Hot work involves any activity that can be a source of ignition when flammable material is present, or which can be a direct fire hazard even if flammable material is not present.
Here are some examples of hot work:
Welding;
Soldering;
Cutting metals;
Brazing;
Grinding; and
Drilling into metal which may cause sparks.
Hot work may even include such activities as taking photographs with a non-intrinsically-safe camera.
Countries such as the USA, Australia, Canada, NZ and the UK have regulations requiring safety permits for hot work.
There are also country-specific industry standards from groups such as the National Fire Protection Association (NFPA), the American Welding Society, the American Petroleum Institute (API), and others, which describe safe procedures for hot work.
If hot work requires that you issue hot work permits, you must be properly trained on your plant requirements and procedures before you can issue any hot work permits.
Unfortunately, the majority of incidents associated with hot work occur because the presence of flammable material was not anticipated.
In many cases, flammable vapors flow into the area where the hot-work is being done by a route which had not been anticipated..
Insufficient flammable vapor monitoring of the atmosphere in vessels or other equipment, or in the general work area, is also a frequent contributing cause to hot work incidents.
What you can do:
Eliminate chemical hazards by draining and cleaning-out tanks, purging residual vapours and establishing an inert atmosphere (e.g., using Nitrogen blanket or filling tanks full with water);
Isolating areas being subjected to hot-work from other process areas to ensure there is no inward flow, using valves (double block and bleed), caps, blind-flanges or other physical devices;
Establishing lock-out, tag-out (LOTO) on all isolation points to ensure that isolations cannot be inadvertently breached;
Understand procedures and permit requirements for safe hot work in your facility;
Understand the hazards of your process. Know what has to be done to prepare the work area for safe hot work and be sure it is done before you start;
Anticipate how far sparks or heat can travel or be conducted. Be prepared if work area conditions change;
Make sure that any activities required during the hot work (for example, monitoring for flammable vapors, maintaining purges) are actually done.
If you do hot work, make sure you understand everything required for you to do each specific job safely, and follow these safety requirements.