'High energy'' lines 1

[gravitate]

We are currently looking at penetrations of pipework through concrete walls and how to do the sealing. As there are a few different designs for the penetrations it shouold be decided which are high energy lines. The pipe work we have are the following:

Cryogenic stainless steel
cooling water (temp difference from 34 deg c to 70 deg c) stainless steel
vacuum stainless steel

Which ones of these would you consider high energy?

 

[C2it]

High energy would usually suggest high pressure, or fluctuating pressure such as found in reciprocating pump / compressor systems. Have a look at your process conditions.

 

[gerhardl]

High energy related to what low/normal energy? At what 'norm', regulations or customary practise? Energy as by temperature expansion/differences, pipeline sizes and material, or mechanical from machinery or other?

Sorry, started speculating, but if not stated in any regulation, we will have to revert to the old-time 'general' standard: 'as 'best used normally customary practise in the branch.'

 

[gravitate]

For instance we have cooling water up to 8.3 Bar max operating conditions. Obviously there will be pumps etc from from 34 deg c to 70 deg c. Would this be classed as high energy? It is stainless steel pipe.
The vacuum is zero pressure obviously and the cryogenic goes down to near absolute zero.
Are any of these high energy lines?

 

[gravitate]

I am trying to establish which lines are 'high energy' so as to select the appropriate penetrations for the pipe through concrete walls. High energy lines will require an outer shield with an expansion bellow in it to allow for exopansion of the pipe. Will you need this with cryogenics?

 

[racookpe1978]

Make a reasonable decision about what is "High Energy" or "High Risk":

For example

Voltages over 120 volts.
AC or DC Amps over 30 amps.
Pressures over 150 psig for non-explosive gases.
Highly Flammable or explosive fluids or gasses over 40 - 60 psig.
Deadly chemicals or gasses at any pressure.

 

[C2it]

Gravitate,

Ref. your most recent post.

You would need an expansion bellows at a penetration only if there were significant movement imposed that could not be abosrbed otherwise, by for instance a local loop. It suggests that 'high energy' is in this context is thermal energy ... i.e. a hot or very cold line.

 

[gravitate]

I see thank you for that answer. I know if it was a steam line you could put an expansion loop either side so compensate for any movement. I thought that the expansion bellow was to account for any movement within the concrete penetration.

Does cryogenic cause as much contraction in a pipe that steam does expansion?

 

[TGS4]

In the piping world, high energy lines are typically high pressure (ASME B16.5 Class 1500 and above) and high temperature - usually corresponding to superheated steam at those pressures. Unless your cryogenic lines are hovering around zero Kelvin, I doubt that they would qualify as high energy. Everything else that you listed is normal service.

 

[cvg]

I think you are getting hung up on energy which is not the criteria I would use. risk is what you want to manage, caused by damage or failure of the pipe or structure or other related facilities due to movement caused by pressure, vibration, thermal, earthquake, other forces. protection level is a function of the risk you wish to take. for instance, if the pipe is subject to extreme pressure surges, high probability of leakage which would consequently shut down the entire plant for a month, that would be high risk. Provide sleeve and bellows. If there is no pressure surge or temp expansion, risk of leakage is very remote and/or leakage would not cause work stoppage and would be easy to repair, than just caulk the joint.

 

[StevenHPerry]

Does cryogenic cause as much contraction as steam does expansion?

It's about the difference in temperatures from the installed temperature. -80C is going to cause roughly the same change in dimensions from a 20C reference point as would +120C. But you can only go so low, whereas steam at 575C is not uncommon.

Although... I did read an article recently that reported some researchers claimed to have gone below "absolute" zero.

http://www.livescience.com/25959-atoms-colder-than-absolute-zero.html

Neutrinos go faster than light and something can be colder than 0K. We are not as smart as we think we are.

- Steve Perry
This post is designed to provide accurate and authoritative information in regard to the subject matter covered. It is offered with the understanding that the author is not engaged in rendering engineering or other professional service. If you need help, get help, and PAY FOR IT.

 

[gerhardl]

gravitate:

All postings above are based on your original question regarding energy.

I agree with cvg in that risk also should be considered, and also size. If you are unsure of consequences of concrete casting around pipeline, what about looking at the question from a practical building solution side?

Possible solution: Penetrate (bore or cast) the concrete wall with somewhat oversized holes for the pipilines. Protect the wall material with tubing pieces fitting outer diameter of holes. Draw the fluid pipelines through and isolate between fluid pipeline and outer tube, and outer tube and wall, for instance with expanding foam isolation.

Extra cost is relatively low, and wall protecting tubes could be low-cost material.

Advantages:
Fluid piping isolated from wall, expansion and contractions will go against elastic isolation, replacement of pipeline through wall easy, expansion loops, joints etc placed if necessary before or after wall, wall protected from condensation or leakage from fluid pipeline.