Water Pipe Sizes

[MangoKorat]

I'm not in Thailand at the moment but will be returning next week.  I'm bringing an electrically operated water valve with me for use in my garden.  I need to concoct something to take the vavle outlet pipe to Thai water pipe and I'd rather do that before I come - finding none standard things in my area is pretty hard.  I've done it before but can't for the life of me remember the internal and external sizes of what the Thai's call 18mm or 1/2 inch.

 

I'm pretty sure that 18mm or 1/2 inch is the internal dimension and if I remember correctly, there are two thicknesses of pipe?

 

Anybody??

[BenStark]

[VocalNeal]

Pipe is measured on the inside. Tube is measured on the outside.

[OneMoreFarang]

I know I tried to measure it before and I failed. 

It seems the most reliable thing is to look what is written on it, like 1/2"

The second number on these things in the picture, 304, is the stainless-steel type and has nothing to do with the diameter. 

 

 

With my condominium renovation the main freshwater pipes are 3/4" and then 1/2". I don't know if that is "normal".

 

[MangoKorat]

29 minutes ago, OneMoreFarang said:

I know I tried to measure it before and I failed. 

It seems the most reliable thing is to look what is written on it, like 1/2"

The second number on these things in the picture, 304, is the stainless-steel type and has nothing to do with the diameter. 

 

 

With my condominium renovation the main freshwater pipes are 3/4" and then 1/2". I don't know if that is "normal".

 

That's different and its complicated but often in plumbing, the size stated does not always equal the size of the pipe.  What I'm trying to do is join two pipes together that are slightly different sizes externally - therefore I can't use a traditional joint.  In this case its not too bad as I can probably just use flexible rubber (plastic) to get from one pipe to the next.  What I have coming out of the valve is a 15mm (UK) copper pipe and I need to cobble something together to join that to the Thai pipe.  The rubber will probably do it because the pressure won't be great.

[MangoKorat]

1 hour ago, BenStark said:

Thanks for that - exactly what I was looking for.  If I'm reading that correctly an 18mm (internal) pipe measures 22mm externally give or take .15mm for a standard pipe?? The internal measurement then reducing according to what quality of pipe is selected (PVC 5, 7, 8.5 etc).

[MangoKorat]

1 hour ago, VocalNeal said:

Pipe is measured on the inside. Tube is measured on the outside.

Maybe by an engineer. In terms water pipe, (for the most part) joints use the external size in order that common joints can be used.  I've been buying 15mm and 22mm copper pipe most of my life in one way or another and I've never heard anyone call it copper tube.

 

This was a simple request, can we not turn it into the usual AN fight?

[MangoKorat]

1 hour ago, OneMoreFarang said:

I know I tried to measure it before and I failed. 

It seems the most reliable thing is to look what is written on it, like 1/2"

The second number on these things in the picture, 304, is the stainless-steel type and has nothing to do with the diameter. 

 

 

With my condominium renovation the main freshwater pipes are 3/4" and then 1/2". I don't know if that is "normal".

 

I can't speak for Thailand because every country seems to use their own plumbing systems but 3/4" and 1/2" is pretty standard in UK domestic water systems. The size however, is where the similarity ends. Pipework in the UK is either copper or plastic push fit. Copper using soldered joints and compression fittings - plastic using matching plastic push fit joints - although joints exist that take copper to plastic.  I've never seen the elbows in your photo used in a domestic water system - usually used for gas.

[OneMoreFarang]

2 hours ago, MangoKorat said:

I've never seen the elbows in your photo used in a domestic water system - usually used for gas.

Ok, sorry, I just looked at the internet for a picture which shows the size as an example.

At my condominium renovation we use the green pipes - I was told those are the best option in Thailand.

 

[MangoKorat]

4 hours ago, OneMoreFarang said:

Ok, sorry, I just looked at the internet for a picture which shows the size as an example.

At my condominium renovation we use the green pipes - I was told those are the best option in Thailand.

 

The green pipe is of far superior quality - I used them when I installed my hot water system because the blue pipe is not suitable for hot water.

 

I'm sure they are not too difficult to use in a new build but they are a real, and I mean real, PITA to use in a suspended ceiling or any other confined space.  The reason is that joints, elbows and t's etc. are 'welded' to the pipe using an electric 'welding' machine.  To use that without burning yourself (especially) in a confined space, you would actually need 3 hands. Being a poor man, only equiped with 2 hands, my arms were quite badly burned by the time I'd finished my house. Still, being the stupid farang who insisted on having hot water, I shouldn't complain too loudly.

 

I learned to make up as many runs as possible on the floor before installation but that is not always possible.

 

The green pipe is not cheap when compared to the cheap and nasty blue solvent weld stuff, nor is the welding machine but at least I have that for my next project ????.

[VocalNeal]

10 hours ago, MangoKorat said:

Maybe by an engineer. In terms water pipe, (for the most part) joints use the external size in order that common joints can be used.  I've been buying 15mm and 22mm copper pipe most of my life in one way or another and I've never heard anyone call it copper tube.

 

This was a simple request, can we not turn it into the usual AN fight?

Was trying to help so that when you measure you measure the correct dimension. Inside vs outside, 

If you have been using metric tubing maybe your valve is metric  and you will need metric connectors or adapters

Maybe show us a picture of your valve so we know if it is metric of imperial etc..

 

That is if you really wish to get input. Or this is not just another AN look at me thread.

Edited September 11, 2023 by VocalNeal