Extinguishing the Flames: Explosions
Explosions, by their very nature, come with no warning - leaving you only to react after the loud noise, after the side of your shop has been blown out, after one of your employees
is on his way to the hospital. That's why it's important to do everything you can to prevent explosions.
By Fred Kjeld
7/1/1997
An explosion is not a mysterious act of God.
It's the release of energy in a sudden - and often violent - manner
that generates high temperature and the release of gases. The
physical elements of an explosion include a source of ignition
and an explosive - any substance or mixture of substances that,
on impact or by ignition, reacts by a violent expansion of gases
and a liberation of relatively large amounts of thermal energy.
But it takes more than just the right physical
elements to fuel an explosion; it also takes carelessness, forgetfulness
and ignorance. That's where you and your employees step in. To
extinguish the possibilities of an explosion occurring in your
shop, you need to know how to properly use, store and maintain
chemicals and other potentially dangerous materials.
To avoid injury and the possible loss of your
business, it's important that you and your employees know what
should be done to prevent an explosive situation and what should
be done if one has already been ignited.
What Would You Do?
Stocked with just the right elements - welding
sparks, gasoline, solvents and other chemicals - collision shops
have numerous potentially explosive scenarios. Take a moment and
put yourself in the following situation:
It's Monday morning, and you're the first
person to arrive at work. You unlock the entry door and step inside
the office. Greeted with the smell of gasoline, you remember that
one of the technicians removed the fuel tank from a badly damaged
vehicle Friday afternoon. Opening the door to the shop, you cautiously
take a look. Sure enough, there's a fuel tank that's tipped over,
and not only is the gas pooling on the floor, it's running down
the floor drain.
What do you do?
Before you answer, think about what happens
in a gasoline-powered engine. As long as the liquid gas is changed
into a fine mist and mixed with the correct amount of air, it
remains a safe, contained miniature explosion - and this miniature
explosion helps to power the engine. If you substituted pure oxygen
for the air, the engine would likely explode. If you pump liquid
gas into the combustion chamber, the engine wouldn't run; it would
flood out because of too much raw gas.
Remember the triangle of combustion - fuel,
oxygen and kindling temperature - you learned about in science?
To start a fire or explosion, you must first raise the fuel to
its kindling temperature, typically with a source of ignition,
and then have sufficient oxygen present to support the burning
process. It isn't the gasoline that actually possesses the explosive
potential; it's the vapors from the gasoline.
The gas that's running down the floor drain
is now restricted or confined to a small area. Under such conditions,
it's not difficult to imagine the entire floor blowing up.
What should you do?
The smartest thing to do is to vacate the
building, use an outside phone to call the fire department and
then make sure no other employees enter the building.
What could have been done to prevent this
situation in the first place? First, the gasoline should have
been removed from the tank prior to its removal. The gas should
have been pumped into an approved container, and the containers
should have been taken outside the shop and placed in an approved
storage unit. The empty gas tank also should have been removed
from the building. This is all common sense, but it does require
a little extra time and effort.
Now that you've had some practice, let's examine
another scenario:
You're a technician working on a vehicle
when, suddenly, there's a loud explosion in the far corner of
the shop. A shop helper, ignorant to the damage he could have
caused, thought it would be funny to fill up a plastic bag with
a mixture of acetylene and oxygen, throw it under someone's work
bench and then ignite it. Another helper, cutting on the rear
section of a vehicle, was the victim. He survived the explosion,
but he doesn't hear very well anymore.
What do you do?
When stupidity is the reason for an explosion,
there isn't much you can do except reprimand the culprit and then
get your employees trained in the proper use, storage, maintenance
and potential dangers of shop chemicals. When was the last time
your employees were trained in the proper use of oxy-fuel equipment?
Because this equipment is rarely used and much of the information
is passed from one technician to another to another, it's a wonder
there aren't more accidents.
What do the above scenarios have in common?
They could've been prevented. Had the workers involved in these
situations been aware of their surroundings and employed some
common sense, these situations would've never occurred in the
first place. No one wants to be told what to do; we all have our
own work habits. But it's the most basic principles of safety
that could have prevented these potentially dangerous situations.
What Should You Have Done?
Now that you have an idea of what to do in
the event that an explosion has already happened, let's look at
what you should do to prevent one. Consider the following situations:
You're welding the front upper rail of
a vehicle and have already made several welds. You realize that
the welding sparks are landing on the vehicle's battery, which
you forgot to remove from the vehicle.
