The New Worker Heat Acclimatization SOP

Purpose

This procedure makes sure that nobody in their first days of heat work, or their first days back, carries a full day's heat load before their body can handle it. Most heat deaths in outdoor work happen in that window, and they happen to workers who said they were fine. Without a written procedure the schedule depends on whichever lead is on that day remembering it, which on a behind-schedule July afternoon means it does not happen. The reasoning behind the percentages is in Heat Acclimatization for New and Returning Workers; this SOP is how the shop runs them.

Scope

Covers: new hires in any season, workers back after seven or more calendar days away from heat work, workers back from an illness with fever, vomiting or diarrhea, workers moved from inside work to attic or rooftop work, and the whole crew when a heat wave arrives. "Heat work" means attics, rooftops, unshaded outdoor work, and hot mechanical rooms.

Does not cover: the daily water, shade and rest-break routine for acclimatized workers, or recognizing and treating heat illness in general. Both belong to Heat Stress + Jobsite Hydration Reference. Where your state has its own heat rule with a written plan (California, Washington, Oregon among them), that plan's terms govern and this SOP should be read as your shop's way of meeting them.

Roles and responsibilities

Procedure

1. Flag the worker before the first heat assignment. On hire, on return after seven or more calendar days away from heat work, on return from a fever or stomach illness, on a move from inside work, or when a heat wave is forecast, the office marks the worker on the dispatch board with the date and which schedule applies: new (20, 40, 60, 80, 100 percent of exposure) or returning (50, 60, 80, 100 percent), the two schedules in NIOSH's criteria document and OSHA's heat illness guidance. A heat wave, as a common starting point, is a heat advisory or a forecast high at least 10 degrees F above what the crew has worked in over the previous two weeks; it flags the whole crew onto the returning schedule. Acceptance: the flag is on the board before the worker's first heat assignment, showing a start date and schedule type. Wrong looks like a returning worker discovered after lunch on his first day back. Stop rule: if the flag was missed and the worker has already done a full heat day, the next day restarts at day 1 of the right schedule, and the lead watches that worker as if day one went badly. Hazard: the missed first day is the most dangerous day this SOP exists for.

2. Set the exposure base in hours. The lead writes down how many hours of heat exposure this worker's normal day would contain, not the hours on the clock. A ten-hour day with two hours of driving and an hour of shop time has a base of seven. The office multiplies the base by each day's percentage to get the daily caps in hours and puts them on the flag. Acceptance: a base in hours and five daily caps, each a constant step apart for the new schedule. Wrong looks like caps computed from clock hours, which sends a worker into eight-tenths of a ten-hour day in the attic when the schedule meant eight-tenths of seven. Stop rule: if the lead cannot estimate the base, use the clock hours minus drive time and correct it after the first day. Hazard: an inflated base quietly removes most of the protection.

3. Assign the day's heat work under the cap, early in the day, with a buddy. The lead places the worker's heat hours in the coolest part of the day, before about 11 a.m. for attics and rooftops, and fills the rest of the shift with non-heat work: staging, shop inventory, ground-side work in shade, ride-along time in the conditioned part of the house. A named, acclimatized buddy is assigned for every heat block, and the worker never enters an attic alone while on the schedule. Acceptance: total planned heat hours at or under the day's cap, and a buddy's name beside each heat block. Wrong looks like the cap respected on paper by splitting it into a morning block and a 2 p.m. block in the same attic. Stop rule: if the day's jobs cannot be arranged under the cap, the worker moves to another crew's lighter work or stays on shop tasks; the job does not override the cap. Hazard: an afternoon attic can run far hotter than the outdoor reading, so time of day matters as much as hours.

4. Run the pre-shift check. Before the first heat block the lead asks four questions: any fever, vomiting or diarrhea in the last 24 hours; less than about five hours of sleep; any new medication or dose change; did you drink water this morning. Acceptance: all four answered, and a no on the first. A yes on illness means no heat work today and the worker re-enters on the returning schedule when well. A yes on sleep or medication moves that day's heat block earlier and shorter, and a medication question goes to the worker's own doctor, not the lead. Wrong looks like the check skipped because the worker "looks fine." Stop rule: an unanswered check is a no-heat day. Hazard: a worker already short on fluid starts the day partway to heat exhaustion.

5. Monitor during every heat block. Cool drinking water is within reach of the work area and the worker drinks about a cup every 15 to 20 minutes. The buddy makes face-to-face contact at least every 30 minutes as a starting point, asking how they feel and watching for the signs in step 6, and the worker takes a rest break in shade or a conditioned room at least that often. Acceptance: check-in times logged, and water available at every check. Wrong looks like the buddy working in the other end of the attic with no eyes on the worker for an hour. Stop rule: a missed check-in means the buddy goes to the worker now. Hazard: people in early heat illness rarely notice their own confusion, so the buddy is the instrument, not the worker's own report.

