What are Hot Work and Cold Work Permits?

Hot work and cold work permits are work permits that authorize controlled work in nonstandard, potentially hazardous conditions. They consist of specific instructions regarding the nature of the job, time and place, and communicate information regarding safety procedures.
Hot Work Permits
Hot work permits are red-colored permits used to authorize work that will generate heat or sparks, such as:
Welding, Drilling, Grinding, Riveting, Cutting
Use of internal combustion engines
Hot work involves working with a source of ignition in an environment with a potentially flammable or explosive atmosphere. Hot works takes into account the presence of flammable and combustible materials as well as combustible gas in the vicinity of the work.
Cold Work Permits
Cold work permits are green colored permids issued for hazardous maintenance work that does not involve the ignition hazards found in hot work.
Cold work situations are determined by conducint a risk assessment for the task and the working environment. If no flammable or explosive risks are identified, a cold work permit is sufficient for carrying out the the work.
How the Permit System Works
The permit system allows work to be carried out safely by specifying everything from the competency of the working party to the methodology and tools employed. It also delimits the work from operations being performed in adjacent areas to prevent interference. The permit system allows for contingency planning and puts sufficient mitigation measures in place to deal with any foreseeable incident arising from planned work.
Standard NFPA 51B
When in doubt, you can always refer to NFPA 51B, the Standard for Fire Prevention During Welding, Cutting, and Other Hot Work. A hot work program that includes a permit system will help prevent fires and losses.
All facilities should have some provisions for hot work. The definition for “hot” is not limited to locations with potentially flammable atmospheres - it refers to any work capable of initiating fires or explosions of any combustible and flammable materials.