Controlling hazardous noise and vibration in the workplace
Hazardous noise is a known hazard for workers and must be controlled immediately.
Hazardous noise in a workplace can be created by mechanical impacts, high-velocity air or fluid flow, and the vibrating surfaces of a machine or of the product being manufactured.
And, in workplaces containing hard, non-absorbent surfacings, the workplace noise level is increased from reflected noise. Examples of non-absorbent surfaces include concrete, marble, wood, tiles, etc to floors, walls, ceilings and other equipment.
Exposure to workplace hazardous noise can cause permanent hearing loss and tinnitus (disabling ringing in the ears or head) in workers – both of which destroy their ability to hear clearly. It can also make it more difficult for them to hear sounds that are necessary to work safely, such as verbal instructions – even warning signals.
Noise-induced hearing loss (NIHL) is the single greatest cause of permanent hearing loss in Australia – and it’s also the most preventable.
But it’s important to know that there are other factors that can contribute and/or cause hearing loss in the workplace, such as:
- exposure to vibration – both hand/arm vibration (HAV) and whole body vibration (WBV), and workers who are exposed to noise and vibration together may be more likely to suffer from hearing loss
- exposure to ototoxic substances , which are chemicals that can cause hearing loss and tinnitus, with hearing loss more likely if a worker is exposed to a combination of ototoxic substances, or a combination of the substance and noise
Employers, businesses and other PCBUs must effectively manage the risks associated with exposure to hazardous noise and vibration (both hand/arm and whole body vibration) to protect workers from to the risk of hearing loss (both gradual and immediate) and any associated tinnitus, and create a less stressful and more productive work environment.
Effective control starts with recognising all potential sources of risk.
You must always try to eliminate and reduce, so far as is reasonably practicable, any health and safety risks in the workplace – including those associated with exposure to hazardous noise and vibration.
Reasonably practicable means doing what you are reasonably able to do, following a systematic risk management process and focusing on the hierarchy of controls from top to bottom to control the risks and ensure the health and safety of your workers.
Consult with your workers at every stage of the risk management process. And, where necessary, consult with building managers and other relevant parties – it’s more likely that suitable, long term solutions to the extreme heat problems can be found when everyone works together.
Usually, a combination of controls is needed to get the best results and any control measures must be determined in consultation with workers (or their HSRs). These measures include:
Eliminate the hazard
New (and renovated) workplaces should be designed and built with health, safety and comfort in mind.
Safe design of structures means the integration of control measures early in the design process to eliminate or, if this is not reasonable practicable, minimise risks to health and safety throughout the life of the structure being designed.
Eliminating hazards at the design or planning stage of new and/or renovated workplaces is often easier and cheaper to achieve than making changes later when the hazards become real risks in the workplace.
It is vital to aim to build the quietest workplace practicable, so PCBUs and designers of buildings and structures must consult with each other, take noise control into account and minimise the noise transmitted through the structure to the lowest level that is reasonably practicable.
You should consider:
- the effect on noise levels of building reverberation, the building layout and location of workstations relative to any plant
- installing automated plant and equipment to mechanically and/or remotely undertake work involving hazardous noise
- the type of plant and equipment to be installed. Consider the type of noise they generate (eg continuous; impact; intermittent; etc) and the noise level. Avoid impact noise as far as is reasonably practicable. So far as is reasonably practicable, purchase items with the lowest noise exposure levels
- where to locate noisy plant, equipment and work processes. Evaluating locations before installation is much cheaper and easier than physically moving it later. Aim to keep machines, processes and work areas of approximately equal noise levels located together
- separating or isolating noise sources away from workers by installing buffer zones, sound-proof barriers and/or enclosures
- selecting structural and other materials to be used to absorb workplace noise and vibration, eg wall and ceiling insulation; sound proofing; cladding; vibration stabilisers; etc selecting the frame, floor and machine bases so that all sources of disturbance can be provided with effective vibration isolation, such as:
- installing rigid, heavy bases for heavy, noisy equipment
- isolating machine bases from direct contact with the rest of the building frame
- designing acoustic treatments for noisy areas, eg: cover ceilings and walls with sound-absorbing material; use floating floors
- using flexible construction joints as building elements
- designing walls, floors, windows and doors to provide the necessary sound transmission loss
- covering floors of office areas with carpets
- consider installing fully automated plant and equipment to mechanically and/or remotely undertake work involving hazardous noise
Isolate the hazard
Isolation controls can include:
- installing a control room to isolate workers
- installing sound isolation booths
- installing remote controlled equipment
- using enclosed cabins on mobile equipment
- separating quiet and noisy areas. Low noise tasks like office work, packaging, cleaning, maintenance and repair work should be carried out in separate low-noise areas
Engineering controls can include:
- installing sound insulation and dampening materials:
- around noisy plant and equipment to reduce the noise level being generated
- to walls, ceilings, floors, doors, windows and other plant to reduce noise bouncing off hard surfaces.
- fitting silencers to machines
- using vibration stabilising pads
- installing sound-proof partial enclosures, barriers, shields, noise cancelling curtains
- installing acoustic baffles (for large surface areas, a spray-on treatment may be more economical)
- changing the work process or design:
- relocate plant and equipment away from hard, non-absorbent surfaces that can increases noise levels due to reflected noise
- use bending machines, pressing methods or glue instead of hammers.
