Lightning Safety for Crane Operations
Lightning is a serious hazard for outdoor crews. With cranes being tall, metal structures, they are prime lightning targets, putting everyone on or near the crane at risk during a storm.
Plan Before the Lift
Check the weather forecast before work and continue monitoring local weather, alerts, darkening clouds, and wind speed. Identify safe shelters, evacuation routes, a communication plan for warnings, and stop work authority procedure. Plan each lift so the load can be landed safely and the task stopped immediately if storm conditions develop.
Recognize the Danger
Crews should understand:
- A crane’s height and metal structure make it a likely strike point, and a charge can travel through the boom and rigging to the ground.
- Lightning can strike before rain begins or after a storm appears to have passed, and there is no safe warning window.
- No place outside is truly safe during a thunderstorm; sheds, tents and covered porches do not protect against lightning.
- Lightning detectors and monitoring services can help, but none can predict or detect every strike.
- CSA Z248-2004 Clause 8.11.3 states “tower crane operations shall be suspended when electrical storms are near enough to be hazardous”.
- CSA Z150-1998, for mobile crane, Clause 5.3.1 states “no crane shall be assembled, dismantled, or operated when the weather conditions are such that hazards to personnel, property, or the public are created”.
Go Indoors When Thunder Roars
At the first sign of lightning or thunder:
- Seek shelter immediately if you count less than 30 seconds between lightning and thunder.
- Land the load and secure the crane based on the manufacturer’s instructions and emergency procedures without increasing exposure to the hazard.
- Avoid being at the highest point of an open area.
- Move away from the crane, ladders, scaffolding, and other tall or metal equipment that would conduct electricity.
- Seek shelter in a fully enclosed building or a hard-topped vehicle with the windows up.
- Remain sheltered and, as a best practice, do not operate a crane for at least 30 minutes after the last sound of thunder.
Emergency Planning and Response
Occupational Health and Safety Regulation (OHSR) Part 4, Sections 4.13, 4.14, and 4.16 requires a written hazard assessment, emergency procedures, and worker training. Lightning should also be addressed at any crane site exposed to thunderstorms.
A lightning strike to a crane would be categorized as a "misadventure" under OHSR Section 14.16.1. The crane must be inspected and certified safe by a professional engineer before it returns to service.
Reference
OHSR Part 4, Sections 4.13, 4.14, 4.16, and Part 14, Section 14.16.1
