s most operators know all too well, indoor swimming pools don’t always have the best acoustics. Some might even say they’re downright loud.
“How many times have you gone to an indoor pool and not understood a word anyone is saying?” says Larry Raffaelli, a veteran pool engineer and owner of Raffaelli Engineering in Rocky Hill, N.J.
A big reason for all the noise is that pool environments demand hard, readily cleanable surfaces, impervious to water or chemical attack. Such surfaces cause sound waves to bounce around the natatorium like rubber balls, creating a noisy echo effect.
But operators and their employees are beginning to discover that the noise is more than just a nuisance.
Put simply, lifeguards who can’t hear over the noise also can’t hear calls for help.
In addition, an extremely noisy environment can be a health hazard for aquatics professionals themselves. Water aerobics instructors, who must scream over the din, can damage their vocal chords. Lifeguards, who must endure the constant clamor, can damage their hearing.
A recent summary of a dozen indoor aquatics facilities assessed by the Professional Aquatic Consultants International for various insurance companies shows why this hazard exists. Sound readings were taken on the decks of the pools during both lap and recreational swims. The results suggest that the aquatics industry has a serious problem on its hands when it comes to indoor noise.
What is too loud?
Sound was measured with a commercial sound meter and recorded in decibels (a unit of measurement for sound) at 12 different aquatics facilities. The average sound levels during lap swims was found to be 79.75 decibels (dB) and the average sound levels during recreational swims was 92.18 dB. The lowest levels were recorded during a lap swim, at 68 dB. (To see how indoor pools compared to other sounds, click here.)
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7 Signs you have a noise problem
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When should poor acoustics become a concern for you, your employees and your patrons? Watch for these seven signs:
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1
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Casual conversations, when in close proximity to a coworker, cannot easily take place without raising your voices.
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2
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Emergency communication (whistle signals, emergency instructions and emergency
responses) is hampered by the poor acoustics.
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3
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Fitness participants, swim lesson students or athletes cannot hear and understand the directions of the instructors or coaches.
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4
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The sounds in the natatorium after a long shift hurt the ears of the employees — employees experience a “ringing in the ears” when leaving work.
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5
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The PA system or sound system is inaudible and music lyrics cannot be easily understood.
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6
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White noise from the HVAC system drowns out the sounds of the PA system, normal conversation and emergency communication.
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7
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A reported occupational hearing loss by one or more of your employees.
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If any or all of the above are a concern, your work environment may need to be tested.
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— K.J.
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To give you some perspective on those sound levels, the Occupational Safety and Health Administration Noise Exposure Standard requires personal protective equipment (ear plugs/ear muffs) at sound levels of 90 dB or higher for a four-hour exposure. At dB of 85 for an eight-hour exposure, OSHA requires action level implementation of a hearing conservation program. This includes scheduling changes to reduce the exposure to noise, as well as continued monitoring of the problem.
Based on our measurements, the aquatics industry may have a serious problem. Ten of the 12 facilities measured 85 dB or higher during recreational swims. Five of the 12 facilities (42 percent) exceeded the OSHA standard of 90 dB during recreational swims; three of 12 facilities (25 percent) exceeded it during lap swim.
Two facilities exceeded the 100 dB mark. One of the air-supported structures measured more than 100 dB with no bathers or activities taking place in the pool area. The highest readings were recorded during a recreational swim at 146.2 dB — louder than a jet airplane.
In extremely noisy work environments that exceed 100 dB, OSHA requires double ear protection (ear plugs and ear muffs). The standard requires an employer to determine if there is an occupational noise hazard and to implement a hearing conservation program when an employee’s overexposure is identified.
Indoor acoustics
Much can be done to combat this noisy problem, but it helps to understand the reasons for it. One of the biggest reasons for the noise is that sound travels quite well over water. The most common traditional indoor pools are rectangular and the surrounding structure mirrors this shape. This design creates an excellent echo chamber.
These reverberations or echoes are measured in terms of seconds in a natatorium. A pool that is well-designed acoustically will have a “reverb” time of 1.5 seconds or less. But some facility designs may cause reverb times as long as 15 seconds, explains Raffaelli.
“This would allow the echoes to override any instructional programs, background music or safety announcements. Such reverbs would make any sound difficult to interpret, much less comprehend or respond to,” he says.
Another part of the problem is that common building materials that are resilient to the humid indoor pool air and water are not the best acoustical choice. Most pool decks (usually tile and/or concrete surfaces), windows (glass), and walls (drywall, concrete block, tile or plaster) provide little acoustical dampening.
“The need to use hard, waterproof materials, including the sound-reflecting surface of the pools themselves, create acoustical problems, which must be resolved through thoughtful architectural design,” says Rob Curry, principal architect at Yost Grube Hall in Portland, Ore.
In addition, a tremendous amount of white noise (referred to as background noise) exists in pool areas: water moving and falling into the gutter system, HVAC systems, fans, motors, and music. Now add 50 to 100 screaming kids into the mix, and you’ve got the recipe for a serious noise problem. So unless noise control was a consideration at the front end of the pool’s design, most pools are acoustically poor at best.
Like the echoing noise, the problems that result are many. Lifeguards may not be as effective if rule enforcement capabilities or emergency communication is hampered by poor acoustics.
“Lifeguards are taught to recognize an emergency by hearing and seeing the situation. Increased noise levels are impeding the lifeguard’s ability to recognize and react to most emergencies,” warns Dawn Bargeron, former aquatic director at the Florida State University in Tallahassee, Fla.
Noisy environments also are known to increase work place stress and decrease work level satisfaction. Employees with long shifts and those working full time in loud environments may have the most to lose — their hearing.
For the pump room operator who is stepping into a noisy pump room, requiring hearing protection makes sense. Wave machines can easily exceed 115dB within the equipment room, making ear protection a requirement.
But for the aquatics staff, ear protection is impractical. Providing a long-term solution by solving the acoustical deficiencies is truly your only alternative.
Sound solutions
Fortunately, there are a number of solutions available to remedy poor acoustics. These solutions include sound panels, baffles, banners, fabric, suspended ceilings, clouds and acoustical decking. Sound panels usually are rigid panels mounted on the walls or ceiling that allow the sound to be dampened behind the panels. Softer materials such as cloth banners or fabric can effectively improve the situation.
“The acoustical designer sometimes must revise the pool architectural design to ‘soften’ the surfaces either by adding cavities to the space (i.e., additional room openings) or by providing ‘soft’ surfaces, such as affixing materials or specially-created acoustical traps to the wall surfaces. Such special surfaces must be selectively placed to optimize their effectiveness,” Raffaelli says.
Curry adds that reducing the number of right angles can be effective, as well as canting walls inward. Suspended ceilings also are effective at combating acoustical problems, but it is necessary to use stainless steel hangers and other noncorroding hardware to prevent a future failure of the material.
Specifically-designed wall tiles can effectively stop reverberation. The face of these tiles has perforations, which have the ability to absorb sound. Sound-deadening acoustical foam is another viable option.
Whatever the solution, it’s important not to turn a deaf ear to the issue of loud indoor facilities. With more than 10 million Americans having measurable hearing losses, acoustical problems must be taken seriously. Doing so will make our aquatics facilities more inviting to patrons and noise-friendly for our employees.
