PDA

View Full Version : Spark proof tools



Bill736
09-17-2011, 01:33 PM
The other day, I was pondering why most of us get away with working on carburetors, fuel injectors, and fuel systems using steel tools. There is usually some spilled gasoline involved . Refinery workers have non-sparking tools, but apparently very few auto mechanics use them. Even safety conscious companys don't seem to require their auto mechanics to use non-sparking tools, as far as I know. Has that changed as of late ? In general, to ignite gasoline fumes, we need to be within the flamability limits with regard to air/fuel mixture, and have enough heat from a spark to start combustion. I think that much of the time we dance around those requirements , mostly by luck, and seldom if ever start a fire. But then, occasionally, somebody will be cleaning parts with gasoline, create a spark , and go up in flames.

Black_Moons
09-17-2011, 01:47 PM
Its all a factor of quanity... of fumes.

First off, cleaning parts in gasoline? Hardly very smart. Kerosene is nearly as effective and MUCH safer.

Second, in a shop, you can stop what your doing and evacuate an area if you spill a large amount of gasoline, and hence a large amount of fumes are created. You can smell gasoline long before it reachs its flamable mixture point.

In a refinery... Fumes are everywhere, You can't shut anything down if you spill something, Beancounters would'nt allow it.

Even if you did spill some gasoline in a shop and ignite it, you'd likey have low fumes (No explosion) and ability to put it out, with minimal risk of it spreading to the fuel tank, and no pressurised fuel lines to worry about. And the tanks are never pressurised so no explosion risk even if they did 'catch fire', Just a slowly building flamethrower as more and more gasoline boils off.

IMO, its safer for the shops to work in a fume free enviorment and use sparking tools, then it would be to try and work in a spark free enviorment and ignore fumes/fuel leaks.

Plus, I would like you to point me to the non sparking welder and the non sparking muffler cutoff saw first :)

How about the non sparking bolt cutter? (Are there non sparking alloys strong enough?)

How about the non sparking spark plug tester? :)

Or the fact that cars are definately not 'non sparking' when the battery is connected/disconnected and any loaded switch opening/closing would likey generate a small spark in a car

Scottike
09-17-2011, 01:50 PM
I always understood that it was because of confined spaces & potentially explosive atmospheres.
It's easier to say "use these tools" rather than "use these tools here and here, but you don't need to use them here"
Given enough time, I'm sure OSHA will get around to it, whether it's justified or not, it's for our own good.

CCWKen
09-17-2011, 02:35 PM
Personally, I've never been in an auto shop that wasn't well ventilated. Most have the doors up all the time. Even when I worked in a Pontiac shop way back in 69-70 in Northern Ohio there was plenty of ventilation. And there were fire extinguishers about ever 10-12 feet. At least one per work stall. That was back when guys would be working on cars with a cigarette hanging out of their mouth. I can't remember any fire incidents. Of course, that was also back when most folks had common sense and lawsuits were as rare as hen's teeth.

By the way, I was at work and we could hear the gun fire coming from Kent State University several miles away. That was the day of the riot when the Ohio National Guard fired on the students. Didn't find out about what the "explosions" were until I got home that night. Tragic day in our history.

CCWKen
09-17-2011, 02:58 PM
LOL... I just happened to recall that gasoline fires weren't on the minds of most of us. There were far more dangerous things around the shop. Balancing the rear tires always scared the crap out of me. It took two people. The rear tires would be jacked-up about three inches off the floor. One person on the balancer ring spinning four inches from your face and another behind the steering wheel holding the throttle at 60mph in drive. :eek:

claymont
09-17-2011, 03:15 PM
I think you'll find most refineries don't use 'spark proof tools' anymore. They don't last and studies showed that they will spark. The place I worked at hadn't used them since the sixties.

Bmyers
09-17-2011, 03:36 PM
I used to work in printing. The ink rooms and wash rooms required spark proof tools and LEL monitors for all work.

KIMFAB
09-17-2011, 04:16 PM
Probably the reason you get away with it is because most carbs are aluminum or zinc based alloys.
Even with steel tools it will be hard to get a spark.

Although I can't use them the chlorinated water based solvents are used more now.

Duffy
09-17-2011, 05:18 PM
The non-sparking tools that I am familiar with are made from berillyum bronze. Working with explosives, particularly in ammo storage, and these were mandatory. They had a few drawbacks:- 1) they cost A LOT, 2) they could not take the same abuse as "normal" tools, 3) they were heavy!
Basically they were a royal pain to use, and some verged on the ridiculous. Think about a berillyum bronze cold chisel or even a claw hammer, and a 4-foot Stillson-pattern pipe wrench weighed a ton! Of course, forged aluminum wrenches had yet to be "discovered!"
And before ANYONE cautions us about the toxicity hazard of berillyum, it is primarily from the dust, and you wont generate much using a non-sparking file!

SteveF
09-17-2011, 06:13 PM
I remember when I was about 9 years old I discovered, much to my profound disappointment, that lit matches dropped into a cup of gasoline simply go out.

