For restaurant owners, the latest COVID-19-era adaptation is a number: 450 parts per million. That’s the maximum level of carbon dioxide permitted in the ambient air of any enclosed dining structure under the new “open-air” dining guidelines released last week by Gov. Jay Inslee’s office.
Indoor spaces with poor ventilation carry a much higher risk of coronavirus transmission through droplets in the stagnant air, so the idea is to use the CO2 level as an estimate of airflow. The average outdoor CO2 level is 400 ppm, according to the guidance document; a score below 450 ppm indicates that a structure has a good supply of fresh air from outside.
Inslee issued a temporary ban on all indoor dining in November in response to a rise in Washington’s COVID-19 cases. That ban remains in effect until individual regions meet the criteria to advance to the second phase of the Healthy Washington “Roadmap to Recovery” plan.
The open-air guidelines offer restaurants a potential way to resume limited indoor seating sooner if the design of their interior space meets the criteria. But it’s proven to be a tough target for Clark County restaurants to hit, and in some cases, it’s made things even more challenging because the CO2 rules also apply to the outdoor dining structures that have popped up in recent months.
“I certainly appreciate them trying to do things to help us, but this may have worked in reverse,” said Mark Matthias, owner of Beaches Restaurant.
Permeability
Under the new guidelines, any structure — be it a traditional building or an outdoor tent — is defined as “indoors” if none of its walls are permeable, meaning air can’t flow through them.
A wall can be considered permeable if its design allows it to be partially opened up for a significant amount of airflow. But just propping a door open won’t cut it; the opening has to consist of multiple large windows or bay doors, according to the guidance from Inslee’s office.
Structures with at least one permeable wall are considered to be open-air and are allowed to operate at 25 percent of their usual seating capacity but only if they’re equipped with onsite CO2 monitors and are able to stay below 450 ppm. Structures with only one wall or just an umbrella or canopy do not require monitors.
The new rules have set off a scramble to order CO2 monitors and try to adapt existing restaurants. During a recurring Zoom meeting for Clark County restaurant owners last week, several participants swapped tips about what kind of monitors to buy and where to pick them up.
The monitors are relatively inexpensive, with several models listed on Amazon for less than $200. Some restaurants may already have them, one attendee pointed out, if they have CO2 storage tanks for soda fountains.
Test runs
A few Vancouver restaurateurs began trying to operate under the new rules this week, but the 450 ppm target has proven to be difficult to hit.
Uptown Barrel Room was lucky enough to have an ideal design for the new rules. The restaurant’s street-facing front wall consists of two garage door-style roll-up windows that each span nearly half the length of the wall, easily creating enough of a gap to pass the permeability test.
The restaurant has a back door that can be opened to create cross ventilation, and owner Dwayne Christensen said he also has large fans and virus-grade filters for his commercial air system.
“We kind of have all the perfect elements, plus we have a two-heat-pump system from our ventilation,” he said.
Despite all of those advantages, Christensen said his interior CO2 level was about 442 ppm — below the limit but not by much. Part of the problem is the outdoor air wasn’t very fresh to begin with, he said, registering about 410 ppm just outside the restaurant. Christensen speculated that the higher concentration was likely due to nearby roads, especially Interstate 5.
Matthias said he installed CO2 monitors over the weekend and then took a first stab at open-air dining on Monday, relying on the building’s bay windows for ventilation.
During the day, it worked; the restaurant was able to stay below the threshold and seat about a dozen tables at a time. But then in the evening, the CO2 levels suddenly jumped to 475 ppm, necessitating a five-minute pause to crank up the fans and drive it back down.
Tent troubles
In theory, the new rules can only be beneficial. Because indoor dining is already banned, the worst-case scenario is simply that a restaurant can’t hit the 450 ppm mark and must remain closed.
The problem, Matthias said, is that the new CO2 rules also apply to tents and other outdoor structures, where owners previously only had to contend with physical design requirements.
It’s a new wrinkle in a problem that restaurants with outdoor seating have been confronting for the past several months: the need for a tent environment that is dry and warm enough to be comfortable without becoming a de facto indoor structure. Rolling up the tent walls brings in fresh air, but at this time of year it’s also frigid air.
“We’ve had some good weather right now,” Matthias said. “When this goes the other way and it’s 30, 35 degrees all day, you’re just really not going to want to sit in there.”
The same issue can crop up in indoor spaces. Grains of Wrath in Camas announced on Facebook that it would reopen for limited indoor dining earlier this week, but the post cautioned that the restaurant’s garage doors would need to be open and encouraged guests to bundle up.
One potential solution is to equip tents with large heaters to balance out the ventilation wind chill, but the new requirements make that approach more difficult because the heaters themselves can push up the CO2 count.
“That’s going to be one of the dilemmas,” Christensen said. “I know a lot of people are using propane inside these tents.”
