cfharris at erols.com
Wed Jul 8 14:03:22 UTC 2009


Hi Nigel,

> He's referring to a standard compression fitting, with  the brass or copper 
> "squeeze ring", more usually called an olive or compression  ring, having 
> tapered ends and being compressed around and into the copper pipe  surface as 
> the nut is tightened.
> Other than soldered joints, which are also  still used, this is the 
> standard fitting here for gas or water in domestic  installations.
>  
> When fitted properly, and they're very easily  fitted, these shouldn't leak 
> at all.

We use them here in the US, for small water fittings... such as refrigerator
ice makers, and toilet tank fills.  They work just fine.  I always put a
little non hardening pipe compound under the ring to prevent seepage that
can occur on poorly made tubing that has mandrel marks left over from drawing
the tubing... I never used to have to do that, but the Chinese and Mexican
manufactured toilet fill tubes we get these days are awful.

...

> I have also never seen an O-ring with jamb nut in a domestic heating  
> system and don't think steel pipe has been used here in regular domestic heating  
> systems since "central heating" took off in the 1960s/70s.

Good!  The UK must be using more sane methods.  I haven't been talking
about steel pipe, I have been talking of straight pipe thread on fittings,
such as shut-off valves on radiators, and fittings on manifolds.

> Steel pipe, often it seems referred to as "gas barrel" even if not being  
> used for gas, is still common in industrial situations but copper is the  
> norm for gas and water in domestic situations with pipe sizes varying to  suit 
> flow and equipment fittings.

Steel pipe is mandated for gas systems in many areas of the US.  I am in one
such area.  It works fine, and is 100% reliable.  Copper tubing is only used
by propane installers, and they form their own codes.  Compression fittings
seem to be universally outlawed for gas, though. Formed flare fittings are
the norm on copper gas tubing.

...

> As compression fittings are very much the norm here  I'm surprised that you 
> don't seem to have encountered them in the US.

As I said earlier, I have encountered plenty compression fittings.  They are
not what I have been discussing.

> Is it possible that what is being supplied to the US from Europe is  more 
> dictated by US plumbing practices and regulations than by what we'd  normally 
> prefer to use  ourselves?:-)

No, these are bog-standard parts ordered directly from the manufacturer's
catalogs, and imported directly into the US.  There was no US code interference
in these transactions.  The work was done as directed by the manufacturers.

You see, I happened to think the Europeans are the masters of the universe
when it comes to hydronic heat.  It is rare to find hydronic heating in the
US because our climate requires both heating and cooling in most areas, and
it is much cheaper to install a single forced air system that does both the
heating and cooling than it is to install two separate systems.

In the US, hot water and steam heating systems are generally found only in
houses that were built before central air conditioning was common.


It's been fun, but we have probably taken a long enough vacation from time
and frequency issues.  I think it is past time to wind this subject down.


-Chuck Harris



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