What a permit is for

A permit-to-work is a written system for high-risk jobs. It forces the hazards to be found and the controls to be fitted before work starts. Someone senior then checks the site and signs to say it is ready.

The permit is not the safety measure. The guard-rail, the gas test and the locked isolator are. The permit proves someone looked. When it becomes a form people sign at the gate, it stops protecting anyone.

Jobs that usually need a permit

Singapore law names some permit jobs directly. Your own risk assessment will add others. Common ones on site include:

  • Work at height where someone could fall more than 3 metres.
  • Entry into a confined space such as a tank, manhole or sump.
  • Hot work such as welding, cutting and grinding near flammables.
  • Work on plant that must be isolated and locked out.
  • Excavation near buried services, lifting operations and demolition.
One job, several permits

A confined space entry permit does not cover hot work inside the space. The WSH Council says you need a separate permit for that. Cross-reference the two permits on each form.

Who does what

Singapore's work at height and confined space systems use the same three roles. Learn them, because each signature means something different.

  • Supervisor (the applicant). Leads the crew through hazard spotting, puts the controls in place and applies for the permit.
  • Safety assessor. Visits the site with the supervisor. Checks every control, may ask for more, then endorses the permit. In a confined space, this person also tests the air.
  • Authorised manager. Approves and issues the permit. Monitors the work and can revoke the permit at any time.
Keep the applicant independent

MOM says the supervisor who applies for a work-at-height permit should not also act as safety assessor on it. An independent check is the whole point.

The four stages

Before signing a work-at-height permit, the authorised manager confirms several things. The hazards are dealt with. Every reasonably practicable control is in place. The crew has been told the hazards and precautions. No clashing work is running at the same spot.

  • 1. Prepare. The crew and supervisor walk the job, find the hazards and fit the controls. The permit form records that a risk assessment was done. No work yet.
  • 2. Apply. The supervisor completes the form, lists the controls and passes it to the safety assessor.
  • 3. Evaluate. The assessor checks the site in person, adds conditions if needed and endorses the form.
  • 4. Approve and post. The authorised manager issues the permit. A copy goes up at the work location. Work starts only now.

During and after the job

A permit is live while the work runs. The supervisor, assessor and authorised manager all keep watching that the job follows it. If conditions change, stop and re-check. A new crew, a gas alarm or heavy rain on a roof all count. Suspend or revoke the permit if the controls no longer hold.

UK HSE guidance stresses handover. When a shift changes, the outgoing supervisor briefs the incoming one at the work location. When the job ends, the supervisor closes the permit. Workers are clear, tools are removed and the plant is safe to return. Keep closed permits on file.

What the rules require

Work at height. Under the WSH (Work at Heights) Regulations, hazardous work at height needs a permit-to-work in workplaces defined as factories. MOM's factsheet says these typically include construction worksites, shipyards and manufacturing plants. Hazardous work at height means a person could fall more than 3 metres, including into a depth. MOM says the regulations set no maximum validity. A long-running permit should not exceed seven days and needs a daily review. A single person may act as both assessor and authorised manager where manpower is genuinely short, if trained for both.

Confined spaces. The WSH Council's technical advisory says no one may enter or work in a confined space without a valid entry permit. The supervisor and authorised manager do the risk assessment together before applying. The assessor tests oxygen first, then flammable gas, then toxic gas. The authorised manager may issue the permit only if oxygen is between 19.5% and 23.5%. Flammable gas must be below 10% of the lower explosive limit. Toxic substances must be within permissible exposure levels. The permit stays posted at the entrance. The authorised manager reviews it daily and revokes it if the space turns unsafe.

Legal requirement

In Singapore factories, work where a person could fall more than 3 m needs a permit-to-work approved by an authorised manager. Source: MOM factsheet on the WSH (Work at Heights) (Amendment) Regulations 2014.

Common mistakes

  • Signing permits in the office without visiting the site.
  • Starting work while the permit is still "being processed".
  • Vague controls such as "PPE to be worn" instead of naming the harness and anchor point.
  • Two permits for clashing jobs in the same area, such as hot work next to spray painting.
  • Permits left open after the job, so nobody knows if the plant is safe.
  • Extending a permit day after day with no fresh check.
The rubber stamp

If every permit gets signed in two minutes, the system has stopped working. Ask the authorised manager when they last refused one.

Use it on site: the permit-to-work systems checklist and the toolbox talk to brief your crew.

Sources

  1. Preventing Falls from Heights (permit-to-work section), WSH Council.
  2. Factsheet on WSH (Work at Heights) (Amendment) Regulations 2014, with PTW FAQs, Ministry of Manpower.
  3. Technical Advisory on Working Safely in Confined Spaces, WSH Council.
  4. Permit to work systems (COMAH technical measures), UK HSE.
  5. Conducting risk assessments, WSH Council.

This is practical guidance, not legal advice. Laws and codes of practice change; always check the current official text and your site's own procedures.