These three readings tell you whether your crew can count safely at full pace or whether you need to change the plan.
Key takeaways
- Air temperature — read at head height in the middle of the floor; at or above 90°F, Washington's high-heat procedures kick in unless cooling controls bring exposure lower
- Relative humidity — sweat evaporation stops entirely at around 90 percent, leaving your crew with almost no natural cooling
- Heat index — Oregon requires a written rest break schedule when it reaches 90°F; a separate humidex over 40 counts as extremely high
- Take readings twice — once at the start of the count and again halfway through, since rooms heat up as doors open and lights run
- Log them on paper — a simple clipboard log with date, time, temperature, humidity, and heat index gives you a record that supports your break schedule and compliance
Why you should log heat before you count stock
A full stock count runs for hours. Your crew walks every aisle. They lift cartons and write on clipboards. On a hot day, that work lands right at the edge of your body's limits.
Your body works to keep its core at 37°C. That is a constant, invisible job. Heat and humidity make the job harder. They slow cooling. They tire people out. Errors creep into the count. Safety risks grow with them.
Three readings tell you what kind of day you are dealing with. They take two minutes to collect before anyone starts counting. They shape the schedule you hand your team.
The three heat marks you need
The first mark is air temperature in the stockroom. Read it at head height in the middle of the floor, not against an outside wall. A wall gives a false high or low.
The second mark is relative humidity. Humidity decides how well sweat evaporates. Sweat is your body's main cooling method. The Canadian Centre for Occupational Health and Safety notes that sweat evaporation stops entirely when the relative humidity reaches about 90 percent. On a day that humid, your crew has almost no natural cooling left.
The third mark is the heat index. It blends temperature and humidity into one number that shows how hot it actually feels. The humidex is a separate measure. Here is the arithmetic in plain form: a temperature of 30°C at 70% relative humidity gives a humidex of 41.
A humidex reading over 40 counts as extremely high. That single figure changes how you plan the whole day.
| Mark | What it tells you |
|---|---|
| Air temperature | How hot the room is on its own |
| Relative humidity | How much sweat can evaporate to cool the body |
| Heat index | How hot it feels when temperature and humidity combine |
| Humidex | A separate scale; over 40 counts as extremely high |
What each mark changes in your counting plan
Temperature sets the threshold for high-heat procedures
Under Washington's heat rules, an employer must implement high-heat procedures when the temperature is at or above 90 degrees Fahrenheit, unless engineering or administrative controls such as air-conditioning or scheduling work at cooler times of the day lower employees' exposure below 90 degrees Fahrenheit. This is spelled out in WAC 296-62-09547.
If your stockroom hits that number, you are in a different operating mode. High-heat procedures kick in.
The rule also gives you an out. If air-conditioning keeps the room under the threshold, the high-heat procedures do not apply. That is worth knowing before you schedule the count. A working AC unit can keep your plan simple.
You can also move the count to a cooler time. Early morning before the sun hits the building is often the easiest shift to build. Late evening works too if your site allows it.
Humidity decides how well your crew cools
Humidity has a quiet effect that catches managers off guard. Sweat only cools you when it evaporates. High humidity slows that evaporation. At around 90 percent relative humidity, evaporation stops.
When sweat cannot evaporate, the body's cooling system is gone. Body temperature starts to climb. The American Conference of Governmental Industrial Hygienists sets an action limit and a Threshold Limit Value to keep workers' body temperature from exceeding 38°C, or 38.5°C for acclimatized workers. You can read that on the CCOHS humidex page.
Those thresholds are about internal heat, not outdoor air. That matters in a stockroom. A room can sit at a moderate air temperature and still push a worker toward those limits if humidity is high.
On humid days, airflow becomes your friend. Fans, open dock doors, and cross-ventilation speed up whatever evaporation is possible. You also shorten work cycles. Rotate counting crews more often so nobody stays in the heat too long.
