Heat checks: 3 costs to include in crew hours

Key takeaways

Mark the forecast hours that cross the applicable heat trigger.
Count shade setup, moves, water runs, and cooling upkeep separately.
Assign written plan time to overhead when that matches your costing method.
Compare estimated hours with actual use after the job.

A crew works slower, needs more water runs, depends on shade that someone has to set up, and spends time on cooling gear and paperwork that never makes it onto the material list. If you price a hot day the way you price a mild one, the difference comes out of your margin.

This post is for estimators who already know their labor rates and their usual productivity. It focuses only on the heat items that change how many hours a day actually costs. It covers three heat checks you can run before you finalize a bid. Each one turns a site condition into hours or dollars you can count against labor.

To make the checks concrete, I use Oregon's heat illness prevention rules, which set a heat index trigger, shade and water requirements, and a written plan that has to cover cooling methods. Your state, your client, or your insurer may have different requirements. Treat these checks as a way to structure your estimate, not as legal advice.

Why the heat index, not the thermometer

Start with the heat index rather than the air temperature.

Oregon's rule uses the heat index directly, so it's the number that matters for the requirements you'll price. If your state uses a different measure, use that one. The logic stays the same: find the hours when conditions cross a threshold, then count what the threshold requires.

Check 1: Read the heat index for the hours you'll work

Don't price from the daily high. Pull the hourly forecast for the site and look at the hours your crew is scheduled to be on the job. A site that peaks at four in the afternoon may stay under the trigger all morning. A crew that starts early may finish before it gets hot. The goal is to know which hours are at risk, not to guess about the whole day.

The standard applies "whenever an employee performs work activities, whether in indoor or outdoor environments, where the heat index (apparent temperature) equals or exceeds 80 degrees Fahrenheit." ( Oregon Secretary of State administrative rules) A hot warehouse, a shop without cooling, or a truck bay in the sun can therefore trigger it. The trigger depends on when work happens, so it's best handled as a count of hours.

Here's a simple method. For each day, mark the hours when the forecast heat index is at or above 80°F. Call those your triggered hours. Shade, cooling upkeep, and the extra water runs in the next two checks should be counted against triggered hours, not spread evenly across the shift. You'll get a more accurate number that way, and you can explain it to a client.

Use the same source on every bid so your numbers stay comparable from job to job.

The rule also names situations that change the count, so check them before you decide what to leave out.

Incidental exposure. The rule lists "incidental heat exposures where an employee is not required to perform work activities for more than 15 minutes in any sixty-minute period." That is a specific test. A brief, occasional trip into the heat may fit it. Continuous work in the heat does not. Don't assume a task qualifies. Check the wording against what the crew actually does.
Mechanically ventilated buildings. The rule lists buildings and structures that have a mechanical ventilation system that keeps the heat index below 80°F as a separate case. Whether an indoor space qualifies depends on that ventilation result, so measure the space before you count its hours out.
Light and rest workloads. Employers whose employees do "rest" or "light" work, as defined in Table 1.1 of Appendix A, are exempt from sections (3) through (10) only when the heat index is less than 90 degrees Fahrenheit ( Oregon Secretary of State administrative rules). A day in the 80s with light work can carry different requirements than a day at 90 or above, so price those days separately rather than blending them into one number.

Check 2: Price shade and water for every triggered hour

Shade is the first cost. The rule requires employers to "establish and maintain one or more shade areas that are immediately and readily available to exposed employees that are outdoors when the heat index in the work area equals or exceeds 80 degrees Fahrenheit." ( Oregon Secretary of State administrative rules) Three words in that sentence drive your estimate: "immediately," "readily," and "maintain."

Price the time needed to keep shade available near the work. Include walking distance and changes in the work area in your estimate. That turns shade into a labor item, not a one-time purchase.

Price shade in three parts:

Setup and teardown. Picking a spot, setting up a canopy, tarp, or pop-up, and taking it down at the end of the day. Count this once for each site move, and again each time the work area shifts far enough that the old shade no longer covers it.
Moving shade with the crew. If the work area changes during the triggered hours, the shade has to follow. Each move is labor, and it belongs in the triggered-hours count.
Maintenance. Shade fabric tears, stakes pull loose, and wind moves canopies. Someone has to check and fix them. Add a short inspection to the daily sheet for any shade you rely on.

Water is the second cost. The rule's drinking water requirement describes water that is "potable water that is suitable to drink and that is cool (66 oF – 77 oF) or cold (35 oF – 65 oF)" ( Oregon Secretary of State administrative rules). Price these items:

Ice and cold storage. Ice, coolers, and chilled dispensers cost money, and the ice has to last through the triggered hours. If the crew is working hot from late morning to late afternoon, plan for the ice to melt faster than you'd like and for someone to restock it.
Water runs. Someone fills, hauls, and restocks. Each trip is labor, and a site far from a supply point takes more time. Count the runs against triggered hours.
Quantity. Base the number on what your crew actually drinks. If you have records from past hot jobs, use them. If you don't, log consumption on the next hot job and build the figure from that log.

Timing matters as much as volume. Water left in a truck bed through the afternoon may drift outside the cool or cold ranges the rule describes. Plan the water runs around the triggered hours so the water the crew drinks is still in range when the heat peaks. That may mean a midday restock rather than one load in the morning.

