Onan DYG Series Operator's Manual And Parts Catalog page 5

FLAMMABLE LIQUIDS
Carelessness is a deadly habit when handling electric generating sets.
The ingredients of an explosion are simple—a combustible mixture and a means of igniting it. Internal
combustion engines operate on natural gas, manufactured gas, gasoline and diesel oil fuel. Liquid
fuels alone will not burn. Air has to be mixed with the fuel so that it reaches what is called a "fumic
state." Only then will a liquid fuel ignite. So it is good to remember that—
IF YOU CAN SMELL FUMES, YOU HAVE HALF THE INGREDIENTS FOR AN
EXPLOSION.
With a combustible mixture, all that is needed is a way of igniting the fumes. There are many: faulty
engine-ignition insulation, arcing relays or brushes, welding, dropping a steel wrench on a concrete
floor, and of course a cigarette.
THIS
DON'T SMOKE
IN THE VICINITY
OF FUEL!
The following example is a vfery real possibility: A loose connection in a fuel line; or dirt in a solenoid
valve allows fuel vapors to escape.
An operator smoking a cigarette is in the vicinity of the escaping fuel. Now, coal at the cigarette end has
a te'mperature of 1000 o F, and rises up to 1175 0 F (538°C to 635° C) when air is drawn through it. That
coal is hot enough to ignite a fuel vapor mixture.
Could the explosion have been prevented? The answer is obviously "yes." This accident happened
because a Planned Maintenance Program was either non-existent, or was not being followed. Most
accidents happen because some individual does not follow the simple fundamental rules of safety.
MOST ACCIDENTS CAN B E PREVENTED!