Sound Strategies

In our bustling workspaces, it is easy to forget that amidst the cacophony lies an insidious risk – noise-induced hearing loss. This invisible occupational hazard, while commonly overlooked, has profound implications for employee health and safety, warranting the same level of attention as any physical danger on the work floor. Preserving hearing is not just a standard, it is a quality-of-life issue.

Employers, safety managers, and workers must have the appropriate training and understanding of the dangers of noise, who is vulnerable to hearing loss, the variety of hearing PPE, the multiple ways it can achieve hearing protection, and the standards that guide its implementation. Remember that when it comes to noise, prevention is the best method to combat hearing loss. Once the damage is done, it is entirely irreversible.

Utilising the Hierarchy of Controls

Before proceeding further, it is essential to consider hearing personal protective equipment (PPE) in the context of the control hierarchy. This widely recognised framework prioritises strategies that first aim to eliminate and then reduce hazards at their source, with PPE typically viewed as the last line of defence. For noise control, if elimination of noise is not reasonably practicable, additional reduction measures that employers should consider include the following. 

The hierarchy of controls is a widely accepted system used in occupational health and safety to minimise or eliminate exposure to hazards. Here is how it applies to noise control in the workplace, along with some examples for each level of the hierarchy: 

1. Elimination: This is the most effective control strategy and completely removes the hazard from the workplace. An example would be replacing a loud piece of machinery with a quieter model or designing a workflow that eliminates the need for noisy equipment.
2. Substitution: This involves replacing something that produces a hazard (such as noisy machinery or equipment) with something that does not. For instance, replace a noisy machine with a less noisy one or use a different, quieter process to achieve the same result.
3. Engineering Controls: This involves changing the equipment, process, or noise source to reduce the level of noise being produced. Examples include installing noise barriers or enclosures around machinery, applying damping or isolation to vibrating surfaces, or using silencers on exhausts. 
4. Administrative Controls: These involve changing the way people work. For instance, you might establish “quiet” zones in the workplace where noise levels are strictly controlled or rotate employees in and out of noisy areas to reduce their individual exposure time. It could also include regular maintenance of machinery to prevent noise increase due to wear and tear. 
5. PPE: This is the least effective control strategy and should be used as a last resort when the other methods can’t adequately control the noise. Examples include earplugs and earmuffs. The key with PPE is that it requires correct fitting and use to be effective, and even then, it only protects the wearer, not reducing the overall noise level in the workplace. 

Remember, the hierarchy of controls is best applied in a top-down approach, starting with the most effective strategies. In the case of noise, this means attempting to eliminate or substitute the noise source should be the first approach before moving on to engineering and administrative controls and finally considering PPE as a last resort.

“attempting to eliminate the noise source should be the first approach before moving on to administrative controls and PPE”

Identifying Vulnerable Workers

Under the UK’s Control of Noise at Work Regulations 2005, employers must protect workers from excessive noise exposure. This duty includes identifying workers who may be particularly vulnerable to noise-induced  hearing loss. Understanding how to identify these workers and comply with Health and Safety Executive (HSE) guidelines is essential to maintaining a safe working environment.

The first step in identifying vulnerable workers involves conducting a risk assessment. This assessment should identify where there might be a risk from noise and who is likely to be affected. The HSE suggests that any worker might be at risk if they must shout or raise their voice to carry out a normal conversation when about
2 metres apart for at least part of the day. Employees working with noisy powered tools or machinery for more than half an hour each day may also be at risk. 

Regarding vulnerability, individuals with pre-existing hearing conditions, those exposed to certain ototoxic substances, and individuals taking medication known to have ototoxic side effects can be more at risk. 

Once these workers are identified, the HSE stipulates several legal requirements that employers must meet. These include: 

1. Reduce Noise Exposure: Employers are legally obliged to reduce noise exposure through measures like introducing quieter equipment, fitting silencers, or organising work schedules to limit the duration and intensity of exposure. 
2. Provide PPE: If the risk persists after all reasonable measures have been implemented, employers must provide workers with suitable hearing protection.
3. Health Surveillance: Regular hearing checks should be provided for all workers who are at risk.
4. Information, Instruction, and Training: Workers must be informed about the risks they might be exposed to, what is being done to control them, and how to protect themselves.

