You should ask yourself if Covid-19 has impacted the health of your building, here is why. It’s pretty obvious that too many people in a building can be a problem – occupancy limits are often posted for fire safety reasons. But under-occupied buildings can also create problems. With more people working from home, fewer people are at work in many office and retail buildings.

Buildings, and the systems inside of them, are designed to conform to building code^[1] for full capacity, which in turn dictates many design assumptions. Heating, Cooling, Ventilation (HVAC) systems, elevators, circulation, plumbing, lighting, and controls all must be designed for full occupancy. Human influences are not just a matter of building use, but of the building’s health. We, humans, are ‘hotter’ than most interior environments (98.6°F inside ~70° system setpoints)^[2] — and put off a fair amount of water vapor through respiration and perspiration. Therefore, buildings that have fewer people inside due to Covid-19 and more people working from home means less heat and humidity load.

Our Observations

Here’s a sampling of building health problems we’ve observed, diagnosed, and solved for several clients in Southwest Virginia in the past year that is directly attributable to Covid-19’s effect of under-occupation:

• The Occupants are too cold – in both summer and winter.
• Spot space-heating will cause utility cost spikes.
• Utility bill costs take a bigger chunk out of net income.
• The building is too dry or too humid, causing aesthetic issues and/or mold.
• Indoor air pollutants build up (pollen, viruses, water vapor, dust, CO2, VOCs, Carbon Monoxide, etc.) due to dysfunctional ventilation systems^[3].
• Risk of Legionnaire’s Disease due to under-used plumbing fixtures^[4].
• Lower maintenance means problems can remain undiscovered and unaddressed, like water leaks or system malfunctions.
• Increased future costs due to deferred maintenance.
• Tenants are looking for ‘greener pastures’; tenant retention is a future risk.

Our Recommendations

Here are our recommendations to reduce your risk, retain tenants and have a healthier building. Remember that every building is different so a customized solution is the only real solution. Buildings are systems of systems, and one of those systems is occupants’ assumptions, use, and behaviors.

• Use building science to diagnose and solve any problem in an existing building. Seemingly simple problems may have complex underlying causes that can be solved in phases, but the order of these phases is important, so you do not waste time or money.
• Instead of relying on the perspectives of one trade or expert, bring trades and experts together. Design solutions based on real on-site conditions and measurements, including the building enclosure and occupancy patterns.
• The ideal and least expensive time to get things right for the whole building’s health is when it is new and at any time significant renovations occur.
• Design for all four conditions: fully occupied, 30% and 60% occupied, and unoccupied. It is nearly certain that the building will exist in all these conditions during its lifespan.
• For all the above – bring a building scientist on the team and at all phases of the project. Their experience and “building-as-a-system-of-systems” approach can save you a lot of time, stress, and money.
• The best design solution will fail if conformance to design intent and specifications fails at the bid, submittal, construction, maintenance, and occupancy phases of the building. Verify at all of these critical points to avoid unexpected costs and keep occupants happy.

^[1] In the most recent Virginia Construction Code as of this writing, this is given in Table 1004.1.2, Maximum Floor Area Allowances per Occupant. This maximum number is nearly always used as the design default for many systems and features of a building, whether it is true or not, and actual capacity often varies dramatically over the life and use of the building.

^[2] Per the 2nd Law of Thermodynamics, heat goes to cold and moisture goes to dry. Humans have a dramatic influence on the spaces they inhabit.

^[3] Where buildings lack functioning outdoor air supply mechanical ventilation that is specifically designed for actual building enclosure characteristics and field-verified / measured infiltration, these conditions may be especially complex. This is usually the case in residential and small commercial buildings.

^[4] Légionnaire’s Disease, which is a result of inhaling water vapor where L. pneumophila bacteria has accumulated under-maintained (or under-utilized) water systems. this disease is even more deadly than COVID-10. Between 1 in 20 and 1 in 3 people die if they contract it, even with quick treatment. There is no vaccine for Legionellosis. https://www.who.int/news-room/fact-sheets/detail/legionellosis

Photo by Marten Newhall on Unsplash

Photo by Nadir sYzYgY on Unsplash