The Lightning Stop Work SOP

Purpose

This procedure gets every outdoor worker into real shelter before lightning reaches them and keeps them there until the risk has passed, on every job, regardless of who is leading it or how far behind the day is. It fixes the four things that go wrong on a thunderstorm day: nobody decided in the morning where the crew would shelter, nobody felt entitled to call it, the crew sheltered somewhere that only looks safe, and the crew went back out when the rain stopped instead of when the thunder did. A step fails when no safe shelter is near enough to reach in time, and that failure is meant to be caught in the morning, not discovered when the first thunder rolls.

For why the rule is built this way and how strikes injure people, see related: Lightning and the Outdoor Crew.

Scope

Covers: all outdoor work and all work on roofs, ladders, towers, pool decks and open lots, plus indoor work on an electrical service, panel, outdoor disconnect or metal piping that runs outside, whenever thunder can be heard or a thunderstorm is forecast for the work area.

Does not cover:

• Storm damage response after a storm has passed, such as emergency tarping and downed lines, which has its own hazards and never begins until this procedure's restart criteria are met.
• Heat and smoke decisions on the same day. See related: The Smoke Day Work Decision SOP.

The rule itself is the National Weather Service's: when thunder roars, go indoors, and wait thirty minutes after the last thunder before going back out. OSHA and NOAA's Lightning Safety When Working Outdoors fact sheet asks employers to put that rule into a written plan, which is what this SOP is.

Roles and responsibilities

Procedure

1. Plan shelter before the first tool comes off the truck. On any day the forecast carries thunderstorm risk, the lead names the shelter for each work position: an enclosed building with wiring and plumbing the crew can get into (the customer's house, with permission asked in advance) or a hard-topped, fully enclosed vehicle. Then the lead times the walk from the farthest work position, plus the time to get off any roof or ladder. Acceptance: shelter named, and total time to reach it from the farthest position is 5 minutes or less, a common starting point to tune. What wrong looks like: the only shelter is an open garage, a shed, a carport or a truck parked a long walk away. Stop rule: move the vehicle closer, get the customer's permission to use the house, or schedule the exposed work outside the forecast storm window; if none of those works, the exposed work does not start that day. Hazard: none physical at this step; the hazard is the long walk under a storm that this step exists to remove.

2. Brief the crew on the call, the signal and the shelter. Tell every crew member that anyone who hears thunder or sees lightning calls stop, that nobody overrules it, what the signal is (a shout plus a radio call, or a horn where equipment noise drowns voices), and where the shelter is. Acceptance: each crew member can say where the shelter is and what the signal is. What wrong looks like: a new hire who thinks only the lead can stop work. Stop rule: re-brief before work begins. Hazard: mowers, saws and compressors mask thunder, and hearing protection does too; on storm days assign one person to listen, or use a lightning alert service, so the noisiest worker is not the only one who could hear it.

3. Watch the sky and the radar while working. On a forecast storm day, check radar every 30 minutes and keep the lightning alert on. Acceptance: checks noted in the job log at the stated interval. What wrong looks like: a cell building nearby on radar with no thunder yet. Stop rule: if a storm on radar is close enough that getting off the roof would take longer than its arrival, start securing now rather than waiting for thunder. Hazard: the person checking the phone on a roof is not watching their footing; check from a stable position, never on a ladder.

4. Call stop at the first thunder. Whoever hears it calls it, the lead confirms over the radio, and the time is noted. Acceptance: every crew member acknowledges within 1 minute. What wrong looks like: someone who says "that was miles away" and keeps going. Stop rule: the lead repeats the stop; the owner deals with an override afterward, not on the roof. Hazard: thunder audible at any distance means the crew is already within striking distance, so the stop is immediate, not after finishing the course or the cut.

5. Make equipment and the roof safe in minutes, then come down. Shut off and unplug power tools, close any open electrical cover so no live conductor is exposed, and tarp an open roof section only if it can be done in a few minutes; otherwise leave it. Come down ladders one at a time with three points of contact. Acceptance: everyone off roofs and ladders, tools off, no live conductor exposed, within the time set in step 1. What wrong looks like: a crew still tarping as the storm arrives. Stop rule: abandon the tarp and get down; a wet attic is a repair, a fall is not. Hazard: wind ahead of a storm lifts tarps and sheet goods and can pull a worker off balance at an edge, so nobody wrestles a tarp at the eave.

6. Go to the named shelter and take a headcount. Into the building or the vehicle, doors closed, windows up. Not under a tree, not in an open garage, porch, shed or carport. Acceptance: headcount complete at the shelter within the step 1 time. What wrong looks like: one person missing. Stop rule: the lead radios and calls their phone; a search goes only as far as the immediate work area and back. Hazard: if the crew decides to leave the site rather than wait, a hard-topped vehicle is still shelter on the road, but do not drive into water over the road, where a vehicle can float.

