Published on medium.com
Written by Devin Malone

COVID-19 has had a significant impact on how we think about the health and safety of the building environment. With so many questions about how to get ready for reopening, it’s hard to know where to start. Below are some things you can do now to ready your building by checking on mechanical and plumbing systems.

For buildings that have been unoccupied for a prolonged time:
- Flush your building water and air systems to prevent legionella
- If your HVAC has been set to unoccupied mode (either using a controls system or manually), start the system to circulate your building air and parking garage air for at least two hours.

In preparation for occupants return:

Ensure proper humidity: Do you have humidity controls? Check that they are set to 40–60% relative humidity.

Ensure proper temperatures:
- Are your building schedules changing? Check that your rooms are set to 68–72 degrees during occupied times.
- Check HVAC units to ensure that condenser coils and evaporator coils are clean, and that fan motors and assemblies are working properly.
- Check that HVAC pumps are operational and in good working order
- Check that drain pans and condensate drains are clear of obstruction and standing water
- Verify chemical treatment of cooling towers and loops
- Inspect heat recovery wheels for operation, leakage, and cross-contamination

Ventilation:
- Check that outside air (OSA) and return dampers are working properly to provide ventilation
- Disable demand control ventilation strategies and keep OSA dampers open and system running at all times at minimum speed. Use caution in extreme climates where outside temperatures get below freezing or above 90F consistently. Additionally, very dry or very humid climates should use caution in increasing OA.
- Complete a 100% OSA flush each day, prior to building occupancy. This can be done via a controls system or manually. Again, use caution in extreme climates.
- Exhaust any garage areas for two hours each day, prior to building occupancy.
- Eliminate stagnant air by checking that building occupants have not intentionally or unintentionally changed airflow by blocking vents or diffusers.

Filtration: Check that filters are clean and installed correctly with no air bypass potential

Plumbing:
- Check that domestic hot water heaters are set at or above 130 to prevent legionella blooms. Proceed with caution as these warmer temperatures could lead to scalding temperatures at fixtures. A system should have mixdown valves in place to allow for higher heating water temperatures at the storage tank but safe temperatures at the faucets/showers.
- Check that water recirculation systems are operational and properly programmed. Keep recirculation pumps on 24/7/365.
- Check that all P and U traps on plumbing drains are wet
- Run water fixtures and test water quality for appropriate chlorine, pH and temperature levels

While performing these system checks, you may be concerned that your systems are not adequate, or you may already know you need to make improvements to your building systems. There are many strategies being marketed during this pandemic (UV lighting, particle ionizers, etc.); however, the most effective upgrades will be done as part of a strategic facility plan that includes an infection control strategy. All products are not equally effective and not all measures will be possible in all buildings, and how one component is implemented may affect the operation of existing systems. An engineering firm can provide a comprehensive assessment of your facility and help you develop a plan to provide a safe, healthy, and comfortable environment for your occupants.

To learn more about how disease is transmitted in buildings, and how building systems may impact the spread of infection, please read this article.

About us:
At Willdan, we evaluate buildings and take comprehensive solutions from design concept to implementation with a collaborative team of engineers, construction managers, and commissioning professionals. Our projects focus on occupant comfort and health, system reliability and resilience, elimination of lingering maintenance challenges, and upgrading antiquated systems and equipment while striving to increase energy efficiency and reduce carbon footprint. We partner with clients in k-12, higher education, local government, and healthcare markets to transform their facilities.