Sound Advice Note 5

Requirements for hearing protection

5.1 For a device to be categorised as personal hearing protection it must be CE-marked showing it meets the relevant European Standard BS EN 352. These set criteria for a range of quality and safety aspects, such as comfort, ergonomics, provision of information, factors related to ageing, quality of production, as well as the level of sound reduction. Employers should satisfy themselves that any devices supplied to workers as personal hearing protection are CE-marked and meet the requirements of the relevant part of BS EN 352.

When should hearing protection be used?

5.2 Personal hearing protection should be used where extra protection is needed above what can be achieved using noise control, and as a short-term measure while other, more permanent solutions, technical, engineering or organisational, are being sought. Personal hearing protection should not be used as an alternative to controlling noise by technical and organisational means.

5.3 The Noise Regulations make the use of personal hearing protection compulsory for employees whose exposure to noise is likely to reach either of the upper exposure action values and for any employees working within designated areas (hearing protection zones). Where the exposure to noise is likely to reach either of the lower exposure action values but be below the upper exposure action values, the employer must provide personal hearing protection to any worker who requests it.

5.4 The use of hearing protection should not be made compulsory where the law doesn't require it. It is bad practice to have a 'blanket' approach to hearing protection; it is better to target its use and encourage people to wear it only when they need to.

Making hearing protection effective

5.5 To be of value, hearing protection needs to:

• control the risk. Choose protectors which will result in an effective personal noise exposure below 85 dB, and reduce peak noise to below 137 dB. The more protection the better, but beware of over-protection;
• not over-protect. Cutting out too much noise can cause isolation, or lead to an unwillingness to wear the protectors. Musicians may compensate by actually playing more loudly and increase their risk of playing injuries;
• reduce the noise level to no less than about 70 dB;
• be comfortable and suitable for the working environment. Consider how comfortable and hygienic the protectors are, whether they will be worn with any other protective equipment, and how the activity of the user can be accommodated;
• be properly used;
• be worn at the right time - whenever there is a noise hazard present. Workers need to be told when and where to wear hearing protection;
• be readily available to all who need it and actively supplied by the employer;
• be properly maintained, in good, clean and undamaged condition.

5.6 People using personal hearing protection should at all times be able to hear any safety alarms and warning signals such as fire alarms, evacuation alerts, reversing vehicles, stage announcements concerning strobe effects etc. Where any doubt exists about the ability of a worker to hear such warnings, alternative means of communication must be provided, for example visible lights or other methods such as vibrating pads.

How much protection?

5.7 Employers should provide protection that at least reduces the noise exposure to below 85 dB. Avoid protectors that reduce the level at the ear to below 70 dB. Employers must provide protection against impulsive noise, such as gunfire or pyrotechnic effects, sufficient to reduce the C-weighted peak sound pressure level at the ear to below the upper exposure action value of 137 dB.

5.8 For workers with variable exposures, employers should ensure that their employees have protectors adequate for the worst situation likely to be encountered, and that they know when and where to use them. It might be that using more than one type of hearing protector is an appropriate solution for people whose work varies significantly during the day or from day to day.

5.9 The Table below gives an indication of the degree of protection that is likely to be suitable for different levels of noise. It is based on the single number rating (SNR) value provided with a hearing protector. This information is intended as a guide, and will not be appropriate if there is significant low-frequency noise.

Noise level in dB	Select a protector with an SNR of:
85-90	20 or less
90-95	20-30
95-100	25-35
100-105	30 or more

5.10 Other methods of estimating the performance of hearing protection, for use where more detailed information on the character of the noise is available, are described in Part 5 of L108. A hearing protection spreadsheet is available on the HSE noise web pages.

5.11 It is important to use the right type of hearing protector and to use it whenever hearing protection is required. It is also important to realise how rapidly the upper action value can be exceeded and how hearing can be damaged in a noisy environment.

Managing hearing protection

5.12 Training should promote the use of hearing protection if it is required and management should ensure it is properly used. Hearing protectors will only provide good protection when used properly - simply handing them out is not acceptable. Consider implementing a systematic programme to:

• include the need to wear hearing protection in the safety policy;
• ensure there are adequate facilities for maintenance and storage of hearing protectors;
• put someone in authority in overall charge of issuing hearing protectors and making sure replacements are readily available;
• carry out spot checks to see that the rules are being followed and that hearing protection is being used properly;
• ensure everyone, including managers and supervisors, sets a good example and wears hearing protection at all times when in hearing protection zones;
• distribute HSE's card Protect your hearing or lose it! to remind people to wear their hearing protection.

