Paul Elcoat's guide to the Arboricultural Association’s Approved Contractor Scheme: PT. 17 Vibration and noise

PROGRESS TO DATE:

• Part 1 – Introduction to the Arb Approved Contractor Scheme
• Part 2 – The Worksite Safety Inspection
• Part 3 – Completed Work and the Named Manager Knowledge Requirement
• Part 4 – Module 3 – Customer Care and Office Procedures
• Part 5 – Insurances, Licences and Policies
• Part 6 – Health and Safety Management and Workplace Inspection
• Part 7 – Control of Substances Hazardous to Health (COSHH)
• Part 8 – Environmental Matters
• Part 9 – Fire Safety Arrangements
• Part 10 – Incident Management
• Part 11 – LOLER and PUWER
• Part 12 – Personnel and Training
• Part 13 – Risk Assessments and Method Statements
• Part 14 – Office, Workshop and Yard
• Part 15 – Personal Protective Equipment
• Part 16 – Reference Material

So, to continue with the project, in this edition I would like to give some guidance around vibration and noise.

VIBRATION

Hand-arm vibration is vibration that is transmitted into the worker’s hands from hand-held machinery such as chainsaws, hedge trimmers and leaf blowers.

Repeated and prolonged exposure to this type of vibration can have serious effects on an operator’s health, including:

READ MORE: Paul Elcoat's guide to the AA’s Approved Contractor Scheme with a look at PPE

• Circulatory problems resulting in vibration white finger (VWF)
• Injuries to joints, bones and tissues
• Nerve damage

The effects are collectively known as hand-arm vibration syndrome (HAVS) and sufferers may not necessarily have all of the above symptoms.

Vibration white finger is the result of damage to the circulatory system. The symptoms are whitening of the fingertips, usually triggered by cold or wet conditions. The first sign that damage is occurring is normally a sensation of ‘pins and needles’ or a tingling feeling, which is often noticed at the end of the working day. Continued exposure to vibration may result in increasingly frequent attacks accompanied by numbness and whitening of the tips of the fingers or ‘blanching’. Continued exposure results in considerable enlargement of the affected area. The whitening is often accompanied by numbness and ‘pins and needles’. The colour may change to a reddening of the area as blood returns to the affected spot, normally accompanied by severe pain. As the condition is often triggered by the cold or wet conditions, this can have a severe impact on the employee’s social and leisure life.

Damage may manifest itself as pains to the soft tissue and bones in the hands, wrists, or arms as well as a general loss of strength in these areas. Carpal tunnel syndrome is a reportable disease when associated with hand-held vibrating equipment.
Damage to the nerves in the hands can result in a loss of sensation and permanent numbness or tingling sensation. Dexterity and the manipulation of small objects may become difficult or impossible.

Clearly, it’s very important to ensure that this doesn’t happen. The last thing anybody wants is for the job we all enjoy to ruin the rest of our lives.

I like step-by-step processes and, from feedback from previous articles, I know readers also find it helpful.

Follow these steps for starters and, once you get this system in place, you can refine it even more.

The equipment part:

1. Make a list of every tool that you have that vibrates that someone holds onto. Chainsaws, hedge trimmers, some stump grinders but not chippers for example because you don’t hang onto those (I am thinking an MS Excel spreadsheet here).
2. Get rid of the old tools that need replacing anyway.
3. Buy new ones and make sure that one of the key purchase criteria is the vibration level. Manufacturers are already very aware of vibration hazards and so even without trying you will be buying something that is miles better than the one you have just put aside for spares.
4. Add the new tools to the list.
5. For each tool on the list, use the manufacturer’s guidance to find out the vibration level and therefore the maximum trigger time (this is the maximum time in use in the day). Add a column for the noise level too – this will make sense later in the article.
6. Add a column with a formula which increases the manufacturer’s stated vibration level by 10 per cent as a factor of safety to account for added vibration when the chain has been sharpened.

The people part:

1. During induction training, include a briefing about vibration and noise hazards and issue everyone with the following leaflets from the HSE:
• Indg 296 – Hand Arm Vibration – Advice for Employees (www.hse.gov.uk/pubns/indg296.pdf)
• Indg 363 – Protect your Hearing or Lose It (www.hse.gov.uk/pubns/indg363.pdf)
2. For all currently employed people, conduct a briefing meeting and issue the above leaflets. Both are an easy read and they say it like it is.
3. Tell everyone that if they ever experience ‘pins and needles’ in their hands they must report it to you straight away because it means that something is going wrong:
• The anti-vibration systems on the tool are faulty or are wearing out.
• The operator is using equipment for longer than they should or perhaps they are using the wrong tool for the job.
• The operator could be particularly susceptible to vibration.
4. Make sure everyone knows which tools are the ones likely to be a problem and that everyone knows the trigger times. We recommend using green labels to show which tools could never be a problem due to the likely duration of use during the day, and red labels where the operator must monitor the duration of use in case they go over the action value time or, worse, the limit value time.
5. Have everyone complete a HAVS tier 1 assessment form to establish a current position and to flag up anyone that could already be having problems. If the form does indicate any problems, speak to a provider of specialist occupational health advice.

