Mezzo-soprano Jamie Barton performs during San Francisco Opera’s “The Homecoming” concert, a one-night-only event, at War Memorial Opera House in San Francisco. Photo: Laura Morton / Special to The Chronicle
As Bay Area audiences return to their beloved venues, they’ll be hearing a lot about upgrades to HVAC (heating, ventilation and air conditioning). Many venue managers tout their use of 100% outside air, for instance, to assuage visitors’ COVID fears.
But all that air pumping comes with complications that homes and office buildings don’t have to deal with.
“Performance areas are really tough, because you blow more air and it’s louder. Curtains can ripple,” said Matt Suidan, a senior product manager at Enpowered Solutions, which has consulted with War Memorial Opera House, Davies Symphony Hall and American Conservatory Theater. Or any theater haze, used for a special effect, could get blown away.
Or, in the case of Davies Symphony Hall, at a certain fan speed, the acoustic dishes that hang from the ceiling can start moving and eventually bang into each other.
Matt Suidan, the senior project manager at Enpowered Solutions, stands on the roof of the American Conservatory Theater in San Francisco before inspecting an HVAC system. Photo: Jessica Christian / The Chronicle
More outside air also means less control over temperature, and the Opera House doesn’t have air conditioning, which isn’t just a patron comfort issue.
“When it comes to the dancers in the ballet and the members of the orchestra, they have stipulations in their collective bargaining agreements about what the temperature can be,” said John Caldon, who manages the War Memorial Opera House, Davies Symphony Hall and the Veterans Building, three San Francisco venues each the size of a city block.
Performing is physical, and if the temperature in the War Memorial’s pit exceeds a certain range, for instance, orchestra members are allowed to take their jackets off so they don’t overheat. (It hasn’t come to that so far this season.)
In the old days, whenever Caldon thought about a space’s HVAC, his primary concern was energy efficiency — how much indoor air he could recycle. More outside air meant more heating and cooling, which would mean more energy and higher costs for the city-owned venues.
“The overnight switch — once the CDC figured out that (the coronavirus) was an airborne infectious disease — was to run everything at 100% outside air,” he recalled, noting that the directive meant environmental concerns became secondary. “The concern is how many times can you turn that air over in a room?”
Individual HVAC ventilation fan systems that lead to various spaces inside American Conservatory Theater’s Geary Theater are seen from the roof of the San Francisco venue. Photo: Jessica Christian / The Chronicle
For Caldon and other venue managers, the pandemic has meant an immersion into HVAC. In May 2020, the American Society of Heating, Refrigerating and Air-Conditioning Engineers, a nonprofit organization, issued its first pandemic guidance for all indoor spaces in collaboration with the Centers for Disease Control and Prevention. They were later modified, as many buildings in extreme climates found their machinery couldn’t handle 100% outside air. Despite the Bay Area’s milder climate, more outside air poses a risk here, too. For instance, San Francisco fog can make equipment more vulnerable to corrosion.
Still, many of ASHRAE’s initial core recommendations remain, including:
- Using air filters with an efficiency of at least MERV-13, which means they can catch not just pollen, dust and pet dander but also smaller particles such as those from wildfire smoke as well as airborne bacteria and some viruses.
- In between a room’s occupied periods, flushing its air supply three times, which should eliminate 95% of contaminants.
Craig Lichtle of Legacy Mechanical and Energy Services checks the filters of a HVAC system leading to the auditorium of American Conservatory Theater in San Francisco. Photo: Jessica Christian / The Chronicle
For local venues — some of which were built a century ago — these guidelines first meant finding out if their existing systems could meet the new standards. After months of assessing equipment produced an affirmative, Caldon recruited a stagehand to use a laser distance measure in all his buildings’ rooms to calculate volume, so he’d know how much air he’d have to move.
Venue managers who wished to exceed minimum requirements, perhaps so that they could prove to timid audiences that they were going above and beyond, quickly learned that only specially built facilities such as labs and hospitals can filter air much more finely and efficiently.
“Some of the ideas that have been suggested from different sources ask for things the building systems literally cannot do without completely ripping out an HVAC system and effectively almost tearing down the building,” said Suidan. “Your ducts can only handle a certain amount of airflow.”
Music Director Esa-Pekka Salonen conducts the San Francisco Symphony during the symphony’s Re-Opening Night at Davies Symphony Hall in San Francisco. Photo: Laura Morton / Special to The Chronicle
And a capital campaign for an entirely new HVAC system would be an unlikely fundraising scheme during a pandemic, especially when staff may have been laid off or furloughed.