Selecting hearing protection

5.13 Hearing protection falls into two broad categories: earplugs and earmuffs. With regard to the particular needs of workers in music and entertainment, there is a greater variety of products within the earplugs category.

5.14 Many workers in music and entertainment, such as musicians, performers and sound engineers, need to hear sounds with as little distortion or colouration as possible, especially in the higher frequencies. This can cause problems when using personal hearing protection, as conventional hearing protectors tend to reduce higher frequencies more than lower frequencies. For example, a compressible foam plug that reduces sounds in the 125 Hz range by 25 dB may reduce sounds in the 4000 Hz range by almost 40 dB.

5.15 Fortunately, hearing protection technology has developed to the point where specialised products can reduce sound levels almost equally across a broad range of frequencies. This means that the user perceives the sound as being far more natural and positive than with ordinary earplugs. These products are usually called 'flat' or 'uniform' attenuation hearing protectors. They come in both earplug and earmuff types. These protectors have been found helpful where there is a particular need for verbal communication, such as for bar staff.

5.16 When there is no concern about sound quality, hearing protection can generally be both simple and inexpensive, and where the appearance of hearing protection is less important, there is a wider range of choice.

Consultation

5.17 The selection process should take account of consultation with employees or their representatives.

Medical disorders

5.18 Before selecting hearing protection, find out whether the user has any medical disorder such as earache and irritation of the ear canal that could influence the selection. Where employees have any such disorders, employers should seek medical advice as to the suitability of hearing protection.

Wind and brass players

5.19 When blowing their instruments, wind and brass players experience their own sound aurally, but also via the skull-bones conducting the vibrations from the instrument to the ears, as they play. Using earplugs can affect this balance as the musician's ear hears less treble sound while experiencing more bass sound via bone conduction. The bass-treble distortion can be extreme. This will be strange for the player, can take some time to get used to and will vary from one individual to another.

5.20 Ordinary compressible earplugs are generally unsuitable for players of reeded woodwind and brass instruments because of the occlusion effect (singers also find compressible earplugs make the voice sound strange). There are two ways of dealing with the occlusion effect:

• use deep-fitting custom-moulded earplugs which reach into the inner bony portion of the ear canal and so reduce potential vibration and jaw resonance; or
• use earplugs with vents that allow the trapped low-frequency sound to escape.

5.21 There is a misconception among some woodwind and brass players that it is not possible to wear earplugs due to the build-up of pressure in the ear and the risk of further damage to the ear canal. This has no basis in fact. With the correct earplugs, with patience and sufficient acclimatisation, brass and woodwind players will find they are able to wear appropriate earplugs and have no need to worry that they will suffer further damage to their ears.

Large dynamic range and impulsive sounds

5.22 Some sources of noise in the music and entertainment sector have a large dynamic range (such as brass, percussion and much woodwind) or can be highly impulsive (such as firearms or pyrotechnics). In these situations 'amplitude-sensitive' or 'level-dependent' hearing protection could be suitable. These use mechanical or electronic mechanisms to allow lower-level sounds to pass relatively unhindered, but 'clip' very high-energy noise. The type with mechanical mechanisms often use the acoustic properties of carefully designed air ducts to give different protection at different noise levels. Amplitude-sensitive hearing protectors come in earplug and earmuff types.

5.23 The tables below provide general guidance on the selection of suitable hearing protection.
Typical problems and selecting suitable hearing protection for live performers

