KRUEGER RadiaFlo Indoor Firing Range User Guide
- July 18, 2024
- KRUEGER
Table of Contents
APPLICATION GUIDE
AIR DISTRIBUTION
DESIGN FOR IN AN
INDOOR FIRING RANGE
RadiaFlo Indoor Firing Range
There are over 16,000 firing ranges in the US, making them a surprisingly
common structure. By the nature of the application, safety is critical, and it
extends beyond that of the firearms. It includes the air distribution system,
which must provide a safe atmosphere for both employees and patrons.
The average indoor firing range consists of a long rectangular space, where
only a small section is occupied. This is known as the bay.
The rest of the space is reserved for the tacticalrange and bullet trap, both
of which are prespecified distances or lengths. (Figure 1)
A major risk factor with
this type of application is lead build-up. This is due to the constant
discharge of lead dust particles within an enclosed space. Over time, it can
become increasingly hazardous for occupants, which is why it is so important
that these contaminants be forced away from the occupied area.
While contaminant control is a priority, occupant comfort must also be
considered. According to ASHRAE 55 ADPI requirements, the temperature should
be within a range (-3°F to +2°F) of the room setpoint and the air velocity
should be less than 70 fpm. Following these guidelines will help ensure that
over 80% of occupants in the space are comfortable and that productivity and
efficiency are maximized.
In terms of supply air distribution design, the goal is to provide clean,
comfortable air directly into the occupied zone and disperse contaminants away
from the occupants with minimal disturbance to the bay or tactical range.
While this can be achieved a few ways, we believe radial diffusers would be
ideal. Not only are these products able to handle large volumes of air, but
they are designed to minimize air speed while radially pushing contaminants in
a uniform, outward motion. (Figure 2)
Krueger offers two radial flow products, the RadiaFlo and the TAD. While both
diffusers provide a true 90° or 180° radial airflow pattern and have various
material and filter options, they do have their differences. The RadiaFlo is a
flush face design that is perfect for an application with limited space. The
TAD has a patented drop face design, which allows it to perform exceptionally
well, even with poor inlet conditions. (Figure 3)
To further illustrate the application, we have provided a few jobsite photos
of TAD units, which were positioned at an angle in the back of the bay of a
newly constructed firing range. (Figure 4)
In terms of exhausting air, the
location and quantity of return devices are important. To properly remove
airborne particulates and excess heat, return grilles must be placed across
the tactical range in larger quantities to prevent lead build-up within the
space and provide a safe area for employees to clean or perform maintenance.
Exhaust fans are also recommended near the backstop of the tactical range to
create negative pressure within the room by pulling the contaminated air
further from the occupied zone. The addition of a filter frame and filter with
the return grilles is also recommended to ensure any air that may be
recirculated into the space is cleansed prior to reentry into the occupied
zone. According to ASHRAE standard 52.2, lead dust requires a MERV 11 filter
to properly ensure that lead particles are not penetrating through the filter
back into the plenum space or ductwork.
Depending on the design requirements, Krueger offers several return grilles
from which to choose, both in fixed blade styles, such as the S80, S580, S85,
and S585 as well as in perforated styles, like the S80P and S580P. There are
also options for stainless steel construction with the 9S80HF or heavy-duty
construction with the S480 or S5480. Each of these models would work in a
firing range application, so the selection would be more dependent upon the
level of aesthetics or rust resistance needed.
Last but not least, we need to address terminal unit selection, specifically
the units that are upstream of the radial diffusers supplying the bay, as that
area will require its own set of airflow and temperature requirements in order
to create a safe environment.
Most bays have no noise level requirements and are located within an interior
zone (15’ from a perimeter wall), so the terminal unit would need to only
provide cooling and airflow control. The most economical and efficient product
to do this would be a single duct terminal unit. Krueger offers a couple of
single duct options, the most common being the LMHS, which is able to meet the
necessary maximum, minimum, and turndown airflow requirements. This is not to
say that a fan powered box could not be used, but the additional cost would
likely outweigh any benefits over a single duct design. (Figure 5)
In summary, when it comes to a firing range application, the specifics of the
design can make or break the long-term efficiency and viability of the
building. The combination of radial flow diffusers, filtered returns, and
single duct terminal units will optimize the indoor air quality and thermal
comfort of this application.
For design assistance or to learn more about the products mentioned, reach out
to your local Krueger Representative or visit us on the web at www.krueger-
hvac.com.
www.krueger-hvac.com
972.680.9136
kruegerinfo@krueger-hvac.com