In this module
Objectives covered: LO 2.8.1, LO 2.8.2. By the end you will be able to:
- Explain how a permit-to-work system controls high-risk jobs.
- Describe the main steps of lockout/tagout (LOTO).
- Explain confined space entry controls and Management of Change (MOC).
8.1 Permit to work (PTW)
A permit to work is a written system that controls high-risk, non-routine work. It makes sure the hazards are identified, the area is made safe, and the right people agree before work starts. Common permits include:
- Hot work (welding, cutting, grinding near flammables)
- Confined space entry
- Work at height
- Electrical isolation and live work
- Excavation
- Lifting operations
A permit states: the job, the location, the hazards, the isolations, the gas tests, the PPE, the time limit, and the signatures of the issuer and the performer. When the job ends, the permit is closed and the area is handed back safely.
8.2 Lockout/tagout (LOTO)
LOTO prevents machines or equipment from starting, or stored energy from being released, while people work on them.
- Prepare: identify all energy sources (electrical, pneumatic, hydraulic, steam, gravity, springs).
- Notify affected workers.
- Shut down the equipment normally.
- Isolate each energy source.
- Apply locks and tags: each worker fits their own personal lock.
- Release stored energy: bleed pressure, block raised parts, discharge capacitors.
- Verify zero energy: try to start it, test with a meter.
- Only then begin work. Remove locks only when the job is complete and everyone is clear.
One person, one lock, one key. Never remove another person's lock.
8.3 Confined spaces
A confined space is large enough to enter, has limited entry and exit, and is not designed for people to stay in, such as tanks, septic pits, manholes and silos. The atmosphere can kill in minutes. Before entry: isolate, ventilate, test the air (oxygen 19.5 to 23.5%, flammable gas below 10% LEL, toxic gases below limits), issue a permit, keep a standby attendant outside, and plan the rescue. Never enter to rescue without breathing apparatus; most confined space deaths are would-be rescuers.
8.4 Management of Change (MOC)
Changes to equipment, chemicals, procedures, staffing or software can bring new hazards. An MOC process makes sure every change is reviewed for hazards, approved, communicated and documented before it is made. "Replacement in kind" (the same part) does not need MOC; anything different does.
- OSHA 1910.147: control of hazardous energy (LOTO).
- OSHA 1910.146: permit-required confined spaces.
- OSHA 1910.119(l): management of change. 1910.252: hot work fire prevention.
- ISO 45001 clause 8.1.3: management of change.
Workers in Bangladesh die every year cleaning septic tanks and underground water reservoirs, often in groups because a second and third person go in to help the first. A Dhaka real estate developer now requires a confined space permit, a portable 4-gas detector, a blower, and a standby person with a rope and harness for every tank cleaning. No one enters until the gas reading is recorded on the permit.
Learning Check
Answer these two questions to check your understanding. You can try again as many times as you like.