 Permit to work is an essential part of control of work (COW), the integrated management of business critical maintenance processes.Control of work is made up of permit to work, hazard identification and risk assessment (RA), and isolation management (IM).Permit to work is a core element of integrated safe system of work (ISSOW) systems, that along with risk assessment and isolation planning, enable as low as reasonably practicable (ALARP) reduction of unsafe activities in non-trivial work environments.