GRP pipe U/G hydrotest 1

[Youbinho]

Hi everyone,

we're installing a GRP (FRP) pipe for see water intake according to AWWA standard, but i can't find specification about the pressure test to be used in the hydrotest neither the holding time.
if anyone have an idea about the process of hydrotest for that kind (refering to awwa standard)

 

[LittleInch]

Of its not in the standard, check the pipe vendor data sheets or installation guides. If it's an intake does it have a design pressure? ?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

American Water Works Association maintains the standards for small and large diameter fiberglass pressure piping in potable water pipelines including:
i. AWWA C950 for Fiberglass Pressure Pipe which outlines general requirements for materials and manufacture.
ii. AWWA M45 Manual of Water Supply Practices which provides information related to design, specification, procurement, installation and understanding of fiberglass pipe.

The AWWA Manual 45 recommends that FRP pressure pipelines be tested after installation but does not provide any test pressures. The lack of more detailed information on field testing in M45 is related to the small amount of FRP used in municipal service. Manufacturers recommend 1½ times the design operating pressure.

 

[Youbinho]

yes indeed, we're planning to make the test pressure test 1.5x design pressure which is 6 bar for our case.
the contractor suggest to use EN 850 standard which only add 1 bar to the pressure of design.

 

[pennpiper]

Now, let's rethink this!
You have a Pump Suction line taking Sea water from the ocean, is that correct?
1. The Design Pressure is based on the depth of the Intake point below Sea Level.
2. The Operating Pressure is near zero considering the suction of the pump.
3. You are going to Hydrotest the pipe before you drop it into the trench, right?
4. How are you intending to close off the pipe at the intake point?
5. How do you plan to keep fish, other critters and Sea weed out of your intake pipe?
6. What size is this Suction Pipe
7. Maybe there is more you are not telling us?

Sometimes its possible to do all the right things and still get bad results

 

[LittleInch]

6 bar for a sea water intake line????

What size are we talking here?
are you client or designer?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Youbinho]

- the intake has stop gates and trash racks, so the problem of sea weed and fishes isn't a matter, they're blocked that level.
- the diameter of the pipe is 3m
- the intake has pumps so the operating pressure is not 0

do you have any idea about pressure test to be done according to AWWA ? and holding time for other dia/pressure ?
i appreciate your answer.

 

[LittleInch]

It's pretty clear from your question and bimrs answer that there is nothing in AWWA to specify this.

Therefore you need to make an engineering judgement on what is a reasonable test pressure and a reasonable holding time.

The test pressure that most pipe vendors will sign up to is max 1.5 x design pressure. Sounds Ok to me, but check with your vendor and vendors data sheet
The test time - give it's location I don't think you're going to get much in the way of thermal change to affect your pipe, so I would go for a min of 4 and max of 8 hours.

Is this pipe upstream or downstream of the pumps? "Intake" normally implies upstream only where you would use discharge or delivery to indicate pipes downstream of the pump.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Youbinho]

thanks fpr the reply,
i guess i'll opt for the 1.5 x design pressure, and keep it 24h, because it's a big line under ground.

 

[rconner]

I noticed the inquiry starts with the introduction "we're installing..." Are you saying the plans and specifications for this extremely large pipeline, that apparently has already progressed to the installation phase, presently contains no requirements for testing the pipeline after installation?