Commercial HVAC Equipment

A Fantastic Solution to Removing Humidity from Your Operating Room

Tuesday, April 5 2016 10:45 AM
By Jon Goering

 Temperature and humidity levels operating rooms must be exact, otherwise patient safety, the comfort of surgical and medical staffs, and the performance of medical equipment risks compromise.

 Everyone knows that a visit to the operating room can cost you big bucks. But the thing we don’t think about is the cost for hospitals to operate their ORs.

Part of the blame falls on temperature and humidity.

Temperature and humidity levels in operating rooms must be exact, otherwise patient safety, the comfort of surgical and medical staffs, and the performance of medical equipment risks compromise. And that can get expensive.

Hospital leaders have long known and addressed this, with mixed results. Fortunately, new technologies exist to make dehumidification in operating rooms less of a problem.

The Issue

Hospitals typically cool their operating rooms to temperatures between 60 – 68°F and set relative humidity levels at 50 to 60 percent. In the past, HVAC equipment has struggled to meet these dehumidification parameters.

To address the issue, hospitals often add additional HVAC equipment or lower their chiller plant temperature. Doing so, however, increases costs and reduces system efficiencies.

What’s more, ORs aren’t the only areas in hospitals that need conditioning. Other spaces – offices, waiting rooms, storage areas and more – require different temperature and humidity set points. The real challenge is to find a way to meet all of these varied heating and cooling demands economically.

The new technologies that better meet the unique heating and cooling needs of operating rooms feature an advanced desiccant wheel added to HVAC equipment.

 A Solution

The new technologies that better meet the unique heating and cooling needs of operating rooms feature an advanced desiccant wheel added to HVAC equipment.

In order to avoid any confusion, we’ll begin by explaining what desiccant is (it’s not as complex as it sounds).

First, moisture can be removed from the air by two methods: 1. Cool the air below its dew point, then remove the moisture by condensation; or 2. Sorption (a common term used for absorption and adsorption) by a desiccant material.

Desiccants are manufactured substances (solids or liquids) that help to keep the areas around them dry by removing water vapor molecules from the air. Hundreds of different types of desiccants exist, each with a specific task and categorized by its ability to absorb water at specific temperatures and humidities.

The “wheel” in a desiccant wheel is a synthetic disk secured inside a casing or cassette. The disk itself is saturated with silica gel (think of the small white bags packaged with electronic equipment – it’s the stuff inside them). The gel acts as a sponge, removing moisture from the air stream.

A desiccant wheel is positioned inside an air handler next to other mechanical components such as blowers, heating or cooling elements and filters. Here, the wheel slowly rotates, performing two functions.

First, it removes water vapor from the air stream, providing drier air to the space being conditioned. Second, as the wheel turns, air leaving the conditioned space again passes through the wheel. As it does, the air strips the moisture captured in the desiccant and carries it away.

The differences in vapor pressures make this transfer of moisture possible. The desiccant collects moisture when the surface vapor pressure is lower than that of passing air and releases moisture when the surface vapor pressure is higher.  


The benefits of desiccant wheel technology in operating rooms are many.

First, cooling efficiency improves because operators don’t need to cool water in their systems to the degree they would without a desiccant wheel, thus saving on utility bills. Additionally, hospitals can operate smaller systems because they do not need the additional equipment necessary to meet their current heating and cooling requirements. And desiccant wheel technologies eliminate the need to purchase additional equipment if a current system without them is not dehumidifying properly.

From an operating standpoint, more patients can be moved through the OR because the room can be cooled more quickly between procedures, thus increasing revenue. The technology also helps to keep components within the system drier, eliminating the risk of mold, which could temporarily shut down the OR - something no hospital administrator desires.


Hospitals looking to build new facilities should consider incorporating desiccant wheel technology into their HVAC systems during the design and planning phase. If remodeling, hospitals will need to replace their current air handling units in order to attain the technologies’ benefits.

Hospitals also want to ensure that the new technologies interface with their existing building automation systems to maintain their system performance and reliability.


Dehumidification in the OR is a critical issue. Too much humidity in the room can lead to comfort issues for surgeons and medical staff, the increased risk of infection and the decreased performance of medical equipment.

Conversely, past solutions to dehumidification problems often led to increased energy costs or the purchase of additional equipment, which hospital administrators and facility leaders preferred to avoid.

Today, hospitals can maintain safe temperature and humidity levels in their ORs without driving up costs – a win-win for hospitals, medical staff, and patients.

Is dehumidification an issue in your hospital? Would you like to know more about adding desiccant wheel technologies to your facility? For more information, please email Jonathon Goering by clicking here or call 316-265-9655.

Knipp Services works with commercial and industrial building owners to identify solutions to reduce downtime and increase building efficiency. We provide services that enable building owners to have a high-performance building.

Topics: Operating Room Dehumidification

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