Welding, Cutting and Allied Processes

Welding, brazing and cutting are essential processes in the manufacturing industry. All these processes depend crucially on industrial gases.

BCGA is committed to ensuring SAFE use of industrial gases in these processes and produces several documents setting out best practice.  At each workplace, where welding cutting and other allied process are in-use, a suitable and sufficient risk assessment must be carried out and, as required, appropriate controls put in place.

Welding, cutting and allied processes must only be carried out by competent people using suitable equipment.

Gases have hazards, their storage, handling and use must be included in the workplace risk assessment.  Each gas has its own hazardous properties, fuel gases are flammable and asphyxiant, oxygen can create an enriched oxidant atmosphere. BCGA CP 52 identifies potential hazards from the escape, leak or accumulation of these gases into the workplace.

There are additional hazards associated with welding and hot cutting processes, including from the fluxes and materials used. The hazards include excessive heat, exposure to bright direct and reflected light, including ultraviolet light, and the inhalation of welding fume, such as airborne gases and very fine particles. These hazards may also affect others who may be in the vicinity, this should be considered as part of the workplace risk assessment.  Controls for managing these hazards include:

BCGA has engaged with the Health Safety Executive (HSE) and others via the Welding Fume Health Partnership to try to influence attitudes and behaviours with respect to welding fume, particularly in encouraging the use of appropriate controls and the safety of those involved.

The HSE provide guidance for the Control of Substances Hazardous to Health (COSHH) for welding and specific guidance on managing welding fume. BCGA supports the Chartered Society for Worker Health Protection (BOHS) and its ‘Breathe Freely’ campaign to control exposure to hazardous substances, such as welding fume, and to prevent occupational lung disease in the construction industry.  Lots more information is available on their website – www.breathefreely.org.uk. BCGA SA 03 highlights the hazards from welding fume.

Fuel gases are mostly hydrocarbon based and each has its own unique properties. The choice of a fuel gas is based on its ability to burn in air or oxygen and will be dependent on the specific requirements of the job, as well as the location at which it is being used. There are several useful fuel gases of which acetylene and propane are the most common. For information on these refer to BCGA TIS 32.

The use of acetylene requires compliance with The Acetylene Safety (England and Wales and Scotland) Regulations. These Regulations require that all mobile systems shall be fitted with a purpose designed regulator for acetylene, a flashback arrestor incorporating a non-return valve and a pressure and/or temperature sensitive cut-off valve. HSE provide information on the safe use of acetylene and publish INDG 327, Working safely with acetylene.

Brazing requires that the work be heated to the correct temperature for the process to take place. There are several different methods for achieving this heating, but the use of an oxygen / fuel gas burner is the most common. Typically, either oxygen / acetylene or oxygen / propane are used, with the higher temperature of the oxygen / acetylene flame giving maximum flexibility. BCGA CP 7 defines how to design, operate and maintain portable and mobile systems for oxygen / fuel gas processes. Fixed installations, which supply gas through a control and distribution system, are specified in BCGA CP 4 and, for acetylene, BCGA CP 5.

Cutting of metals is often carried out using oxygen / fuel gas equipment. The process consists of heating the work using the flame, and then using excess oxygen to burn the metal. Depending on the scale of the job either oxygen / acetylene or oxygen / propane systems can be used. As appropriate refer to BCGA CP 4, BCGA CP 5 and BCGA CP 7.

There are several options when welding, including gas, electric arc, metal inert gas (MIG), tungsten inert gas (TIG), etc. For gas welding of ferrous metals a high flame temperature which produces a low level of oxidisation is required.  The most suitable gas mixture for this application is oxygen and acetylene. Modern electric arc welding requires the use of shielding gas to protect the weld from the atmosphere. Sometimes this shielding gas is a single gas, very often argon, but the use of gas mixtures is increasingly common, with mixtures tailor-made according to the metal being welded. As appropriate refer to BCGA CP 7 and BCGA CP 47.

All gas equipment must be suitable for the purpose for which it is provided, be safe to operate, and be subject to regular inspection and maintenance. BCGA CP 7 sets out the requirement for carrying out assembly checks, before and after use checks, and a periodic thorough inspection.  BCGA TIS 29 provides a quick guide for the selection and assembly of oxy-fuel gas equipment.

Guidance on carrying out a thorough inspection is provided in BCGA GN 44.

BCGA TIS 18 provides information to assist in identifying the inspection and replacement date markings on certain items.

Welding, cutting and allied processes are well supported by published standards, which are increasingly either European (CEN) or International (ISO). BCGA is very active within BSI in the development of these standards, via the Welding Committee WEE/18.

Committees

Within BCGA, welding, cutting and allied processes are the responsibility of Technical Sub-Committee TSC 3. Members can access information on TSC3 via the Committee Meetings page.

Publications