Permit to work systems are fundamental to ensuring that work is safely actioned. The purpose of the permitting system is to ensure that all work to be performed will not adversely affect plant operations, and that it can be safely actioned with regard to the process, and other work activities that may be occurring at the same time.
No work must be performed until all the required permits are authorised and the permit holder and workers are fully aware of the limitation of the permits and any special conditions that apply to the work. Limitations may include special safety equipment or checks such as: fire extinguishers, harnesses, gas monitoring, etc. There are many types of permits required to ensure safety at work. These can include:
- cold work permits
- hot work permits
- isolation permits
- confined space entry permits
Most workplaces have specific systems in place, which may differ significantly.
Cold work permits – These permits are required for any work not conducted by Operations personnel provided that the work cannot create a source of ignition, and no tools capable of causing an ignition are to be used. The main purpose of the permit is so that Operations personnel are aware of the work activities being actioned and can safely manage the different activities that may be occurring in a specific area. Examples include external inspections, working on intrinsically safe electrical equipment, installing cables in existing cable trays, etc.
Hot work permits – In hazardous areas, permits must cover the usual risks associated with working in and the potential ignition risk of flammable atmospheres. The ‘hot work’ permit is usually associated with work in or near a hazardous area for any work that could introduce an ignition source. Most plants have identified ‘Hot Work Areas’ where hot work permits are required if potential ignition sources can exist due to the work. The ‘Hot Work Areas’ will include all hazardous areas. Examples include photography, using any non-intrinsically safe test equipment, welding, grinding, cutting, drilling etc. Usually the ‘Hot Work Area’ will be defined by rigid geographical boundaries such as road and fences to reduce ambiguity. Hot work permitting will usually require combustible gas monitoring prior to commencement of the work, and either continuous or periodic monitoring during the work.
Isolation permits – These permits are required to isolate equipment. The objective of the permit is to ensure that the isolated item of plant cannot be inadvertently ‘livened’ whilst the work is in progress. The isolation will cover all forms of energy from electrical, pressure, gravitational, etc. This type of permit is usually issued in conjunction with a cold work permit.
Confined space entry permits – These permits are required to enable safe access to confined spaces. The objective of the permit is to ensure that the entry of personnel into items of plant will only occur when the plant is isolated from energy sources, and the atmosphere has been deemed to be safe (or suitable breathing apparatus is used).
Vehicle entry permits – These permits are required if vehicles are to leave designated roads into hazardous areas, or areas where the vehicle could present other risks.
