Exclusion Zone Distance For Pneumatic Testing

A 76in pipeline 1.3km long has an internal volume of around 3800m³.

The energy needed to achieve 3.85bar in this line is in the order of 1.5GJ.

20J is well sufficient to crush someone's foot.

If the end of the pipe lets go then there is sufficient energy for the pipeline to become one enormous torpedo. So an exclusion zone well in excess of the length of the pipeline is in order.

Unless, of course, the thing were to be tested hydraulically with water instead, which is what any sane, responsible person would do rather than filling the thing up with air!

One presumes the Engineer/Surveyor for the company responsible for supplying burst indemnity insurance for this pipeline has not been contacted so far, and is probably well outside the exclusion zone at this time.

The original suggestion is quite ridiculous.

Please make sure all other CR4 readers are in another country before carrying out this test.

http://en.wikipedia.org/wiki/Darwin_Awards

ramil barrosa-

Why did anyone even consider pneumatic testing of this pipe? This is similar, and probably more dangerous than the compressed air "Pumpkin Chunking" done annually in the state of Delaware, USA. At least they use materials and components designed to handle the compressed air. A pipeline is not! It should be hydro (water) tested, not air.

In the USA this system would have to be hydraulically tested before being put into use. Compressed air leaks would cause a potential explosion because there is a lot of compressed air behind the initial blast. A leak with water only causes a small dribble resulting in wet feet. Water is not compressible, air is!

Good Luck, Old Salt

Don't do it!

I have been diggin up/working in the crater of a gas pipeline almost your pipe size that burst out due to corrosion. We never found the middle piece in the surrounding fields. It ain't pretty!

Went thru all this 6 months ago for testing the gas side of economisers.

There is a lot of information on the web, but heres a couple of references.

I used AS-NZS 3788 for the calculations.

ASME PCC-2 Part 5

USDOE PNNL-18696 Pressure System Stored Energy Threshold Risk Analysis

Sea Gulf Oil & Gas Development Company - Method Statement for Pneumatic Testing for Piping System

ABSA- AB-522 Standard Pneumatic Test Procedure Requirements for Piping Systems

I hope this helps.

John B

If there is a reasonable way to avoid same, please do so (too many have died, and hydro is a better test).

Mr. ramil barosso,

Pl. do not even think and attempt to do compressed air test (to a pressure of 3.85 bar) since it involves enormous danger, perhaps end up in catostrophic damage.=. Even inert gas like Nitrogen is also not advisable.

The magnitude of danger by compressed air testing for this volume of pipe and the pressure referred by you is very huge. The pressure referred by you is equal to 4.046 Kg/cm^2 and in terms of water column it is 1650.94 inches of water column and in the event of rupture, the inital velocity of escape of compressed air will b will be as high as 1302,52 Feet/Sec, (397.11 Metres/Sec) since the vol. of air will be max. 14928.57 M^3 has to escape instantly.

3.928 M^3 air to be compressed to get one M^3 of compressed air at 3.85 bar and as Mr. PW Slack estimated 3800 M^3 is to filled. I am considering the worst scenario that the pipe birsts near to 3.85 bar.

I have seen even at 15 inches of water column air blown by ID Fan of a person lost his balance and blown off and you can imagine the draft 1650.94 inches initially and the danger will persist till the air pressure falls to 3 inches of draft water column. If it fails in the middle of the pressure build up the intensity may be less but danger is danger.

If you use water for hydraulic testing for a pressure of 3.85 bar you mave have to use 77,600 litres or 77.6 M^3 of water as against 14928.57 M^3 of air (192 times more volume than water) and as water is highly incompressible, in the event of rupture, the pressure drop will be instantaneous and danger is relatively small.

I hope you understood the impending danger for air pressure testing

DHAYANANDHAN.S

http://www.wermac.org/misc/pressuretestingfailure1.html