Planning Guides · OregonThe Oregon Resource Library
How Oregon's Heat Index Rule Works on a Real Job Site, and What Counts as a Cool Rest Area
Oregon adopted a permanent heat illness prevention standard in May 2022, effective that June. The general industry rule is OAR 437 002 0156, with a twin rule at 437 004 1131 covering agriculture. The two carry the same key requirements, so a grower and a general contractor are having the same conversation with different citation numbers. Oregon OSHA has since updated the package, so pull the current version rather than a cached copy.
The first thing that surprises out of state contractors is what Oregon measures. Most rules use dry bulb air temperature. Oregon uses the heat index, the apparent temperature that accounts for humidity. The standard applies whenever an employee performs work activities, indoors or outdoors, where the heat index equals or exceeds 80 degrees. Eighty degrees of air at seventy percent humidity already reads as a heat index of 83. In the Willamette Valley and along the coast that combination shows up constantly on days a superintendent would never describe as hot.
The second surprise is that one rule covers indoor and outdoor work. California needed two separate standards to do that. Washington's rule covers outdoor work with indoor rulemaking still pending. Oregon wrote a single standard, which means a crew working inside an unconditioned shell building is inside the same rule as the crew on the deck outside it. On a construction site that distinction matters, because the shell is exactly where people go to get out of the sun.
So what qualifies as a rest area. The rule spells out the shade area specification directly: it must either be open to the outside air on at least three sides, or provide mechanical ventilation for cooling. That single sentence separates a cooled trailer from a parked conex or a borrowed storage box. An enclosure that traps heat is not shade under this rule. An enclosure that actively removes heat is. The employer's written plan then has to state, at section 8(e), how workers will be provided sufficient space to rest in a shaded area or cool climate controlled area.
The exemption at section 1(a)(D) is the cleanest line in the standard. Buildings and structures with a mechanical ventilation system that keeps the heat index below 80 degrees are exempt from the requirements of the standard. Oregon OSHA repeats it in plain English in its own fact sheet: the rules do not apply to buildings and structures that have mechanical ventilation keeping the indoor heat index under 80 degrees. Separately, section 5 provides that high heat practices attach only when engineering controls such as fans or air conditioning, together with administrative controls, fail to hold exposure below a 90 degree heat index.
Those two provisions do different jobs and should not be blurred together. One is a scope exemption for the conditioned space itself. The other decides whether the high heat obligations attach to the work at all.
Then there is the detail that decides where the unit gets parked. Rest break time counts only while the worker is actually in the shade, and the break is treated as a paid work assignment except where it lands on an existing unpaid meal period. Put those together and a break area at the far end of the site costs paid walking time on every single break, for every person, every day. That is the argument for staging conditioned space at the work face rather than at the compound gate.
One correction worth making, because it circulates widely: Oregon does not set a square footage minimum per worker. The test is qualitative, whether everyone on break can sit in a normal posture fully in the shade, with a larger allowance for meal periods. So the sizing question is always headcount, never floor area. Federal OSHA has separately proposed a national heat rule using the same 80 and 90 degree heat index triggers, and its text names air conditioned trailers as a compliant break area. That rule remains proposed and is not final, so plan against Oregon's standard, which is in force today.
Sources: Oregon OSHA fact sheet on the permanent heat illness prevention rules
Wildfire Smoke Is Oregon's Second Season, and a Filtered Enclosure Is a Named Control
Most people planning an Oregon job site think about heat and stop there. That misses half the calendar. Oregon has a separate permanent wildfire smoke standard, and in an average year it starts biting right as the heat season winds down. Heat runs roughly May through September. Smoke runs July through October. Together they cover close to half the working year, and the two rules ask for overlapping but not identical things.
The citation to use is OAR 437 002 1081, Protection from Wildfire Smoke, adopted in May 2022. This matters because several third party summaries cite 437 002 0157, which is wrong. If your written program carries the wrong number, an inspector notices. Pull the rule from Oregon OSHA's own division 2 subdivision Z materials rather than a summary.
The rule ladders on air quality rather than temperature. At PM2.5 of 35.5 micrograms per cubic meter, an air quality index of 101, the rule triggers and the employer owes two way communication, training, and exposure controls aimed at getting below AQI 101 unless doing so is functionally impossible. At AQI 251 the employer must supply NIOSH approved filtering mask respirators under a wildfire smoke respiratory protection program. At AQI 501 a full respiratory protection program under the federal respirator standard applies. When the EPA changed how AQI is calculated in 2024, Oregon OSHA confirmed the underlying PM2.5 concentration triggers did not change.