The lack of burning auto repair shops would seem to suggest that gasoline isn't quite as easy to ignite as some would think.

Steve

gary350
09-17-2011, 06:45 PM
Last time I checked none sparking plyers were $450 compaired to $5 steel plyers.

I brass barrel bung wrench is about $500 compaired to $15 steel wrench.

I don't think the brass makes the tools expensive the low sales quantity makes them expensive.

John Stevenson
09-17-2011, 06:55 PM
I used to work in printing. The ink rooms and wash rooms required spark proof tools and LEL monitors for all work.

Interesting.
I used to make ink mixing machines, only small ones like a food mixer on steroids.
The company these were for Coates Lorelliux later Sun Chemicals had some big hydraulic mixers that could mix 1 tonne at a time.

Only hydraulic to get the torque needed to move the paddle thru what was basically tar before the temp got up as it mixed.

All the other mixers were just 3 phase standard motors.

I didn't recall any emphasis being put on sparks or fire other than standard risks

firbikrhd1
09-17-2011, 07:09 PM
During the course of my career as a firefighter for 29 years in a Department that is the 7th largest in the nation (240,000+ calls/year when I retired) I never responded to a vehicle fire caused by sparking tools. There were many vehicle fires with other causes; electrical shorts and welding/cutting operations being the most prevalent. As was stated by KIMFAB, the materials used in most vehicle manufacture aren't prone to sparking. Not that it can't be done, but try to get a spark by striking a piece of mild steel with a wrench or even something harder like a chisel. Although not impossible it isn't something that readily occurs therefore it is unlikely that simply dropping a tool would induce a spark.

The exception to that being someone who drops a tool across an electrical connection causing a short. Then all bets are off, but it wouldn't matter what non sparking material the tool was made of unless it was non conductive as well. Given the advances in plastics and composites one day there may be tools made with those properties that are strong enough to withstand working forces, wear well and can be produced cost effectively.

There is also the issue of air/fuel ratio. Most automotive fuels have a relatively narrow flammability range in comparison to gases like acetylene. That range is rarely attained under most shop circumstances.

Temperatures also play an important role. For example, many people treat diesel as if it were pretty safe. It is rated as a combustible liquid, not flammable (as is kerosene). In fact a lit fusee can be inserted into liquid diesel under the right conditions without causing ignition. The rating is dependent on Flash Point based on temperature. Even so, a diesel fuel spill on pavement in Florida during a hot summer day must be treated as a flammable liquid spill. It will flash as easily as gasoline will under less severe conditions due to increased temperatures.

rohart
09-17-2011, 08:40 PM
Remember how difficult it is to flambee ? We do it over here with christmas pudding. You absolutely have to heat the brandy before pouring it on the hot pudding and plate, or it is very hard to light.

Same with petrol/gas. At room temperature it won't do much. Maybe in the heat in the southern states it might, but even then you'll only get a naked flame that you can put out with a blanket.

I worked in the mining industry when portable computing equipment was coming along, in the 70's and 80's. Inspectorate were very nervous of new equipment being taken underground. It was several years before they trusted the kit not to develop induced voltages high enough to ignite escaped methane. And that was when, as soon as you knew there was an escape of gas, you should be legging it out anyway.

But it wasn't the damage of an explosion that was the problem, but the fact that after the explosion, and any subsequent burning, the availability of breathable oxygen was reduced. You could work with gas filters on your belt, but you couldn't work with a tank on your back all day long.

jhe.1973
09-17-2011, 09:33 PM
I remember when I was about 9 years old I discovered, much to my profound disappointment, that lit matches dropped into a cup of gasoline simply go out.

The lack of burning auto repair shops would seem to suggest that gasoline isn't quite as easy to ignite as some would think.

Steve

DISCLAIMER: CAUTION, DO NOT TRY THIS AT HOME!

Just out of high school in 1965 I was stuffing a 413 cu. in. Chrysler engine into a rusted out 1957 T-Bird.

Following drag racing practice at the time I was re-locating the biggest truck battery I could find to the trunk.

Too lazy to drag out an electric drill & extension cord & my oxy/acet cutting torch was right there, sooooo I punched a quick hole in the floor of the trunk for the hold down bolts.

Looking through the hole, I saw what looked like more of the POS undercoating they used back then (which is why the car was so rusty) and used the torch to punch another hole through the 'undercoating'.

BIG flame shot up, and I think I filled my pants as I was jumping out of the trunk expecting the car to explode.:eek:

Watched for an instant as the flame went out by itself w/o no intervention from anything.:confused:

I am NOT recommending this to anyone, I am just adding a personal experience to second the statements that several factors have to be in place for a fire/explosion to occur.

Allow me to repeat:

DISCLAIMER: CAUTION, DO NOT TRY THIS AT HOME!

