5-1
Chapter 5
W
elding Operation
Chapter 5 Welding Operation
This chapter explains the procedures from preparation to completion of the welding operation.
5.1 Precaution at Welding Operation
This section explains the safety precautions for welding operation.
5.1.1 Precautions for air discharge and use of respiratory protective
equipment
To prevent suffocation or gas poisoning in the welding operation, ensure to follow the instructions
below:
To prevent any health damage due to poisonous gas or particle substances (fume) emitted in the welding
operation, ensure to follow the instructions below:
• When welding is required in tank, boiler, reaction tower, or hold of a ship, closed space,
or any other places of poor ventilation, ensure to provide ventilation equipment.
• Gas of larger gravity than that of oxygen, such as carbon dioxide gas or argon gas,
retains at the bottom part.
To prevent anoxia due to the retention gas, provide ventilation equipment.
• When it is difficult to provide ventilation equipment or the ventilation equipment does
not give sufficient performance, ensure to use respiratory protective equipment.
• For preventive measure from falling due to anoxia, apply lifelines such as a safety belt.
• For the welding operation in a narrow space, perform the operation with the trained
supervisor.
• Periodically inspect the ventilation equipment to ensure correct and proper
performance of ventilation.
• To reduce the dust concentration, install a partial exhaust facility such as fume suction
device, or install the collective ventilation equipment.
• When it is difficult to provide a partial exhaust facility or the ventilation or exhaust
facility does not give sufficient performance, ensure to use the respiratory protective
equipment.
• In performing welding or cutting the coating steel plate or galvanized steel sheet,
provide a partial exhaust facility or let the welding operator as well as the surrounding
operators use respiratory protective equipment. (Welding or cutting the coating steel
plate or galvanized steel sheet will cause toxic gas or fume.)
• Do not perform welding operation in the vicinity of degreasing, cleansing, or spraying
operation. Performing the welding operation in such places may generate poisonous
gas.
