User:Lvolzke2/sandbox

Earmuffs:

Some passive earmuffs have an electronic component and microphones that allow the user to control their access to communication while attenuating background noise. When in loud, hazardous settings, the wearer may still be required to listen to outside sources, such as machinery work, their supervisor's commands, or talk to their colleagues. While the material and design of the muff allows for a reasonable attenuation (roughly 22 dBNRR), the user has the option to allow some sounds in that are necessary for their job. These earmuffs incorporate a volume control to increase and decrease the attenuation.

-         Passive earmuffs do not have electronic components. When earmuffs have electronic components, it becomes an active earmuff. I would add this section the active noise reduction earmuffs section.

Chester Greenwood invented the thermal earmuff in 1873, at the age of 15.[7][8] He reportedly came up with the idea while ice skating, and had his grandmother sew tufts of fur between loops of wire.[9] He was awarded patent #188,292 on March 13, 1877. He manufactured these ear protectors, providing jobs for people in the Farmington, Maine area, for nearly 60 years.[7][10] Every year, on the first Saturday of December, the town of Farmington celebrates "Chester Greenwood Day" with a variety of activities. A parade in Chester's honor is a part of the festivities. Everyone participating in the parade must wear earmuffs.[11]

-         This article is about earmuffs as hearing protection. The history of thermal earmuffs is not necessary. I would delete this section.

This single number is called the Noise Reduction Rating, or NRR. The attenuation is higher when measured in laboratory testing than worn in the field, or in real word settings

-         Real word changed to real-world.

When persons are exposed to excessively loud environments (85 dB or more), hearing protection devices are recommended to prevent noise-induced hearing loss.[13][14] Hearing protection should be worn whenever power tools, loud yard equipment, or firearms are used.

-       Any noise greater than 140 dB can cause permanent hearing loss. Firearms range from a noise level of 140 dB to 175 dB depending on the firearm type. It is recommended to use dual hearing protection (earmuffs and earplugs together) when using firearms.

-        https://www.asha.org/public/hearing/Recreational-Firearm-Noise-Exposure/

-         Exposure to loud noises damages the hair cells in the inner ear that are essential for sending neural impulses to the brain in order to perceive sounds. Loss of these hair cells leads to hearing loss that may cause speech and sounds to be muffled or distorted. Tinnitus is often associated with hearing loss; there is no cure for tinnitus.

-         http://www.wba.aplusanywhere.com/R85Content/media/video/health_as3/swfs/health_31_hearing_loss.pdf

Individuals will require earmuffs of differing sizes.[26]

-         Styles- There are different earmuff style options for HPD users. Styles include: cap-mounts for hard hats, neckbands for use with welding helmets and faceshields, folding earmuffs are meant to be portable and easy to store, and multi-position earmuffs worn in varies positions are useful for versatility to wear both earmuffs and other safety ware, such as glasses or masks. [4]

Structural transmission

Vibration of the earmuff

Exposure to high level noise (190 dB SPL) may cause the earmuff to vibrate off the external ear causing a leak which would allow hazardous exposure to dangerous levels of noise.[29] In loud enough environments, the ear canal can vibrate, causing the air trapped inside the earcup to vibrate as well. This typically only occurs with low frequency noise, but can reduce the effectiveness of the hearing protection device.[28]

-         Technology in earmuffs is developing and shows promise in reducing the effects of airflow vibrations in the ear muffs. [4]

It is possible for sound to transmit through the earmuff materials, reducing the device's effectiveness. This transmission is primarily seen above 1000 Hz.[28]

Deterioration

-         How long do ear muffs last? According to some manufacturers, ear cushions showed be replaced every 6-8 months if used regularly. If earmuffs are used very frequently then the cushion should be replaced every 3-4 months.

-         http://www.howardleight.com/hearing-protection/caremaintenance-of-earplugs-and-earmuffs

According to OSHA, hearing aids should not be used in areas with dangerous noise levels. However, OSHA allows for the professional(s) in charge of the hearing loss protection program to decide on a case-by-case basis if a worker can wear their hearing aids under an earmuff in high-level noise environments. However, workers are not permitted to wear their hearing aids (even if they are turned off) instead of using HPD.

-         Grammer correction: take out the second “however.”

Whereas, HPD that attenuate equally across the pitch range, can provide more comfort and balancing of loudness across the pitches for these individuals.

-         Highlighted correction: Individuals with hearing loss.

-Detriments to wearing earmuffs

-       Makes it difficult to communicate because it blocks speech noise which may make speech sound muffled or unintelligible.

-      It also makes it difficult to localize sound.

http://www.wba.aplusanywhere.com/R85Content/media/video/health_as3/swfs/health_31_hearing_loss.pdf

-         Noise induced hearing loss: causes and symptoms