Check 3: Count cooling equipment upkeep and the written plan

Oregon's rule requires a written plan, and the plan has to address cooling. In the rule's words, the Heat Illness Prevention Plan "must include the use, care, and maintenance of the alternative cooling methods, in writing" ( Oregon Secretary of State administrative rules). That sentence creates two costs.

The first cost is the plan itself. Someone has to write it, keep it current, and update it when a job, a crew, or a cooling method changes. My suggestion is to carry plan time in overhead, since it's roughly the same for every job, and carry equipment upkeep in the job cost, since it changes by site. For related cost allocation, see variable overhead rates.

The second cost is the cooling equipment. Whatever cooling you bring to a site, such as fans, misting units, or cooling vests, should be covered in the plan, with its use, care, and maintenance spelled out. Check the plan against each piece of equipment you intend to run. If the plan doesn't address a piece of gear, don't assume it's covered.

Upkeep tasks to price include:

Cleaning, filling, and testing misters and fans before the shift.
Charging batteries and running generators, plus the fuel runs.
Replacing filters, pads, and hoses when they wear out.
Inspecting equipment at the start of each triggered period.

Decide how to count each one. If the equipment only runs when the heat index triggers, count its upkeep against triggered hours. Either way, write the basis on the estimate sheet so the next estimator can follow it.

Assign one person to own the plan and the equipment checklist. If the estimator writes the plan and the foreman runs the equipment, decide in advance who updates the upkeep numbers when something breaks. Unowned tasks tend to show up as surprises on the job.

Put the three checks into one bid

Work through the bid in a fixed order so nothing gets skipped:

Pull the hourly forecast for the site and mark the triggered hours (check 1).
Put any light-work days in the 80s and any days at 90 or above on their own lines (check 1).
For each day, total shade setup, moves, and checks for the triggered hours (check 2).
Total ice, water runs, and restocks for the same hours (check 2).
Add cooling equipment upkeep for the equipment you actually run (check 3).
Note any indoor space you're counting as under the trigger, and the ventilation result that supports it (check 1).
Confirm where the written plan's time sits, following your overhead allocation method (check 3).

Keep the heat items on their own lines of the estimate sheet. A single "heat allowance" hides which assumption is driving the cost. If your sheet allows it, use separate columns for triggered hours, shade hours, water hours, cooling upkeep hours, and plan hours. When a client asks why a summer bid runs higher than a winter one, you can point to the rows that changed.

Revisit the count when forecasts change. A hot week can move the triggered hours a lot, and a cold front can take them away. Build the sheet so you can update the triggered-hours count without rebuilding the whole estimate.

Illustrative example: Count the hot part of a shift

Consider a crew working outdoors on an open lot. The forecast shows the heat index crossing 80°F from late morning and staying there past mid-afternoon. Morning work stays under the trigger. The triggered hours fall in the middle of the shift, and the estimate should show that.

For the triggered block, the estimate picks up shade setup at the start of that block, one shade move when the crew shifts from the east side of the lot to the west side, and a daily shade check. Water is counted as ice, a cooler refill at the midpoint, and a restock run before the afternoon block. The cooling fans run only in the triggered block, so their upkeep is counted there. The written plan is already in overhead, so it doesn't appear on this job's sheet.

Common mistakes to avoid

Several errors show up again and again in heat estimates:

Pricing shade as a one-time purchase. Shade is labor every time the work moves.
Spreading heat costs across the full shift. If the triggered hours are in the afternoon, a morning-weighted estimate under-counts the afternoon and over-counts the morning.
Guessing water quantity. Use logs from your own crews, not a rule of thumb from someone else's job.
Mixing rest breaks into heat costs. Break time is its own line, with its own rules. See paid-time and overtime costs when reviewing the rest of your crew hours.

Each mistake is easy to fix once you know it's there. The fix is almost always the same: separate the lines, count against triggered hours, and write down the basis.

Track actual use to improve the next bid

The best heat estimate is the one you check against last month's job. Keep a simple log on hot jobs: which hours were triggered, how many shade moves happened, how many water runs, how many hours of equipment upkeep, and how long plan updates took. Compare the log to the estimate afterward. If the estimate was short on water runs every time, you have your correction. If the shade was never moved, you may have over-counted. Review the log at the end of each job while the details are fresh, and note any hours that didn't match the forecast.

Over a season, that log becomes your own data. Your numbers will fit your crews, your sites, and your equipment better than any general figure, including the ones you'd find in an article like this one. The log is also the best evidence you have if a client asks how you arrived at a heat line.

What to tell the client

Clients often see a heat line on a bid and ask why it's there. Keep the explanation short and specific. Say which hours are affected, what the trigger is, and what the crew needs during those hours: shade near the work, cool or cold water, and cooling equipment that's maintained. Name the rule your estimate follows, and say the cost moves with the forecast, not with the calendar.

If the client has its own heat policy, read it before you bid. A client's requirement can be stricter than the rule, and your price should reflect the stricter one.

Final check before you send

The rules quoted here come from one state. Before you rely on any number, confirm your state's requirements, your client's specifications, and any insurance terms. Then update the sheet when the forecast changes.

Today, take one upcoming outdoor bid, mark its forecast triggered hours, and add separate estimate lines for shade, water runs, and cooling upkeep.

Common questions

What should I record when the forecast changes?

Record the revised triggered hours and which estimate lines change with them. Keep the basis visible so the next estimator can follow the adjustment.

What should I do when actual water runs exceed the estimate?

Use the job log to adjust the water-run allowance for the next comparable job. Check the trip time and supply-point distance before changing the estimate.