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carried out with a subsequent ignition of worker's clothes and fatal burns.
b)
TAKE CARE in confined spaces: Do not leave blowpipes or hoses connected to the supply gases within confined
spaces during work breaks or overnight. Even slow leaks can result in very hazardous situations, with possible fire and
explosion on re-ignition of the blowpipe.
c)
VENTILATE confined spaces: In flame cutting not all of the oxygen released from the cutting nozzle is necessarily used
in cutting. In confined spaces this may result in a dangerous increase in oxygen content in the air, pointing to the need
for adequate ventilation in such situations.
d)
DO NOT use oxygen as a substitute for compressed air: There are many examples of this situation where oxygen has
been used, such as in cleaning, resulting in serious and fatal accidents due to fire or explosion from spontaneous
ignition. NEVER use oxygen to start engines, drive air tools etc.
e)
DO NOT use oxygen or compressed air to dust off clothes. Clothes can become readily flammable and even
self-igniting through oxygen enrichment.
f)
DO NOT KINK pressure hosing: Kinking or nipping hose to interrupt gas flows or whilst changing torches is a very
dangerous practice. Gas can still bleed through the system, or more seriously, escape rapidly should the operator lose
his grip or the hose rupture.
Fuel Gases
Each of the fuel gas-oxygen combinations warrants care in use, from handling of the gas supplies through to the point of
intended ignition. There are greatly increased risks of fire and explosion in the case of leaks. Asphyxiation is also possible due
to exclusion of air in leakage situations.
All fuel gases have special properties, which warrant additional precautions:
a)
Acetylene:
Cylinder colour is Claret / Maroon. Acetylene has a distinctive garlic smell. It is non-toxic, but asphyxiation is possible
through depletion of oxygen. Acetylene is lighter than air and not likely to collect in ducts and drains, but could collect in roof
spaces. It requires minimum energy to ignite in air or oxygen. A concentration of as little as 2.5% in the air can burn. Acetylene
is a potential fire and explosion hazard. Adequate ventilation and leak free systems are required. Hot metallic particles or hot
slag can cause ignition of leaks remote from the area where welding or cutting is taking place.
This gas, in its free state under pressure, may decompose with explosive violence. For this reason it is supplied in special
cylinders . Explosions can occur in pure acetylene subjected to excessive temperature or pressure. Mechanical shock to the
cylinder due to mishandling, or overheating when under high pressure, may also cause decomposition, giving rise to high
temperatures and possible detonation even in the absence of oxygen. Another possible cause of detonation is flashback in
welding, heating or cutting blowpipes, and safety devices are recommended in blowpipe gas supply.
Under certain conditions, acetylene can react with metals such as copper and silver to produce explosive acetylides. This
places a restriction on materials which can be used for the construction of pressure regulators, other equipment and piping.
Copper alloys containing more than 70% copper or 43% silver should never be used with acetylene.
Free acetylene must never be used outside the cylinder at pressure exceeding 150 kPa gauge.
The properties of acetylene are taken into account in systems developed for its storage and supply, and with adherence to safe
procedures, dangerous situations will not arise.
b) Liquefied Petroleum Gas (LPG):
Cylinder colour is aluminium. LPG is usually supplied as a mixture of gases with propane as the main constituent.
Standard LPG has been odourised and has a fish-like smell. It is non-poisonous, but may cause asphyxiation through depletion
of oxygen.
It is denser (heavier) than air and will collect in low or confined spaces, e.g. ducts, drains, basements, boats, ships and closed
tanks. A concentration of as little as 2.2% in the air can burn. It is a fire and explosion hazard, and requires minimum energy to
ignite when mixed with air or pure oxygen. LPG will ignite and burn instantly from a spark or piece of hot metal.
Gas Supply
General
Your Uni-Flame gas welding and cutting equipment is designed to be used by gases delivered to the point of use from porta-
ble compressed gas cylinders. In all cases, gas supplies may be subject to statutory or regulatory provisions. Many Australian
Standards cover the subject. The location, separation, allowed quantities and signage of gas storage should be in accordance
with the relevant statutory requirements and manufacturer's provisions.
INSTRUCTION MANUAL FOR UNI-FLAME
GAS WELDING, FLAME CUTTING AND GOUGING KIT
