The Road Back, Chapter 4: The Wide World of Ventilation

“Don’t submit a plan until you have the ventilation figured out.” 
- Actors’ Equity Association, in a conversation with Managing Director Carrie Van Hallgren about getting permission to produce for in-person audiences. 

In its application for in-person performances, Equity made it very clear that proper ventilation would be a major factor in whether or not we would be able to produce. In fact, of the 19 pages outlining special COVID protocols, a full six pages are filled with HVAC requirements. They aren’t messing around about this.

But, you may ask, APT is an outdoor theater; what does HVAC have to do with anything? It’s true that the Hill Theatre makes our job a bit less complicated, but unlike the early days of APT, most of the work needed to bring the show to the stage takes place indoors. Rehearsal halls, production shops, dressing rooms – all of these and more are subject to the strict ventilation requirements. And, of course, we also hope to produce in the indoor Touchstone Theatre this season.

In order to explain what we’re up against here, we have to get technical about the requirements. For those of you out there who have experience with HVAC – as a job or a hobby (no, really, I’m sure that’s a thing) – this is probably very familiar. For the rest of you…get ready to be amazed. And maybe a little perplexed.

Equity lays out three main factors that have to be addressed:

First, Air Changes per Hour (ACH). One air exchange is when the volume of air coming through the diffuser equals the volume of air in the room. This does not, however, mean that the air in the room has been replaced. Because the air flows slowly into the room through the diffuser and mixes with the air already present, it takes many air exchanges in order to completely replace or purge the air in a room. The rate at which these air exchanges are delivered is measured in air changes per hour (ACH).

Second, Outdoor Air (OA). While air exchange measures how often air is changed in a room, OA refers to how much fresh air is brought in. Many HVAC systems provide 10 to 20% fresh air, but that’s not enough to dilute the virus. You could set it to 100% but that would raise heating and cooling costs to crazy high levels.

Finally, the MERV Filter. In this case, MERV is not the popular 70s TV host turned media mogul (That’s Mr. Griffin to all you young folks). Rather, it stands for Minimum Efficiency Reporting Value, a numbering system the professionals created to track which filters are more effective in keeping out different sizes of particulates (including COVID-19 particulates). The higher the MERV number, the better.

So, what does Actors’ Equity require when it comes to these three factors? We need:

• An ACH of 6 (6 air changes per hour)
• MERV of 13 or higher (it goes up to 20)
• And OA…well, that depends on what your MERV is. The higher your MERV, the lower you can have your OA. But, in general, definitely more than the 10% to 20% that many HVAC systems have.

These ventilation requirements, together with a number of other strict safety measures, make it safe enough for the actors to rehearse or perform without masks on. If you’d like to read more about why that’s true, check out this guidance document from the American Industrial Hygiene Association.

Unfortunately, our buildings aren’t currently equipped for these specs. In fact, most buildings aren’t, unless it’s a hospital or other structure that specifically needs super specialized ventilation. So, we have work to do.

We asked Cari Stebbins, APT’s Operations Manager, to explain the upgrades we’ll need to make. She said we’ll be overhauling the HVAC systems in the Touchstone Theatre and dressing rooms, two rehearsal halls, and the Hill Theatre dressing rooms. The plan is to install a supplemental system, called an Energy Recovery Ventilator (ERV) that will pair with our current mechanicals. Working in concert, the two systems will be able to achieve MERV 13, 6 ACH and 40% OA – adding up to lower risk for our actors and artists to rehearse and perform. And, in the case of the Touchstone Theatre, makes it safer for the audience to watch a play. Smaller rooms at APT – such as the stage manager’s booth, fitting rooms and offices – will be treated with commercial grade HEPA filter units. Also, it’s worth noting: we aren’t depending completely on exemplary ventilation to keep artists and audience safe – it is just one component of our larger safety plan.

The work comes at a cost – upwards of $200,000 – but it is unavoidable if we are to produce plays this season. Money for the upgrades will come from our capital reserve fund, which is used regularly to keep up with repairs and improvements at APT – things like replacing a roof, or buying a new band saw, or upgrading the computer system. This is an expense that we didn’t plan for, but one that we can handle.

The work is set to begin next week, and scheduled to take more than two months. Thermodynamics, a local Spring Green company that we have worked with on other projects will be doing the job. We’ve also contracted with Talaske, the acousticians that worked with us on both the Touchstone and the Next Great Stage Project, to be sure that the new upgrades won’t damage the acoustics of either the Touchstone or Hill Theatre.

As we keep saying, this is a challenge. But if it means we can safely produce plays this summer with you in the audience, it will absolutely be worth it.

Next week, The Art of the Bubble: Housing and Podding and Testing (Oh my!)