Humidity, Temperature & Ventilation Control in Industrial Environments

Industrial facility with tanks and piping at sunset, part of a banner about building automation and better operations for industrial facilities.

A room can be at the right temperature and still be out of control.

The thermostat may show the expected temperature while humidity drifts outside the acceptable range. A data center may have ample cooling capacity while poor airflow management allows hot exhaust air to recirculate toward server inlets. A semiconductor cleanroom may maintain temperature while pressure, humidity, or ventilation moves outside the conditions required by production.

In industrial and mission-critical facilities, environmental control is rarely about one number.

Temperature, humidity, ventilation, airflow, pressure, filtration, heat loads, and equipment operation influence one another. In facilities such as data centers and semiconductor manufacturing plants, these conditions are not merely matters of occupant comfort. They can directly affect equipment reliability, product quality, process stability, production uptime, energy and water consumption, and operating cost.

An industrial temperature controller may hold one variable at setpoint, but an industrial temperature control system still has to account for the broader interaction among heat, moisture, air movement, pressure, and process loads.

That changes the purpose of HVAC and building automation.

The objective is not simply to make the building comfortable. It is to create, maintain, and continuously verify the environmental conditions the operation requires, using resources as efficiently as practical.

Environmental Performance Starts with Facility Design

Controls matter, but the efficiency of a thermal-mechanical system begins long before the first controller is programmed.

Facility layout, equipment selection, airflow paths, cooling architecture, ventilation and exhaust strategies, heat rejection, zoning, filtration, pressure relationships, redundancy, sensor locations, and opportunities for heat recovery all influence how much energy and water will ultimately be required to maintain environmental conditions.

That is particularly visible in thermally intensive facilities.

A well-designed data center can separate hot and cold air streams, deliver cooling where computing equipment actually requires it, take advantage of favorable outdoor conditions where appropriate, optimize fan and pump operation, and potentially recover or reuse heat.

A poorly designed facility may spend its operating life compensating for air mixing, unnecessary pressure drops, excessive cooling, competing humidity-control strategies, oversized equipment, or other fundamental inefficiencies.

The same principle applies to manufacturing.

A production facility designed around the actual environmental requirements of the process can control critical areas precisely without necessarily conditioning every cubic foot of the building to the same tolerance.

The hierarchy is therefore:

Design → Control → Measurement → Optimization

Good design establishes an efficient physical system. Controls operate it. Measurement verifies what is actually happening. Continuous monitoring and optimization help maintain performance as loads, equipment, and operating requirements change.

The most efficient ton of cooling is the one good facility design makes unnecessary. The next most efficient is the one controls deliver only when and where the operation actually requires it.

Data Centers: High Energy Use Is Not the Same as Energy Waste

Data centers have attracted understandable attention because they can consume enormous amounts of electricity and, depending on the cooling architecture, significant amounts of water.

But total consumption alone does not tell us how efficiently a data center operates.

The useful work of a data center is performed by its IT equipment. Additional facility energy is required for cooling, pumps, fans, electrical distribution, lighting, and other supporting infrastructure.

That relationship is commonly evaluated using Power Usage Effectiveness (PUE):

PUE = Total Data Center Energy ÷ IT Equipment Energy

A theoretical PUE of 1.0 would mean essentially all facility energy is being delivered to IT equipment, with almost no additional energy consumed by supporting infrastructure.

That distinction matters.

A large, highly optimized data center can consume substantially more electricity than a small legacy facility while using a much smaller proportion of that energy for cooling and other overhead. Comparing the facilities only by total megawatts would therefore tell us very little about their relative efficiency.

The same caution applies to water.

Water Usage Effectiveness (WUE) can help quantify water use relative to IT energy consumption, while Energy Reuse Effectiveness (ERE) can help evaluate beneficial reuse of energy such as recovered heat.

No single metric tells the entire story.

Responsible data-center design and operation require looking at useful computing work alongside energy, water, thermal performance, reliability, climate, cooling architecture, and the operating requirements of the IT equipment.

Better Thermal Management Can Reduce Data Center Waste

Data centers provide an unusually clear demonstration of why environmental control should be treated as a system.

Servers generate concentrated heat loads. The objective is not to make the entire room cold. It is to maintain appropriate conditions at the IT equipment intake while efficiently removing the heat produced by the equipment.

