Unless a target range is ice-cold or broiling, few shooters give a second thought to the HVAC system. But for range operators, it’s an entirely different story. As the National Shooting Sports Foundation points out, depending on their role and the design of the HVAC system, shooting range workers “may be exposed to lead daily. Short-term, low-level exposures do not usually present a significant health risk. However, consistent daily exposure has the potential, if not properly managed, to result in a lead poisoning problem.”

Mike Hansen is a long-time project manager with MILO Live—a leading designer of state-of-the-art shooting range and live-fire training systems. MILO Live has over 35 years of experience in shooting range HVAC system design, engineering, and construction. Their teams have installed hundreds of custom independent HVAC, air-handling, and ventilation systems for shooting ranges.

Hansen firmly believes that every indoor range’s HVAC system needs four key characteristics to create a safe and healthy work environment—one that reliably protects employees and visitors from the hazards of lead exposure:

1. It should be entirely independent of the building’s HVAC
2. It should always draw in clean outside air
3. It should efficiently move air downrange away from shooters and staff
4. It should exhaust air that’s not just free of extra contaminants (like lead dust) but actually cleaner than the outside air it initially brought in

#1 Ensure an Independent HVAC System

Hansen says, “The shooting range air-handling systems should be completely independent of any other buildings, rooms, control booths, classrooms, weapons cleaning rooms, or vestibules.”

If anything goes wrong, the last thing you want is to create a lead hazard in areas that you had every reason to believe were healthy and safe. MILO Live always opts for an independent HVAC system that meets OSHA, NIOSH, and EPA regulations for safety. They include these as standard on every Ready Range and design them for each of their custom indoor shooting range systems.

 

#2 Create Negative Pressure

The shooting range should always draw in clean outside air, regardless of weather, temperature, occupancy, or activity level.

The shorthand for this is “laminar supply airflow that is uniform and at the proper volume and velocity” and provides a “negative air pressure” throughout the range. To accomplish this, the designed supply air pressure inside the range is always at a fixed engineered value, and the exhaust air handler is adjustable to exhaust approximately 10% more volume than the supply air, creating a slight negative air pressure within the range and ensuring the down range laminar airflow.

“It’s just like a hospital clean room,” Hansen explains. “With a negative pressure inside the range, anyone entering or exiting the range is bringing fresh air into the range, and all air leaving the range passes through the 99.97% HEPA filtration system, then out of the range”

 

#3 Recognize the Importance of Laminar Flow

Air should always move downrange—away from the entrance, shooters, and staff—as efficiently as possible. This pattern of air movement is known as “laminar flow.”

Air with a laminar flow moves in smooth layers in one direction with no mixing or turbulence. This is important in a shooting range because lead dust tends to accumulate downrange, away from visitors and workers. You’d never want to create backdrafts or vortices that flowed downrange a distance, picking up lead dust, and then swirled back toward the room’s occupants.

“This is so important,” Hansen explains. “And it can be a challenge to accomplish, depending on material choices for the floor, ceilings or walls. We use various methods, “Radial Plenums, Registers, with Vertical and Horizontal Louvers”,  to spread the supply air into the range from the very back wall, starting eight to sixteen feet behind the shooting stalls, depending on the range design. That gives the air enough space to settle out, basically creating a cube of laminar airflow prior to reaching the shooting stalls and shooter. This ensures that all air is moving downrange past the shooter, meeting the minimum requirement of 75 cubic feet per minute past the shooter measured at one foot, three feet, and five feet off the floor. This meets the OSHA/NOSH requirement and is just the safest way to do it. We also complete a test and air balance (TAB) report and pop smoke into the range after installation is complete, so we can see how the air is moving, make minor adjustments to ensure there are no areas that can cause backflow, or are failing to flow downrange.”

 

#4 Use HEPA Filtration

Like any good neighbor, your range should return what it’s used in better shape than what it received. Exhaust air from your range should not just be free of extra contaminants (like lead dust) but actually cleaner than the outside air in general.

“That means using a HEPA filtration system,” Hansen explains. “This ensures that the air leaving the range is cleaner than the air entering the range from the outside.”

To meet U.S. Department of Energy standards, HEPA (high-efficiency particulate air) filters must remove at least 99.97 percent of airborne particles with a size of 0.3 microns. That is generally regarded as the “most penetrating particle size”—i.e., the hardest one to capture.

Importantly, this specification (capturing 99.97 percent of all particles 0.3 microns) is the worst-case performance. Particles that are larger than 0.3 microns are trapped with even higher efficiency. This is great news for range operators because lead particulate is roughly 100 times larger than a viral body. HEPA filters that can reliably capture 99.97 percent of bacteria, viruses, mold, pollen, and smoke will capture lead particles and dust at much higher rates.

 

Protecting the Health and Safety of Your Workers and Visitors

Health and safety are at the core of MILO Live range design. That starts with ballistic containment—but doesn’t end there. Every MILO Live indoor range includes integrated vertical “media-free” bullet traps and its own independent HVAC system, with downrange laminar flow and HEPA filtration. This makes it easy to meet even the most stringent workplace health and safety expectations.

Looking to build a safe and healthy shooting range? Call us today to discuss your needs and allow us to put our expertise to work for you.