Grounding PVC Piping: Advice for Flammable Gas Transfer

[spenser.good]

I am looking to use a PVC pump to push a flammable, explosive gas of minimal gage pressure (3 mbar) between two rooms. I chose PVC because it is non sparking, but I am concerned about static electricity build up. The pump will be used for 10 minutes at a time in a portable application, I am concerned about sparking between the PVC and the gas or the lubricant in the pump, resulting in a potential explosion. Are there any thoughts/concerns or advice on grounding PVC piping?

 

[UltrafastPED]

PVC piping is an insulator; it cannot be grounded - you can only ground a conducting material!

 

[meBigGuy]

wrapping a grounded wire around the pvc or running a wire along the pipe with clamps may help bleed off static charges. It seems there is anti-static pvc pipe available (i just googled it). I'd advise using pvc pipe manufactured with anti-static additives or researching anti-static after treatments (look up anti-static agents).

 

[the_emi_guy]

I am looking to use a PVC pump to push a flammable, explosive gas of minimal gage pressure (3 mbar) between two rooms.

First of all the gas can't be flammable and explosive if it is 3mbar.

Secondly, if it were flammable and explosive you should not be transporting it unless you know what you are doing (i.e. the gas company). Metallic pipes and special pumps are mandatory for such applications.

Third, you don't manage the safety of venting flammable/explosive gasses by trying to prevent sparks. Best practice is to render the gas non-explosive by, for example, diluting it with an inert gas such as nitrogen before pumping.

 

[Baluncore]

Maybe pack the PVC tube with copper wool such as pot scourers. They can be grounded with a single copper wire and they should also prevent a flame propagating along the tube.

 

[Okefenokee]

If you believe Baluncore's post then I advise you to watch the Mythbuster's sewer explosion episode. Packing the tube with anything other than an actual flame retarding screen will cause the flame to spread more quickly and create a greater explosion. Just ask Jamie Hyneman.

Anyway, don't do what you are doing. It sounds dangerous and if you are asking here then you must not know what you are doing.

This is what we have experienced tradesman for. Call a propane line company. They can probably point you in the right direction.

By the way, do you simply want to clean bad air from a room? Pump fresh air in instead of pumpimg bad air out.

 

[Baluncore]

Okefenokee. The OP requirement was to ground the inside of a PVC pipe to prevent static electricity building up. Copper wool will do exactly that. I have been using copper wool as a flame screen for many years as it works well at preventing flashbacks. That is a bonus.

Your suggestion that spenser.good should consult an “experienced tradesman” seems quite ridiculous. Where do you expect spenser.good to find an intelligent tradesman experienced in static electricity at 3 mBar. An Upper Atmosphere Physicist would be more appropriate. If your only experience with the safe handling air-fuel explosives is from watching Mythbuster's engineered explosions for television then you really should not be offering negative advice.

 

[the_emi_guy]

I just noticed that the OP indicated 3mbar gauge pressure (I had been thinking absolute pressure). This is 3mbar above atmospheric or 1003mbar. This would put it potentially above the flammability curve.

Given this, there are a number of standards (NFPA, OSHA, ENxxxx) that may be applicable.

Here is an informational article. I am not a fire protection engineer, but my understanding is that the preferred method is to render the gas non-flammable by diluting it before pumping it out.

http://www.edwardsvacuum.com/uploadedFiles/Resource/Technical_Articles/Pumping%20potentially%20explosive%20atmospheres.pdf