Situation	Typical problems	Possible protection
Amplified instruments or sound systems	Often over-loud.	Uniform attenuation earplugs. (Note: using in-ear monitors may remove the need for, or allow reduced levels of, reproduced sound in working areas.)
Singers	Own voice may be over-loud. Other instruments make monitoring voice difficult.	Solo: Vented/tuned earplugs. Accompanied: Uniform attenuation earplugs
Reeded woodwinds	Proximity to brass or percussion sections. Jaw resonance (occlusion effect) makes it difficult to monitor instrument while using conventional earplugs.	Near trumpet or percussion sections: Vented/tuned earplugs Uniform attenuation or amplitude-sensitive earplugs Near amplified speakers: Uniform attenuation earplugs.
Flutes and piccolos	Loud peak levels, intense high frequencies. Existing right-ear hearing loss results in perceived distortion.	Generally: Uniform attenuation or amplitude-sensitive earplugs. Right-ear hearing loss: Asymmetrical vented/tuned earplugs.
Brass	Jaw resonance (occlusion effect) makes it difficult to monitor instrument while using earplugs.	Near percussion or other brass instruments: Vented/tuned or amplitude-sensitive earplugs. Earmuffs. Near amplified speakers: Uniform attenuation earplugs.
Violins and violas	Conventional earplugs remove higher-frequency sounds.	Uniform attenuation earplugs Some prefer amplitude-sensitive - particularly if near loud neighbours.
Basses, cellos, harps	Proximity to brass section.	Vented/tuned earplugs.
Pianos and harpsichords	Conventional earplugs remove higher-frequency sounds.	Uniform attenuation earplugs.
Drums and percussion	High sound levels, intense higher frequency sounds such as cymbals. Conventional earplugs reduce sound levels too much and may result in over-hitting to compensate.	Uniform attenuation or amplitude-sensitive earplugs. Earmuffs.
Pit orchestras	Often over-loud.	Uniform attenuation earplugs. Headphone monitors.
Conductors and music teachers	Conventional earplugs remove higher frequency sounds.	Uniform attenuation earplugs
Note that while the problems are common, personal and environmental factors vary widely. Employers should consult performers before selecting particular hearing protection. Professional advice is desirable.

Typical problems and selecting suitable hearing protection for other workers

Situation	Typical problems	Possible protection
Live sound engineersStudio performers and engineers	Very loud. Competing external sounds.	Uniform attenuation earplugs. (Note: using headphone monitors or in-ear monitors may remove the need for, or allow reduced levels of, reproduced sound in working areas.)
Theatre and other live-performance cast and crew	Continuous sounds (generators) .Impulse sounds (pyrotechnics, gunshots).	Earmuffs. Compressible earplugs. Premoulded earplugs.
Concert venue workers	Need protection against high sound levels while retaining ability to communicate.	Communication not an issue: Compressible earplugs. Earmuffs. Need to communicate: Uniform attenuation earplugs.
Bars and clubs	Need protection against high sound levels and may need ability to communicate.	Glass collectors: Compressible earplugs. Earmuffs. Premoulded earplugs. Bar staff: Uniform attenuation earplugs. DJs: Earmuffs with sound restoration devices (ANC) fitted. Managers, security staff: Uniform attenuation earplugs with comms fitted. (Note: using headphone monitors or in-ear monitors may remove the need for, or allow reduced levels of, reproduced sound in working areas.)
Note that while the problems are common, personal and environmental factors vary widely. Employers should consult workers before selecting particular hearing protection. Professional advice may be desirable.

Earplugs

5.24 Earplugs fit into the ear or cover the ear canal. They are less visually intrusive than external ear protection but need careful selection as they represent a very personal protection against specific noise sources under specific conditions. All earplugs should come with an indication of the theoretical noise reduction. The description of the reduction may be a single number or it may give an indication of the reduction at different frequencies. It should be remembered that the theoretical attenuation of 'off the shelf' earplugs is based upon a system of averaging and it is often appropriate to take a 'real world' view and assume that the reduction is 4 dB less than stated on the packet.

5.25 Instructions for all earplugs should give advice on the correct method of use as the seal created between the earplug and the ear is fundamental to its effectiveness. Where earplugs are supplied by an employer there is a duty to ensure that correct training is given. In circumstances where a health surveillance programme is in operation it would be best to incorporate the appropriate selection, fitting and training as part of that programme. The certification of different earplugs to comply with European Standards is progressing as new types of earplugs are developed. Trade literature should clearly identify if the type of earplug on offer has been certified. (Further details may be found in HSE publication L108.)

Compressible earplugs (disposable)

5.26 The advantages and disadvantages of compressible earplugs are:

Advantages

• Inexpensive and simple to use.
• Effectively protect against high sound levels.
• Smaller than earmuffs - can be carried in a pocket.
• More comfortable than earmuffs in hot environments.

Disadvantages

• Provide uneven frequency attenuation - remove more high frequencies than low.
• Occlusion effect distorts sound perception for reeded woodwind and brass musicians
• Interfere with speech communication.
• Require careful insertion to ensure effective protection.
• Risk of infection from dirty hands.

Useful for

• Crew, venue staff, and other workers in situations in which sound quality and speech communication are not issues (especially non-music applications).
• Emergency applications (such as forgetting or losing custom-moulded earplugs).

5.27 This type of earplug is more suited to job functions where the user does not need to hear the full frequency range of the sounds. Musicians and sound engineers may not find these suitable during a performance but they are useful as a last resort.

