1 bar leak test

[hamedhpt]

Does anybody know what is a "1 bar leak test"? and how this test performed for a boat?
Sealing different parts of a boat is very very important.I want to test a boat compartments to see are they watertight or not.Can anybody introduce some standards for this type of tests?

[gonzo]

Positive or negative pressure? I bar is about 14.5 PSI. Where in a boat? For what standard?

[daiquiri]

Fill the piping (or the tank) with water and pressurize it to 1.5 times the maximum design pressure of the piping. The pressure is intended as gauge (or relative) pressure. Take note of the manometer readings for a sufficiently long time (the more is better - 24 hours is a common practice). If the pressure readings are stable (without a significant decrease) then the piping has passed the test.

You can use compressed air instead of pressurized water, but be very careful because compressed air contains a lots of energy which, if something goes wrong, can lead to an explosive failure of piping.

If you have to perform the "1 bar leak test" (for what, pipings for natural gas?) then I guess the procedure would be similar to the above - only the pressure changes and becomes 1 bar gauge pressure.

Cheers

[hamedhpt]

Hi.I want to test different compartments in a boat to see are they watertight ?For example in the engine room, are the cable penetrations sealed perfectly?Or the places where bulkheads are connected to the deck, are they watertight? I am searching some standards for these kind of tests.For instance in BV or GL or DNV.

[Ad Hoc]

Originally Posted by hamedhpt

Hi.I want to test different compartments in a boat to see are they watertight ?For example in the engine room, are the cable penetrations sealed perfectly?Or the places where bulkheads are connected to the deck, are they watertight? I am searching some standards for these kind of tests.For instance in BV or GL or DNV.

This is usually done with the "soapy water test".

High pressure air hose one side, and soapy water the other. If you get bubbles...you have a leak

[Mat-C]

Can I ask what sort of boat you are talking about here?

[murdomack]

A system leak test is normally done at working pressure to prove joints and system integrity. The component parts of the system should have previously been proof tested to either 1-1/2 times the design pressure (in shop testing) or 1-1/2 times the operating pressure (in situ testing).

The testing required here is different. It is a test of the integrity of enclosed areas. Using 1 bar pressure in a test of this nature would be suicidal, remember that 1 bar is 14.7 lbs per sq inch and there could be a lot of sq inches in a bulkhead.

Use a manometer and limit the air pressure to a few inches of water, then, either do a soapy water test, as mentioned by AdHoc, or if an access problem prevents this, leave the pressure standing for a few hours and see if there is any pressure drop, which would signify a leak. Be aware that changes in temperature can cause pressures to vary but if the trend is always downwards you will definitely have a leak.

[CDK]

Tests mentioned by daiquiry and murdomack are used for pressurized systems only.
I had to fill my LPG tank with water to the brim, then the inspector used a plunger pump to pressurize it to 20 bar, way beyond the worst case operating pressure, waited 15 minutes and checked for pressure loss. Then he increased the pressure to 24 bar to make sure the safety valve opened.

To check the integrity of a bulkhead I do not encourage such testing methods unless we are talking about submarines. Soap and water seems the way to do it.

[daiquiri]

I'd like to learn more about the soapy water method. How does it work? Do you just brush some soapy water over the welds and then pressurize?
Cheers!

[hamedhpt]

Originally Posted by Mat-C

Can I ask what sort of boat you are talking about here?

Hi.Fiberglass boats and also aluminum boats.

[murdomack]

Originally Posted by daiquiri

I'd like to learn more about the soapy water method. How does it work? Do you just brush some soapy water over the welds and then pressurize?
Cheers!

Yes, you just apply the soapy solution and look for bubbles. You can buy a solution called Snoop, or Snoopy, but Fairy Liquid (washing up liquid) does the job as well, just mix some in a basin when your better half is not looking ansd if you can blow a bubble with it that's all you need.

