Paul Industries designs, builds and qualifies cleanrooms and controlled environments across Oklahoma. Two things make this state a genuinely different design problem from the coasts, and both are about what happens outside the building. Oklahoma’s outdoor design conditions span an enormous range, so equipment has to perform at both ends rather than at a comfortable average. And severe weather here is a routine planning assumption rather than a remote contingency, which makes continuity part of the specification.
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Designing for both ends of a wide range
A cleanroom’s air handling has to condition outside air to a tightly controlled internal condition, and the work involved depends entirely on how far the outside air is from the target. In a mild marine climate that distance is modest most of the year. In Oklahoma it is large in both directions and the direction reverses seasonally.
Summer brings heat and humidity together, so the make-up air system is doing substantial cooling and substantial dehumidification simultaneously. Winter brings genuinely cold air that is also very dry, so the same system is heating and, for many processes, humidifying. Those are opposite duties requiring different equipment, both of which must be present and neither of which is used year round.
Three consequences follow that a coastal design would not face.
Equipment is larger for the same room. Sizing for both extremes means more installed capacity than a milder climate requires, and that is capital rather than an avoidable inefficiency.
Part-load performance matters more than peak. A system sized for two extremes spends most of the year at neither, so how it behaves at forty percent load determines the running cost far more than its rated efficiency does. This is the specification detail most often skipped and it is worth pressing suppliers on.
Humidification is a real system, not an accessory. Winter air in Oklahoma is dry enough that a room requiring controlled humidity needs genuine humidification capacity, with the water treatment, maintenance and hygiene management that comes with it. A humidifier is also a potential microbiological source in a controlled environment, so its design and its cleaning regime belong in the specification.
| Season | Duty | Equipment implication |
|---|---|---|
| Summer | Cool and dehumidify | Refrigeration plus reheat or desiccant capacity |
| Winter | Heat and humidify | Heating plus humidification with water treatment |
| Shoulder seasons | Modest, variable | Good part-load control; free cooling opportunity |
| Any season | Reject internal heat | Cooling required year round regardless of weather |
| Continuous load | Per year | Over ten years |
|---|---|---|
| 50 kW | $25,579 | $255,790 |
| 100 kW | $51,158 | $511,580 |
| 200 kW | $102,316 | $1,023,160 |
Oklahoma’s 5.84 cents per kilowatt-hour is 0.72 times the 8.13 cent national average (EIA, 2024), among the cheapest industrial power in the country, and it genuinely offsets the larger installed capacity this climate demands. A room that would be expensive to run in the Northeast is affordable here, which is a real part of why processing capacity continues to locate in the state. It does not, however, make oversizing free, because capital and maintenance both scale with installed capacity whatever the tariff.
Weather resilience, and the part people forget
Hail and high wind damage outdoor equipment, and the equipment that matters is on the roof.
Protect the coils. Condenser and dry cooler coils are thin aluminium fins and hail flattens them. A damaged coil does not fail outright; it loses capacity, progressively and invisibly, and the plant experiences a room that cannot hold condition on hot days for reasons nobody connects to a storm months earlier. Hail guards are inexpensive, they are standard practice in this region, and they are omitted surprisingly often.
Anchor and restrain. Rooftop units, ducting, and anything else exposed needs restraint appropriate to the wind loads the code requires for the location, and the fixings need to be inspectable.
Protect the intakes. Outside air intakes take in whatever the weather brings, including driven rain and debris. Intakes positioned and detailed so that a storm does not deliver water into the air handling system are worth the attention, because water in an air handler is a microbiological problem long after the storm.
The part most often forgotten is what happens to the room itself during an interruption.
A qualified cleanroom that loses air handling stops being a qualified cleanroom quickly. Pressure cascade collapses, so air moves in from wherever it wants. Temperature and humidity drift, which may affect product directly. Particle counts rise. And the question that then arises is a documentation question rather than an engineering one: what does the plant do about product that was exposed during the interruption, and what has to be demonstrated before production resumes?
Deciding that in advance is far better than deciding it at two in the morning during a storm. The engineering that supports it is a decision about which loads go on standby power, monitoring that records conditions through the interruption so the plant knows what actually happened rather than estimating, and a documented recovery and requalification procedure with defined criteria.
Standby power for full cleanroom air handling is expensive and is not always justified. Standby power for the monitoring that tells you what happened is cheap and almost always is, and the two decisions are frequently conflated into a single yes or no when they should be taken separately.