The heat index ties temperature and humidity together
The heat index gives you one number for the whole room. Two mornings might read the same temperature. One is dry and comfortable. The other feels oppressive. The humidex separates them. It tells you which morning needs a stricter plan.
Log all three marks at the same moment, right before the count starts. Take them again halfway through. Rooms heat up as doors open and lights run. Your plan should track that rise, not just the starting number.
How the marks shape your break schedule
Oregon's heat rules require employers to develop and implement a written rest break schedule that protects employees exposed to a heat index equal to or greater than 90 degrees Fahrenheit. That requirement appears on the Oregon OSHA heat stress page.
Written means written. A plan you describe verbally does not count. Your break schedule lives on paper, posted where the crew can see it. For more on timing breaks, see Stock count breaks: 9 steps for planning staff time.
That schedule grows directly from your logged marks. A room with low humidity needs a lighter break pattern than a room with high humidity. Both are under the 90-degree threshold for Washington's high-heat rules. The humidex tells you which one feels worse to the people working in it.
Oregon ties its written schedule to a heat index of 90 degrees Fahrenheit. Washington ties its high-heat procedures to an air temperature of 90 degrees Fahrenheit. Two different measures, same number. Log both the temperature and the heat index so you can apply the right trigger for your situation.
Build the breaks into the count plan
Do not treat breaks as something the crew asks for. Build them into the schedule you hand out.
Set fixed stop times. Everyone stops at the same moment. That keeps counting zones consistent when people rotate back in.
Rotate workers through cooler zones. Someone who has been in the hot back aisle moves to the front near the door. Someone from the cool zone moves back. Everyone shares the heat load.
Watch for the person who never takes a break. Some workers push through. They are the ones most at risk. Your supervisors should notice and send them to the water station.
Hydration, clothing and cooling on count day
Oregon's page also lists the basics that keep people upright in heat. Drink water frequently, even when you are not thirsty. Rest in the shade when you need to cool down. Wear a hat and light-colored clothing.
Those points sound simple. They work because the body's cooling depends on them. Drink early. Waiting until you feel thirsty means you are already behind.
Set up a water station in the stockroom itself. Not in the break room down the hall. If water is far away, people skip the trip. Keep cups or bottles stocked before the count starts.
Shade matters even indoors. The back of a stockroom under a metal roof can hold heat long after morning. Move paperwork and clipboards to the coolest part of the room. Take readings there too, so your logged marks reflect where people actually stand.
Light-colored clothing helps because it reflects heat rather than absorbing it. In a stockroom, this usually means short-sleeve shirts in pale colors and a hat under bright overhead lights. Long sleeves in dark colors trap heat close to the skin.
Acclimatization is not optional
Your body adapts to heat over time. A crew that has worked in the stockroom all summer handles a hot count better than a crew returning from a mild week. ACGIH recognizes this with a slightly higher body temperature limit for acclimatized workers.
If your team has had time off, or if new staff just joined, treat the first hot count as a training run. Shorter cycles. Closer supervision. More breaks. The full pace comes back once the body adjusts.
How the heat marks change your counting method
Heat changes not just when you count, but how you count.
Shift the order of the aisles
Start in the hottest zone. Move toward the cooler zones as the day warms. If the back aisle sits under a roof that bakes all morning, schedule it first when the room is still cool.
If the hot aisle becomes unbearable later, leave it for a second shift. Split the count across two sessions. Accuracy beats a single heroic run.
Reduce the stretch of each counting block
On a comfortable day, a counter might work an hour before a pause. In a high-heat room, shorten that block. Frequent short pauses keep the mind sharp. Tired minds miss cartons and misread labels.
The break schedule you wrote earlier sets those pauses. Heat marks tell you how short to make each block.
Pair people up
Two counters watch each other. One notices if the other looks flushed, dizzy or slow. That early warning prevents a bad outcome.
