Design of static-proof process building

Hi

I currently tasked with converting a steel Portacabin-type box into a lab and process building for static-sensitive equipment and materials.

If there are any ESD gurus on here, I’d appreciate any advice please.

I’ve ripped out all the vinyl, floored it with aluminium treadplate, clad the walls in painted aluminium sheets, and left the ceiling in the original painted steel.

Worktops are in Trespa anti-static material, there’s a metal fume cupboard, and metal cupboards and shelving. Everything is bonded together, and earthed TT. Earth impedance is good.

I’m also intending to run a bonded copper strip all round the worktops, with little sockets for plugging in flying earth leads for loose equipment, wrist straps and so on. Conductive shoes will be worn, and no plastics or other insulators allowed in the building.

But this is all new to me: have I missed anything? The most dangerous errors are those you don’t know you’ve made!

And two questions please:

  1. Is it OK to use 10mm John Guest plastic plumbing pipe (Polybutylene), tucked away under the worktops? I need to run ring mains of mains water, Type 2 pure water, vacuum, and gas. There are no great flow velocities.
    I believe copper is often used, but I’m neurotic about having copper anywhere near where there might be picric acid. Would a little bit of plastic plumbing, screwed to a metal wall, really be a problem? (I suspect less of a problem that a copper picrate explosion in 20 years time!) And it’s so much nicer to install.
  2. There will be a ring of 100 x 50 galvanised conduit around the room, carrying power and other electrical services. If this were replaced with PVC might it be OK? It’s visually much better and has separate compartments to keep power and data separate. Again screwed directly to a metal wall.

Apologies for the long post. I’m in a hurry and didn’t have the time to write a shorter one :- )

Best regards and stay safe out there, Mark

6 answers

  1. Answered by steven james

    Hello,
    https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/892649/DSA_03_OME_PART_2__JSP_482__CH_08__Nov_19__-_mod_gov_uk.pdf
    This might be able to point you in the right direction. or at least help. I would suggest if you are looking at primaries or very sensitive materials, go for fully conductive work tops and floor. get yourself a HAPTM as well.
    these are just suggestions, there will be more experienced who can advise better
    cheers

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  2. Answered by GOUR CHAND SEN

    1 Plastic pipe is OK

    2. It will be safer if PVC pipe around the room

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  3. Answered by Malc Ingry

    Mark

    Hope you are well give Charles Adcock a ring at

    Precision Energetics

    He will help you out with your question

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  4. Answered by Mark Ribbands

    Steven: Thanks for the link. That’s a very recent document which I hadn’t seen, and is most informative. I’ve just read the whole thing. I’ve already gone the conductive floor route (I spent this afternoon laying bonded aluminium sheets.) Oddly the MoD document prohibits aluminium bonding strips which are exactly what I used today! Maybe they are concerned about dissimilar metal corrosion, but that hardly applies if the floor itself is aluminium, whereas using their recommended stainless steel bonding would cause exactly that problem.
    For worktops I think Trespa is better for chemical work, with separate conductive mats which may be deployed whenever full ESD protection is required. That way I get the best of both worlds. A HAPTM? Of course, that’s trivial, and a humidifier and RH meter.
    My main concern, and reason for asking a question on here, if that I may miss some detail, then have to spend ages retrofitting something which would have been easy during the build.

    Gour Sen: I don’t understand. Surely PVC is one of the worst materials for generating and holding static?

    Malcolm: Great to hear from you after all these years 🙂 Are you still in the business?

    IExpE general: Can we have proper forum software please? This systems is horrible! (Can’t even edit typos.)

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  5. Answered by Brian Roberts

    Hi Mark,
    I design Ex process buildings for the Australian Defence Force. I agree with Gour Sen , in that to remove static, plastic or pvc should not be used. Any tubing should be steel and bonded to remove all static. Another suggestion is to use pneumatic devices such drills etc. most earthing of containers is done on alternate corners. However if you wish to guarantee your earthing bond all corners. Hope this helps. Brian

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