How do you determine if an air leak you have found with your brand new ultrasound gun is bad enough to repair? I have easily found a bunch of air leaks but some of them that measure 25db to 35db can barely be felt by hand, are they worth spending the money to repair? For example, I found some plastic tubing fittings that are leaking where the tube slides in and measure about 35db but when you put your hand around them you can barely feel them. I know you have to calculate the expense of repairs against the expense of the lost air but is a leak that you can barely feel with your hand worth bothering with, even if repair costs are relatively low? Also how can you estimate the air loss from a leak? I have seen charts that show the loss from a certain sized orifice at a certain pressure but most leaks don't come from perfectly round smooth orifices. Most of the leaks I have found come from threaded connections, bad gaskets, tube fittings, etc.

Thanks for your help.

This sounds interesting. I have seen mechanical people detect steam leak from a 24in check valve (after reported by operations) using first a flexible strip (anything suitable picked from the ground) and hold it against each bolt around the check valve. When it is flipping, there is a leak from that bolt. Then they hold their hand palm on the suspected leak (as a sensor) to confirm it. In this case, it appears difficult to justify for an ultrasonic detector. Next corrective action is to furmanite/seal the leak.

This message has been edited. Last edited by: Josh,

Josh,
they used to use a similar system in many UK power stations - that was until a couple of people received severe steam burns - now they almost all use ultrasound!

Randle,
you are of course correct, there are many leaks which create considerable turbulence but with little flow. SDT have documented some very interesting research which they performed which examined orifice size, shape, pressure, flow rate and measurement angle.

Best Regards,
Tom Murphy

quote:

Then they hold their hand palm on the suspected leak (as a sensor) to confirm it. In this case, it appears difficult to justify for an ultrasonic detector.

Sounds like the guy who put his hand in a fan to check if it is running, I would check the accident rate of this company. Never put your hand to detect a leak, when there is pressure involved, even a hydraulic cylinder. I have seen pressure washers cutting cutting a brick in two pieces, and a firewater hose bowling with with two operators at the moment of a hose burst.

Randle many small leaks, make a big one, and the leak will get bigger and bigger and more expensive to repair. The next step is another compressor/boiler to guarantee the air/steam supply. If your demand has increased without any new equipment/installation added you are probably too late.

Accident report: NO LTI, no injuries due to steam leaks because the mechanic palm surface is very hard due to hands on works!

Do you allow touching a machine to check whether it's vibrating or not?

Don't you listen to noise from a machine using ears or strictly ear-plugged?

Do you write a guide on using human senses for machinery surveilance in the HSE manual?

This message has been edited. Last edited by: Josh,

Hi Josh,
Wearing gloves of some description will help prevent accidents in a variety of industries and prevent skin cancer or dermatological disorders in many others. But, gloves have never stopped me feeling a machine.
I am very fond of my hearing - which I use to listen to music and hi-fi reproduction. I therefore always wear ear plugs or normally ear muffs. In high-noise environments, ear protection will actually enhance some of the sounds you are trying to pick up.
"A job is not worth doing if it can't be done safely".
When I leave this industry, I still want to have hands, ears and eyes for use in my retirement!

Best Regards,
Tom Murphy

That's good Tom. I guess the statement "A job is not worth doing if it can't be done safely comes from BP.

This message has been edited. Last edited by: Josh,

Josh that statement can come from anyone who is working, and attribute it to BP would bring back memories of the overflowing of an archaic blowdown stack killing several people not so long ago.

Randle,
Your question about leak size depends on the type of system and its function. A compressed air leak can be judged in terms of severity a number of ways:
1) Energy loss due to additional power to make the compressed air
2) Moisture entrainment if air is very dry and environment has high humidity
3) Noise affects personnel hearing or voice communications
4) Pneumatic control system response
5) Dust generation or air contamination

A small tubing leak may have low energy loss (item-1), but one or more of the other items may be a significant issue. I suggest you define your leak survey objectives and assign a severity ranking scale to each issue that is important.

Walt

For instrument air, the pneumatic control system response is really important.

Svanels, you are right but one day maybe you thought it's safe but actually is not esp'ly when acquiring new assets, no matter how much we think about Good To Your Neighbour.

Hi guys,

May be we will plan to have an Ultrasound Testing equipment next year.. Compressed Air loss is better compared to Compressed Process Gas.. CO leaks are common in our DR Plant.

Can anybody guide me in finding an instrument for determining leaks??

Have a nice day!!