Poor airflow management can mix cool supply air with hot exhaust air before either reaches its intended destination. Operators may compensate by lowering supply-air temperatures or increasing fan speeds, using additional energy without addressing the underlying problem.

Better designs can separate supply and return air using hot-aisle/cold-aisle arrangements and containment strategies. Sensor placement can verify conditions where the IT equipment actually experiences them. Variable-speed fans and pumps can respond to changing loads instead of operating continuously at peak capacity.

DOE guidance also cautions against unnecessarily cold temperature setpoints and overly narrow humidity ranges. Excessive control can increase chiller, fan, pump, humidification, dehumidification, and cooling-water demand without improving equipment reliability.

This is an important lesson for anyone evaluating data-center resource consumption:

Prudent environmental control is not about cooling as much as possible. It is about removing heat as efficiently as possible while maintaining the conditions the computing equipment actually requires.

Depending on climate and facility design, additional strategies may include air-side or water-side economization, higher chilled-water temperatures, direct liquid cooling, dry or hybrid heat rejection, and heat recovery.

The appropriate solution varies by application. There is no universal cooling architecture that is optimal for every data center.

Design and Controls Have to Work Together

KMC Controls has seen the importance of integrated design firsthand.

At Intel’s IDC 9 design and data-center facility in Haifa, Israel, energy efficiency was considered during the facility’s design rather than being treated solely as an operating problem to solve later.

KMC Controls digital controls were integrated with Schneider Electric programmable logic controllers and GE SCADA systems, giving Intel engineers control and visibility across the facility’s air-handling infrastructure. The project also incorporated carbon dioxide monitoring, condensate recovery for irrigation, and reuse of heat generated by air-conditioning equipment and data-center computers.

According to KMC Controls’ published case study, the sustainable design resulted in a 17% reduction in total building energy use, with projected annual savings of approximately $200,000.

The significance goes beyond the savings percentage.

The project demonstrates that controls deliver their greatest value when they participate in a broader facility strategy involving mechanical design, integration, measurement, resource recovery, and ongoing operation.

Semiconductor Manufacturing: When the Environment Becomes Part of the Product

Data centers are not the only industrial environments where thermal management becomes inseparable from the work being performed.

Semiconductor and other advanced manufacturing facilities can take that relationship even further.

Temperature, humidity, airflow, filtration, cleanliness, and pressure relationships can directly influence process stability, contamination control in manufacturing, equipment performance, product quality, and production uptime.

At TDK’s Headway Technologies semiconductor manufacturing facility in Silicon Valley, environmental control is a production requirement.

Its cleanrooms require approximately 68°F ±1°F and 45% relative humidity ±2.5%. According to KMC Controls’ published case study, even a 30-minute humidity excursion could result in hours of lost production.

In that environment, temperature and humidity are not comfort preferences.

They are process variables.

That changes how efficiency should be evaluated.

Reducing cooling, airflow, or humidity control in manufacturing at the expense of the required manufacturing environment isn’t optimization. But maintaining those conditions with substantially more energy than necessary isn’t good engineering either.

The objective is to satisfy the process requirement reliably while minimizing unnecessary resource consumption.

At TDK’s Headway Technologies, a comprehensive optimization effort addressed air handlers, pumps, chilled and hot water, steam, boilers, VFDs, sensors, and control sequences while maintaining the environmental conditions required by production.

The project reduced continuous electrical demand from 5.4 MW to 4.7 MW, generated more than $800,000 in direct cost savings, and achieved an approximately 10-month return on investment.

The lesson applies well beyond semiconductor manufacturing:

Environmental performance, production requirements, and energy performance often need to be evaluated together.

Temperature and Humidity Are Connected

Temperature is usually the most visible environmental variable because everybody understands a thermostat.

Humidity is less cooperative.

Relative humidity describes the amount of moisture in the air relative to how much moisture that air can hold at its current temperature. Change the temperature and relative humidity can change even when the actual moisture content remains relatively stable.

That means industrial humidity control and temperature control in industry cannot always be treated as independent control problems.

A system may satisfy its dry-bulb temperature setpoint while humidity moves outside the acceptable range. Depending on the application, that can contribute to condensation, corrosion, static electricity, dimensional changes, material problems, microbial growth, or other undesirable conditions.