We had a thread here last year, maybe earlier, about testing tanks, and in the end we all agreed that the right and safest way was with a manometer. Your testing would be similar and I am sure there are procedures in place with the various authorities.


Pressure testing integral fiberglass diesel tanks
tank testing

[aranda1984]

Hello Friend.

It is very difficult to make a pressure test on a large boat for a very simple reason: you can't seal off the engine room perfectly towards the inside, unless it is a perfectly watertight door and compartment!

First of all, let's take a small door of 36" by 60" on an engine room.
That has an area of 2160 square inches. If you pressurise the engine room to one bar pressure, that will have the total resultant force of over 31 thousand pounds on the door. (Can you imagine the pressure on the hull area?

Second; can you imagine spraying soapy water over a 37' (or a larger boat) and try to see if the soapy film is developing bubbles. (As you spray it, the solution forms bubbles anyway.)

Putting a pressure gauge someplace to see if you have a pressure drop will never tell you if it is the internal door that leaks or it is the connection at the pressure gauge, or if it is the hull that is compromised.

On aircraft, the usual testing method used to be: fill the inside with smoke. Build it up to required pressure and watch out for the colored smoke to escape through the fuselage.

On large bodies like this, an air pressure test might say that it is ok, yet a hydrostatic pressure test might indicate failure.

Study up on "non destructive" test methods.

You can buy a red dye that you spray over the joint or weld surface. Wash it off with the cleaner supplied, and spray the white powder that comes with the dye over it. (They come as a kit!)

If there was a crack in the weld or in the surface, the red dye would have penetrated the crack (capillary action) and now the white powder will bring that out and indicate a poor weld or surface crack.

In case if there is no fault or crack present, the powder remains white!

As far as I am concerned it is from a view point of a stress concentration area at the poor weld or joint and not a leak that is most important.

If it leaks, you will see it in no time. It doesn't have to leak to be a future stress failure point.

In every case it is the repeated or cyclic loading that is making these hidden faults dangerous.

On metal hulls the normal process of fixing cracks is to grind out the faulty line and layer by layer weld new metal to fill the area.

You must make a red dye test after the repair again!

An alternate test method for steel hulls is: place a large piece of magnet on the suspected area. Spread steel filings around and you will see the flux lines formed by the filings.

Any crack line will show up in the lines as the electromagnetic flux lines will form along the crack.

...You know the driill on fiberglass hulls.
If you suspect an area, put a patch over it! (Smirk!)

Regards,

Stephen

[TeddyDiver]

Using soap water is done with a spray bottle like is used for window washing etc.. so it's not needed to soap everything at once, just check one place with a spray and move to next. Good test for plumming etc..
Doors and hatches are commonly tested with pressurized water hosed against the closed one. ISO standards include specific instructions how such a test should be done. Solas has different requirements for commercial vessels..

[Landlubber]

....you are kidding right...do not apply 14 lbs pressure to a vessel, it will blow up. There is no need to do this to just see if something is watertight.......

...just as an example, an inflatable that is pumped up rock hard is about 4 lbs.....to do this sort of pressure to a vessel is to bust it

[murdomack]

Originally Posted by hamedhpt

Hi.I want to test different compartments in a boat to see are they watertight ?For example in the engine room, are the cable penetrations sealed perfectly?Or the places where bulkheads are connected to the deck, are they watertight? I am searching some standards for these kind of tests.For instance in BV or GL or DNV.

What you could do for testing bulkhead connections individualy is to seal wrap them on one side with masking tape, apply a regulated supply of air pressure into the envelope, maybe 1 psi, and then spray a soapy solution to the other side to see if air is coming through.

Welding inspection should be enough proof of the integrity of metal bulkheads. A visual inspection should suffice for well finished fibreglass joints. If you still need to fill the whole compartment with air, use a manometer set-up as it is the safest way. Feed your air through a pressure regulator pre-set to give a couple of feet of water in your manometer tube. Spray the suspect areas with soapy solution and check for bubbles.