- lower materials carefully instead of dropping. Reduce drop heights for materials that must drop
- use mains powered electrical equipment instead of diesel generators; use electrical drive instead of drive by compressed air or internal combustion engine; replace work vehicles with electric or gas powered alternatives
- use radiation drying instead of flow drying
- use laser beam cutting in place of cutting shock or punching
- use hydraulic breaking or bursting techniques rather than pneumatic impact breaking methods for demolition
- use gas cutters to cut metal rather than using grinding methods to dismantle metal structures
- use bored piling rather than hammered piling
- lower impact noise by reducing the driving force; reducing the distance between components; balancing rotating equipment; or installing vibration isolation fittings
- fit silencers to liquid or air noise sources to reduce flow velocity and turbulence; turn down the volume, change fan speeds
- improve crane configuration and storage arrangements
- line steel trestles and benches, product bins and scrap bins with wear-resistant rubber. (Note: alternative earthing arrangements may be needed). If a hard surface is required, line the underside of the bench or trestle.
- use wear-resistant rubber floor-mats and wall brackets in storage areas
- place work pieces on a durable rubber mat instead of hard bench or floor
- adapting plant and equipment that generate hazardous noise and/or vibration:
- replace hard guarding plates with mesh guarding plates (mesh disperses the noise better)
- extend the guarding and line with acoustic dampening material, where practicable
- reduce drop heights of manufactured items from conveyor systems. Place absorbent material (eg: sponge) in landing container
- provide quiet rooms for rest breaks that are fully enclosed with well-sealed doors and windows to reduce background noise levels as far as possible
The least effective controls in the hierarchy are administrative actions and personal protective equipment (PPE) because they:
- do not stop hazardous noise at the source or in its pathway like the higher level controls
- rely on worker compliance and behaviour, and
- require a lot of supervision to ensure worker compliance
Administrative actions should provide a systematic framework that support the higher level WHS controls used and include:
- Establish a 'buy quiet' policy to prevent sources of hazardous noise from entering your workplace. Establish acceptable noise criteria for new equipment. When purchasing new plant, include them in any purchase specifications and tendering process. Obtain noise emission data before purchasing to choose the quietest available and affordable plant
- Provide quiet lunch and rest areas with low background noise levels where workers can spend their breaks away from noise.
- Safe work procedures that are developed in consultation with workers and enable them to undertake work activities safely, eg:
- rotate workers to reduce individual exposure times
- restrict access to noisy areas
- proper maintenance program for plant, equipment and tools
- schedule activities involving hazardous noise to be done outside of normal hours or on shifts with fewer workers present, where possible
- Workplace noise assessments to identify hazardous noise sources and recommended controls. SafeWork NSW recommends noise assessments are done in high-risk workplaces and workplaces with shift lengths of 10 hours and over.
They should be carried out whenever there is:
- installation of new, or removal of, machinery
- a change in workload or equipment operating conditions that are likely to cause a significant change in noise levels
- a change in building structure that’s likely to affect noise levels
- modification of working arrangements that affect the length of time workers would spend in a noisy work environment
In order to get a true indication of a workers exposure, the PCBU needs to take both personal and general workplace noise measurements whilst equipment is being operated.
A workplace noise assessment will provide the necessary information for you to:
- identify the workers who are exposed to hazardous noise
- identify the machines and processes that are generating hazardous noise
- work out which high level controls will be the most effective
- also work out what level of hearing PPE that may be required for any leftover risk
The report should be made available to managers, health and safety representatives and regulators, and the main findings included in training provided to workers.
- (Occupational) Noise Management Plan – particularly in high-risk industry sectors, such as manufacturing, construction and transport/storage.
The plan should:
- identify what action needs to be taken
- identify who is responsible and by when, and
- be based on the results of any workplace noise assessment
- include the established acceptable noise criteria for new equipment
SafeWork NSW recommends that the noise management plan includes a systematic workplace hearing conservation program to protect workers from the risk of hearing loss.
- be displayed in any area where exposure to hazardous noise might occur and be located at the entry points
- identify the boundaries of these areas
- indicate that hearing PPE must be used
Information and training should be provided to:
- all exposed workers
- their managers and supervisors
- health and safety committees and HSRs
- those responsible for:
- the purchase/hire of plant
- the purchase of noise control equipment
- the purchase of personal hearing protectors, and
- the design, scheduling, organisation and layout of work
The contents of the training program should include:
- the health and safety responsibilities of each party at the workplace
- how hearing can be affected by exposure to noise
- the detrimental effects hearing loss and tinnitus have on a person’s quality of life – both at work and socially
- the tasks and areas at the workplace that have the potential to expose a worker to NIHL and the likely noise exposure level
- how to use existing noise control measures
- how to select, fit, use, maintain and store hearing PPE
- how to report defects in hearing PPE and noise control equipment, or raise any concerns regarding hazardous noise, and
- the purpose and nature of audiometric testing
Hearing personal protective equipment (PPE)
Hearing PPE is the last and the least effective control in the hierarchy and should only be used to manage any risk that is leftover after all higher-level controls have been implemented.
Read hearing personal protective equipment – the facts for information on this topic.