The Risk Management Tool Box Blog

Hot working involves all jobs that create ignition sources and these include flames, sparks, welding flash, and electrical arcs.

History demonstrates that there is a particularly high risk of uncontrolled fire or explosion when undertaking hot work on vessels, tanks or containers that contain, or have contained, flammable or combustible hazardous substances.

Such hazardous substances include petrol or diesel, thinners, engine oil, anti-freeze, and solvents.

These hazardous substances are in common use in many industries including manufacturing, mining, engineering, vehicle servicing, energy and utilities and farming.

In all cases, although tanks or containers may appear to be empty, sufficient residue may exist in seams, creases or rust-scale within the container leading to vapours at explosive levels.

Hot work may ignite the vapour contents leading to high-energy explosive releases.

In order to prevent these types of incidents, managers and workers should always ensure that hot work on vessels, tanks, or containers is undertaken using the most appropriate hazard and risk management controls.

These controls include:

1. Eliminating hot work which may not actually be necessary;

2. Substitution of safer alternatives to hot work, including disposal of containers rather than their repair;

3. The use of cold-cutting or cold repair methods;

4. Using specialist contractors who know how to manage the risks involved in hot work;

5. Using engineered controls involving cleaning, purging and inerting prior to hot working;

6. Isolating tanks being worked on from other tanks or vessels that may still contain vapour at the LEL;

7. Ensuring that employees performing hot work are competent to undertake the job safely;

8. Ensuring that an appropriate gas testing and monitoring regime is in place prior to any hot work; and

9. Ensuring that appropriate administrative controls are in place prior to undertaking hot work on tanks which may include a risk assessment, a permit to work and/or a Job Safety Analysis.

A JSA for generic "hot work" can be found by clicking here.

More detailed information is contained in the the UK HSE Code of Practice  entitled  Safe Maintenance, Repair and Cleaning Procedures, Dangerous Substances and Explosive Atmospheres Regulations (2002).