We build the rooms, the air handling and controls, the weather protection and intake detailing, the monitoring and its power arrangements, and we carry out the qualification: classification to ISO 14644-1, recovery testing, filter integrity, and pressure cascade verification, with ISO 14644-2 governing the ongoing monitoring plan.
Standards referenced: EIA electricity price data · ISO 14644-1 · ASME BPE · ISO 14644-2
Frequently asked questions
Do you build cleanrooms in Oklahoma?
Yes, across Oklahoma City, Tulsa, Lawton, Enid and statewide: design and construction, air handling and controls, weather protection and intake detailing, monitoring and standby power arrangements, and the full qualification package.
Why is Oklahoma’s climate a design problem?
Because the outdoor design conditions span a wide range in both directions. Summer requires simultaneous cooling and dehumidification; winter requires heating and, for many processes, humidification. Those are opposite duties needing different equipment, both of which must be installed and neither used year round.
Does that mean bigger equipment?
Yes. Sizing for both extremes means more installed capacity than a mild climate requires, which is capital rather than avoidable inefficiency. It also means the system spends most of the year at neither extreme, making part-load performance more important than rated peak efficiency.
Is humidification really necessary?
Where the process requires controlled humidity, yes. Oklahoma winter air is dry enough that genuine humidification capacity is needed, with the water treatment and maintenance that comes with it. A humidifier is also a potential microbiological source, so its design and cleaning regime belong in the specification.
What does hail actually damage?
Condenser and dry cooler coils, whose thin aluminium fins flatten under impact. The unit does not fail outright; it loses capacity progressively and invisibly, so the plant experiences a room that cannot hold condition on hot days for reasons nobody connects to a storm months earlier.
Are hail guards worth it?
Yes, and they are inexpensive and standard practice in this region. They are omitted surprisingly often, usually on projects specified by people unfamiliar with the climate, and the resulting capacity loss is expensive to diagnose and expensive to correct.
Why do intakes need attention?
Because they take in whatever the weather brings, including driven rain and debris. Water delivered into an air handling system by a storm becomes a microbiological problem that outlasts the storm considerably, so intake position and detailing are worth designing rather than defaulting.
What happens to a cleanroom during a power interruption?
It stops being qualified fairly quickly. Pressure cascade collapses so air moves in from wherever it wants, temperature and humidity drift, and particle counts rise. The resulting question is what to do about exposed product and what must be demonstrated before production resumes.
Do we need standby power for the whole cleanroom?
Often not, and the decision should be split. Standby power for full air handling is expensive and not always justified. Standby power for the monitoring that records what actually happened during the interruption is cheap and almost always justified. Those two questions get conflated more often than they should.
How do I get a quote for an Oklahoma cleanroom?
Use the form on this page or call 201-450-8280. Useful inputs are the class or grade required, room footprint and internal heat loads, temperature and humidity requirements including whether humidification is needed, existing rooftop equipment and its protection, and your standby power arrangements.
What design conditions should an Oklahoma cleanroom use?
A summer design point near the hottest hours of a typical year and a winter design point near the coldest, both taken from local climate records rather than from a national default, with equipment sized to hold the room at both. The range between the two is what makes Oklahoma harder than a milder state.
What does an Oklahoma winter do to a cleanroom's humidity?
It drives the indoor relative humidity down to levels that cause static discharge, dry out gaskets and, in pharmaceutical rooms, fall below the validated range, because cold outdoor air holds very little moisture. Humidification is needed for the winter months even though the summer is humid.
Where is a cleanroom's mechanical plant most exposed to hail?
Rooftop air handling units, condenser coils, intake hoods and exhaust stacks, all of which take direct impact, with condenser fins the most easily damaged. Protecting the coils with guards and placing critical equipment under cover are the design responses.
What sequence should a cleanroom follow when utility power is lost?
Critical air handling transfers to standby power, non-critical loads are shed, the room is held at pressure or, where standby is not provided, doors are secured and the room is treated as unclassified until it is recovered and verified. The sequence is written, tested and known to the operators before the storm season.
Does the cleanroom need to be a storm shelter?
The cleanroom itself is not usually the shelter, but the building's severe weather plan has to cover the people inside it and the recovery afterward. Shelter locations and the cleanroom's shutdown procedure are part of the same plan.
How are outdoor air intakes designed for the Oklahoma environment?
