a. When using welding equipment in a closed area make certain to provide
proper ventilation and be sure that no traces of gasoline, acetylene, or other
explosive vapors are present in the area. Station an assistant outside the danger
zone. This assistant should be instructed to look out for fires and take other
necessary action in case of any emergency.
b. The fumes of burning paint or those generated during brazing, welding, or
cutting of brass, lead, zinc, and galvanized or cadmium plated parts are filled
with poisonous particles of oxides, lead, or zinc.
Under the action of an electric arc, nitrogen and oxygen from the air are
converted into poisonous compounds. If welding is conducted in a
confined and insufficiently ventilated space these compounds may become
highly concentrated and, if inhaled in any appreciable quantity, they may
cause serious disability or death.
c. Because welding operations usually generate harmful gases, fumes, and dust,
adequate ventilation is essential. Local exhaust systems should be provided to
remove such substances. Where the nature of the work requires further protection,
special respiratory equipment should be furnished the operators. Many unknown
toxic hazards can be encountered, particularly in experimental welding of new types
of materials. Required ventilation standards and standard operating procedures
should be cleared through the safety inspector before starting such a new operation.
6. SAFETY IN OXYGEN AND ACETYLENE WELDING. In addition to the information
listed in paragraphs 2 through 5, the following precautions must be observed when
involved in oxygen and acetylene operations.
(1) Do not experiment with torches or regulators in any way.
Do not use
(2) Always use the proper tip of nozzle, and always operate it at the proper
pressure for the particular work involved. This information should be taken from
work-sheets or tables supplied with the equipment.
(3) When not in use make certain that the torch is not burning and that the
valves are tightly closed. Do not hang the torch with its hose on the regulator or
(4) Do not light a torch with a match, from hot metal, or in a confined
space. The explosive mixture of acetylene and oxygen might cause personal injury
or property damage when ignited. Use friction lighters, stationary pilot flames,
or some other suitable source of ignition.
(5) When working in confined spaces provide adequate ventilation for the
(6) Keep a clear space between the cylinder and the work so that the
cylinder valves can be reached easily and quickly.
(7) Use cylinders in the order received.
Store full and empty cylinders
separately and mark the latter MT.