Post-Covid Systems Adapt to Maximize Air Quality


Advances and adaptations in mechanical systems that regulate air flow and quality continue to evolve since the outbreak of the coronavirus.

As professionals continue returning to the office – at least for some of their work week – those responsible for ensuring optimal air quality in these environments are increasingly choosing to upgrade their air filtration systems to trap as many troublesome particles as possible before they reach the workspace.

“At the start of the pandemic in Spring 2020, some cities and states such as New York (state) mandated the use of higher-grade air filters,” says Chris Currie, vice president at Charles E. Jarrell Contracting Company Inc. “New York’s governor required shopping malls to upgrade to MERV-13 (Minimum Efficiency Reporting Value) filters as a condition of reopening. As guidance rather than a mandate, the Centers for Disease Control and Prevention recommended that all businesses improve their central air filtration systems with MERV-13 filters.”

Over the past two years in particular, mechanical contractors nationwide have been busy engineering modifications to air handling systems that allow for a higher-rated MERV filter, according to Currie, although obtaining the necessary materials remains a challenge.

“The higher the MERV rating, the higher the pressure drop,” he says. “Fan motors must have enough surplus capacity to handle this pressure drop. Thus, we’re continuing to see clients updating their commercial HVAC (heating, ventilating and air conditioning) systems, but oversized systems, their parts and pieces are hard to come by.”

Bipolar ionization is another technology that aids building owners in maintaining healthy levels of air quality. Currie says the concept behind BPI involves introducing electrical probes into the supply and/or return airstream so that any microparticles floating past these charged electrodes will adopt the probe’s positive or negative charges. Then as the particles become charged, they stick to each other. The larger collective particle, comprised of individual particles that glom together, either drops out of the air or is filtered by a lower-grade MERV filter.

“Bipolar ionization has been around for 20 years,” he says, “but now it has broader application.”

Specialized Engineering Solutions Associate Principal Scott Winfrey says making sure a facility is designed with enough fan-handling units to support the usage of upgraded HEPA (high-efficiency particulate absorbing) filters is critical.

“Another option is to install HEPA racks that you do not intend to use in air handlers under normal operations, and only use the HEPA filters in a pandemic situation,” says Winfrey. “Consider engineering your air handling units to handle dual conditions for heating and cooling coils … minimum outside air intake for normal conditions, and 100 percent outside air for pandemic and emergency conditions.”

The use of high-intensity ultraviolet (UV) lights or other similar air treatment systems at the cooling coils, Winfrey adds, can help keep coils clean but are also effective in killing a high percentage of virus particles passing through the air handling unit.

“The pandemic has taught us the impact of HVAC systems in keeping occupants safe and designing flexibility into spaces,” he says.

U.S. Construction Adds 11,000 Jobs in July, Nonresidential Still Far Below Pre-Pandemic Levels


Construction employment – both nonresidential and residential – totaled 7.42 million as of July 31, an increase of 1.5 percent over June, but the lion’s share of that gain came from hiring in the residential sector.

AGC of America Chief Economist Ken Simonson said soaring materials costs, long or uncertain delivery times and hesitancy by nonresidential project owners to commit to construction are the factors contributing to a still-stalled pace of commercial construction across the U.S.

The numbers hail from an August 6 government data analysis by the AGC.

“Recovery has been especially slow in infrastructure construction,” Simonson said.

Construction employment in July represented a gain of 11,000 jobs following three months of job losses, according to Simonson, however the rebound was limited to residential and specialty trade contractors. Nonresidential building and infrastructure construction firms continued to lose workers.

Residential building contractors including single-family homebuilders added 8,399 employees in July, while employment was unchanged among residential specialty trade contractors. Simonson said the two residential segments have added a total of 58,500 employees, or 2.0 percent, to their workforce nationwide since February 2020.

In contrast, nonresidential building contractors shed 2,500 employees in July. Employment declined by 2,100 among heavy and civil engineering construction firms, the segment most connected with building and rehabbing infrastructure. Nonresidential specialty trade contractors added 7,500 employees last month.

Following the huge loss of jobs between February and April 2020 at the start of the pandemic, infrastructure-centric contractors have added back only 37 percent of lost jobs. According to the AGC analysis, nonresidential building and specialty trade contractors have each regained about 60 percent of lost workers, while the total nonfarm payroll economy has recouped 75 percent of workers.

“There are an unprecedented number of construction material price increases,” said Simonson. “The problems of these extreme price increases and long lead times for production or delivery to project sites mean fewer construction workers are being employed. Some owners are delaying project starts, adding to the drag on industry employment.”