6. Stop at the first symptom, and treat a heat stroke sign as an emergency. Headache, dizziness, nausea, cramps, unusual fatigue, or heavy sweating with weakness: stop heat work, move the worker to a cool place, loosen clothing, give water, and stay with them; they do not go back into the heat that day. Any sign of heat stroke - confusion, slurred speech, hot skin, stopped sweating, fainting, seizure - means call 911 immediately and cool the worker while waiting: soak them with cool water and fan them, ice or cold packs at the neck, armpits and groin, or immersion in cool water if it is available. Acceptance: symptoms resolve within about 30 minutes of cooling and rest, or emergency care is on the way. Wrong looks like a worker who sits ten minutes in the truck and goes back up because he "feels better." Stop rule: symptoms that do not ease within 30 minutes, or that get worse, mean emergency care regardless of what the worker says. Hazard: heat exhaustion can tip into heat stroke, and heat stroke kills through delay.

7. Decide each evening whether to advance, hold or restart. The lead reports the worker's actual heat hours and any symptoms to the office. If the day ran at or under the cap with no symptoms, the worker advances to the next step tomorrow. If any step 6 symptom occurred, tomorrow repeats today's percentage rather than advancing, and the first heat block back is shortened to the morning with the buddy checking every 15 minutes for the first hour. A heat wave starting tomorrow holds the step. Acceptance: tomorrow's cap on the board before the lead leaves. Wrong looks like an automatic advance after a symptom day because "it was the afternoon, he'll be fine in the morning." Stop rule: a second symptom day on the same step goes to the owner, who decides whether the worker needs a medical check before more heat work. Hazard: the return after a stop is the next exposure of a body that just showed it was not coping.

8. Release and close observation. After the worker completes the 100 percent day with no symptoms, the owner releases them to the normal schedule. Close observation continues through day 14 from the start date, with the buddy check kept on any afternoon heat block. Acceptance: the release date, initials, and a day-14 end date on the flag. Wrong looks like the flag cleared on day five and the worker on a solo afternoon attic call on day six. Stop rule: any symptom before day 14 returns the worker to step 7's hold rule. Hazard: the first solo afternoon is a new exposure even for a released worker.

The record this produces

One acclimatization card per flagged worker, kept in the worker's file and visible to dispatch: the trigger and start date, the schedule type, the exposure base and the daily caps, the daily actual heat hours, pre-shift answers (yes/no only, never medical detail), buddy names, check-in times, any symptoms and what was done, and the release date with the owner's initials. The office reads it each morning to set the board; the owner reads it at release; and if a worker is ever hurt, it is the document that shows the shop ran a program rather than claimed one. Keep it at least as long as your other safety training records.

Worked pass

A helper starts on a Tuesday in early July. The flag goes on the board Monday afternoon: new schedule, start date Tuesday. The lead sets the base at 7 hours (a ten-hour day less two hours of driving and an hour of shop time). Caps: 1.4, 2.8, 4.2, 5.6 and 7.0 hours.

• Day 1, cap 1.4 hours. Pre-shift check all clear. Morning attic air-handler swap from 7:30 to 8:50, which is 1.3 hours; buddy check-ins at 8:00 and 8:30. Afternoon on truck inventory. No symptoms. Advance.
• Day 2, cap 2.8 hours. Pre-shift clear. Rooftop unit 7:00 to 9:45, which is 2.75 hours, check-ins every 30 minutes. Advance.
• Day 3, cap 4.2 hours. Pre-shift: about five hours of sleep, which moves the block earlier. Attic install from 6:45, with check-ins every 30 minutes. At 10:15, about 3.5 hours in, the buddy notices the helper has gone quiet, pale and drenched, and the helper, answering clearly, reports a headache and nausea. Step 6 stop rule taken: out of the attic, into the conditioned living room, shirt loosened, water, cool wet towel on the neck. The buddy stays with him and the lead is called. Symptoms ease by 10:40, about 25 minutes, with no sign of confusion at any point, so no 911 call; had they lasted past 30 minutes or worsened, the call would have been made. No more heat work that day; afternoon on shop tasks.
• Day 4, held at 60 percent, cap 4.2 hours. Step 7 applied: the step repeats rather than advancing to 80 percent. Block 7:00 to 10:00, which is 3.0 hours, with 15-minute check-ins for the first hour. No symptoms.
• Day 5, cap 5.6 hours (80 percent). No symptoms.
• Day 6, cap 7.0 hours (100 percent). No symptoms. The owner releases him, and close observation runs through day 14.

The held day pushed the release from day 5 to day 6, exactly one day. Reading the procedure back against this pass: every heat block landed under its cap, the stop came from the buddy's observation rather than the worker's report, and the symptom day did not advance, which are the three places this SOP is built to hold.

References

• NIOSH, Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot Environments (2016), acclimatization schedules and heat illness first aid
• OSHA, Heat Illness Prevention guidance and Heat National Emphasis Program
• California Code of Regulations, Title 8, section 3395 (close observation of new employees for 14 days)
• See related: Heat Acclimatization for New and Returning Workers
• See related: Heat Stress + Jobsite Hydration Reference