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Noise  Reduction Strategies  for

Modern  Ranges

 By Tony L. Jones

As expanding communities continue to encroach upon rural shooting ranges, solutions to the problem of noise must be found.

   Remote areas that are suitable for firing ranges are becoming rare, especially around large population centers. Indeed, expanding communities are encroaching on shooting ranges which, a number of years ago, were out in rural areas. It’s no surprise, then, that sound or noise is probably the most common source of complaints concerning shooting ranges from the community at large. Noise is sometimes defined as sound that is too loud, unexpected, uncontrollable, disagreeable, unwanted, annoying, generally irritating, or occurs at the wrong times.

Government Guidelines

Noise from a variety of sources has been found to reduce the quality of life to the point that state and local laws have been enacted which place an emphasis on community noise from industrial and recreational activities. While some of these laws include definite methods for measuring sound, and clearly define acceptable levels, others are very vague. Additionally, agencies that range owners may have to address include the U.S. Department of Housing and Urban Development (HUD) and the Environmental Protection Agency (EPA). Both of these agencies have developed “impulsive sound” guidelines focusing on a day-night average sound level that must be met under all circumstances. It is very important for range developers/operators to become familiar with all of the requirements and restrictions of laws applicable to their facility. Thus, the recognition of sound and how it affects the public has prompted range developers/operators to address this issue.

Anatomy of Gunshot Noise

Each gunshot normally results in two distinct noise events consisting of a muzzle blast and a supersonic projectile shock wave. This noise event is sometimes called a “crack and thump.” The muzzle blast originates at the end of the muzzle and propagates spherically in all directions. Further, muzzle blast is directional, being louder in front of the gun compared to behind. The projectile sound is emitted all along the projectile path and continues to travel supersonically for long distances. Any firearm projectile whose velocity is over 1080 feet per second is traveling faster than the speed of sound and will often create a “mini-sonic boom.”

Proactive Solutions

Range operators should be proactive in assessing potential problems before   they impact their facility. Firearms ranges produce high levels of sound and sound waves often travel far beyond the boundaries of the range property. These escaping sound waves may be perceived as unwanted community noise by neighboring property owners. Numerous noise reduction solutions exist; however, they vary in effectiveness. Thus, site specific solutions should be chosen. For example, it may be in the best interest of range owners to work with the local zoning board and designate the       facility as a noise park. This designation may make the range more visible to zoning planners and developers prior to the actual development of neighboring properties.

Range owners should also implement noise reduction programs. These programs should actively pursue the goal of preventing conflict before it occurs and may include the services of an acoustical consultant. Regardless, sound levels should be measured at the property lines during normal operating times. The findings should be documented and evaluated to determine if the range satisfies local sound laws. Of course, these findings may also be used as a baseline comparison as changes are made to, and around, the range.

Sound usually travels from the source to the receiver via multiple paths known as direct and reflected paths. Sound levels can be significantly reduced by blocking, diffracting, refracting, and/or otherwise bending sound waves. These effects may be produced by installing back walls, side walls, and firing line covers complete with insulation material. Note: These structures should be made of a full wooden shingle type construction, since other construction materials are likely to ring when   “excited.” The effect of enclosing a firing line in this manner is to direct the sound of the firearm in a forward direction and away from noise sensitive areas.

Natural Barriers

Natural barriers such as trees and vegetation (shrubs, undergrowth, grasses, etc.) are often effective in reducing noise by providing interference between direct and reflected sound waves. Planting should be dense to form a natural barrier. Branches and trunks provide sound scattering: High frequencies are absorbed by foliage and tree spacing, and low frequencies are absorbed by ground vegetation. Furthermore, barriers located close to the source will generate maximum effectiveness.

Backstops and berms located in conjunction with significant land features such as mountains or large hills are often very effective in reducing noise. Backstops and berms bend lower frequencies, reflect higher frequencies, and diffract both frequencies into shadow zones (the area located directly behind the barrier/berm). Typically, barrier/berm(s) should be more wide than high and are more effective the closer they are to the source or receiver.  Also, increased mass increases effectiveness and there should be no openings included in the barrier.

Baffles

Baffle systems are also effective in reducing noise. Effective baffles reflect sound upward into absorbing surfaces several times before    the originating sound is reflected back to the shooter. Some baffle  systems cause a 50% loss in loudness. Tube ranges are another solution. Tube ranges require a shooter to fire from a fixed position, usually from a bench. The muzzle is enclosed and muzzle blast is reduced in many directions. However, the projectile will still generate noise. Generally, tube ranges will not benefit law enforcement officers who must shoot from a variety of positions and during movement.

Administrative Control

Of course, some administrative rules may be adopted for sound abatement purposes. For example, “quiet hours” may be established. Quiet hours may be designated which forbid the firing of weapons during certain hours considered to be disruptive to the quality of life of the surrounding community; for example, 11:00 p.m. to 6:00 a.m. Additional quiet hours may preclude firing weapons on holidays and/or Sundays. Quiet hours may be further extended to comply with existing noise ordinances. Of course, quiet hours may cause a problem for most departments who require dim light/no light qualifications or those who use tactical lighting systems (night vision equipment, invisible lasers, thermal imagers, etc.) during qualifications. Additional administrative controls may focus on the specific use of certain types of weapons and ammunition.

Effective Public Relations

Another good preventative step includes the development of a public relations effort designed to cultivate goodwill with neighboring residents and landowners. This effort should include a complaint management procedure; sensitivity to the community’s concerns; and identifying a procedure to notify the public of particularly noisy events in advance. When handling noise complaints, officials should focus on who is complaining; identify the specific complaint; and reference and/or research any existing noise ordinances, to include noting actual language and annotated exemptions. If there is no ordinance, there should be no violation of the law. However, it will normally benefit range operators to institute engineering and/or administrative solutions to address noise complaints which may generate costly public hearings and civil/criminal court processes.

Summary

In conclusion, present conditions may exclude some ranges from sound abatement concerns, but situations may rapidly change on the range or in the area surrounding the range, so some type of noise reduction plan should be developed. More often than not, good public relations with range neighbors, community leaders and the community at large is essential. Ranges operated by personnel representing agencies intent on only reacting to a problem (informal and/or formal complaint) after it transpires are likely to see their range shut down and are probably headed for additional legal action.

About the Author: Tony Jones is the owner of a training company called Sheriffs’ Training Services, specializing in law enforcement, corrections, and private security courses. To date, he has provided tactical/security consulting and training to a variety of private and government agencies. Additionally, he is a published author who has written six books and more than 100 magazine articles and holds a master’s degree in management.

Tony has more than 14 years of experience in SWAT operations and nuclear security and 24 years of military service. He is a certified training instructor in a number of subjects. He can be reached at Sheriffs’ Training Services, PO Box 370, Piketon, OH 45661; phone (740)941-0900, or fax (740)941-0800.