Welding Method Statement Prerequisites

There are many different welding processes, but the most commonly used in the construction industry are gas welding and electric arc welding. In order to ensure that all welding works takes place in a safe manner, the suitability of the following should be ensured:

A-  The Arc welders

B-   The working welding equipment

C-   The working pipe location

D-  Working Instructions / Procedure

A – Arc Welders

• The welders Personality
• The welder is to be trained and certified.
• The welder must be in good health
• The welder must be trained for safe work

Personal Protective equipment: 

Safety equipment will be made available and the arc welder is to ensure that the equipment and welding supplies are used as follows:

• Welding face shield or goggles with correct filter fitted, at all times
• Leather gauntlet gloves at all times.
• Screens to protect neighboring workers at all times
• Safety boot, at all times
• Breathing apparatus for enclosed vessels, at all times

B- Welding equipment

Gas welding => Cylinder identification

• Oxygen cylinders are painted black and outlet valve threads are right handed
• Acetylene cylinders are painted brown and outlet valve threads are left handed
• Propane painted blue

Storage of gas cylinders

• Gas cylinders should be kept on a hard standing in a safe place in open air. In a secure area.
• Oxygen cylinders should be stored at least 3m away from acetylene
• Acetylene cylinders whether full or empty should always be kept upright
• Oxygen cylinders may be stacked horizontally for maximum high, and wedged to prevent rolling.
• Cylinders should be shielded from direct sunlight or other heat sources

Cylinder handling

•  Hands and clothing should be free from grit, grease and oil when cylinders are handled to prevent them from slipping and prevent grit from getting into the valves.
• Cylinders in use should normally be kept in purpose built secure compound and moved in purpose built trolleys, if it is necessary to move cylinders which are not in a trolley, regulators and hoses should be detached.
• Acetylene cylinders must always be transported and used in the vertical position

Gas Regulators

• Regulators must always be fitted to the cylinders to reduce the gas pressure from that in the cylinder to the working pressure of the blowpipe
• The adjusting screw of the regulator must always be released before the cylinder valve is open.

Gas Hoses

• Hoses should be kept for one type of gas only
• Color code for identification

–          Red for acetylene or other fuel gases

–          Blue for oxygen

• Hoses should be free from cuts, scratches, cracks or burns
• Non-return valves and flash-back arrestors to be fitted as necessary

The Welding Circuit

• On construction site, are welding is usually carried out with direct current (DC), supplied from diesel driven generator

Cables and cable couplings

• Welding leads and welding return cables are frequently dragged over rough surface:
• Their insulation should therefore be suitable for resisting wear and tear

• The cables and couplings should be examined frequently for defects.
• The part of the cable which is connected to the electrode holder should be as flexible as possible
• The welding return should be firmly connected tot the metal by constructed clamp

Electrode holder

• The holder should be fully insulated
• Electrode holder is essentially a pair of spring loaded Jaws

Hazards associated with welding

The principal hazards associated with gas welding are:

• Fire
• Explosions
• Burns
• Eye damage
• Heat stress
• Respiratory disease
• Systemic poisoning

Hazards & risks associated with electric arc welding are:

• Fire
• Explosions
• Burns
• Eye damage
• Heat stress
• Respiratory disease
• Systemic poisoning

• Electric shock
• Ultra-violet radiation
• Ozone depletion

C- Working Location for Arc Welding

To ensure that before commencement of welding

• Don’t attempt to wild enclosed resets
• Keep hose lines clear of traffic lanes
• Stand on an insulated mat
• Arrange good ventilation in the welding area

 

D- Working Instructions For Welding

• Fire extinguisher is required with welding, at all times
• Personal safety equipment’s to be used all the time
• Face Screen to be used when necessary
• Avoid welding near flammable materials
• Don’t leave torch on when not in use
• The area should be checked before leaving for source of fire

PIPE FLARING AND REAMING

• The expanding of copper pipe ends to form accurate joints in pipes, is an industry recognized standard practice.
• The pipe is flared at one end using proprietary trade tools with steel expansion heads assuring precise expansion.
• Circumferences of the expanded pipe are to fit onto the next pipe length (the new I.D. is equal to the original O.D.)
• An accurate and reliable joint is made in the pipe itself  forming continuity in pipe runs, with only one brazed joint required which ensures less potential leaks, with the brazing drawn down into the joint from one side.
• The use of flaring pipe joints does not in any way compromise the soundness of durability of the piping system, but compliments the system by ensuring accurate and reliable joints.