TREND IN HEARING PROTECTION TECHNOLOGY MOVING TOWARDS "SOUND MANAGEMENT"
industry expert outlines product development trends emphasizing communication and "targeted attenuation"

According to industrial audiologist Brad Witt, the days of striving to develop Hearing Protection Devices (HPDs) that could simply block the most sound are over. "Today," said Witt, who is Audiology and Regulatory Affairs Manager for the Bacou-Dalloz Hearing Safety Group, "the focus is definitely more on sound management; on attenuating the hazardous noise to a level that still allows communication and warning signal detection."

"In noise-hazardous environments, we are not trying to eliminate all sound," said Witt. "There are still sounds we want to hear, such as co-worker voices, warning signals, mobile radios, and even some machinery noise that may alert us to malfunction or maintenance needs. Wearing high-attenuation protectors without regard to communication creates a feeling of hazardous isolation, being cut off from the verbal and audible cues that keep us safe and connected with our work."

In response, Witt said, HPD manufacturers are increasingly working to develop more innovative products that protect without compromising these basic communication needs. One way this has been accomplished, according to Witt, is designing HPDs with "flatter" attenuation characteristics.

"First-generation earplugs and earmuffs were not so effective against low-frequency noise, but attenuated high-frequency noise quite easily. These ski-slope attenuation curves created a distorted sound while wearing HPDs, making speech difficult to understand."
In contrast, newer generations of hearing protectors have raised low frequency attenuation significantly, nearly matching the high-frequency attenuation. "This flatter attenuation curve creates a sound while wearing HPDs which is more natural," said Witt. "It still blocks the noise, but with less distortion of speech and warning signals. The effect is most noticeable for workers who have some existing hearing loss, even a mild loss."

Another innovative approach to managing the sound in loud environments is through sound amplification earmuffs. "How many times have we seen workers remove their earplugs to hear a radio call or lift up their earmuff to talk to a co-worker?" Witt asked. "Sound amplification earmuffs have microphones, placed directionally on the ear cups, which amplify normal sounds to a safe level while still protecting from the hazardous workplace noise. The result is that workers have more control over hearing what they need to hear, without compromising protection."

Witt predicts this trend will guide new product development for several years to come. "We are just now beginning to take full advantage of recent advances in material and manufacturing technology which make these new approaches to hearing protection possible and economically viable," he said. "This, in turn, has sparked new developments in the design of these systems so we can better control not only how much, but the manner in which sound reaches the human ear."

But new technology is not the only way safety officers are seeking to "manage" sound in their workplace environments. "One of the simplest things they can do is provide HPDs with a range of attenuation ratings (NRRs)" said Witt. "By targeting attenuation to the level of the noise heard, workers can be assured of adequate protection, while not totally blocking their ability to hear and communicate on the job."

Bacou-Dalloz Hearing Safety Group

ENERGY CHAIN AND CHAINFLEX CABLES

provide solutions in the baking industry

Igus® Inc. has been providing Weldon Solutions with plastic machinery components for over 10 years. Weldon Solutions use Energy Chain® and Chainflex cables on a wide-array of Weldon products.

One component that incorporates both igus lines is used in the baking industry. Emtrol automated pan storage systems, manufactured by Weldon, are a vital part of the production cycle for many bakery customers. The storage system allows pan storage and retrieval to be done with ease.

Weldon uses System E4/0 Energy Chains, along with Chainflex power and control cables on all pan storage systems. The System E4/0 is designed for heavier duty applications, making it well suited for the storage system. When the Emtrol product line was redesigned in 2000, festoon systems were replaced with Energy Chain, eliminating a number of maintenance and space issues for Weldon customers. By phasing out the festoon system, customers no longer have to worry about clearance limitations and enjoy reduced installation time.

Energy Chain also ensures a clean environment for the baked goods. With a festoon system in use, cables dangled from above, allowing any dust caught in the system to potentially fall on top of exposed food or containers. Energy Chain, however, is mounted below the pan storage system keeping unwanted dust on the floor.

Charles Gales, Automation Sales Manager of Weldon Solutions, noted the positives of using Energy Chain. "The reliability of the igus cable carrier is a big plus for our customers," he said. "The open design of the Energy Chain also works well. The chain can be easily blown out with an air hose, helping our bakery customers maintain a sanitary environment."

For the past five years, Emtrol storage/retrieval systems also have been using an Energy Chain feature called AUTO-GLIDE. With 75 to 125 feet of cable carrier on each pan storage system, AUTO-GLIDE eliminates the need for a trough.

AUTO-GLIDE incorporates a ribbed design along the inner radius of the carrier that interlocks to create integrated channels for the carrier to glide along. AUTO-GLIDE can also be equipped with a positioning guide and floor bumpers that prevent the top of the chain from derailing or misaligning.

Igus, Inc.

Canadian Industrial Equipment News April 2006

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