Piping standards within design 3

[DJSweeney]

I am currently working on a design that has two piping systems, Natural Gas for fuel and 50/50 Glycol/Water Cooling. Do these two systems need to be design, built and tested to the same standards?

 

[RVAmeche]

What do the client/project docs say? Are they both the same Class 150 CS B31.3 pipe spec?

 

[DJSweeney]

RVAmeche,
I followed B31.1 during the design process as per my firms practice, so yes. And when drawings were released, they were released with the note to follow company welding and testing procedures, which is a reflection of B31.1 or B31.3 depending on the customers system. In this case the customer has a concern of the cost for testing to such standards, specifically for the coolant piping. I am just wondering if there is a section that I am missing that says if the Fuel piping is designed and tested to standard B31.1, then all piping must be held to same testing. Or coolant can be welded to lesser standard like AWS D1.1 and minimal testing standards.

 

[1503-44]

They should both be B31.3 system designs.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[DekDee]

I agree with 1503-44.
You need to review B31.3 to see what classification your piping fits into for your pressure, temperature and product.
It cannot be AWS D1.1 as this is a Structural code.
Possibility the Fuel piping would be NFS (Normal Fluid Service) with the Coolant piping falling into Category D (which requires much less testing).
You have the info on the 3 x things I noted so you should be able to decide what your requirements are.

 

[DJSweeney]

Thanks for the guidance, this has pointed me in the right direction. In B31.3 I was able to find:

300.1.3 Exclusions. This Code excludes the
following:
(a) piping systems designed for internal gage pressures
at or above zero but less than 105 kPa (15 psi),
provided the fluid handled is nonflammable, nontoxic,
and not damaging to human tissues as defined in 300.2,
and its design temperature is from −29°C (−20°F)
through 186°C (366°F)

Since my coolant piping falls within these criteria, I am comfortable with recommending other testing for the welding and assembly on this system.

 

[StressGuy]

I'm curious how these kinds of questions keep coming up. The design code should have been agreed to by your firm and your client as part of the contract before you ever started working on anything.

B31.1 doesn't sound like the right code for any of this.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[DJSweeney]

StressGuy,

Good questions, the code was agreed upon, the clients misunderstood that we would apply the code for all the piping we designed.

My understanding is that AMSE B31.1 applies to Power Piping and B31.3 applies to Process Piping.
The explanation given to me is that B31.3 is used to design piping system to transfer fluids during processing, in the design of a Refinery or similar. While B31.1 is used to design the piping system that supply fluids to power a system, in the design of a Power Plant or similar.

Our design is the piping for a fuel and coolant line to Natural Gas engine. Would a Natural Gas Fuel line be considered process piping and not power piping?

 

[RVAmeche]

"Power piping" is generally stuff associated with boilers/piping and steam turbines used for power generation. Some clients may decide that they want their process steam powerhouse to be B31.1 even though they don't have a turbine, which is their call.

Otherwise B31.3 is definitely adequate for both services you're describing.

 

[DJSweeney]

RVAMeche,
Thank you for the clarification.