Premoulded earplugs (reusable)

5.28 Premoulded earplugs are generic-fit earplugs shaped for the average user's ear canal. Most have a triple-flanged plug that fits inside the ear canal. These plugs are generally reusable but require regular cleaning. Various types are available including uniform attenuation and amplitude-sensitive.

5.29 The advantages and disadvantages of premoulded earplugs are:

Advantages

• Less expensive than custom-moulded earplugs.
• Easy to insert properly.
• Last longer than compressible earplugs.
• Do not require custom-fitting - available off-the-shelf.
• Reusable - if kept clean.

Disdvantages

• More expensive than compressible earplugs.
• Uniform attenuation types generally not as 'flat' as custom-moulded uniform attenuation earplugs.

Useful for (uniform attenuation types)

• Musicians and vocalists who want a relatively inexpensive earplug with relatively uniform attenuation for practice and rehearsals.
• Bar staff and other workers who want relatively inexpensive earplugs that do not muffle voices and other higher-frequency sounds as much as compressible plugs.

Custom-moulded earplugs

5.30 The silicone earplug is moulded to the shape of the user's ear canal and should be fit-tested. They are typically made by a laboratory that supplies local audiologists and hearing clinics. They can come in filtered or vented/tuned varieties. Here each plug is bored out, and then fitted with an adjustable vent or capped with a button-sized filter attached to its outer end.

5.31 In filter types, the filter, in conjunction with the air inside the bored-out section, offsets the loss of high frequencies that normally occurs when an object is inserted into the ear. Not only can the frequency attenuation of the fitting be specifically tuned to the user's needs, but also the plugs themselves will be comfortable and highly effective and are readily reusable. Filters are available which, for example, reduce overall noise levels by 9, 15, and 25 dB.

5.32 The vented/tuned earplug, which does not reduce sound levels up to about 2000 Hz, reduces higher frequencies significantly. Typically, vented/tuned earplugs attenuate higher frequencies by about 20 dB when the adjustable vent is wide open. Closing the vent increases higher-frequency attenuation to as much as 28 dB (performance similar to compressible earplugs). Most ear-mould laboratories can make custom-moulded vented/tuned earplugs.

5.33 The advantages and disadvantages of custom-moulded earplugs (filter types) are:

Advantages (filter types)

• Can provide even attenuation of frequencies up to about 6000 Hz.
• Can be modified to adjust high-frequency attenuation.
• May be flesh-coloured and unobtrusive.

Disdvantages (filter types)

• Expensive.
• Need custom-fitting by a qualified professional.

Useful for (filter types)

• Musicians playing or seated nearby to instruments that produce higher-frequency sounds (for example, violins, trumpets, piccolos, and pianos).
• Anyone working with or around amplified sound (for example, musicians, vocalists, DJs, sound engineers, conductors, and teachers).
• Anyone who needs sound reduction with minimal distortion or colouration.

5.34 The advantages and disadvantages of custom-moulded earplugs (vented/tuned types) are:

Advantages (vented/tuned types)

• Allow musicians playing lower-frequency instruments to hear themselves while screening out surrounding higher-frequency sounds.
• Very little occlusion effect.
• Right and left earplugs can be adjusted separately to compensate for right-ear hearing loss in flute and piccolo players.
• Small 500 Hz resonance improves vocalist's ability to monitor voice.

Disdvantages (vented/tuned types)

• Expensive.
• Need custom-fitting by a qualified professional.

Useful for (vented/tuned types)

• Musicians playing bass and lower-frequency instruments (for example, lower strings, reeded woodwinds, and low brasses) who wish to shield themselves against high-frequency sounds from percussion or trumpet sections.
• Those solo vocalists who need protection against own voice.

Canal caps/semi-insert earplugs

5.35 Canal caps and semi-insert earplugs come on a headband. Canal caps (sometimes called semi-aural plugs) generally have rounded tips that cover the entrance to the ear canal, while semi-insert plugs generally have tapered tips that are pushed into the ear canal. Both types are convenient for situations where the hearing protection has to be taken on and off frequently. They are not designed for continuous use.

Semi-insert earplugs

5.36 Where patterns of exposure to excessive noise are likely to be repeated and short-term, earmuffs or canal caps (semi-aural/semi-insert earplugs) may be preferred because they are quick and easy to fit and remove, and therefore more likely to be fitted when exposure occurs.