For comparison, California's smoke rule triggers at AQI 151. Oregon triggers fifty points lower. That means an Oregon crew is inside the rule on days a California crew of the same trade is not, which is one of the reasons the smoke argument carries more weight here than it does further south.
Where our equipment comes in is the exemption and the control language, and both are explicit. Section 1(a) frees enclosed buildings and structures in which the air is filtered by a mechanical ventilation system, provided the employer keeps windows, doors, bays, and other exterior openings closed except to briefly enter and exit. Section 7(a)(A) then lists appropriate engineering controls, and the first named one is temporarily relocating outdoor workers to available indoor areas or vehicles where the air is adequately filtered.
So the regulation itself points at a filtered, enclosed, closed up space as the answer. On a site with no permanent building, that space has to be delivered. On a rebuild site, an incident support yard, or a corridor job, it is often the only enclosed structure within miles.
The scale of Oregon's recent seasons explains why contractors have stopped treating this as an occasional problem. The 2026 season became the largest on record in the state at 1,991,419 acres burned, ahead of the roughly 1.93 million acre record set in 2024, with suppression spending running more than 34 million above the prior year. Fire officials issued that warning in late July with August and September, historically the worst stretch, still ahead. For contrast, 2025 burned 338,551 acres across 2,734 fires. A single 2026 fire near Burns and Hines in Harney County passed 100,600 acres.
The practical planning point is that smoke does not respect the same geography as heat. A fire in southern Oregon puts smoke over the Willamette Valley, and a fire in eastern Washington puts it over Portland. Crews far from any flame front end up inside the AQI ladder. If you are already renting break room trailer rentals for the heat season, extending through October usually costs less than mobilizing twice, and it keeps a filtered room on the site through the part of the year when you are most likely to need one.
Sources: Oregon OSHA rule text for protection from wildfire smoke
Sizing Break Space for an Oregon Data Center or Fab Campus During Construction
Oregon holds three distinct data center geographies, and each one produces a different break space problem. Hillsboro is the dense metro cluster, with roughly sixteen tracked sites, vacancy near zero, and hundreds of megawatts under construction across the Portland and Hillsboro market. QTS is building an 88 acre campus planned for five buildings and more than 250 megawatts. STACK holds about 50 acres with a campus plan reaching 230 megawatts. Digital Realty, NTT, EdgeConneX, and Flexential all hold positions in the same few square miles.
Prineville is the single campus story, and it produces the most useful number in the state. Meta reports 1,000 skilled trade workers on site at peak construction on its Crook County campus. That figure comes straight from the owner rather than a trade estimate. A thousand tradespeople on one site is a capacity question before it is a comfort question, and it is exactly the kind of headcount Oregon's rule asks you to plan around, since the standard sizes rest space by how many people are on break at once.
Morrow and Umatilla counties are the scale story. AWS has invested billions across the two counties and employs more than 1,800 people there. Amazon then acquired roughly 1,300 acres near Boardman for an hyperscale campus described publicly at up to twenty buildings, about four million square feet, and roughly a gigawatt of load, with the county planning commission approving a first batch of 816,000 square feet east of the Boardman Airport. Alongside it, the approved Sunstone Solar project covers 9,442 acres with more than 3.9 million panels planned and 1.2 gigawatts of capacity.
What all of these share is the construction phasing, and that phasing is what creates the gap. Greenfield to service on a hyperscale build typically runs somewhere between thirty and sixty six months. Occupancy is phased, so it is entirely normal for several buildings on a campus to be live and operating while several more are still shell and core. The site is simultaneously a working facility and a heavy construction project, and the trades on the construction side generally cannot use the operating side's space.
The mechanical timing compounds it. Before servers land, the building has to hold a tight temperature and humidity window, and permanent HVAC systems cannot hold that window at partial construction load with doors open and trades moving through. Commissioning happens near the end. For most of the schedule the building has no usable conditioned space, which is why a trailer compound appears by name on campus logistics plans right alongside the main gate and the laydown yard.
