none perceptible movement on tightness testing

[carrpaul]

can any one refresh me on the none perceptible movement on tightness testing with a fga .

 

[solutions]

my understanding is there either is no perceptible movement or depending on how measured that movement is at a fraction of a level measurable on a u gauge. Essentially if measured on a u gauge would the drop be perceptible. Of course their are the regs that factor in the nature of the test and the allowable drop based on wheher the carcass is new or existing, or there is a smell of gas, new appliance install etc.

 

[EPH]

Use a U gauge.

 

[Ermintrude]

On a gauge measuring to two decimal places I.e

20.00mbar the permissible movement is +/- 0.25mbar.

Handy tip, if timer is on 1.54 mins and movement goes to -0.26 rub gas pipe by meter will soon get back to -0.16

 

[iain85]

Had this discussion with a Bg engineer other day. He thinks u gauge has no tolerance and I was trying to inform him 0.5mb is the tolerance of no perceptible movement.

 

[beesley121]

On a gauge measuring to two decimal places I.e

20.00mbar the permissible movement is +/- 0.25mbar.

Handy tip, if timer is on 1.54 mins and movement goes to -0.26 rub gas pipe by meter will soon get back to -0.16

Why bother? , providing there drop is within spec and that there's no smell of gas by the customer, it's a pass anyway

 

[erpkid]

As erm say reading to two decimals it is 0.25. This is effectively the limit on what you would see in a water gauge. Electronic is nice and you can get a print off but can drive you mad waiting.

 

[Barry98]

Moved to private forum , ALL gas posts from gsre should be in the private section of the forum

 

[sheff paul]

tested the other day with FGA,custard opened a door adjacent to a long run of surface 22mm gas pipe the incoming cold air cooled the pipe and registered a drop,wouldnt have noticed on a u guage.

 

[leethegasman]

Why bother? , providing there drop is within spec and that there's no smell of gas by the customer, it's a pass anyway

May be working on new installations not every one works on existing installs.

 

[bennygas]

I could've sworn there was something in the corgi manual that said something about 0.25 mb on u gauge and 0.1mb on electronic being the criteria, I'm probably wrong/ out of date - hardly touch gas these days

 

[Ermintrude]

If resolution to two decimal places on electronic gauge and it's domestic perceivable movement i. 0.25 mb
If it's a manometer test for 25 seconds and guess what ur initial reading was.

 

[bennygas]

Guess? Eh? Not quite with you mate...been a loooooong day

 

[Pssst]

I always use a U guage,nice and clean,bleached every month to prevent stiction in the tube. A U tube is rarely wrong..

 

[albatross]

I thought it was 0.5mb on a u-gauge and 0.33mb on a digital gauge.

 

[Ermintrude]

Always been 0.25. Unless your gauge measures in 0.66 increments. ( must be French) I'm sure that the gauge was brought to 0.25 when igup/1b was amended last year?

 

[tamz]

0.25mb on a gauge is perceptible movement. Perceptible movement means what you can see moving so if you are using a gauge and see it move, however little, it is a fail (new customers only):smile:

 

[Resolute]

I always use a U guage,nice and clean,bleached every month to prevent stiction in the tube. A U tube is rarely wrong..

Bleached utube? I only ever change the water if I drop it!

 

[Pssst]

Yes but im a blind git now...I'll soon have to get a monocle to read my u guage..

 

[GrahamM]

I thought it was 0.5mb on a u-gauge and 0.33mb on a digital gauge.

As mentioned perceptible movement is 0.25mb for a U-Gauge. The increments are 0.5 mb but any movement between the 0.5mb graduations are perceptible.

 

[Ermintrude]

wow, some of you guys are arguing a BASIC skill in GAS

If you don't know how to do this, you shouldn't be in here IMO

I find this very concerning

But who actually bothers with a TT any way?

 

[albatross]

wow, some of you guys are arguing a BASIC skill in GAS

If you don't know how to do this, you shouldn't be in here IMO

I find this very concerning

Don't worry Simon, no one has said more than 0.5mb. I think I speak for many of us that when you have been doing it years it's second nature. You pop the gauge on and see if it's sound or dropping and if so fix it. If I feel it's borderline or have to question it I find the leak or cap it. Err on the side of safety. But that is rare.

 

[Pssst]

A gauge is not the is not necessarily the final arbiter anyway. I have been to many a leak that can be smelled but which is just not perceptible on the gauge. Thats why i bleach my gauge regularly and treat it as a precision instrument. It gets clean water,and i make sure there is no drag or stiction of the water in the u tube and that it is crystal clear and easily read.

 

[jase158]

on my anton, I open gas valve and it shoots up to 40mb (not possible on domestic meters) I then release pressure down to 10mb, do let-by. increase pressure to 20mb (after it shoots back up to 40mb) and perceptible movement is between 0.4-1.5mb every time. I have given up on it as never correct. U gauge shows no movement.

 

[Ermintrude]

Was it like that after service? If so send it back as they haven't calibrated it properly.
When working on large detached houses in sticks standing pressure about 65mbar.

 

[AWheating]

digital gauges are too sensitive for the job of tightness testing. wata aye so sensitive and doh cost you alot to fix/refil when you leave it on the van roof and drive off