Earmuffs

5.37 Earmuffs (sometimes referred to as 'ear defenders') are hard plastic cups that fit over and surround the ears and are sealed to the head by cushion seals. Tension to help the seal is provided by a headband. They are easy to fit and use, once appropriate training is given, and their use is easily monitored. Helmet-mounted earmuffs may be appropriate for riggers.

5.38 Some earmuffs provide sound restoration. These have a microphone on the outside and a speaker on the inside, often electronically limited, to enable the wearer to hear external signals. This electronic system can introduce a tiny but sometimes noticeable time delay.

5.39 Some earmuffs incorporate systems to relay communication or other audio signals (for example, music for DJs). These devices reduce the ambient noise levels and therefore allow the wearer to listen to the music at a reduced level. They can provide an alternative to headphones in noisy environments. Earmuffs should comply with BS EN 352-68 and BS EN 352-8. Check that limiters are fitted to limit the level of sound reproduced at the wearer's ears.

5.40 Earmuffs, like all hearing protectors, should be selected on the basis of comfort, practicality and hygiene to help ensure they are worn properly. Any attempt to alter the earmuffs or using damaged earmuffs could make them ineffective. Comfort considerations include:

• Pressure from the seals on the head - resilient seals only need a low headband force.
• A large contact area between the seal and head helps reduce the contact pressure but in hot conditions may cause sweating.
• Weight - the lighter the better but the cups need to be large enough to fit right over the user's ears.

5.41 The advantages and disadvantages of earmuffs are:

Advantages

• Inexpensive and simple to use.
• Easier to slip on and off than earplugs.
• More comfortable than earplugs in cold environments.
• Less occlusion effect than with compressible earplugs.

Disdvantages

• Heavier and more obtrusive than earplugs.
• Can be uncomfortable in warm or humid conditions - earplugs may be preferred.
• May not be effective for use with spectacles, long hair, beards and jewellery.

Useful for

• Crew members who need protection while working around loud sound and who are not concerned with how the earmuffs look.

Training and effective use

5.42 Users must be trained how to correctly fit and use hearing protection, including:

• why hearing protectors are provided and where and when they must be used;
• the need to follow the manufacturer's instructions;
• how to avoid items such as spectacles, long hair, earrings and costume accessories, and any other personal protection, interfering with the effectiveness of the hearing protection;
• the need for full acclimatisation;
• the importance of wearing hearing protection at all times in a noisy environment (removing it for only a few minutes will lower the protection to the wearer very considerably);
• cleanliness - all protectors should be thoroughly cleaned before use and stored hygienically. Earplugs should be inserted only after washing hands thoroughly. Disposable earplugs should be discarded if unwrapped and after use and should not have passed their expiry date;
• earplugs, canal caps and in-ear monitors should not be shared;
• how to store, care for and frequently check their hearing protectors to make sure they remain in a good, clean condition;
• where to report damage to their hearing protectors and how to obtain replacements or new protectors. Earmuff seals and caps should not be damaged, with no reduced tension of the headbands.

Glossary

For a more detailed explanation of terms see Useful information and glossary.

Bone conduction: Transmission of sound signals through the bones of the skull. The signal is directed straight into the inner part of the ear, bypassing the middle and outer parts of the ear.

BSEN: European Standard adopted as a British Standard.

Exposure action values (EAV): Levels of exposure to noise at which certain actions need to be taken (see Useful information and glossary).

Health surveillance:For the purposes of this guidance, ongoing assessment of the state of aural health of an employee as related to exposure to noise.

Hearing protection zones: Areas where the wearing of hearing protection is compulsory.

Hz: Hertz, SI unit of frequency. The human ear can detect frequencies between 10 and 20,000Hz.

In-ear monitors: Essentially earplugs with built-in miniature monitors (loudspeakers). It is essential that they are fitted with noise limiters.

Noise exposure: 'The noise dose', which can be calculated, takes account of the actual volume of sound and how long it continues. Noise exposure is not the same as sound level, which is the level of noise measured at a particular moment.

Noise limiter: Sometimes known as volume regulatory device (VRD), controls noise exposure from amplified music. Modern noise limiters can be fitted with anti-tamper relays connected to external switches to improve system security

Occlusion effect: Occurs when an object (like an unvented earplug) completely fills the outer portion of the ear canal. This changes the way sounds are produced in the ear canal, especially noises produced by the body (for example breathing, swallowing and noise travelling through bone and tissue.) The result is these noises appear louder.

Single number rating (SNR) value: Method of indicating the degree of protection offered by a hearing protector.

Bibliography