How the pandemic changed thinking on fab shop ventilation

Not too many people are interested in working in a dusty or hazy factory. The pandemic only reinforced people’s interest in indoor clean air. Aerogondo/iStock/Getty Images Plus

People are breathing easier now that COVID-19 vaccines have been developed, and life has returned to a more familiar pre-pandemic routine. But that doesn’t mean they’ve totally forgotten what’s been learned over the past two years.

One of the most important lessons is that a lack of indoor air circulation can lead to a greater potential of exposure to pollutants or contaminants, including viruses. Proper ventilation, particularly with outside air, can reduce the concentration of airborne contaminants and even the likelihood of surface contamination because particles are removed from the air before falling on surfaces.

While proper indoor ventilation is always better than a stagnant indoor environment, this doesn’t greatly reduce the chance of transmitting something like a respiratory particle that contains the COVID-19 virus. In fact, the Center for Disease Control and Prevention states: “Indoor spaces are more risky than outdoor spaces where it might be harder to keep people apart and there’s less ventilation.”

From a manufacturer’s perspective, this might be looked upon as good news. Proper ventilation is encouraged and required to meet OSHA regulations, but nothing more is expected as it relates to battling COVID-19 or other viruses for that matter. Technically that’s correct, but it’s misleading. The FABRICATOR spoke with Chrissy Klocker, an applications engineering manager, Donaldson Co. Inc., to explore how the pandemic definitely has changed the way people are thinking about indoor air quality in manufacturing settings.

The Indirect Effect

Because of the current state of the economy where everyone seems to be looking for employees, manufacturers are faced with the reality that it’s a job seeker’s market. Employees are in positions where they are dictating the types of environments in which they want to work, and they aren’t interested in working in a shop with dirty work surfaces and a constant haze hanging in the air, Klocker said.

“If a person has the choice to work for Company A, which offers more money to work in a dirty shop, or Company B, which offers slightly less money to work in a properly ventilated and clean environment, he or she is going to choose the latter,” she said. People can be more picky in an employer, and that’s forced manufacturers to meet the demands for cleaner indoor air.

The good news is that manufacturers are showing interest in doing just that. COVID-19 caused the world to shut down for a time, but as everyone learned to live with the virus, consumer demand roared back, causing manufacturers to ramp up quickly. And they’ve stayed busy for the past couple of years, providing them the desire and resources to invest in systems to improve indoor air quality.

But before manufacturing companies set forth on a path to create a cleaner work environment for its current and future employees, Klocker said they should understand what sort of systems they have, what they want to accomplish, and what steps they need to take to accomplish the goal.

What Does the Current Ventilation/Filtration System Do?

If a manufacturer has thermal cutting or welding capabilities, it probably has some sort of ventilation/filtration system. That leads to the important question: Is the system that was set up for specific reasons still able to accomplish the same goal? Change is inevitable, but if an indoor air treatment system hasn’t changed with shop floor activities, it is likely not performing as effectively as it should, according to Klocker.

In the most basic sense, this can be observed in manufacturing settings where thermal cutting operations have evolved without the consideration to adjust particulate capture at the source. As an example, Klocker said the presence or lack of a presence of haze tells the story.

A well-designed hood capturing dust and debris at the source is the best option to prevent contaminants from leaving the work area.

Oils often are found on metals, and a thermal cutting process like plasma cutting can turn those oils into airborne particulates. If they are not captured at the cutting source, they can become dispersed in the indoor air environment and create a haze that automatically reminds people of the dirty and grimy factories of the early 20th century.

“Relying on general air movement and forced ventilation simply isn’t going to clear that particulate from the indoor environment. For the haze to be eliminated, the particulate needs to be captured at the source,” Klocker said.

From a broader perspective, the ventilation system’s performance can be affected by the simple addition of a backup filter. Klocker said this was the case during the pandemic as people added HEPA filters to their ventilation system as an added layer of security. In some case, the end result, however, was an ineffective dust and contaminant collection system.

The basic premise of a ventilation system is for air to be pulled from one point to another. The air velocity is optimized so that the flow of the air—and contaminants with it—can flow through the filters, where the contaminants are captured.