Perhaps for related reasons, Alyse Falconer, who is a board member of ASHRAE’s Golden Gate Chapter as well as an associate principal at San Francisco engineering firm Point Energy Innovations, hasn’t seen a surge of HVAC business since the pandemic hit.
“The problem is that nobody’s going into offices,” she said, which means some clients figure they can delay improvements. Still, Falconer said of the pandemic, “everybody instantly became an indoor air quality specialist, which is kind of funny. It’s interesting to explain what a MERV filter is to someone like my mother.”
Craig Lichtle of Legacy Mechanical and Energy Services adjusts and repairs various elements of an HVAC system on the roof of ACT’s Geary Theater. Photo: Jessica Christian / The Chronicle
With many entertainment venues, high ceilings can be a virtue, but the tight seating of theaters, auditoriums and stadiums means that HVAC interventions can only help so much to prevent the spread of COVID-19. Vaccinations and masking are still key.
“You can have amazing airflow, and somebody right next to you coughs in your face,” Suidan posited. “(The HVAC) doesn’t matter. You’re not going to be able to engineer that away.”
That doesn’t mean that HVAC can’t help reduce the risk of airborne transmission during a pandemic, but it’s difficult to quantify its role in practice, according to William P. Bahnfleth, a professor of architectural engineering at Penn State and chair of ASHRAE’s pandemic task force.
“We know that poorly ventilated facilities and ones that don’t have other ways of cleaning the air have been the places where there have been clusters of infections, super-spreading events,” he said. “We know more what doesn’t work than how well things actually work, and that’s a hard concept to get across to the public.”
The Warriors’ Stephen Curry lobs a pass to a teammate in a game against the Minnesota Timberwolves at Chase Center in San Francisco. Photo: Scott Strazzante / The Chronicle
Venues have still other industry-specific concerns.
Chase Center, which marked its opening in September 2019 with a sold-out concert by Metallica and the San Francisco Symphony, has much greater HVAC capacity than many older performing arts venues. The facility has 16 air handlers that regulate and circulate air; 12 smaller ones about the size and shape of a truck’s box trailer, approximately 20 feet in depth; and four larger ones, for the bowl, that could fit multiple San Francisco apartments. By contrast, ACT’s Geary Theater has six air handlers, and its largest is about the size of one of Chase Center’s smaller ones.
But the home of the Golden State Warriors still has its limitations.
“I’m sure Steph Curry doesn’t want to be shooting into headwinds,” said Ian McDoom, Chase’s director of engineering. Not only must the center keep the temperature between 65 and 72 degrees for guest and talent comfort, it must also maintain relative humidity below 55% or the basketball court’s wooden floorboards might start to warp.
Chase Center is seen ahead of a game between the Warriors and the Pelicans in November. Photo: Santiago Mejia / The Chronicle
McDoom’s task has been to flush the air in the facility, which occupies a little more than 1 million square feet, with 100% outside air at least four times per hour. Accomplishing that, he estimates, has meant the arena’s electricity bills have increased by 10%, though pre-pandemic comparisons for the young facility are hard to come by.
For Bahnfleth, pandemic-era upgrades might have the virtue of furthering industry experts’ longer-term HVAC goals. He’s part of a group of advocates who have been pushing for better indoor air standards for decades.
“We’ve known for a long time that buildings that have higher ventilation rates, which means lower contaminant levels indoors, generally tend to have fewer sick building syndrome symptom complaints,” he said, referring to the well-documented phenomenon by which poor ventilation in offices and schools causes a variety of health problems, including headaches, fatigue and respiratory, skin and gastrointestinal problems. Well-ventilated buildings, he said, “have a positive effect on the learning of schoolchildren, higher worker productivity. The economic impact of that is hundreds of billions of dollars per year in the U.S., but it’s fallen on deaf ears for a long time.”
Craig Lichtle of Legacy Mechanical and Energy Services adjusts and repairs various elements of an HVAC system on the roof of ACT’s Geary Theater in San Francisco. Photo: Jessica Christian / The Chronicle
His hope, he said, is that “the desire to do something about diseases like the COVID epidemic or the seasonal influenza” can spur action to “step up the standards for indoor air quality.” Pre-pandemic standards, he noted, were focused on disease and odor.
“That’s a different approach than saying we’d like to have indoor air quality that promotes the best levels of productivity and cognitive function and reduces other types of illnesses.”