Protecting vulnerable workers from noise-induced hearing loss requires a comprehensive approach that includes risk assessment, control measures, regular health surveillance, and continuous education. As the HSE asserts, “prevention of noise risk is a legal requirement, not an optional extra.” By complying with these guidelines, employers can ensure they uphold their legal duties and safeguard the hearing health of their employees. 

Selection, Comparison, and NRRs

The selection of appropriate personal protective equipment (PPE) is vital in protecting workers from the risk of hearing damage. With a myriad of hearing protection devices on offer, understanding their benefits and potential drawbacks is key to making an informed choice: 

Earplugs

These compact devices, designed to fit into the ear canal, are available as disposable or reusable units, with some even offering a custom-moulded fit for the individual user. They offer the convenience of compatibility with other PPE, like safety goggles or helmets, and their compact size lends itself to ease of use. However, their effectiveness is contingent on correct insertion, and they may not be suitable for individuals with specific ear conditions.

• Disposable: Earplugs are relatively cost-effective, with disposable foam versions costing only pennies per pair, making them an economical choice for many businesses. However, custom-moulded earplugs may be a better option for employees regularly exposed to high noise levels.
• Custom-moulded: These range from £50 to £150 per pair but offer enhanced comfort and protection. Reusable and custom earplugs should be cleaned regularly according to manufacturer instructions to maintain hygiene and effectiveness.

Earmuffs

Providing an air seal around the outer ear, earmuffs offer consistent protection, needing no individual fitting. Their visibility facilitates safety compliance checks, an advantage over less conspicuous earplugs. Despite these benefits, they might prove uncomfortable in warm conditions, and factors such as glasses or long hair can interfere with the seal, compromising their effectiveness.

The cost of earmuffs can vary widely depending on the noise reduction rating (NRR), the brand, and additional features (such as built-in radio). Basic models start at around £10, while high-end models can exceed £100. Maintenance usually involves regular ear cushions and headband cleaning with a mild cleaning solution. Over time, the cushions and foam inserts may wear out and lose their effectiveness in providing a good seal. These components are often replaceable, extending the earmuffs’ lifespan and are more cost-effective than replacing the entire set. 

Canal Caps

Sitting between earplugs and earmuffs, they are held on a lightweight headband, making them easy to insert and remove. This design is particularly beneficial for workers exposed to intermittent noise. However, they tend not to provide the same noise reduction level as earplugs or earmuffs. 

Canal caps fall between earplugs and earmuffs in terms of cost, typically ranging from £5 to £30. They are a cost-effective solution for workers needing to wear and remove their hearing protection frequently. Maintenance of canal caps is similar to reusable earplugs and earmuffs; regular cleaning is necessary, and any worn-out parts should be replaced to ensure optimal protection. 

Noise Reduction Rating

Each of these devices carries a Noise Reduction Rating (NRR), indicative of its capacity to reduce noise exposure – the higher the NRR, the better the noise reduction. 

In the UK, workplace noise guidelines are overseen by the HSE, which assesses noise reduction using Single Number Ratings (SNR). This rating offers a simplified means to estimate the level of protection against harmful noise. All hearing protectors sold in Europe should be tested and labelled with an SNR value, reflecting the reduction in noise exposure in decibels when the device is correctly fitted.

Moreover, British Standards Institution (BSI) lays out specific standards that hearing protection in the UK should adhere to:

• BS EN 352-1:2002, outlining the requirements for earmuffs attached to an industrial safety helmet.
• BS EN 352-2:2002, specifying the requirements for earplugs.

Understanding these considerations can guide employers to select the most effective PPE for their working environment, safeguarding their workforce’s hearing health. 

