In addition to physics, I studied meteorology in college and learned that the concepts are the same for the outside as they are for inside. That’s exactly what HVAC engineering is all about—controlling the weather inside your building. Psychrometrics is the study of air thermodynamics—moisture and temperature of air, relative humidity, dew point, and heat transfer. Basically, it’s meteorology inside your building.
By Understanding Temperature and Humidity Inside Hospitals, We Keep Patients Safe
When we design hospitals, we’re very concerned about temperature and humidity. You certainly don’t want mildew growing inside of a hospital. People are already sick, and many of them can’t physically stand one more disruption. For some patients—burn victims and small babies, for example—it’s important to keep warm and moist. Their rooms must be warmer with higher humidity, and sometimes it’s difficult to maintain while keeping low temperature and humidity in the next room.
It’s also important to keep the doctors and staff comfortable. In an operating room, they’re wearing gowns, masks, and sometimes a lead apron—for hours. Surgeons and nurses battle over temperature—the surgeons are always hot, while the nurses and other staff aren’t necessarily. In the end, surgeons usually hold the trump card. And as a patient, you want them comfortable. If you’re on the table, you don’t want them thinking about how hot it is!
Providing a Reliable Solution When Converting Standard ORs to Pediatric ORs
Earlier this month, I got an urgent call on a Monday from a client who needed to convert two standard operating rooms (OR) to pediatric ORs. He and the hospital operating engineer were concerned that the HVAC system serving the standard ORs could not provide the temperature, humidity, and fast changes needed for pediatric cases. They expected to install additional electric heating coils and modify the humidification system, which would be disruptive, cost more than $50,000, and may have been difficult to complete within the 30 days available for the project.
Because of our well-established relationship with the client, we already had drawings of their OR suite scanned into our Drawing Management System. After examining the drawings and doing a few calculations, we asked the hospital engineer to conduct a few simple tests after hours on Tuesday night. We met with him on Wednesday morning, and after combining his test results with our research, we determined that the current system was capable of performing as they desired with only a few modifications to the control sequence. These modifications were implemented by Monday of the following week, saving the hospital approximately $50,000 and multiple days of disruption. Two weeks later, the client let us know that the new way of controlling the rooms seem to be working well.
The solution was much simpler and more reliable than the anticipated work. It required the willingness of all of us to consider the entire system and clarify the real “problem.” This holistic view, combined with knowledge of psychrometrics led to our solution.
As an HVAC engineer, we must understand what the hospital is trying to do and why they want things the way they want it. It’s then our job to make the systems do that. We must understand the procedures, both from the physics point of view and the medical point of view.
DAN KOENIGSHOFER ON THE NUMBER ONE HVAC PROBLEM IN HOSPITALS
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