What should have been done to prevent this
situation?
You should have removed the battery before
starting to weld, making the reason for this potential explosion
pure forgetfulness. Car batteries have the potential to explode,
spraying acid everywhere, and sparks from welding can provide
just the necessary ignition.
You're plasma cutting the floor pan of
a vehicle. Out of the corner of your eye, you notice a fire. Lifting
your helmet for a better view, you see there's a pile of masking
paper on fire next to your work bench. At the edge of the work
bench is a gallon can of grease and wax remover. You know that
a paper fire is bad, but a gallon can of solvent fueling the fire
will make it even worse.
What should have been done to prevent this
situation?
Leaving masking paper on the floor is poor
housekeeping. Take the time to clean up after a job and put waste
in its proper receptacle - you could pay deadly consequences if
you don't. Also, keep all combustibles away from sources of ignition.
Remember, what starts out as a fire could end up an explosion.
If you use products such as wax and grease removers, don't forget
to replace the caps when you're finished and keep the containers
away from all heat sources.
To prevent the above explosive scenarios -
or any other one that may occur in your shop - the first step
is to identify any potentially explosive elements. The next thing
you need to do is identify any potential ignition sources. Welding
and cutting will probably top the list, but don't forget grinding,
smoking and electrical fires, which can start in two places -
the building's wiring and a vehicle's wiring.
Once you've identified the potentially explosive
materials and sources of ignition in your shop, minimize the potential
for an explosion. Keep the explosives separated from the ignition
sources; if you can't remove the combustible, cover it up with
an appropriate fire-retardant material. Also, eliminate all unnecessary
sources of ignition.
Ignite Your Training Program
After doing what you can within your shop,
it's time to ask for professional advice and formal training.
The most logical place to begin would be with your local fire
department, which should be willing to help identify potentially
explosive situations and materials. Fire-extinguisher manufacturers,
compressed-gas distributors (usually welding distributors) and
outside safety consultants are other sources of help. Some may
even offer safety training at no cost. One of the best ways to
help defray the cost of safety training is to work through a local
trade association or community college.
The OSHA Handbook for Small Businesses is
another source for safety tips. This document is based on a four-point
workplace program: point one - management commitment and employee
involvement; point two - worksite analysis; point three - hazard
prevention and control; point four - training for employees, supervisors
and managers.
The guidelines listed in the handbook aren't
mandatory, but they make good safety sense. If you're currently
following these guidelines, you're practicing valuable safety
rules. If you're still having trouble buying into all of this
safety stuff, remember this: If you have a fire or explosion at
your shop, you can be certain OSHA will be knocking at your door
soon after the flames are extinguished. It's to your benefit to
use OSHA as a consultant in preventing fires and explosions rather
than as an enforcer after the fact.
Fueling the Fire
The biggest roadblock to preventing explosions
is complacency. Let's say you're a shop owner or technician with
20 years of experience in the business. In those 20 years, you've
never experienced an explosion, so why worry about one now?
The fact is, unless every employee in your
shop diligently follows proper safety guidelines regarding the
use, storage and maintenance of shop chemicals and other materials,
you can't be sure the next 20 years - or 20 days - will be as
unexplosive.
Writer Fred Kjeld is a contributing editor
to BodyShop Business.
Check It Out
To avoid injury and the possible loss of your
business, it's important that you and your employees follow strict
safety guidelines for preventing explosions:
- The first step in prevention is to identify any potentially
explosive elements. Next, identify any potential ignition sources,
such as welding, cutting, grinding, smoking and electrical fires.
- Keep the explosives separated from the ignition sources. If
you can't remove the combustible, cover it up with an appropriate
fire-retardant material. Also, eliminate all unnecessary sources
of ignition.
- Take the time to clean up after a job and put waste in its
proper receptacle. If you use products such as wax and grease
removers, don't forget to replace the caps when you're finished
and to keep the containers away from all heat sources.
- Look to your local fire department for professional advice
and formal training. Fire-extinguisher manufacturers, compressed-gas
distributors (usually welding distributors) and outside safety
consultants are other sources of help.
- The OSHA Handbook for Small Businesses is another source for
safety tips. Though the guidelines listed in the handbook aren't
mandatory, they make good safety sense.