Facilities teams therefore need to understand:

      • Which variables actually matter: temperature, relative humidity, dew point, or another measure
      • Where the environmental requirement applies
      • How much variation is acceptable
      • How long an excursion can persist before action is required
      • Whether sensors accurately represent the process or equipment being protected
      • What the control system should do as conditions approach or exceed acceptable limits

The tighter the tolerance, the more important sensing, placement, calibration, control sequencing, and trend history become.

Control the Condition That Matters, Not Just the Sensor

A perfectly accurate sensor can still provide misleading information if it measures the wrong location.

That is obvious in a data center.

The temperature experienced at a server inlet is more meaningful than the temperature measured on a distant wall. Poor sensor placement can hide hot spots, airflow recirculation, or overcooling elsewhere.

The same problem appears in industrial facilities.

Production equipment creates localized heat. Washdown or open processes can introduce moisture. Loading doors expose areas to outdoor conditions. Exhaust systems alter pressure and airflow. Tall spaces stratify. Racks, machinery, partitions, and products themselves affect air distribution.

This creates an important engineering question:

Are we controlling the condition that matters, or merely controlling the condition at the sensor?

Sensor placement should follow the process requirement.

More sensors can improve visibility, but only when each measurement answers a useful question about the environment, equipment, or control strategy.

Ventilation Is About Air Path, Not Just Air Quantity

Industrial ventilation control systems require the same systems thinking.

Moving more air through a facility does not necessarily mean the ventilation strategy is working better.

OSHA distinguishes between general or dilution ventilation and local exhaust ventilation. Local exhaust captures contaminants at or near their source, while general ventilation introduces and removes air to dilute contaminants.

Facilities searching for an “ASHRAE standard for industrial ventilation” should distinguish general building ventilation from process exhaust and hazard-control requirements. ASHRAE Standard 62.1 addresses ventilation and acceptable indoor air quality for many commercial and institutional spaces, while industrial process applications may require other standards, regulations, and engineering analysis.

Both depend on a more fundamental question:

Where is the air coming from, what is it carrying, and where is it going?

An exhaust fan can move its scheduled CFM and still create problems elsewhere.

If exhaust increases without sufficient replacement or makeup air, a building or zone can become more negative than intended. Outdoor air may enter through uncontrolled pathways. Doors can become difficult to operate. Conditioned air can be pulled away from adjacent spaces. Pressure relationships can change.

Poor supply and return-air arrangements can likewise create short-circuiting, stagnant regions, or unwanted mixing.

Data centers demonstrate the same principle in another form. Mixing hot return air with cool supply air increases the thermal work required to maintain acceptable server-inlet conditions.

CFM matters. Air path matters just as much.

Start with the 4 S’s

Once the facility’s physical design and environmental requirements are understood, the 4 S’s: Sensors, Setpoints, Sequences, and Schedules provide a practical framework for evaluating control performance.

Sensors

Are we measuring the variables that actually matter, and do those measurements represent the equipment, process, or environment being protected?

Setpoints

Do temperature, humidity, pressure, and airflow targets reflect actual equipment or process requirements?

Overly aggressive setpoints can waste resources just as easily as loose setpoints can jeopardize performance.

Sequences

Do cooling, heating, humidification, dehumidification, ventilation, supply, return, and exhaust systems cooperate?

Or is one system quietly fighting another?

Schedules

Do environmental requirements remain constant around the clock, or should operation change with production states, IT load, occupancy, cleaning cycles, shutdowns, or other conditions?

These questions help distinguish a genuine capacity problem from a design, measurement, or control problem.

Environmental Drift and Control Drift Are Different Problems

Industrial and mission-critical facilities experience two related forms of drift. Environmental drift occurs when temperature, humidity, pressure, airflow, or another physical condition moves outside its required range. Control drift occurs when the automation system continues operating according to assumptions that are no longer true. Loads change. Equipment is replaced. A production schedule changes but the HVAC schedule does not. A server rack is added and changes the local heat density. An exhaust system is modified without reconsidering makeup air. A technician overrides a sequence to solve an urgent problem, and the override quietly becomes permanent. Filters load. Dampers deteriorate. Sensors drift. The controls may still be doing exactly what they were programmed to do.