Positioned high and away from ground dust and from exhausts, screened against debris and birds, fitted with rain hoods that also shed hail, and given staged pre-filtration that can be changed frequently during pollen and dust seasons. The intake is where the outdoor environment enters the room.
How is the envelope built for temperature swings?
With insulation and vapour control designed for both directions of vapour drive, because in summer moisture drives inward and in winter it drives outward. An envelope designed for one direction fails in the other season.
Does Oklahoma's cheap power change the cleanroom design?
Low electricity cost reduces the running cost penalty of generous air handling, but equipment still has to be sized for the extremes, and oversizing costs capital. Efficiency measures pay back more slowly here than in high-tariff states, so the design leans on doing the sizing right rather than on recovery equipment.
How is a cleanroom recovered after a weather-related shutdown?
By restoring air handling, verifying pressure and filtration, cleaning and disinfecting where the room was uncontrolled, and confirming environmental results before production resumes. The procedure is written before it is needed.
What sectors in Oklahoma need cleanrooms?
Aerospace and defence manufacturing, medical device and pharmaceutical operations, food and supplement processing with controlled areas, and electronics. Each has its own classification rules; the climate considerations are shared.
How does induced seismicity affect cleanroom design?
Cleanroom ceilings, filter housings, equipment and piping are supported and braced with seismic considerations that older Oklahoma buildings did not include, so that a tremor does not drop a filter or break a line. It is a modest addition when designed in.
What redundancy should air handling have?
Enough that a single fan or chiller failure does not lose the room, typically N+1 on critical components, with automatic changeover. The level is set by what a loss of the room costs the business.
How is the cleanroom monitored during extreme weather?
Continuously, with alarms on pressure, temperature, humidity and airflow, and with remote notification so that a problem during a storm is known before the shift returns. Monitoring is what makes the recovery plan actionable.
What does a smaller Oklahoma manufacturer need in a cleanroom?
A room designed to its classification with the climate handled properly, which is usually a modest ISO 7 or ISO 8 space with reliable humidity control and a plan for outages. The principles scale down without losing their importance.
What is the commonest problem in existing Oklahoma cleanrooms?
Humidity out of control at one end of the year or the other, because the air handling was designed for one season. It shows up as static problems in winter or condensation in summer, and it is fixed by adding the missing capability.
What the outside air actually contains here
There is a quieter regional factor that shows up on the maintenance budget rather than in the design calculation, and it is worth designing around because it is cheap to accommodate and expensive to ignore.
Oklahoma is windy, much of it is agricultural, and dry conditions put a great deal of soil and plant material into the air. A cleanroom’s outside air intake is therefore handling a considerably heavier particulate load than the same installation would on a coast, and that load arrives in episodes rather than steadily: a windy day during field work delivers more in an afternoon than a quiet month does.
The consequences are entirely predictable and they compound.
Pre-filters load faster. Change intervals derived from a generic schedule will be too long here, and a loaded filter means rising pressure drop, which means fan power rising continuously between changes. On a system running every hour of the year, that is real money.
Terminal filters pay for the pre-filters. This is the expensive consequence. Pre-filters exist to protect the expensive final filtration, and where they are undersized or changed too late, the load passes through to filters that cost several times as much and are far more disruptive to replace, particularly where replacement means entering a qualified room and requalifying afterwards.
Coils foul. Particulate that reaches cooling and heating coils deposits on the fins, reducing heat transfer and raising air-side pressure drop. It presents as a room struggling to hold condition and is often diagnosed as a refrigeration problem.
The design responses are unremarkable. Size the pre-filtration generously, with a large filter area so that the face velocity is low, which both extends life and reduces pressure drop. Instrument the pressure differential across each filter bank and trend it, so changes happen when the filter needs it rather than when the calendar says. Site intakes away from obvious local sources such as unpaved roads, yard traffic and agricultural land where the layout allows. And allow proper access, because a filter bank that is awkward to reach gets changed late.
None of this is exotic, and the reason it is worth stating is that cleanroom specifications are frequently written by people working from a template developed somewhere with cleaner air. A filter schedule appropriate to a suburban site on a coast will underperform badly next to a section-line road in July.
Building or reviewing an Oklahoma cleanroom?
Tell us whether your rooftop coils have hail protection and what is on standby power. Those two questions surface most of the regional issues. Call 201-450-8280 or use the form below.