Inch to Metric Pipe Fittings

This: http://homepages.tesco.net/~A10bsa/bspgo.htm might come in handy.

Are the pipes ,etal or some other material such as plastic? If plastic, then http://www.georgfischer.co.uk/index.cfm?uuid=43135CA050934B40A988F9CB44EAEDF3 ought to be able to help.

I have the BSPP & BSPT specifications.

The fittings would be steel or maleable iron. I am designing for PN10, PN16, & PN25.

I live in the US and am not familiar with what is common in the rest of the world.

If I went to the hardware store in say....Germany or Denmark, what kind of pipe plugs would I find? And which threaded hole (BSPP, BSPT) would that plug be screwed?

I can not imagine that a tapered plug would make a good seal in a parallel hole.

What's in the pipe, its temperature and pressure?

water

10 Deg. C to 100 Deg. C up .... temp up to 16 Bar

The temperatures are a bit high for most plastics, though PTFE is a suitable sealant material for temperatures as above; glass-filled PTFE can take even higher temperatures though it is stiffer and will probably be found in special items like seats in ball valves and in joints. Plastics are becoming common in domestic heating and hot water supply situations up to, say, 60degC though many will not trust their long-term integrity close to heat sources.

Potable or not? Unprotected steel is not suitable for potable; malleable iron [MI] is, and the joints are usually flanged/bolted, or socket-and-spigot joint for underground, anchored by thrust blocks at the corners. The lowest diameter of MI is limited by the mould size, say 2in. For non-potable water, mild steel pipe in any size would do, and it can be flanged in the larger sizes and screwed in the smaller. Sedimentation of rust and general crilge is a problem in steel systems, and strainers are fitted upstream of critical equipment.

It wouldn't do to put hot water undeground without a suitable drained pipe trench, insulation and supports, which calls for an experienced piping designer to become involved at an early stage.

For small diameters indoors at ambient and higher temperature, try galvanised steel or soldered- or compression-fittings in copper for potable; copper is usually supplied in metric diameters with metric fittings, ending in a metric compression fitting in brass with a BSPT screw thread for going onto something else; domestic plumbing in the UK is often done this way. For non-potable, screwed steel or black-iron would suffice for economy; typical uses are the heater battery in an air-handling unit and condensate return piping from steam-powered processing equipment. Fittings for small bores are screwed BSPT, with flanges on the larger sizes. One usually finds parallel threads on special pipe line items like pressure gauges; these are screwed into a BSPP female with a joint ring as it is not possible to get a tight fitting on BSPP without one, and to secure the orientation requires a parallel thread with some 'give' in the seal ring.

Copper is available readily down to 8mm diameter with solder and brass compression fittings. It is possible to go smaller using stainless steel with swage-locking (usual disclaimer applies) fittings; BSPT and BSPP are both available. It is not normal to use swaged fittings above, say 10mm.

At higher temperatures most pipes would need to be insulated and finished, for both economy and personnel protection, depending on circumstance. A burn from a small-bore copper pipe at 135degC is not at all pleasant (been there, done it...).

International companies may already specify pipe standards to be used and these may be immediately applicable to USA-based circumstances. One's employer's pipe codes can often be used to avoid much pain, embarrasment and expense, and are there to avoid the need to reinvent the proverbial wheel.

Most metric pipe fittings are consolidated into either:

1. ISO G a straight fitting with an O-Ring or elastomer face seal.
2. ISO R a tapered metric fitting.

From Norgren fitting catalog:

ISO G Male will mate with Female ISO G, BSPP, JIS B 0202

ISO G Female will mate Male ISO G, BSPP, ISO R, BSPT, JIS etc With thread sealant.

ISO R Male will mate with Female ISO Rc, BSPT, ISO G, BSPP, JIS~ W thread sealant.

ISO Rc Female will mate with Male ISO R, BSPT, JIS B 0203 With thread sealant.

The pipe sizes or female hole are similar, i.e. 1/4" NPT is about the same size as a G02 ISO-G and an 02 ISO-R.

Typically the tube fittings with ISO G or R threads fit metric OD tubing. Some cross over fittings are available for those who own an Italian made machine and want to use inch size tubing for replacement.

The large industrial suppliers in your area have been through this many times. They may have cross reference material and would be glad to sell you an ISO R pipe plug to fit a BSPT port.

BSP is not a metric thread. Use metric, or sometimes known as DIN fittings.

BSPP & BSPT are pre metric British standards, in Australia they are still widely used for traditional screwed pipe fittings.

Metric for pipes is something else again which has not yet caught on in this country at least, although most other screwed fastenings have gone to metric standards.

The old BSP fittings were mostly tapered, and you are right a tapered plug into a parallel hole doesn't seal very well, although it's marvellous what can be achieved with half a roll of teflon tape.
I guess the thing is that screwed pipefittings are really going the way of the dodo so it wasn't worth the trouble of metricating them. I think people with heritage systems and us dumb farmers are the last ones screwing pipes together.

NG pipelines in commercial and residential here in NYC are still black threaded pipe. What else can you use? Not in NYC mind you but other locations. Just curious

They seem to be all a yellow plastic here, as far as I know. They were in Wagga Wagga when we were connected anyway.

Double check on this one, but I think I remember in the 1/8" pipe threads the inch had 27 threads per inch,and metric had 28. I would run into problems putting aftermarket gauges on American motors, and vice versa.

Cheap pipe connectors will be tubing straight threaded right through. Cast ones will be tapered from both ends in.

The straight threads were fine for conduit. I've seen 3" and 4" connectors with straight threads.

Like the other posters, I think the npt is pretty common worldwide.

Tell you where I did find a difference...on splines....I was putting a Houdaile (British) hydraulic pump into an American made transmission,,, wouldn't go easy at all. I think there is a little difference. Had to have the splines manually ground down a little() to make it fit.