The problem is that what they were programmed to do no longer matches what the facility needs.

Continuous monitoring and periodic commissioning help identify both kinds of drift before inefficient and unstable operation becomes accepted as normal.

Control the Environment and Verify the Result

For process-sensitive environments, maintaining a condition is only part of the job.

Facilities may also need to know whether that condition remained stable over time.

At OPTODEV, Inc., an ophthalmic-lens manufacturer, production required precise temperature and relative-humidity control along with pressurization, 100% outside air, and at least 10 air changes per hour in controlled areas.

Before automation, personnel manually monitored clean environments using chart recorders. Those records provided historical information but could not automatically alert personnel as conditions began moving outside acceptable limits.

Automation changed both sides of the equation.

Controls maintained the environment while supervisory monitoring provided trends, alarms, and reporting that helped personnel verify what had occurred over time.

KMC Controls’ case study reports approximately 25% operating-cost savings during the first year of the initial automation project. Later optimization produced an additional 15–20% operating-cost savings, while plant capacity increased by more than 20% and energy consumption per unit of production decreased by more than 20%.

That illustrates an important distinction:

Control answers, “Are we maintaining the required condition?”

Monitoring answers, “Can we demonstrate what conditions actually occurred over time?”

For mission-critical, process-sensitive, and regulated environments, both can matter.

Where KMC Controls Fits

Efficient environmental control requires a chain of good decisions.

Design → Control → Measurement → Optimization

KMC Controls supports the automation and information layers that allow those decisions to continue after facility construction is complete.

Environmental sensors from KMC Controls and KMC Conquest® NetSensor® devices provide information about conditions such as temperature, humidity, occupancy, and carbon dioxide in supported applications.

KMC Conquest controllers provide programmable control for HVAC and environmental systems, allowing equipment and sequences to respond to actual facility requirements rather than relying solely on fixed operation.

Where accurate airflow measurement is important, KMC AFMS™ can provide stable, high-accuracy airflow measurement in appropriate mixed-air systems. Reliable airflow information can improve ventilation control and help facilities verify whether intended airflow performance is actually being delivered, without the recurring calibration burden associated with many traditional airflow-measurement technologies.

At the supervisory level, KMC Commander® can provide remote visibility, trending, alarms, and notifications across connected systems. Historical information allows facilities teams to investigate not only whether an excursion occurred, but also what equipment and environmental conditions were doing before, during, and after the event.

And industrial and mission-critical facilities rarely contain equipment from only one manufacturer.

KMC Controls’ open, BACnet-based approach can help owners integrate building-system information across mixed-vendor environments, preserving flexibility as equipment, technology, and operational requirements evolve.

The value is not any single component.

It is the ability to connect environmental conditions, equipment operation, airflow, controls, alarms, and historical performance into an operating system people can understand and continuously improve.

Efficient Environmental Control Is a Lifecycle Strategy

Good industrial environmental control begins with a deceptively simple question:

What condition are we trying to protect, and where does that condition need to be true?

From there, design determines how efficiently the physical infrastructure can create that condition.

Controls determine how intelligently the equipment responds.

Measurement tells us what is actually happening.

Monitoring and optimization help maintain performance as the facility changes.

That framework matters whether the facility is protecting a server rack, a silicon wafer, a pharmaceutical process, a precision-manufactured product, or the people working inside the building.

It also provides a more useful way to think about the resource demands of modern facilities.

A data center can consume a great deal of electricity and still employ highly efficient thermal and electrical infrastructure. A semiconductor facility can require extraordinarily tight environmental tolerances while using sophisticated controls to minimize the energy needed to maintain them.

Resource consumption and resource waste are not the same thing.

The better question is whether the facility is delivering the environmental conditions its mission requires with an efficient design, an effective control strategy, reliable measurement, and continuous operational visibility.

For a complete overview of how KMC Controls supports environmental stability, energy performance, connected operations, and uptime in industrial and mission-critical facilities, explore our Industrial Building Automation Solutions.

Ready to improve environmental performance across your facility? Find a KMC Controls Partner to discuss a control and monitoring strategy built around the conditions your operation actually requires.

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Many thanks for Jesse Shoemaker, VP of Business Development at KMC Controls, for contributing to this article.