Guides
Lockout/tagout on construction sites
Written by the OK Sécurité team · Updated September 9, 2026
Lockout/tagout protects workers from unintended energy release. Here's a structured approach for practical field application.
Why lock out
Every year, workers are injured or killed because a machine restarted or residual energy released during maintenance. On a construction site, CSTC 2.20 applies: lockout or an equivalent method before any work in the danger zone. RSST 188 applies to establishments.
On a construction site, energy sources are diverse: electrical, hydraulic, pneumatic, gravitational, spring, thermal. Lockout must cover all identified sources.
Basic steps
1) Identify all energy sources and isolation devices. 2) Notify affected personnel. 3) Shut down equipment normally. 4) Isolate each energy source. 5) Apply locks and tags. 6) Dissipate residual energy. 7) Verify zero energy before starting work.
CSTC 2.20.3: each person with access to the zone applies their own unique-key lock. Cutting a forgotten lock follows 2.20.12 — not an improvised bolt cutter.
Construction-specific challenges
Multi-trade coordination makes lockout more complex: electricians, mechanics, and plumbers may work on the same equipment. Multi-lock hasps allow each person to apply their lock.
Heavy construction equipment (cranes, pumps, compressors) may need adapted lockout procedures since isolation points can be far from the work zone.
Documentation and training
Document procedures per equipment or intervention type. Train each worker before they perform lockout and review procedures after any incident or equipment change.
OK Sécurité lets you create custom checklists for your specific lockout procedures.
This guide does not replace your company's lockout procedures. On a construction site, CSTC 2.20 prevails. Consult your SST lead for complex situations. For information only — this is not legal advice. OK Sécurité is an independent company with no affiliation to the CNESST: we are not mandated, endorsed or certified by it. Where there is any discrepancy, the official text published by Légis Québec or the CNESST prevails.
Sources
Informational only. Confirm obligations with your prevention program and:
- CNESST — Mesures spécifiques pour les chantiers de construction
- Safety Code for the construction industry (CSTC) and Regulation respecting occupational health and safety (RSST)
Official rules
Related checklists
Checklists for mechanical and electrical work:
Common questions
- Does lockout apply to heavy construction equipment?
- Yes. Any machine whose inadvertent startup could injure a worker must be locked out. The operator removes the key and applies their lock.
- Who can remove a lock?
- CSTC 2.20.12 governs removing a lock whose owner is absent. It is not a verbal go-ahead from the foreman.
- How long to keep records?
- Neither CSTC 2.20 nor the RSST sets a single retention period for these records. Follow your prevention program and any other duties that apply — do not treat “3–5 years” as the rule.
- Does OK Sécurité have a lockout template?
- You can create a custom list based on your procedure and assign it to the team. Electrical and industrial-mechanic lists also cover some lockout items.