Static Buildup- Explosion Hazards?
 

Here's a couple of posts I found on-line at "IPilot" in the Message
Board section of this week's (11/20) edition. The articles on-line
referenced some situations which may cause an explosion due to static discharge. Two areas of concern to modelers are listed.

"Recently I was reading about building a ventilation system for my basement woodworking shop. They stressed that if you use plastic tubing you have to run a ground wire down the tube to drain static buildup from the air friction inside the tube. They said the wood dust/air mixture can become explosive when ignited by a static spark."

This second article pertains to the plastic gas cans modelers often use for the transportation and dispensing of gasoline for their aircraft:

"When filling a plastic container, the potential between the container and the fuel source (the nozzle and pump) isn't an issue; it's bonded via the fuel. However, a potential still exists between this container, and the vehicle.

"When filling into those little red plastic gas cans, a good way to
risk an explosion is to fill the can while it's resting in a plastic
truck bed liner. The cans themselves can develop some potential simply by being rubbed, or from air friction. Placing the can on the ground allows any potential between the can and the underlying surface, to dissipate, and reduces the explosion hazard (but does not eliminate it)."

While I am not sure how much "danger" is present, these are points one might want to consider. The posts can be found at:
http://www.ipilot.com/forum/message.aspx?pid=19397
and are titled "Airplane VS. Auto Fueling"
( Note: a portion of the above post is also listed in RCU under
RC Fuels)

Regards,

Al Parry
[email protected]

Gasoline containers
 

This is exactly the reason why the only legal gasoline container in NZ is metal. Plastic and glass containers were outlawed several (20+) years back. The main cause for the ban of plastic containers here was the fact that over time the plastic hardens and cracks. (We get too much rain here for static to be a problem :D:D:D:D)

While you are speaking of the dangers of filling gasoline containers, the signs in gas stations here have a recent addition.

"No Smoking
"Turn off your engine
"Turn off your cellphone

:D

Static Buildup- Explosion Hazards?
 

I have heard too that dust and static can be bad. I recall as a kid on the prairies that there were a number of grain elevator explosion/fires because of grain dust and static. I once even saw it demonstrated in school in a fire safety "class". The guy had a 3D model of a house, sprinkled some sort of dust (flour?)into it, shook it up, stuck a match in at the bottom and it popped the top off the display (it was in a mesh case, so I guess it was safe?). He also did a demo were he added a few drops of gas at the top of the house(to simulate someone cleaning something with gas).. he had a candle in the bottom of the house...it popped the top off too... this was I suppose to show the dangers of using gas a solvent in a country where we often have have a gas/oil furnaces or water heaters in the basement!

As far as the warnings about cel phones while filling your tank (which we have here too), I don't know that there has been a documented case of fuel ignition due to a cel phone, but when I was flying aboard full scale aircraft, we were not permitted to transmit on any radio or make any switch selections while being fueled. Also, when preflighting, the radar operators were told they were "clear to shine" in a specific direction or sector so that we were certain there were no fuel trucks in the way. Now I realize we were pumping out a bunch more power than your cel phone, but the "off" button is probably a good idea!

Static Buildup- Explosion Hazards?
 

I have a central vac in the house. Today I was cutting a small section of the plastic piping out to install another line. As soon as the small manual hand saw I was using broke through into the pipe, I saw and felt a discharge from the saw to my hand. It hurt like hell! Thought I cut into a 120V line for a sec. I would have never believed it, but the static build up was intense. I had used the vacuum about 20 minutes prior to cutting the pipe. The vacuum sucks a lot of fine wood dust through those pipes! Think I might look into the grounding thing real soon.

static explosion hazards
 

I am a fire fighter of 23 years. I have seen fires that have occurred from static discharges. Airless spraying is one I remember in particular. The gun of a fiberglass spray rig was not bonded and when the atmospheric condition got right there was a discharge and ensuing fire.

If you are making a dust collection system for saw dust the best piping is metal. Running a wire inside plastic pipe to make a bond will cause particles to accumulate and hang up dust. Just make sure that the pipe has a common ground with the machinery that it is hooked up to it.

A study has been done recently is the fire trades concern static discharge at gas stations. It seems that most occur when the occupant starts fueling and then on a cold day gets back in the car and then slide back out to shut the nozzle off. The static builds up just like it does when you slide your feet across a carpet as you slide across the seat. Touch the metal part of your car before touching the nozzle to release the static electricity.

Re: static explosion hazards
 

When I wear my Columbia ski jacket and a sweater and get out of my car I nearly kill myself from the static discharge of simply sliding out of my seat. Good thing I'm smart enough to not re-enter my car when I fuel it. That BSEE I have is really paying off! ;)

Static Discharge
 

Oddly enough, when we did our land &sea survival training, we were shown the various collars and nets that a helicopter could use to pick you up. We were told never to grab the wire the helo was lowering before it came in contact with the ground... apparently those blades whirling around can build up quite a charge.

Static Buildup- Explosion Hazards?
 

My friend had a plastic gas can explode on him and burn him bad. Can't fill them in the back of the truck. I have also felt the discharge in the shop vac when I am vacuuming my saw and sander. Hurts like heck. Ground line is a great idea.