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Permissible drop and TT

View the thread, titled "Permissible drop and TT" which is posted in UK Plumbers Forums on UK Plumbers Forums.

Just add (an excuse myself from being wrong!) I have used electronic gauges for a while now so the 0.25 has stuck in my head
 
Sometime in the last 6 years or so i think. I noticed it when i last did my acs as i wrote down 0.5 without even thinking and it was wrong. Looked it up and it is now 0.25mb
 
It has been out for a while now Loe and is usually a question in an acs exam.
It was changed to 0.25mb a wee while back.
This is what it says about it.

Note: A movement of 0.25 mbar or less on a fluid (water) gauge is considered to be “not perceptible”. Therefore, if the gauge is seen to move, it can be inferred that the pressure within the installation has altered by more than 0.25 mbar.
It follows that, where a gauge that can register perceptible movement of less than 0.25 mbar i.e an electronic gauge, is used, the pass criteria of “no perceptible movement” has to
be considered to be a maximum of 0.25 mbar except for those gauges that read to one decimal place when “no perceptible movement” is considered a maximum of 0.2 mbar.

another rule change to keep the training industry afloat its the same gas and the same gauge so what other reason can there be?
 
Get a grip, haha, how much did the training centre make extra on each candidate by telling them the change

£1.37 ?? 😉




as regards changes : changes for the sake of safety or technical improved knowledge are welocmed. the ones i find hard to take are when they change the name of something. When i did my electrical training over a 4.5-5 year period they changed the name of the live,neautral and earth about 3 times. Each time it was "they have changed the name phase to line conductor, so we have to alter all your diagrams and books to suit" the teachers used to laugh about it because it seems to go around in circles.
 
another rule change to keep the training industry afloat its the same gas and the same gauge so what other reason can there be?

Better glasses these days?

No one can tell a 0.25mb drop on a water gauge with that degree of accuracy so they now say if you see it move at all then that is a perceptible movement.
 
Better glasses these days?

No one can tell a 0.25mb drop on a water gauge with that degree of accuracy so they now say if you see it move at all then that is a perceptible movement.

That would be a rule change that would make sense for once
 
Just for once I'm spot in, never heard of the permissible drop rule . Thought a drop was a drop, for once I'm right. Yay.
 
Just for once I'm spot in, never heard of the permissible drop rule . Thought a drop was a drop, for once I'm right. Yay.

Sorry, but if you have passed your CCN1 you HAVE heard of permissible drop, you may have forgotten but you did answer questions on it on your theory
 
Kirk, what is your opinion on the question I raised at the end of post #62 albeit with the wrong figures. If I had a drop on an electronic gauge of 0.2mb but the customer could small gas (unlikely I guess) would you cap or would you class as no perceptible movement?....
 
Kirk, what is your opinion on the question I raised at the end of post #62 albeit with the wrong figures. If I had a drop on an electronic gauge of 0.2mb but the customer could small gas (unlikely I guess) would you cap or would you class as no perceptible movement?....

That's easy peasy, ANY smell of gas means there is a leak, if its less than perceptible movement then the leak could be on the other side of the reg which has locked up,
If its a theoretical question I would say its very unlikely to smell gas that's less than 0.2mb over 2 mins, but its straight forward by the statement that they smell it so there is something to be rectified

This leads to another question scenario:
As you have said, they smell gas but there is no movement on the u gauge, what is the procedure you MUST carry out
 
That's easy peasy, ANY smell of gas means there is a leak, if its less than perceptible movement then the leak could be on the other side of the reg which has locked up,
If its a theoretical question I would say its very unlikely to smell gas that's less than 0.2mb over 2 mins, but its straight forward by the statement that they smell it so there is something to be rectified

This leads to another question scenario:
As you have said, they smell gas but there is no movement on the u gauge, what is the procedure you MUST carry out

Post a business card through the neighbours door?
 
Just to throw one out there,

On a cloudy day you bring your manometer to 20mb, it sunny and rises 2mb, the cloud comes over and drops 3mb, or you raise your manometer to 20mb whilst it is cloudy, it drops 2 mb, then the sun comes out and raises it by 3mb??

Do you define that a leak or not??
 
This leads to another question scenario:
As you have said, they smell gas but there is no movement on the u gauge, what is the procedure you MUST carry out

If there is no movement on the gauge then there may be a leak upstream of the ECV or coming from an adjacent property. The only correct course of action is to call the gas transporters emergency number and report an uncontrolled leak.
 
Just to throw one out there,

On a cloudy day you bring your manometer to 20mb, it sunny and rises 2mb, the cloud comes over and drops 3mb, or you raise your manometer to 20mb whilst it is cloudy, it drops 2 mb, then the sun comes out and raises it by 3mb??

Do you define that a leak or not??

I do all my testing in scotland, what is this thing "sunny" you speak of?
 
If there is no movement on the gauge then there may be a leak upstream of the ECV or coming from an adjacent property. The only correct course of action is to call the gas transporters emergency number and report an uncontrolled leak.

Correct,
But when asked, a lot of re-assessment guys say they test the install and if there is no leak found they tell the customer they don't know what they are smelling as it isn't gas :-o
 
Just to throw one out there,

On a cloudy day you bring your manometer to 20mb, it sunny and rises 2mb, the cloud comes over and drops 3mb, or you raise your manometer to 20mb whilst it is cloudy, it drops 2 mb, then the sun comes out and raises it by 3mb??

Do you define that a leak or not??

Throw a dust sheet over the exposed pipework.....
or a pair over the lpg bottles 😉
 

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