Remember that the cost of hearing protection devices is often dwarfed by the potential costs of noise-induced hearing loss claims. Regular training on adequately using and caring for these devices is crucial to an effective hearing conservation programme.

Dual Hearing Protection

In certain high noise exposure environments, one form of hearing protection may not be sufficient to safeguard against noise-induced hearing loss. In these situations, implementing dual protection strategies – using two types of hearing protection devices together – may be necessary. 

The most common combination in dual protection involves wearing earplugs and earmuffs simultaneously. This strategy is particularly beneficial in environments where noise levels exceed 100 decibels, as the increased protection can significantly reduce the risk of noise-induced hearing loss. 

Although one might intuitively think the SNRs of two protective devices simply add up to estimate total protection, the process is more intricate. Yes, the inverse square law dictates that sound intensity diminishes proportionally with the square of the distance from its source, but we must also consider bone conduction. 

This phenomenon allows sound to be transmitted through the skull bones, reaching the inner ear, even if the ear canal is fully blocked. Therefore, despite best efforts to obstruct noise, some can still permeate due to bone conduction.  

Consequently, the combined effect of wearing earplugs and earmuffs does not equal the sum of their individual noise reduction capabilities. According to the HSE in the UK, when earplugs and earmuffs are used together, the total noise reduction is estimated by taking the higher SNR of the two devices and adding 4 dB.

However, as with individual devices, these ratings should be considered as maximum values under optimal conditions. In real-world applications, effective noise reduction is likely less due to improper fit, intermittent use, or wear and tear on the equipment.

Case Study

In anticipation of introducing a new mobile wood chipper to our landscaping team, I conducted a comprehensive noise survey. The manufacturer specified the wood chipper’s noise levels at 120 dB, necessitating an extensive exclusion zone for non-PPE wearers. 

A review of our existing hearing protection – over-ear muffs on forestry helmets with an SNR of 31 – revealed they were inadequate for these noise levels. Using the HSE’s Hearing Protection and Daily Noise Exposure Limit Value Calculators, it identified the need for enhanced over-ear protection with an SNR of 31 and in-ear plugs with an SNR of 37. This dual hearing protection would bring the combined SNR to 41, using the HSE’s guidance on adding 4dB to the highest-rated SNR hearing protection. 

Beyond combined hearing PPE, additional noise control measures, such as time limitations and operator rotation, were incorporated. Following these adjustments and targeted training to the landscaping team, a live noise test validated the chipper’s peak noise levels at 120 dB when chipping hardwood. Health surveillance was also deemed essential, particularly for those operating the woodchipper or working nearby. Regular hearing checks were initiated as part of ongoing preventive measures. 

This condensed case study underlines the proactive approach to noise control that all employers must make, aligning themselves with HSE guidelines to ensure worker safety and protection against noise-induced hearing loss.

“in an incessantly noisy world, preserving the gift of hearing is an imperative that cannot be overstated”

Final Thoughts

In an incessantly noisy world, preserving the gift of hearing is an imperative that cannot be overstated. As employers, the responsibility weighs heavy – not merely for the financial implications of non-compliance, but because the issue transcends the realm of legal obligation, touching the core of corporate ethics and moral duty. 

Choosing the appropriate PPE and ensuring its correct and consistent use is paramount in reducing the risk of noise-induced hearing loss in the workplace. It requires a nuanced understanding of the specific needs of the workers, the nature of the job, the work environment, and the noise exposure level. Remember, the most effective PPE is the one that workers are comfortable wearing – because even the highest-rated hearing protector will only prevent noise-induced hearing loss if used consistently and correctly. 

Ensuring we follow HSE guidelines helps us mitigate potential financial losses from non-compliance and fortifies the trust and respect between employers and employees. In so doing, we construct a culture of safety that goes beyond mere rules, echoing in the everyday actions and attitudes of our people. 

Employers and safety leaders must rise to the challenge and ensure that workplaces are not just spaces of productivity but also sanctuaries of health and safety. As the famous Helen Keller once said, “blindness separates people from things; deafness separates people from people”.