7. Run the thirty-minute clock from the last thunder. Log the time of every thunder heard. The earliest return is thirty minutes after the last one, and each new rumble restarts the clock. Acceptance: thirty full minutes logged with no thunder. What wrong looks like: the rain stops and someone wants to go back out. Stop rule: the clock decides, not the sky. Hazard: inside the shelter, stay off corded phones, away from plumbing fixtures and away from the electrical service and wired equipment; nobody steps out to check the sky.

8. Re-walk the site before restarting. When the clock clears, the lead inspects before anyone climbs or powers up: roof surface and ladder footing, tarp condition, standing water near cords or equipment, and any electrical equipment that got wet. Acceptance: walking surfaces drained and grip tested, ladder re-set on firm ground and secured, wet cords and tools dried, and every power tool plugged into a GFCI that trips and resets on its test button before use. What wrong looks like: a roof that is still slick, or a cord lying in a puddle. Stop rule: do ground tasks until the roof is walkable, and take a tool out of service if its GFCI test fails. Hazard: this restart is when falls and shocks happen, because the crew is behind and the surfaces are wet; if thunder returns during the re-walk, the clock restarts at step 7.

9. If anyone is struck, treat first and shelter as you go. A struck person carries no charge and is safe to touch. Call 911, start CPR on anyone not breathing normally, use an AED if there is one, and when several people are down treat the ones who look lifeless first. Move the victim and helpers into the shelter if the storm is still active and it can be done quickly. Acceptance: 911 called and CPR started within the first minute on anyone not breathing. What wrong looks like: helpers frozen, waiting for the storm to pass. Stop rule: anyone struck goes for medical evaluation even if they feel fine. Hazard: rescuers are still under the storm, which is why moving into shelter is part of the response.

The record this produces

The job log records, on any storm day: the forecast, the named shelter and the timed walk from step 1, the time of the stop call and who made it, the headcount time, every thunder time, the restart time, and the result of the restart inspection. The office adds the customer delay. The owner reviews stops monthly, looking for two things: stops that took longer than the step 1 time, which means the shelter plan is wrong, and jobs restarted less than thirty minutes after a logged thunder, which means the clock was cut. A shop that logs stops is also the shop that can show, after a strike nearby, that it had a plan and used it.

Worked pass

A two-person lawn crew, Luis (lead) and Dee, mowing an 8-acre rural property. Forecast: thunderstorms likely after 2:00 p.m.

• Step 1, fail. The truck was parked at the road. From the back field, the far end of the job, it was about half a mile, roughly 10 minutes on foot at 3 miles an hour, against a 5-minute standard. The house was locked and the customer away. No safe shelter was near enough, so the step failed and Luis took the stop rule.
• Stop rule taken. Luis drove the truck through the field gate and parked it at the back field's edge, cutting the walk from the farthest position to about 2 minutes, and changed the order of work so the back field was cut first, before the storm window.
• Step 1, re-run, pass. Shelter: hard-top truck, about 2 minutes from the farthest position, 3 minutes from the front lawn.
• Step 2, pass. Dee could name the shelter and the signal, a horn blast plus a radio call, because both mowers drown out voices.
• Step 3, pass. Radar at 12:30 and 1:00 showed cells forming to the west; Luis kept the alert on.
• Step 4, pass. At 1:40 Dee heard thunder over her mower and hit the horn. Luis confirmed on the radio at 1:40.
• Steps 5 and 6, pass. Both mowers shut off where they stood. Both in the truck, windows up, at 1:43, inside the 3-minute walk from the front lawn where they were working.
• Step 7, pass. Thunder at 1:40, 1:52, 2:09 and 2:20. The rain stopped at 2:35 and Dee asked to restart; the clock said no. Earliest return: 2:50, thirty minutes after 2:20.
• Step 8, pass with a hold. At 2:50 the lawn was soaked and the side slope near the pond was slick. Luis held the slope and the riding mower until 3:20, finishing flat ground with the push mower first. No electrical tools were in use.

Without the morning fail, the 1:40 stop would have found Dee in the back field with a 10-minute walk to the road under the storm's leading edge, which is the exact case this procedure exists to prevent.

References

• National Weather Service, Lightning Safety program (when thunder roars, go indoors; the 30-minute rule; safe shelter)
• OSHA and NOAA, Lightning Safety When Working Outdoors fact sheet (employer lightning safety plans)
• See related: Lightning and the Outdoor Crew
• See related: The Smoke Day Work Decision SOP