Buddy pairing also speeds up tricky sections. Two people verify a shelf instead of one person guessing.
Slow down the walk, not the pen
Heat makes people rush to finish and escape the room. Rushing causes count errors. Tell your crew to walk slower and write carefully. A slower pace with a correct number beats a fast pace with a recount later.
Reading the room: where and when to take your marks
Take your three readings in the spot where counting happens most. Not near the AC vent. Not by the dock door. In the middle of the aisles.
Take them at the start of the shift. Then again mid-count. Rooms change. Doors open. The sun moves across the roof.
Keep a simple log on a clipboard at the station. Date, time, temperature, humidity, heat index. Five columns and a few rows. The record shows your pattern over the season and helps you argue for improvements like better ventilation or a repaired AC unit.
What to do if the readings climb mid-count
If the second reading jumps sharply, stop and reassess. You may need to pause the count and move people out. You may shorten the remaining blocks. You may bring in extra staff to split the work.
The plan you wrote before the count should include this trigger. Decide in advance what a jump in the numbers means. That removes the debate when everyone is hot and tired.
A full-day plan built from three marks
Here is how the pieces fit together on a real count day.
Before the shift, walk the floor. Take temperature, humidity and heat index. Write them down. Check the thresholds in your rules. Confirm the count itself is ready with Stock count conditions: 3 tests before count day.
Under Washington's rules, if the temperature is at or above 90 degrees Fahrenheit, you must apply high-heat procedures unless cooling controls keep it lower. Check the same page linked earlier for how those controls work.
If the heat index reaches 90 degrees Fahrenheit, Oregon's rule requires a written rest break schedule. Write it even if you are not in Oregon. The practice protects your crew everywhere.
If the humidex reads over 40, treat the day as extremely high. Stricter breaks. Closer watching. Shorter blocks.
Hand the crew their schedule with the readings at the top. People respect a plan built on data. They know the manager looked at conditions, not just the calendar.
During the count, rotate crews, keep water flowing, and log the second set of readings. Adjust the remaining blocks if the numbers climbed.
After the count, review. Did the breaks match the heat? Did errors spike in the hot zone? Did anyone feel unwell? Write it down for the next count. To reconcile the numbers, see Physical inventory reconciliation: 5 count steps.
Your next step today: Take a clipboard onto the stockroom floor and read the three marks in the middle of the floor. Write them down, then check them against the 90°F thresholds above.
Frequently asked questions
What if my stockroom has no thermometer or hygrometer? Buy both. Without them, you are guessing. Your break schedule and your compliance both depend on real numbers.
Should I take readings outside or inside? Inside. The stockroom is where your crew works. Outdoor readings miss the roof heat, the lack of airflow, and the humidity trapped in the building.
Does a fan solve the problem? No, not on its own. Fans help only when sweat can still evaporate. At very high humidity, evaporation stalls. A fan moves air but cannot cool skin that is already saturated. Use fans alongside water and breaks, not instead of them.
Who should I ask if my situation is not covered by these rules? Talk to your state's occupational safety agency or a qualified safety consultant about any stockroom question these rules do not settle. They can read your specific layout and give you a direct answer.
Do these marks matter if the count only takes an hour? Yes. Heat builds quickly in an enclosed room. An hour of lifting and walking in a hot aisle still stresses the body. Take the readings and plan the breaks even for short runs.
How often should I log the marks? At the start of every count session and again partway through. Over a season, the log shows you when heat becomes a recurring problem and helps you plan ventilation or scheduling fixes before the hottest weeks arrive.
Closing the count safely
Three marks — temperature, humidity and heat index — turn a hot-day guess into a clear plan. They tell you when high-heat procedures kick in. For Oregon sites, a heat index of 90°F means a written break schedule is required. They tell you when the room has crossed into extremely high territory.
Log them. Read them. Build your schedule from them. Your crew counts better when they are cool, hydrated and rested. Your numbers stay right. Everyone goes home well.