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Hydraulic Test in a Fire Water line

Hydraulic Test in a Fire Water line

Hydraulic Test in a Fire Water line

(OP)
The standard for the Fire wáter system is ANSI.B31.3
The client wants to buried the pipe in the trench without visual inspection.
The lines is coated with polyguard.
They want to test controlling the pressure during 4 hours recording the pressure
Does ASNI permits this option'
Regards
Luis

RE: Hydraulic Test in a Fire Water line

In B31.3 Fire Water would be classified as a Category "D" Fluid and as such it can be Commodity tested.
The pressure for the test and the duration of the test can be stipulated by the Client.

prognosis: Lead or Lag

RE: Hydraulic Test in a Fire Water line

(OP)
Pennpiper

Does ANSI permit to do the HYDRAULIC TEST without visual inspection during the test?
The client wants to fill the trench and cover the line before the Hydraulic Test.
Yes. Fluid is category D, but the owner added 3% RT and 18 bar for Hydarulic Test.
Thanks

RE: Hydraulic Test in a Fire Water line

I assume you explained that it will be very difficult to find leaks if you do the test and the line does not hold pressure.

This is Fire Water! The client should consider this the second most important line in his plant.

We already know he thinks the first most important line is the straight line to the bank.

prognosis: Lead or Lag

RE: Hydraulic Test in a Fire Water line

you really need to backfill first. placing backfill and compacting will load the pipe and sometimes this results in leakage. Also, the pipeline may not be fully restrained without the backfill. finding and repairing leaks is the contractors problem and hopefully will motivate him to install correctly in the first place so it will not leak.

RE: Hydraulic Test in a Fire Water line

Wait just one minute! Maybe I am all wrong. WoW!
The original post said "The line is coated with Polyguard." By that I assumed the line was steel pipe with butt welded joints not Bell & Spigot" (a slip joint). Someone, please correct me if I am wrong.

Now, if it is in fact a welded joint line and it needs Back Fill to hold it together, why don't we need Back Fill over the lines up in the overhead pipe rack when we hydrotest them.

prognosis: Lead or Lag

RE: Hydraulic Test in a Fire Water line

again, backfilling and compaction could put significant stress on the pipe and might cause it to leak. our standard specs require final acceptance testing after backfilling for all buried pipe, regardless of the type of corrosion protection, pipe or joints.

RE: Hydraulic Test in a Fire Water line

Visual inspection is mandatory

you must get smarter than the software you're using.

RE: Hydraulic Test in a Fire Water line

lganga,

The real issue here is in your first sentence. B31.3 does not do buried pipe very well at all and this sort of thing is one reason why. cvg, I agree with you that the pressure test needs to be done on the pipe in its "as installed" condition. pennpiper - clearly backfilling a rack pipe is silly when this is its installed condition.

So, what I suggest is that you write to the owner noting that the piping design code requires visual inspection of the joints and welds, however for buried piping this is not practical or in fact desirable as it does not test the pipe in its as installed condition. Therefore the pressure test can take place, but if any leaks are found, there will be considerable difficulty in locating them and some disruption (excavations etc). However this is no different to pipelines where a similar situation exists. Therefore you need to note to the client that this (burial before testing) is an exception to the code which requires his approval.

It would be good to know exactly what sort of pipe and jointing is being proposed - "3% RT" sounds like welded pipe, but maybe you need to increase that plus 100% visual inspection by a welding inspector

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

RE: Hydraulic Test in a Fire Water line

(OP)

Littleinch
The pipe is A53B, buttwelded.
My alternative was to put the line into the trench and not filling it, till the Hydraulic test.
Due to the rainy weather , the client prefers to fill it.
LittleInch we have a welding inspector for checking visually 100% for the welded joints
Any way I think that a comment HYDRAULIC TESTED WITHOUT VISUAL INNSPECTION should be added to the TEST REPORT
Many thanks to all of you

RE: Hydraulic Test in a Fire Water line

If you are in the USA, NFPA is the 'correct' code. As noted above, B31.3 does not 'do' buried piping very well. It is for process piping inside a plant.

