To paraphrase a quote that has been falsely attributed to Albert Einstein “Insanity is asking the same question time and time again and expecting a different answer”
I run into this quite frequently at work.
Escitalopram really helps.
People who should know better, keep asking the same question in the hopes that the answer will change the next time they ask the question. Like there’s a magical switch that I just have to flip in a mechanical room that will take select between “Operate at 1970’s ASHRAE Standards” and “Operate at 2026 CSA Standards”
No matter how many wishes are made; hopes, dreams, and best of intentions are not enough to take equipment that was designed and built to 1970s standards and make it function as if it was built to the latest CSA standards.
The only way for equipment to meet today’s exacting and specific standards is for a copious amount of $$$$$$$ to be spent either upgrading the equipment or outright replacing the equipment.
In the 1970s, HEPA filters weren’t seen as being beneficial to anyone in a hospital except for burn patients and possibly orthopedic surgery.
Nowadays everything in a hospital pretty well requires HEPA.
However, you can’t just go slapping HEPA filters in to fan systems that were never designed for HEPA filters.
Let’s say you have an air-handling unit with four 610 mm × 610 mm × 355 mm MERV 14 V-bank filters. You can’t simply pull out the MERV 14 filters, replace them with HEPA filters, and expect the fan to maintain the same downstream static pressure and airflow. HEPA filters can impose substantially greater resistance to airflow, and the original fan, filter plenum, and ductwork were never designed around that additional pressure drop. If the particular HEPA filters selected require roughly four times the filter face area to maintain an acceptable face velocity and pressure drop at the existing airflow, your four-filter bank may suddenly need to become a sixteen-filter bank. At that point, you’re not changing filters anymore—you’re redesigning the air-handling system.
In the 1970s room temperatures for specific areas were required to have a range of adjustment from 20C to 24C. Nowadays those same areas call for temperatures of 18C to 22C. You’d be surprised how badly this change will affect a supply fan that was designed to operate under the old standards. Especially when that fan is designed to operate off 100% fresh air. If the original cooling coil of the equipment was specified as having a pressure drop of 210 Pa at 21,000 L/sec, doubling the thickness of the cooling coil will increase the static resistance and decrease your downstream static pressure and airflow.
Other areas went from very casual dress codes in the ’70s to everyone wearing head to toe PPE and lead aprons. I know that you’re hot. But welcome to 1970s HVAC. My job title and authority don’t place HVAC upgrades in my ball court.
In the 1970s the amount of technology in a facility was minimal. Nowadays computers, monitors, and “machines that go PING!” are everywhere.
Just lowering the thermostat isn’t enough to remove all of this heat energy.
Humidity control is another area that drives me up the wall. In the 1970s ASHREA had very broad ranges for humidity levels. In the year 2026, CSA has very exacting levels for humidity. A cooling coil that was spec’d in the 1970s as being able to extract “X” amount of litres of moisture per hour out of a specific volume air isn’t going to be able to extract more water out of the air just by running the chilled water colder or pushing more air through the fan. Especially when this fan is running from 100% fresh air, 0% return air. When a cooling coil is rated for 2.5 m/sec of velocity, you can’t push it to 3.4 m/sec velocity without other consequences.
A chilled-water cooling coil designed around 7 °C entering water, 24 °C entering air and 16 °C leaving air was primarily selected to cool the air, not to provide the aggressive dehumidification required for tight humidity control. To remove moisture, the coil has to cool the air below its dew point so that water actually condenses on the coil. With a 100% outdoor-air system, the problem becomes much harder because every litre of air entering the building brings the outdoor moisture load with it; there is no dry return air available to dilute it. On a warm, humid day, a coil designed to deliver air at 16 °C may simply not have enough latent capacity or a sufficiently low apparatus dew point to remove the required amount of water. Turning the chilled-water temperature down or opening the valve to 100% cannot magically give the coil more surface area, more rows, longer air-to-coil contact time or greater drainage capacity. Proper tight humidity control on a 100% outdoor-air system generally requires a properly sized dehumidification cooling coil, adequate chilled-water and refrigeration capacity, sufficient coil surface area and rows, appropriate air velocity across the coil, proper condensate drainage and moisture-elimination provisions, accurate temperature and relative-humidity/dew-point sensors, modulating chilled-water valves and controls, and usually reheat downstream of the cooling coil. Reheat is important because effective dehumidification often means deliberately cooling the air well below the desired supply or room temperature to wring the moisture out of it, then reheating that now-drier air to the required supply temperature. In other words, temperature control and humidity control are not the same thing: a system capable of making the room cold is not necessarily capable of making it dry.
It’s six months to go until the acute care here moves over to the new facility and I can finally relax.
“Seeing how things really work behind the scenes is like touring the slaughterhouse before eating the hamburger—you can never quite look at the finished product the same way again.”