When an extra set of filters of any kind are added to the ventilation system and the air flow is not adjusted, the system can’t pull enough air, causing the dust and contaminants to escape. The false sense of security that HEPA filters might deliver is accompanied by the fact that the main dust collection system might not work as intended. Unless a company understands the impact of that change, it could be doing something worse than they intended to do originally.

To reinforce the idea of just how important air flow is in a manufacturing facility, consider the basic practice of shops opening their bay doors on beautiful spring or summer days.

“The amount of air movement introduced by those open doors is incredible, keeping the particulate from concentrating. It’s akin to being outside,” Klocker said. “On the other hand, anywhere that stale or stagnant air is the norm is a place where particulates could concentrate in the air.”

What’s Next?

Once a manufacturer conducts a survey of their existing ventilation equipment and how it might be working, it can focus on any potential improvements or changes. Klocker said some of the questions that a manufacturer wants to ask include:

• What areas in the facility need addressing?
• What’s the contaminant that needs to be captured?
• What are the steps necessary to accomplish the task and keep meeting system performance expectations?

A company might have an idea of the contaminant it wants to address, or a test might be required to define just what particulates are floating around in the facility.

For example, hexavalent chromium, also identified as Cr(VI), is a toxic compound that is released during the cutting and welding of stainless steel and other nickel alloy metals. When Cr(VI) contaminants are inhaled, absorbed, or ingested, the toxins target certain human organs, including the lungs, liver, and kidneys. Workers exposed to Cr(VI) can experience symptoms such as sinus irritation, nosebleeds, ulcers, wheezing, and shortness of breath.

OSHA has defined two levels of exposure for Cr(VI): a permissible exposure limit (PEL) and an action level (AL). The current PEL for Cr(VI) is 5 µg/m³ for a single employee over an eight-hour shift. This PEL of 5 µg/m³ was reduced from the previous standard of 52 µg/m³.

The second exposure limit, AL, currently is 2.5 µg/m³. This is the concentration of airborne Cr(VI) present in a work environment and calculated as an eight-hour, time-weighted average (TWA). At either of these levels, employers are required to take specific actions, and failure to do so may result in penalties.

If Cr(VI) is present in the air of the manufacturing facility, it has to do the following:

• Implement air sampling
• Conduct medical monitoring and provide employee notification of monitoring results
• Implement engineering controls
• Adopt respiratory protection program
• Demarcate work areas containing Cr(VI)
• Execute an employee training program
• Provide OSHA regulations and company policy to employees

Tracking Cr(VI) is serious business. The frequency of air sampling a company must do depends on what level of Cr(VI) was discovered in the facility. If the area tests above the PEL of 5 µg/m³, testing has to be done every three months. If the area is above the AL of 2.5 µg/m³ but below the PEL, then a company is only required to do air sampling every six months. If the area is below the AL, the company is required to record an initial baseline, and then it is left up to the facility hygienists to decide on a sampling frequency. Sampling yearly is a typical strategy in this case.

“With a clear understanding of the contaminants that need to be addressed and what current equipment is in place, a manufacturer can begin to figure out what equipment strategy makes sense for the task,” Klocker said.

For instance, collection equipment using cartridges with pleated filters often are desired because the filters are easy to change and provide maximum particle-holding capacity in a compact footprint.

There is also the question of location, Klocker added. If a company decides to collect contaminants at the generation source, it might want to use a point-of-use layout where one collector is connected to one welding operation or station. Because each welding point has its own extractor, it’s smart to select an extractor with a small footprint that can be placed directly adjacent or close to each workstation.

In other shops, however, it might work best to use a centralized strategy. In these installations, one collector serves multiple workstations, and the stations are connected to the extractor through a network of ducts. In these layouts, the centralized collector is typically located some distance away from the welding points and might be a good option if floor space is limited near the welding.

Investing for the Future

Installing or modernizing shop ventilation systems is a large investment and one that takes plenty of planning and time for implementation. It’s no wonder manufacturing companies might be hesitant to dedicate resources to such an effort, particularly given the current robust manufacturing economy in North America.

But today’s workers have different expectations than previous generations. If the manufacturing company wants to sell itself to potential employees based on its cutting-edge equipment and exciting career opportunities, it needs to provide clean and modern work environments too. There is no room for dust and haze.

“If a manufacturing company improves the work environment, employees are going to be happier and likely more productive,” Klocker said.

That’s a recipe for retaining current employees and welcoming new ones into the fold.