A proper NFPA underground pipe hydro test requires 200 psi for 2 hours, and the ability to measure the leakage; how much water did you use to maintain that 200 psi. It was designed for bell & spigot, and is VERY generous for welded lines. And it works, and it is NFPA. You'll have to look up the allowable leakage; it is a function of line length and diameter of the hydro boundary valves.

RE: Hydraulic Test in a Fire Water line

I certainly understand a mindset of wanting to keep lines exposed for close examination during testing (I believe that really originated long ago, in an era of prevalent lesser quality welding/materials and/or more labor-intensive/reliant joint designs than employed today). However, some quite compelling points have been made on this thread relative to testing of pipe for buried service "buried", beginning with the observation by cvg that the fully backfilled condition, after whatever extent of exposure or "conditioning" occurs from the time the pipe is placed in the the trench through backfill, is indeed exactly where/how buried pipes will serve the Owner and public.
I would only add a couple other considerations, that in this age where some level of "Risk Management" and "Vulnerability Assessment" is increasingly also expected, leaving substantial lengths of open trench or many open inspection pits etc. could also be problematic in these respects. Another manner of risk has been touched on, that being that as many locales are subject to rains or even "flash floods" (and the pipe trench after all may often be the lowest area of a site), the exposed pipeline is subject to flotation or damage in same, and the bedding and trench walls are also subject arguably/unnecessarily to some degree of contamination/ruination or erosion in that process.
Last but not least in increasingly not insignificant matters of risk are "safety" considerations. Since time immemorial people and animals (a good example of the latter perhaps in current news at e.g. http://phys.org/news/2014-08-ancient-bones-wyoming...), and for whatever reasons other than the indomitable end influence of gravity, have been been injured or met untimely ends in the bottom of "holes". Accidents involving open pipe trenches occur more often than perhaps many people realize, now involve all manner of errant vehicles, sometimes with more or less happy endings like http://nycrpd.org/?p=1752 or http://www.dailymail.co.uk/news/article-2350774/Ho... , but unfortunately with some worse consequences. While there are still too many fatalities in trench collapses, I also I noticed e.g. bullets at the site with the following "lead in" did not include incidents of collapse,
<<<The following are the main causes of lost-time injuries in the sewer and watermain industry:
• materials and equipment falling into the trench...>>>
While I guess the project nature and accident involved in the particular incident http://www.cdc.gov/niosh/face/stateface/wa/02wa034... might also be considered inapplicable, the conclusions arrived at in the statement, "Cones and other delineating devices can be useful to define the proper traffic lanes from the work zone, but they provide little to no physical protection for workers from an intruding vehicle that might enter the work zone. With today’s driving public, it is not unusual to find drivers who are impaired, who are inattentive, who are speeding, who drive aggressively and who pose a danger to not only themselves but to other drivers. They also present a serious hazard to workers situated in highway and road work zones. As demonstrated in this incident report, the current work zone control methods were ineffective in preventing the fatality and serious injury that occurred to the two utility workers in the work zone..." may not be.
While efforts are sometimes made in specifications to assign primary responsibilities for safety/welfare and minimal disruption to operations and the Public to the Contractor (where I guess most should indeed be), some parties including specifying Engineers, Inspectors, Owners and Regulators etc. now also appear to have at least some influence and interest in these areas as well. When long lengths of pipe trench are required to be left open for extended durations of work completion, and then e.g. for exposed or partially exposed testing purposes, in reality it may be neither inexpensive nor easy for the Contractor to achieve the contrapositive to the above insert (i.e. effective, as opposed to "ineffective" work zone control methods or barriers), and if/when (God forbid) something bad happens, I guess I can see arguments ensuing as to what was reasonable or meant or approved, or were there other reasonable approaches by all parties to the issue?
I feel many contractors on many jobs in particularly crowded urban or industrial areas might now generally prefer to get in, do a good job, get out(backfill) as quickly as practical (at least when all the required underground work connections in the hole are completed), and move on for eventual test leaving the area (of course in Boy Scout fashion) surely better than they found it! All have a good weekend.

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