What is a permit to work?

A permit to work is a written, signed system that controls high-risk work. It confirms the hazards were assessed, the plant is isolated and the area made safe before work starts, and that it was returned to a safe state when the work finished. It does not make a job safe on its own: the controls written on it do.

Who signs a permit to work?

Typically the permit issuer (authorised person) who controls the area or plant, and the permit receiver (performing authority) who leads the work crew. Isolations are signed by the isolating authority, and gas tests by a competent gas tester. Each worker signs on to the permit or toolbox talk.

What does prove dead mean?

Before touching a conductor, test it with an approved voltage indicator. Prove the tester works on a known source, test every conductor combination, then prove the tester again. Only then can you treat the circuit as dead.

How far must combustibles be kept from hot work?

NFPA 51B uses 35 ft (about 11 m) from the hot work point: remove combustibles or protect them with fire-resistant covers, and keep a fire watch during the work and for a period after it. Follow the site's own fire rules where they are stricter.

Permit to Work & Site Safety Lab

Every MEP site job starts with the paperwork that keeps people alive. Choose the activities you are planning and the lab tells you which permits and certificates you need, then lets you practise a risk assessment, a full electrical isolation with proving dead, a hot work permit check and a site day where permits overlap.

How a permit to work system works

A is a written agreement between the person who controls an area or plant and the person who will do risky work in it. Click each stage to see what happens and who signs.

Who is who on a permit

The golden rule: a permit is only as good as the checks behind it. If the conditions on site do not match the permit (wrong area, different equipment, gas alarm, weather change), stop the work and go back to the issuer.

Permit selector

Tick every activity your crew will do on this job. The lab builds the permit pack: permits, supporting certificates, PPE, key controls and any conflicts between them.

1. What work is planned?

Risk assessment builder (5 × 5)

Rate each hazard as × , add controls from the , then rate the . Click a cell in the matrix to set the selected row.

Matrix: select a hazard row

1–4 Low5–9 Medium10–16 High20–25 Critical

Bands differ between companies. These are typical; use your project's HSE plan bands.

Add a hazard

From library (filtered by your permit selector picks)

Or type your own hazard

Risk register

Isolation, lock out tag out and proving dead

You need to replace an outgoing MCCB inside SMDB-L3-02. Put the isolation steps in the right order by clicking them. Wrong order? The lab tells you why. Then prove the board dead using the sequence.

Scenario

Single line view

LiveIsolated / deadBack-feed source

Your next step

Prove dead: test every combination

A three-phase board with neutral has 10 combinations. Prove your tester first, test all 10, then prove it again. Click the tester buttons and each pair.

Hot work permit check

Fill in the permit the way a permit receiver would. The issuer's check on the right updates as you go and only turns green when the permit could be signed. Default values are a deliberately unsafe first draft: fix it.

Permit request

Issuer's check

Fire watch timeline

3D site model and 4D permit day

A mid-rise building in the MEP fit-out stage. Tap a zone to see its hazards and the permit it needs. Then play the site day: the 3D zones light up as permits go live, and the lab flags simultaneous operations that clash.

Drag to rotate · scroll or pinch to zoom · tap a zone

06:00

Live now

SIMOPS check across the day

Regional rules and references

The PTW idea is the same everywhere. The legal framework and a few numbers change. Pick a region. Always check the current version of each document and your project's own HSE plan.

Engineer's notes

Lessons from site that are rarely written in the procedure.

Quiz

Score 0

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