I am sure you’ll agree this is all fairly simple so far. The slight complication is that every minute of operation of any tool results in that amount of vibration being added to the exposure of the operator that day, so you must bear in mind this is a cumulative total of the day’s activity.

I have seen several ways to tot it all up, from clock dial cards to forms to be completed daily, and all of this helps. Ultimately though, if the operators understand about vibration hazards and they build a few simple habits into their day, they will significantly reduce the likelihood of problems.

1. The machine must be correctly and regularly maintained
2. Anti-vibration mountings must be checked regularly and replaced when found to be defective
3. Anti-vibration mountings must be replaced in line with manufacturers’ guidance
4. Operators encouraged to wear gloves when using power tools
5. Operators encouraged to stop smoking
6. Operators encouraged to share vibration-heavy tasks, such as ringing up with the big saw, around the team
7. Report any pins and needles to a manager
8. HAVS tier 2 assessments undertaken annually
9. Where the tier 1 or tier 2 assessment reveals early signs of vibration injury, seek advice immediately

We have used the Stihl vibration calculator to work out the Exposure Action Value (EAV) and the Exposure Limit Value (ELV) of each tool in the inventory and then discussed whether, in a day, the operator is likely to exceed the action or limit value times. If ‘no’ then we have used a green label showing the action time and limit time and if ‘yes’, a red label.

The labels are then applied to the tools to warn the operators of the hazard as in the photograph below. Thanks to our colleagues at T&W Engineering in Hong Kong for allowing us to use the photo.

NOISE

Control of the hazards arising from noise exposure is even easier than those needed for vibration.

The problems of excessive noise exposure have long been recognised and a number of ‘exposure action and limit values’ have been established at which the employer has to take corrective action.

Noise-induced hearing loss can be divided into:

• Temporary hearing loss (temporary threshold shift)
• Permanent hearing loss (permanent threshold shift)

Temporary hearing loss occurs where exposure to high levels of noise results in a reduction in the sensitivity of hearing, such as is encountered after leaving a club or pop concert. If the period of recovery is long enough then hearing sensitivity will return to normal.

Permanent hearing loss occurs when people are exposed to high noise levels without sufficient recovery time as would be encountered through exposure in a noisy work environment. There is insufficient time for the hearing mechanism to recover from the previous exposure, with the consequence that there is a gradual but definite reduction in hearing sensitivity. As the process is gradual, people do not realise that there is a change occurring until the hearing loss is significant.

I was talking to Paul Smith at the Arb Association recently and he told me about a good test for hearing loss. Does your family tell you that the telly is too loud when they come into the room?

It isn’t just hearing loss that is a hazard arising from noise. Headaches, stress and lack of concentration could all lead to other accidents and low productivity.

As with the ‘pins and needles’ sensation with vibration, tell everyone that if they experience the ‘disco-ear’ feeling at work, they must report it immediately. It could be that the equipment requires maintenance, their ear defenders are not up to the job or are damaged, or that they are particularly susceptible to noise.

Thinking back to the tool list that I wrote about above, once you have everything listed on it including noise levels, you will probably notice that everything you use emits noise at a level higher than the first action level of 80 dB(A). In fact, you will probably be looking at levels around 100 dB(A) for chainsaws and much higher still for woodchippers in use.

Notice on this sheet I have added a formula column to subtract the SNR rating of the ear defenders from the published or measured noise level. The MS150, for example, emits 96 and by using chainsaw-rated 24SNR ear defenders, we can achieve a resultant exposure of 72, which is well below the action level of 80.

We need to control operator exposure to noise for every noise-emitting operation we do.

There is a slight complication here, though. The ear defenders on the chainsaw helmets may not be sufficiently rated for using the woodchipper or for working in the proximity of the woodchipper, so operators may be getting more than they think. I have measured the noise levels 10 m and 15 m from a chipper and there is hardly any reduction due to the distance.

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The simple solution is to make sure the ear defenders on your helmets are rated for the chipper.

When I make this suggestion to our clients, a lot of people say they are worried about not being able to communicate with each other if they upgrade to the more robust ear defenders. In practice, however, they find that this isn’t a problem.

If your climber genuinely never operates the chipper, then perhaps they would be fine with chainsaw-rated protection. The key is to choose the right PPE for the likely exposure.

Paul Elcoat runs Elcoat Ltd which specialises in helping arb businesses get things right and achieve better contracts. Paul would be happy to take questions or comments from readers by email: paul@paulelcoat.co.uk or telephone: 07800 615900