:D

mike os
09-18-2011, 04:40 AM
too much hollywood bull, not enough science...

mike4
09-18-2011, 07:16 AM
too much hollywood bull, not enough science...
Diesel will burn if the temperature is high enough and if a source of ignition is available .

Under some circumstances all you will get is a thick cloud of white smoke which is irritating and messy .
I have seen people actually weld cracked fuel tanks on machines while the tank was full of fuel ,yes there was a lot of yellow/orange flame . But it extinguised the moment the fuel leak was welded closed.
The only thing that the people welding enforced apart from fire extinguisers was remove the filler cap and make sure that the tank was full .
The only tanks that I have seen explode were empty ones where the heat caused the fuel to go way past its ignition point and there was more than enough oxygen present .
Diesel is harder to ignite than petrol and in the open air will burn if conditions are right .
Common sense dictates that you dont fool with highly flammable liquids like petrol /avgas etc.
During my tenure in a brick plant as a maintenace person , I was called upon to assist in the extinguising of a pressurised diesle line which had caught fire due to someone not following procedures correctly ,an operator did not isolate a burner fully before changing it for a repaired one.
The diesel was spraying into a firebox which was around 1100degrees celcius .
quite spectacular flames and enough heat in twelve minutes to cause a 1.5 inch fuel main to sag about a foot before the fuel was cut off and everything doused in dry chemical fire retardent .
We had everything back to reasonabley normal operation in under an hour as every minute that firebox was out of action was risking a weeks production and the livelihood of 40 people .

That was before all of the over the top safety people were allowed to start shutting plants down .None of use were ever burnt , some serious accidents did occurr but both of them possibly would have still happened even in todays "safe " workplaces as both were caused by inattention to what was happening .Nothing that any guarding or safety training /inductions would have covered .
Michael

Gravy
09-18-2011, 10:48 AM
Last time I checked none sparking plyers were $450 compaired to $5 steel plyers.

I brass barrel bung wrench is about $500 compaired to $15 steel wrench.

I don't think the brass makes the tools expensive the low sales quantity makes them expensive.


It's not nearly that bad. Grainger has non-sparking pliers for $58 and non-sparking bung wrenches for $44

Thruthefence
09-18-2011, 11:23 AM
"First off, cleaning parts in gasoline? Hardly very smart. Kerosene is nearly as effective and MUCH safer. "

I'm an aircraft mechanic, and I have accumulated a little collection of old Aviation trade school books from the 1920's up through WWII. In one of the older ones, there is a drawing of how to construct a siphon gun for the cleaning of engine parts during the overhaul process; the recommended "solvent"?

Gasoline!

I wonder how many were incinerated during the cleaning process in those days?

There was an incident several years ago, where a mechanic was removing the lower wing fuel cell panels on an avgas powered aircraft with a battery powered drill motor, an apparently the commentator through enough sparks from the brushes, that as the seal broke on the panel, the fumes ignited & caused an explosion, killing the mechanic, & destroying the aircraft.

And here's a pic of an explosion apparently caused by a switch arcing inside an aircraft that had a fuel leak inside the cabin.

http://www.aero-news.net/index.cfm?do=main.textpost&id=c7aad273-7aff-484f-b3c6-9edbe3668c12

Kinda makes you take notice when you smell gasoline fumes, huh?

Black_Moons
09-18-2011, 02:40 PM
Kinda makes you take notice when you smell gasoline fumes, huh?

Exactly!!
If you can smell the fumes, thats serious danger indication!

Thats when you go, walk away, Put out your cig :eek: , mop up the gas, and go out for a beer while the rest evaporates away. :rolleyes:

jhe.1973
09-19-2011, 12:20 PM
too much hollywood bull, not enough science...

I don't know if the above remark was directed at my post but because I remembered something I thought I'd pass it along.

I asked a chemical engineer a couple of years later as to why my car didn't explode, or even burn for that matter.

He explained that the only thing that actually burns is combustible vapor.
It doesn't matter if the 'fuel' is solid or liquid.

ANY fuel has to be reach a point where it gives off combustible vapors & it is the vapors that burn which starts a chain reaction where the heat of the burning vapors causes the release of more flammable vapor.

This is because w/o enough oxygen molecules surrounding the fuel molecules no fire can start.

He pointed out this situation is obvious if you try to start a flooded engine - not enough air, no fire.

While writing this something else occurred to me that has been in the news out here in the desert southwest.

We have been getting advice concerning static electric sparks igniting vapors when filling our vehicles.

What strikes me as another proof of what this engineer told me decades ago is the current advice:

If you do get a flash flame at the filler spout do not panic and pull the nozzle and hose out. The flame will likely go out.

If you pull the nozzle out in the presence of a flame, all bets are off.

I don't know if this qualifies as enough 'science' but it's the best I can do.

I can and will, relate my own personal experiences to the best of my ability, but I cannot make anyone believe me.

Something about leading a horse to water, but not being able to make it drink comes to mind.

:) ;)

P.S. I believe that Black Moons has had it correct right from the start w/his zeroing in on the fumes/vapors.