Sizing in practice comes down to three questions. How many trades are on site at peak, not on average. Whether breaks are staggered by crew or taken together, since a single simultaneous break changes the answer completely. And how far the work face is from wherever the space sits, because Oregon counts rest time only while the worker is actually in the shade, so distance converts directly into paid walking time.
The honest answer on most large Oregon campuses is more than one unit, staged in more than one place, moving as the work face moves. Contractors who start with one unit at the compound gate almost always add a second closer to the active building within the first season. It is cheaper to plan for that at mobilization than to discover it in the middle of July.
It also helps that the same unit does double duty. Two built in desks, Starlink connectivity, a 32 inch screen, and 24 linear feet of magnetic whiteboard wall mean the space that feeds the crew at noon runs the look ahead meeting at six in the morning and hosts the inspector in the afternoon. On a campus where every square foot of conditioned space is spoken for, that flexibility is usually what gets the rental approved.
Sources: Federal OSHA rulemaking page for the proposed heat injury and illness prevention standard
Delivering to Eastern Oregon and the Coast, and What Changes When the Site Is Three Hours Out
Two thirds of Oregon's land area sits east of the Cascades, and a good share of the state's industrial construction sits out there with it. Boardman, Hermiston, Umatilla, Pendleton, The Dalles, Ontario, Burns, and La Grande are all normal deliveries for us, and so are Coos Bay, Newport, Astoria, and Brookings on the other side. What changes on a long haul delivery is not whether we come. It is what we confirm before the driver leaves.
Start with the climate, because it flips completely across the state. Medford averages nearly 54 days a year at or above 90 degrees on the official averages and 9.2 days at or above 100. Independent daily records put Ontario at 60.7 days above 90 and 10.8 days above 100, Hermiston near 50, The Dalles near 43, and Pendleton near 37. Those are the hot markets, and they are also where the data centers, packing sheds, and irrigated ground are. Portland and Salem look mild by comparison at twelve to fifteen days, which is exactly why the heat index matters more than the thermometer in the valley.
Then the season turns. Redmond and Bend average 181 days a year at or below freezing and Burns averages 200. A Central Oregon contractor is renting the same unit for heat in January that a Rogue Valley contractor rents for cooling in August. The 24,000 BTU mini split does both, and two 1,500 watt backup heaters cover the mornings when the mini split is working hardest.
Access is the practical variable on a remote delivery. The unit is a dual axle trailer with electric brakes and a 240 volt 50 amp shore cord. It needs a route in that a truck and trailer can actually negotiate, a reasonably level place to sit, and a power source. On a solar field or a port industrial park that is straightforward. On a forest road, a jetty, or a ranch two track it is a conversation worth having before the delivery date rather than on it, and we would rather ask the awkward questions early.
Lead time is the other variable. Portland metro, the Willamette Valley, and the I 5 corridor are the fastest turnarounds we run. Eastern Oregon and the coast add drive time in both directions, which affects delivery and service visits alike. On a two week outage that is the thing to nail down first, so tell us your window when you call and we will build backwards from it.
The work out there justifies the drive. Morrow and Umatilla counties carry hyperscale campuses, a 9,000 acre port industrial park, and a heavier freight load along I 84 than anywhere else in Oregon. South Hermiston Industrial Park broke ground and is adding a 179,000 square foot distribution center. Malheur County is unofficially the largest onion producing county in the nation, with a new advanced packing operation shipping out of Ontario. Sherman, Gilliam, and Morrow counties are all carrying utility scale renewable projects.
The coast has its own pipeline. The Pacific Coast Intermodal Port at Coos Bay is a 175 acre ship to rail container terminal on the North Spit with a 2 million container capacity target, and construction activity is scheduled to run from late this year through 2028 across terminal construction, rail upgrades, and channel work. The Port of Astoria is pursuing dredging and Pier 3 marine terminal development, and the Coast Guard is expanding on the dock facilities at East Tongue Point. The Port of Newport is rebuilding both Yaquina Bay jetties.
One last thing about coastal jobs. Out there the pitch is almost never heat. It is wind, horizontal rain, and a crew that has nowhere dry to eat, plus smoke in late summer when the interior burns. The same signature unit answers all of that. It is the same conversation we have behind Arizona office trailer rentals for very different reasons, which is the point of running one national fleet: whatever the site throws at your crew, the unit that shows up is delivered, set up, and serviced by one team.
Sources: Business Oregon CHIPS Fund program page
