Mezzo-soprano Jamie Barton performs at the San Francisco Opera’s The Homecoming, a one-night-only event, at the War Memorial Opera House in San Francisco. Photo: Laura Morton / Special on The Chronicle
When the Bay Area audience returns to their beloved venues, they will hear a lot about upgrades to HVAC (heating, ventilation, and air conditioning). For example, many event managers are promoting the use of 100% outside air to allay visitors’ fears of COVID.
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 pucker, ”said Matt Suidan, a senior product manager at Enpowered Solutions who has consulted with the War Memorial Opera House, Davies Symphony Hall and the American Conservatory Theater. Or any theater fog used for a special effect could be blown away.
Or, in the case of the Davies Symphony Hall, at a certain fan speed, the acoustic shells hanging from the ceiling can start moving and eventually crash into one another.
Matt Suidan, 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 / Die Chronik
More outside air also means less control over temperature, and the opera house has no air conditioning, which isn’t just a guest comfort issue.
“As far as the dancers in the ballet and the orchestra members go, they have regulations in their collective agreements on how the temperatures can be,” says John Caldon, who runs the War Memorial Opera House, the Davies Symphony Hall and the Veterans Building, three venues in San Francisco each the size of a city block.
The performance is physical, and if the temperature in the war memorial pit exceeds a certain range, for example, orchestra members are allowed to take off their jackets to prevent them from overheating. (It hasn’t got that far this season.)
When Caldon used to think about a room’s HVAC, his main 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’s own venues.
“The overnight switch – once the CDC found out that (the coronavirus) was an airborne infectious disease – should run everything in 100% outside air, ”he recalled, noting that environmental concerns were becoming secondary. “The concern is how many times you can turn that air in a room?”
Individual HVAC fan systems can be seen from the roof of the San Francisco venue, leading to various rooms in the Geary Theater of the American Conservatory Theater. Photo: Jessica Christian / Die Chronik
For Caldon and other venue managers, the pandemic meant a dive into HVAC. In May 2020, the American Society of Heating, Refrigerating and Air-Conditioning Engineers, a not-for-profit organization, in partnership with the Centers for Disease Control and Prevention, issued their first indoor pandemic guidelines. They were later modified as many buildings in extreme climates found that their machines couldn’t handle 100% outside air. Despite the milder climate in the Bay Area, more outside air poses a risk here too. For example, San Francisco fog can make equipment more susceptible to corrosion.
Still, many of ASHRAE’s original core recommendations remain, including:
- By using air filters with an efficiency of at least MERV-13, you can catch not only pollen, dust and animal hair, but also smaller particles such as from forest fire smoke as well as airborne bacteria and some viruses.
- Flush the air supply three times between occupancy times of a room, which should remove 95% of the impurities.
Craig Lichtle of Legacy Mechanical and Energy Services checks the filters on an HVAC system that leads to the auditorium of the American Conservatory Theater in San Francisco. Photo: Jessica Christian / Die Chronik
For local venues – some of which were built a century ago – these guidelines initially meant finding out whether their existing systems could meet the new standards. After months of positive results from the devices, Caldon hired a stage worker who used a laser rangefinder to calculate volume in every room in his building so he knew how much air to move.
Event managers who wanted to exceed the minimum requirements, perhaps to prove to a shy audience that they were going above and beyond, quickly learned that only purpose-built facilities like laboratories and hospitals can filter the air much finer and more efficiently.
“Some of the ideas that have been suggested from various sources ask about things that the building systems literally cannot do without completely ripping out an HVAC system and practically nearly demolishing the building, ”Suidan said. “Your ducts can only process a certain flow of air.”
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 on The Chronicle
And a Fundraising an all-new HVAC system would be an unlikely means of raising funds during a pandemic, especially if employees have been laid off or on leave.
Perhaps for similar reasons, Alyse Falconer, who is a board member of ASHRAE’s Golden Gate Chapter and an associate principal at San Francisco engineering firm Point Energy Innovations, has not seen a surge in the HVAC business since the pandemic broke out.
“The problem is, no one goes into the offices,” she said, which means that some customers think they can delay improvement. Still, Falconer said of the pandemic: “everybody immediately became an indoor air quality specialist, which is kind of funny. It’s interesting to explain to someone like my mother what a MERV filter is. “
Craig Lichtle of Legacy Mechanical and Energy Services fits and repairs various elements of an HVAC system on the roof of ACT’s Geary Theater. Photo: Jessica Christian / Die Chronik
In many entertainment venues, high ceilings can be a virtue, but the tight seating of theaters, lecture halls, and stadiums means that HVAC interventions can do only limited things in preventing the spread of COVID-19. Vaccinations and masking are still important.
“You can have amazing airflow and someone right next to you coughs in your face,” Suidan suggested. “(The HVAC) doesn’t matter. You won’t be able to construct that away. “
That doesn’t mean 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, professor of architectural engineering at Penn State and Chair of the ASHRAE Pandemic Task Force.
“We know that poorly ventilated facilities and those with no other means of purifying the air were places where infections were piled and super-spreading events,” he said. “We know more about what isn’t working than how well things actually work, and that’s a difficult concept to convey.”
Stephen Curry of the Warriors throws a pass to a teammate at the Chase Center in San Francisco during the game against the Minnesota Timberwolves. Photo: Scott Strazzante / The Chronicle
Venues also have other industry-specific concerns.
The Chase Center, which opened in September 2019 with a sold out concert by Metallica and the San Francisco Symphony, has much larger HVAC capacity than many older performing arts venues. The system has 16 air handling units that regulate and circulate the air; 12 smaller ones the size and shape of a truck box trailer, approximately 20 feet deep; and four larger ones for the bowl that could fit several San Francisco apartments. In contrast, ACT’s Geary Theater has six air handling units, and its largest is about the size of one of the smaller ones in the Chase Center.
But the home of the Golden State Warriors still has its limits.
“Steph Curry doesn’t want to face headwinds,” said Ian McDoom, director of engineering at Chase. For the comfort of guests and talents, the center not only has to keep the temperature between 65 and 72 degrees, but also keep the relative humidity below 55%, otherwise the wooden floorboards of the basketball court could warp.
Chase Center can be seen ahead of a game between the Warriors and the Pelicans in November. Photo: Santiago Mejia / The Chronicle
McDoom’s job was to purge the air in the facility, which occupies just over 1 million square feet, at least four times an hour with 100% outside air. Achieving this, he estimates, has seen the arena’s electricity bills rise 10%, although pre-pandemic comparisons are difficult for the young establishment.
For Bahnfleth, pandemic-era upgrades could have the benefit of fueling longer-term HVAC goals from industry experts. He belongs to a group of proponents who have campaigned for better indoor air standards for decades.
“We have long known that buildings with higher ventilation rates, ie lower indoor concentrations of pollutants, are generally prone to fewer symptoms of sick building syndrome,” he said, referring to the well-documented phenomenon of poor ventilation in offices and schools cause a variety of health problems, including headaches, fatigue, and respiratory, skin, and gastrointestinal problems. Well-ventilated buildings, he said, “have a positive effect on student learning, higher work productivity. The economic impact of this amounts to hundreds of billions of dollars a year in the US, but has long fallen on deaf ears. “
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 / Die Chronik
His hope, he said, is that “the desire to do something about diseases like the COVID epidemic or seasonal influenza” can inspire action to “raise indoor air quality standards.” He noted that pre-pandemic standards focused on diseases and odors.
“This is a different approach than saying that we want indoor air quality that promotes the highest levels of productivity and cognitive function, and reduces other types of disease.”