Changing to EN 13480 from ASME B31.3 1

[steadag]

Hi all,

I am a mech engineer working on common plant/balance of plant systems for power plants. So your aux services like fire, demin water, comp air etc. We also do piping of gas and liquid fuels to a limited extent; typically from a terminal point at the site fence or from containers on site to a pump/filter at a gas turbine.

I joined my current company recently and am trying to create a foundation for pipe designs which is currently lacking. The current mind set is to take info from previous projects as oppose to having an established pipe design criteria. The work on previous projects is also not that great, mostly put together by junior engineers who didn't have real project exposure from what I understand. There aren't any real pipe design calcs, only hydraulics. The pipe spec being used is also in need of an update as it comes from the refinery industry (so more stringent than what we require) and is 30+ years old.

We are based in South Africa and work a lot with European clients and so are trying to steer towards European standards. The company's current pipe spec is all ASME, 'designed' to ASME B31.3 (and I guess ASME B31.8 for the gas).

My experience for aboveground steel piping design is solely based on ASME B31.3. I was also previously a Client's engineer and haven't done much pipe design in terms of stress analysis etc. My experience is more in layouts, integration and hydraulics. I have no experience in gas pipelines; thankfully, the company is looking to hire someone who does...

So, to my actual question. If the company moves to using European pipes and fittings (BS, EN, ISO etc.) how feasible is it to adopt EN 13480 (and associated codes) for our designs? Is it worth learning the EN codes or rather taking the time to qualify BS, EN, and SANS material, pipe and fittings to ASME B31.3/8?

I don't think anyone in the company looked at this before because our services are almost all low pressure, low temperature. But in my mind, you never know when something will go wrong for whatever reason and you need to be able to prove that there was some thought into your design. I don't want to get caught with my pants around my ankles saying "I used sched 10S pipe because the last project did".

I know this is a bit of a lame question as there are numerous factors involved but I need to make a decision urgently and am stuck. What I am hoping for is insights or comments from someone who was in similar shoes at some point.

Thanks,
Alastair

 

[BigInch]

"Designs" will be very similar, I wouldn't think there is advantage to change solely based on that. Material lists and material spec references will be considerably different. If you're going to move to EN, of course you need to learn the EN codes and materials. Start now.

The real question is, "Why is there the need for change?" You seem to be lost in the reasoning. If it's no trouble to learn, we should change vs We shouldn't change, because it's too much trouble. Is that how you will decide? If the reasons driving the change (EN materials cheaper since the Euro value has dropped, EN materials are more available, home office is in EU, etc.) are significant enough to warrant the change, then change.

 

[steadag]

BigInch, thanks for the response.

You got me exactly right. I was a bit lost in the reasoning. The pressure to make this decision and get specs out for project deadlines had got me running in circles.

Cleared my head and spoke to the director, suggested we stick to ASME for the current projects and look at EN later on. There is good reason for us to change, for example our low pressure systems mostly need PN10 flanges and fittings and so there is a cost saving compared to 150 psi equipment. At the moment we are only functioning as design consultants though and so this will be more relevant when EPC work comes up.

Waiting will give me a chance to read up on the EN stuff and prepare pipe and material specs when I get a chance. He agreed so problem solved (for now).

Now I just need to help the draughty incorporate imperial pipes and fittings into a metric model...

Thanks again BigInch.

Alastair

 

[BigInch]

Glad you managed to clear that up so easily.

 

[XL83NL]

The EN 13480 is still pretty new, and from my (humble and little) experience so far, Ive found the code to contain certain imperfections and inconsistencies. The design rules are much more extensive than B31.3, there's a formula for almost anyting in the code. On the other hand, there are a lot of similarities w/ B31.3. Some parts are 1:1 copies of B31.3, with exact phrasing. You can manage to get over all these imperfections by reading the code several times, to see the bigger aprty, and asking intepretations to the Code committee. Dont expect a very clear format for replies though.

One advantage for EN 13480 over B31.3 Ive found is that when you (need to) work acc. the PED, the code is completely written to the assessment modules related to the categories of the PED. Big plus there, and youll find some nice to haves when it comes to e.g. testing.

On the other hand, Ive found the European market isnt up to the code standards so far. Flanges youll easily get in EN. Fittings is whole different story though. The fittings standard is, I think, based on the former German 'reihe' model, but the market supply in Europe for such fittings acc EN standards isnt there (yet). Ive found a hard time to e.g. find a standard 1.4404 tee, or reducing tee. This may have to do with our market (Im Dutch), but during one project our supplier looked around in Germany, Netherlands and Austria and found only 1 manufacturer that could supply us with a standards 1.4404 tee with a certain (typical) wall thickness for a normal size like DN50. Ive found most pipe and fitting suppliers dont supply what the code requires on a reasonable (unless you want to run a custom mill for few fittings, pay $$$, and can accept few months of delivery time). Another thing is that basic materials, like A105 flange and A106-B in the equivalent EN grade dont really match up with what the EN 13480 code requires. There's e.g. no real (readily) available equivalent of A105(N) flanges.

Give the code a few years, and keep an eye on it how it develops. You can easliy do B31.3 work combined with PED.

 

[steadag]

Thanks for the info on EN 13480 XL83NL, appreciate it.

I will definitely look around for EN fittings here to see if sticking to the EN code is feasible. I know flanges are easy to find since they are the same as the old BS 4504 ones. Haven't looked for tees yet though.

This equivalent material issue could be a problem... Can you explain why the A105 etc. equivalents don't meet the EN requirements?