Grounding PVC Piping: Advice for Flammable Gas Transfer

Click For Summary

Discussion Overview

The discussion centers on the safety and feasibility of using PVC piping to transfer a flammable gas at minimal gauge pressure (3 mbar) between two rooms. Participants explore concerns regarding static electricity buildup, grounding methods, and the overall safety of the proposed application.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • One participant expresses concern about static electricity buildup in PVC piping used for transferring flammable gas and seeks advice on grounding methods.
  • Another participant states that PVC is an insulator and cannot be grounded, suggesting that grounding is only applicable to conducting materials.
  • A suggestion is made to wrap a grounded wire around the PVC or use anti-static PVC pipe to mitigate static charge buildup.
  • One participant argues that the gas cannot be both flammable and explosive at 3 mbar, emphasizing the need for proper safety measures and the use of metallic pipes and specialized pumps for such applications.
  • Another participant proposes packing the PVC tube with copper wool to ground it and prevent flame propagation.
  • A counterpoint is raised against using copper wool, referencing a safety concern about flame propagation and suggesting that the original poster should consult professionals for safe handling of flammable gases.
  • One participant defends the use of copper wool as effective for grounding and flame screening, criticizing the suggestion to consult tradesmen for expertise on static electricity at low pressures.
  • A clarification is made regarding the gauge pressure, indicating that 3 mbar gauge pressure translates to a total pressure that could potentially be above the flammability curve, leading to discussions about applicable safety standards.
  • A link to an informational article is provided, discussing methods to render gases non-flammable before pumping.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the safety of using PVC for flammable gas transfer, grounding methods, and the implications of the gas pressure. The discussion remains unresolved with no consensus on the best approach.

Contextual Notes

Participants highlight various assumptions about the nature of the gas, grounding techniques, and safety practices, which may depend on specific definitions and standards. The discussion reflects differing levels of expertise and experience among participants.

spenser.good
Messages
8
Reaction score
0
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?
 
Engineering news on Phys.org
PVC piping is an insulator; it cannot be grounded - you can only ground a conducting material!
 
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).
 
spenser.good said:
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.
 
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.
 
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.
 
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.
 
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
 
Last edited by a moderator:

Similar threads

  • · Replies 22 ·
Replies
22
Views
8K
  • · Replies 15 ·
Replies
15
Views
4K
Replies
7
Views
2K
Replies
9
Views
8K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
14
Views
6K
  • · Replies 6 ·
Replies
6
Views
5K
  • · Replies 3 ·
Replies
3
Views
17K
  • · Replies 14 ·
Replies
14
Views
3K
Replies
4
Views
2K