Hi, when pressure testing a system and capping or linking the pipes before starting to test the pipework with a wet test. Does air have to be removed from the system or not? Also what pressure should plastic pipework be tested to?
Pressure testing
- Thread starter CAESAR32
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No
Each manufacturer of plastic has different specs for test pressure.
Polypipe for instance is 18bar for between 15mins to 1hour
Each manufacturer of plastic has different specs for test pressure.
Polypipe for instance is 18bar for between 15mins to 1hour
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I must have been doing it wrong all these years then. How would you remove all the air? Surely the air just gets compressed?
If the air expands due to a leak you will see a pressure drop. Otherwise how on earth could you dry test pipework, or Gas pipework ?
As said each manufacturer has their own guides, but a good rule of thumb is 1.5x the working pressure of the system, so heating and rad pipe work 4.5 bar.
As said each manufacturer has their own guides, but a good rule of thumb is 1.5x the working pressure of the system, so heating and rad pipe work 4.5 bar.
That's what I was thinking. The water won't compress, the air will, but you keep pumping until you get the pressure you want.
Bit of a nightmare trying to get every last bit of air out of a big ch or water system.
Exactly...
If you are testing plastic pipe it's best to check the manufacturers reccomendations.
It depends on where the grab ring is as to the required pressure, on Polyplumb and the very early Hep2o fittings the "O" ring is first and the grab ring second when you insert pipe and they should be pressure tested upto 18 bar.
The new Hep2o is grab ring first and "O"ring second and requires a pressure test of 1.5 times the max working pressure.
A long low pressure test should also be carried out, because if there is a score in the pipe or a small amount of swarf or grit under the "O" ring, it may seal under the higher pressure but when relaxed it may weep.
On site the pressure tests are done at 1st fix stage, before radiators, boilers, shower valves etc are fitted
It depends on where the grab ring is as to the required pressure, on Polyplumb and the very early Hep2o fittings the "O" ring is first and the grab ring second when you insert pipe and they should be pressure tested upto 18 bar.
The new Hep2o is grab ring first and "O"ring second and requires a pressure test of 1.5 times the max working pressure.
A long low pressure test should also be carried out, because if there is a score in the pipe or a small amount of swarf or grit under the "O" ring, it may seal under the higher pressure but when relaxed it may weep.
On site the pressure tests are done at 1st fix stage, before radiators, boilers, shower valves etc are fitted
You should remove any air using the standard air vents at high points.
The air compresses; if there is a leak, it causes a slow reduction in the system pressure and similarly requires the expenditure of a lot of pumping effort to bring the system up to the test pressure.
A system with no air in it will pressurize with very few pump strokes and will similarly lose pressure rapidly through a small leak.
The energy stored in any compressed air is a hazard if there is a burst. There was someone killed a few years back whilst doing hydraulic pressure tests of valves (at very high presures) because the air was not being vented from the system. Everything went well until a defective valve was tested.
The required test pressure is in the pipe manufacturers' installation instructions or in the Water Regulations; 10 bar is standard, ISTR. Any components that won't tolerate the pressure should be isolated or removed.
There is a different test method for plastic pipes to allow for it to stretch under pressure.
The air compresses; if there is a leak, it causes a slow reduction in the system pressure and similarly requires the expenditure of a lot of pumping effort to bring the system up to the test pressure.
A system with no air in it will pressurize with very few pump strokes and will similarly lose pressure rapidly through a small leak.
The energy stored in any compressed air is a hazard if there is a burst. There was someone killed a few years back whilst doing hydraulic pressure tests of valves (at very high presures) because the air was not being vented from the system. Everything went well until a defective valve was tested.
The required test pressure is in the pipe manufacturers' installation instructions or in the Water Regulations; 10 bar is standard, ISTR. Any components that won't tolerate the pressure should be isolated or removed.
There is a different test method for plastic pipes to allow for it to stretch under pressure.
The difference is that the air can kill you, at a surprisingly low pressure. Water probably won't.
Do not confuse leak testing with pressure testing. In the latter, the aim is to force a burst of any weak pipework or components.
If it takes 10 minutes for a dullard with a 3 kW compressor to pressurize a pipework system, then how much energy is released when one of his crappy pipe joints fails?
Hi, I've just had my boiler installed and I'm noticing some wet patches on the ceiling.
The room above the utility is the bathroom, which has a tiled floor.
I was informed the plumber pressured tested the system, so where wouldn't be any issues. However I'm now seeing these wet patches just an hour after the plumber left.
So I'm trying to find out what is exactly involved in a pressure test.
The reason for this, is that another plumber carried out the work for the bathroom / ensuite, to the plumber that sorted the central heating.
So when pressure testing a house, does that include the pipe work for the bathroom, or would it have just been the central heating pipes?
Thank you for any information in advise!
The room above the utility is the bathroom, which has a tiled floor.
I was informed the plumber pressured tested the system, so where wouldn't be any issues. However I'm now seeing these wet patches just an hour after the plumber left.
So I'm trying to find out what is exactly involved in a pressure test.
The reason for this, is that another plumber carried out the work for the bathroom / ensuite, to the plumber that sorted the central heating.
So when pressure testing a house, does that include the pipe work for the bathroom, or would it have just been the central heating pipes?
Thank you for any information in advise!
NC....You should really start a new thread, it makes it easier to miss if you don't.
With copper pipe, only the CH circuit would be tested with water set to 1 1/2 times the working pressure for an hour with no leaks/pressure drops. If it's plastic then it is also tested with water pressure but significantly higher.
If it is a combi and connecting to the HW circuit, should he have tested that too? Hmmm, tricky 1 .... if it was going from gravity to mains pressure. Personally I would have asked if it was new and had it been tested or checked into it's history if existing.
Time to get your plumber back methinks.
With copper pipe, only the CH circuit would be tested with water set to 1 1/2 times the working pressure for an hour with no leaks/pressure drops. If it's plastic then it is also tested with water pressure but significantly higher.
If it is a combi and connecting to the HW circuit, should he have tested that too? Hmmm, tricky 1 .... if it was going from gravity to mains pressure. Personally I would have asked if it was new and had it been tested or checked into it's history if existing.
Time to get your plumber back methinks.
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