This briefing explains the need for hearing protection and familiarizes users with various types.
Workers need to use hearing protection when job-site noise level is hazardous. This raises questions such as, what protective devices do I use? Will it interfere with normal hearing at the site? Will I be able to hear warning sounds, backup beeps or even normal conversation? Hearing protection reduces noise levels, but only by the level indicated on the device. If you select the proper device, you will be protected and still able to hear critical sounds.
Sound is measured in decibels. Each hearing protection device has a Noise Reduction Rating (NRR) in decibels (dB). To ensure you are not exposed to noise over the maximum safe exposure (85 dB over 8 hours), the NRR of the hearing protection device is matched with your level of exposure (loudness and duration of exposure).
For example, if you are exposed to 90 dB of noise and wearing earplugs with an NRR of 29, your actual noise exposure will only be 61 dB. Alarms are required to be louder than ambient or surrounding noises and typically range from 90–110 dB. This is well within the range of hearing, even with the protection. Some alarms even adjust according to the ambient noise to ensure they are 10 dB higher. Some protective devices also adjust according to ambient noises. If you need to hear subtle changes in the sound of machinery, this kind of device can amplify the low-level noises while decreasing dangerous noise levels.
Since all types of hearing protection have an NRR rating, selecting the style is about comfort and ease of use. The basic types are:
- Expandable foam plugs
- Premolded, reusable plugs
- Canal caps
Expandable foam plugs are made of a formable material that fits to the shape of a person’s ear. To fit properly, the plug must be rolled until it is thin enough to fit halfway into the ear canal. The main drawback is that it’s difficult to roll the plugs small enough to make them fit. A few manufacturers offer a small expandable plug.
Premolded plugs can be made of silicon, plastic or rubber, and come in a variety of sizes. Although typically sold as pairs, you may need a different size plug for each ear to get the proper fit. Plugs should seal the ear canal without being uncomfortable. The main advantages are that they are relatively inexpensive, washable, reusable and come in many sizes. They also reduce sound more evenly than expandable foam plugs.
Canal caps consist of flexible tips (similar to premolded plugs) on a lightweight headband. The main advantage to canal caps is that they are quick to put on and take off and easy to store around the neck. This makes them ideal for intermittent use. However, they provide less protection than either plugs or earmuffs.
Earmuffs have rigid cups with soft plastic cushions that seal around the ear to block noise. Easy to use, they block out noise by completely covering the outer ear. Some styles adjust to job-site noise. They are expensive, but worth it, if necessary. Some users find earmuffs hot and heavy in certain environments. They also don’t work as well for those with heavy beards, sideburns or glasses, which may break the seal of the earmuffs and allow noise in.
Discuss hearing protection options with your supervisor. They will work with you to select the type that best suits you and the tasks you have to perform. Knowing the pros and cons of what is available, as discussed here, should be helpful.