fiberglass piping information

[ifran31]

Hello, first time poster with a query regarding firefighting calculation.

Can anyone help me to give some information regarding the piping?

I have 02 projects:
The first project:
Firefighting project: the piping is made on fiberglass for the 02 chips loading (product is oil) by water and foam protection,
My questions are:
Is there any difference (for fiberglass) in flow calculation, flexibility….?
For Installation accessories or other pieces like hydrant, valve….
If not, is there any one has experience in this type of the design (fiberglass for firefighting)?
The second project:
The project is piping connection for connecting 04 tanks (fuel, gasoline, jet A1 and super) and installation firefighting piping,
Following the data climate, the winter temperature is -4 ° C, but these days it really falls temperatures,
Is that the pipe insulation requires protection or other network for water and foam to resolve the problem of freezing?
Also, for connection piping system
Other question
Both installations will be carbon steel A106 API 5L GrB or GrB? i.e. piping diameters is 3/4’’ to 12’’ for two projects.

Thanks in advance for your help
(Sorry for my English I’m beginner)

R.B (mechanical engineer)

 

[zdas04]

I don't think you have anything to apologize for in your language skills. Your written English is better than a lot of native English speakers.

When you first said "firefighting" I thought to how those guys throw stuff around and shuddered. But reading through your post it sounds like stuff they would use in the fire station without alarms jacking up their adrenaline.

FRP (Fiber Reinforced Plastic, fiberglass) pipe is about as slick as HDPE so in calculations you want to use 5E-6 ft for absolute roughness (steel is most often published as 150E-6 ft). If you are using an equation with an explicit efficiency number I usually use 95% for new steel and 100% for new FRP (it usually doesn't matter, but I find that I match measured data at high Reynolds numbers better with 100% than with 95%). Other than that you use the same calculations.

Typically, I tend to end the FRP with an appropriate Class flange bolted to a steel flange for a valve set. There are some plastic and FRP valves, but I'd still rather use steel for the stuff people touch.

FRP is as unforgiving in freezing conditions as steel is. It just isn't very flexible so if you get a contained freeze you will get broken pipe. If I was coming to the surface with a fluid that has a freezing point within 25C of the record low temperature I'd be nervous. I've been looking at spoolable composite pipe like FlexSteel, FiberSpar, SoluForce for stuff like that. I've had produced water freeze hard in this stuff and found that it has enough give to handle the 4% volume change without breaking or even yielding. It has all the corrosion resistance characteristics of FRP, but installs much more quickly (it is on spools), is not at all delicate, and seems to do pretty well in phase change (when the line freezes it still stops flow so from a process standpoint you don't want the line frozen hard, but at least it tends to not break when frozen).

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[SNORGY]

In addition to the above, a secondary driver for the requirement for insulation might be UV protection.

 

[zdas04]

I don't think about UV with FRG because I've buried every inch that I've ever installed. I go to a flange and convert to steel before I get within a meter of the surface. I REALLY don't want FRG to freeze or get hit by a road grader.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[SNORGY]

Agreed, David.

It was unclear to me from reading the original post whether or not some of the piping was above grade. The reference to a winter temperature of -4 C implied that some pipe was A/G, since my biased assumption was that buried pipe, when U/G, would typically be below frost level, so winter ambient would be irrelevant.

 

[ifran31]

Thank you guys for your messages,

after reading your messages above; able to keep the firefighting piping, it must be completely U/G? Except the connection lines of the pumps.

Pleased to reading you, thanks a lot

Have nice day

R.B (mechanical engineer)

 

[zdas04]

I never bring FRP to surface (I generally transition to steel a full joint away from the riser so I'm not carrying any of the weight of the valve set on the _fiberGLASS). The risk seems too high to me. Others do bring the FRP to surface. I know one Engineer that has been doing it for over 10 years and his results must be adequate or he'd stop. He has lost 6 lines that I know of (1 to freeze, 5 to being struck by vehicles), but he's still doing it. It all comes down to Engineering judgement.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[MiketheEngineer]

Could it melt??? during a severe fire??

 

[zdas04]

I investigated a dehy fire a few years ago. For reasons that I never understood, the glycol line into the reboiler was FRP. The fire got hot enough to burn off all the exterior paint on the reboiler, but the FRP looked fine. I'm pretty sure I'd hydro the line before I used it again, but visually it was in better shape than anything else on the skid. In a full-on raging fire of a pooling liquid (for example) I would almost bet that it would outperform steel. At least the fires I've investigated around FRP tanks, they outperformed steel tanks in the same fire.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[MikeHalloran]

In the world of big yachts, FRP is often used for engine exhaust pipes and mufflers. ... but there's a trick; some of the seawater that has been used to cool the engine is sprayed into the pipe to quench the exhaust gas, which would otherwise be flowing at ~800F. When the water flow stops, or the sprayer fails to work correctly, the pipe overheats, and softens enough to collapse under its own weight. There is usually some warning, in the form of a strong 'plastic' odor, if someone is there to detect it.

The resin in FRP is a 'thermoset', so it doesn't melt and resolidify like wax, but it does soften, weaken, lose strength and ooze a bit before it actually burns.

I agree with David that an FRP pipe completely full of liquid should resist an external fire for quite a while. ... it won't look good, but it will still be a pipe. When the liquid boils off, that changes.



Mike Halloran
Pembroke Pines, FL, USA

 

[ifran31]

good morning,

I need to install U/G FRP piping, 10cm of the thickness of sand bed is sufficient?

Thank you for your message and for useful collaboration
R.B (mechanical engineer)

 

[zdas04]

I've never put a sand bed down at all. I do have the guys crumb the ditch to get rid of most of the sharp rocks, lower the pipe very gently by hand, pad with a bucket padder (think of a huge flour sifter) a foot or so above the pipe (the pad will compress a good bit), and then backfill with spoil from the ditch. It has worked for me.

Just about every FRP failure I've had could be traced back to rocks from the spoil pile falling on the pipe prior to padding. This bruises the pipe and cause interlayer delamination. These bruises almost always pass hydro, but over time become a leak. Evaluating the leaks is really easy (they are always top of pipe and small areal extent), but the leaks themselves are a real pain.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[ifran31]

ZDAS04,

Good morning

thank you for your attention
R.B (mechanical engineer)