Dentists React to COVID-19 Response with HVAC Solutions

We recently received a call from a dentist in the Virginia Beach area. His office, like all other dental offices, are struggling with what to do about the pandemic and the Governor's Executive Order 51. The order prohibits "...all inpatient and outpatient surgical hospitals, offices...from providing procedures and surgeries that require PPE." The exemption to dental offices is "...treatment of patients for 'emergency' or 'urgent needs.'"

In other words: dentists are effectively closed. So what to do? Our client asked us to evaluate some engineering systems he could install during the downtime. The idea being that he can assure his patients that additional preventative measures are in place to mitigate contamination when he reopens.

The following are a few ideas we've talked about for dental offices that range in their complexity and costs. We ordered the ideas from the least expensive and least complicated to the most expensive and most sophisticated.

1. Fan Schedules

free, fast, no construction required

A free solution is merely changing your thermostat settings. The odds are that your current HVAC system only runs the fan when the system calls cooling or heating. When your system works like this, it means air is only moving intermittently (i.e., when the equipment needs to heat or cool the space).

Most thermostats allow you to control your fan separately from your compressor, furnace, and heating element. Set your fan to run continuously during the occupied mode. Ideally, the fan turns on an hour or two before and after your business hours.

Scheduling your fan to run continuously during occupied hours moves the air continuously through your air handler, allowing the filtration systems to work to their maximum effectiveness. The goal is to maximize the "air changes" in your building. The more often the air changes, the more often it is filtered.

If you have a simple HVAC system, we recommend installing a Nest or an Ecobee thermostat. These thermostats allow you to program your fan schedules from your phone or web browser and are extremely easy to use and to install.

Nest thermostats (or ecobee) can be used to easily program your fan schedule for occupied hours.

2. Air Scrubbers

$, fast installation

The research is still unclear as to the effectiveness of UV light for the novel coronavirus. However, it still can be a relatively cost-effective way to upgrade your existing mechanical systems. Aerus makes a simple technology that treats the air, killing viruses and other contaminants.

These can be added quickly without disruption to your existing patient care facility. You can install them within your existing HVAC system or as a stand-alone purifier.

Installing AirScrubber in an existing HVAC system.

Another consideration is in the installation of higher-grade filters on your existing HVAC system. Installing a HEPA filter would add a considerable pressure drop to your system, reducing its air delivery effectiveness. Installing HEPA filters without first consulting with an engineer or HVAC contractor is not recommended.

3. Nail Salons?

$$, fast, phased install

So this idea came from the client, and we love it. It is a derivative of a simple code requirement for nail salons, and it offers guidance for a promising solution for dental practices.

The International Mechanical Code (IMC) Table 403.3.1.1, note b states that "...each manicure and pedicure station shall be provided with a source capture system."

Source capture is a critical factor. The risk to dental offices is their proximity to the source of contaminant: other people's mouths and noses.

Try a Google search of "source capture system," and the first recommendation is to add "for nail salons." The existing code requirement is excellent news for the dental community because it means there is turnkey infrastructure already in place to help mitigate the risk of contamination.

Ceiling Mounted Source Capture Device Used in Nail Salons

Dentists can purchase prefabricated ventilation systems installed within the drop ceiling. Many of these systems also include filtration to help clean the air on its way out of the building. The HealthyAir Ceiling Mount Source Capture System uses a pre-filter, HEPA filter, and Activated Carbon Filter to capture airborne particles to "...kill microorganisms, including dust, gasses, odors, VOCs, smoke, allergens, virus, bacteria, and mold.

It is important to note that this equipment is not rated for evacuating medical waste, such as a WAGD, or other listed medical vacuum systems. The intent is to remove contaminants from an occupied space at a source. In this scenario, the source is the high concentration of contaminants in the air near the patient, dentist, and hygienist.

4. Makeup Air

$$, requires planning and design, moderately disruptive

So the problem with the ventilation systems is something called "makeup air." The idea is that: what goes out must come in. Dealing with this isn't easy, and certainly not cheap.

Imagine a 90 degree, high humidity day, and you are bustling with patients, every patient room full. Teeth are being cleaned, and all is well. Well, except for the fact that you are now dumping damp 90-degree air into your medical facility. Not only does this create major comfort issues, but it also causes moisture issues. Over time, you create a breeding ground for contaminants in your dental office.

Makeup Air System - Untreated Outdoor Air

5. Energy Recovery Ventilator

$$$, requires planning and design, highly disruptive

One way to pre-treat the outside air for "free" (in terms of energy) is to use an energy recovery ventilator (ERV). The idea is to pass the leaving inside air over the entering outside air. Using an ERV removes some heat and moisture from the airstream before it enters your building.

The downside is the risk of cross-contamination in this process. When using an ERV, select a Class 1 rated ERV with HEPA filtration and UV light on the incoming air. Look for hospital-grade equipment.

Basic ERV Functionality

Makeup Air System - Treated with ERV

6. Dedicated Outdoor Air Systems

$$$$, requires planning and design, highly disruptive

The best way to handle the makeup air problem while controlling your indoor relative humidity (RH) levels is to install a Dedicated Outdoor Air System (DOAS). These systems can fully modulate the airflow based on demand saving tons of energy costs. They also can couple with the ERV to completely treat the incoming air by removing moisture and contaminants. The DOAS is capable of removing or adding moisture to the airstream to give full control of the indoor air quality.

Makeup Air System - Treated with DOAS

7. Other Ideas

Other ideas require some level of architectural design and planning but are still worth noting here.

For example, your dental office can carve out small safe zones of their facility. Your architectural team could help plan a dedicated zone of the facility for at-risk patients (patients with pre-existing conditions or senior patients).

A dental practice could install all of the HVAC solutions mentioned above on a phased basis, with the priority being the safe zone area for at-risk patients. This way, the facility can focus capital on the first phase of construction and then, after operational, use the operating cashflows to help underwrite and fund future development of the office.

The idea is to create isolated zones from the rest of the facility with a dedicated entrance and circulation mechanism. Measures could be considered on the floorplan to implement social distancing standards with signage, floor markings, and seating arrangements.

From an HVAC perspective, the zone pressurization would stay positive relative to other areas, ensuring no contaminants from adjacent spaces enter the safe zone. No air from adjacent zones should recirculate into these zones. At this point, your engineer and architect may be looking to ANSI/ASHRAE/ASHE Standard 170 for guidance on how to arrange spaces to create sterile environments for your patients.

Pressure Relationship between Rooms

Consider installing hands-free bathrooms, fixtures, and doors.

These safe zones might also require some administrative coordination, such as dedicated staffing and hygienists for that particular zone, business circulation rules, and implementing virtual tools like digital reception and consultation. Your architectural and engineering team can help work those considerations into the layout of the renovated space.

Disaster Relief Funding, SBA (EIDL)

All of this raises the question to the SBA: does disaster relief funding include funding renovations to existing at-risk facilities for COVID-friendly environments?

The SBA is entering uncharted territory, but can we make the case about the impacts on the buildings themselves?

Does economic injury include the permanent loss of business to facilities that cannot afford to make the changes required to build consumer confidence in their place of business?

Our hope is the SBA considers measures like these as part of the funding required to bring the economic and public health back to a place of normalcy.

PermitZIP is actively pursuing answers to some of those questions.

Let us know your thoughts in the comments below. If you're a dental office, have you been consulting with HVAC engineers on potential solutions? How is your industry reacting?

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