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Chapter 26 NOISE and the NOISE ASSESSMENT

In this chapter, I would like to look at NOISE and the NOISE ASSESSMENT

As you know, Noise is covered by the NOISE AT WORK REGULATIONS 1989. These Regulations, as in all the other EC Health & Safety inspired legislation, come under the enabling act, the Health & Safety at Work Act 1974, and reinforce the requirements for protection from noise at work. The Noise Regulations have been updated in 2006

Noise is measured in decibels (dB), which indicates the intensity or energy of the sound. The scale is a logarithmic one, which means that an increase of 3 dB doubles the noise energy being received. This is not the same as the loudness we hear, in fact if we wish to make a sound seem twice as loud, we have to increase the sound level by 10 dB, which is equivalent to a 10x increase in sound energy.

Hearing damage is caused basically when SOUND ENERGY x TIME reaches a critical level.

The European maximum was put forward as 80 dB for 8 hours, because there are a small percentage of people who would be harmed by noise levels above this. This is known as the 1st Action Level. Above this level an employee can request ear protection and the employer must provide it free of charge.

In the UK however, it was argued that 85 dB for 8 hours was a more reasonable standard - noise levels under this would not affect the vast majority of the population. This is known as the 2nd Action Level. Above this level an employee must wear ear protection and his employer must insist on its use.

Where workers' daily noise exposure is likely to reach 85 dB(A), you must reduce exposure to noise (other than by providing ear protection) so far as is reasonable practicable. Only after you have done everything possible, can you provide ear protection. The aim is that Operators should only be exposed to a maximum of eight hour daily personal noise exposure of 80 dB.

As the energy, created by the noise, doubles for every increase in noise level of 3 dB, it means that the same energy created by a noise level of 85 dB for 8 hours is the same as a noise level of 88dB for 4 hours.

8 hours at 85 dB is the same as
4 hours at 88 dB
2 hours at 91 dB
1 hours at 94 dB
30 minutes at 97 dB
15 minutes at 100 dB
7½ minutes at 103 dB

NOTE that exposure above the Second Action Level i.e. 85 dB for 8 hours or 105 dB for 7½ minutes, in some individuals can leave permanent damage to the ears after only one occasion!

For every item of equipment you should make a noise assessment:


NOISE ASSESSMENT

Manufacturer


Model


Item


Description


Powered by


Noise level idling

................................... dB
Noise level at working power speed

.................................... dB
[ ] Tick here if this equipment is above 1st Action Level Ear Defenders/ plugs must be given to the operative if he/she so requests
[ ] Tick here if this equipment is above 2nd Action Level Ear defenders/ plugs must be worn at all times by operator using this equipment
[ ] Tick here if this equipment is above 100 dB in the 2nd action level. Some Ear Defenders & ear plugs are unlikely to be effective Ear defenders with a noise attenuation of .............dB must be worn when operating this equipment

Signed .............................................. Date ...............................


If you have difficulty holding a conversation in normal tones at a distance of a metre, then the noise level is liable to be above 85 dB.

The regulations ask you to assess the noise in your work environment - measured at the ear level of the operator.

Under the Equipment Regulations, you will have seen that all new equipment now has to inform you about the noise levels likely to be encountered during use. This is part of the CE (European Standards)

Over the past few years, I have taken noise readings of various items of equipment used by Greenkeepers and Groundsmen. The noise measured was the noise at the frequencies the human ear hears (A weighting) and was measured at ear level.

Please do not take these as accurate, but use only as a guide as an item of equipment which has not been properly oiled and serviced will probably have a higher noise level than a well maintained one.

Equipment manufacturers are now under great pressure to produce equipment that will not go above 2nd Action Level or in the future 1st Action Level

Equipment Idle dB Working dB

EQUIPMENT dB at idle speed dB at working revs.
Jacobsen General purpose vehicle 75 83
Ransomes Cylinder Mower 78 84
Jacobsen Greensking IV 78 86
Cushman Diesel Work Vehicle 81 86
Cushman with implement 81 87
John Deer 4600 Tractor with cab 77 88
MF 1010 mini tractor at pto revs 81 88
Toro Greensmaster Triple Cylinder 3200D 73 89
Jacobsen Verticut 78 90
Countax pedestrian rotary mower 80 91
MF 1035 tractor with roll bar 82 92
International 454 tractor 80 92
J deer 220A Pedestrian Cylinder mower 78 92
Kubota B2400 Compact tractor 80 93
MF 1030 Tractor with roll bar 81 93
MF 360 with cab 75 94
Toro Diesel Triple 80 94
Echo leaf blower 82 104
Kubota D420 strimmer 80 106
Kawasaki strimmer 83 108
Chainsaw 2 stroke 83 114
Hedge trimmer 2 stroke 81 110


A 'Noise' Risk Assessment must follow the usual Risk Assessment procedure :

  1. can we eliminate or substitute - e.g. buy new equipment, ensure equipment is maintained adequately
  2. are there any controls which would protect the operator - e.g. use of muffles etc.
  3. Use of PPE (Personal Protective Equipment)

.

.

If we have decided that there is no other way except to issue PPE we must assess the PPE to ensure it protects the operator in use.

The choice of Ear Protection is basically between Ear Plugs and Ear Muffs (Ear Defenders).

Ear Plugs are plastic plugs which when inserted in the ear, mould themselves to the ear canal sealing it off. In general, ear plugs can be used on equipment up to around 100 dB.

Ear Muffs are generally a foam plastic cup closely covering both ears and held together by a headband. In general ear muffs are used on equipment up to around 115 dB, but be careful, some do not even approach this and it is as well to check the specification.

The choice depends on circumstances of use and operator comfort e.g. ear muffs can be awkward to wear for a person having thick spectacle frames. Generally Ear Muffs give better protection than Ear Plugs.

As part of the assessment you should look at the level of protection given by the ear protection and if it will control the noise to an acceptable level for the operator - 85 dB as a maximum and as far below this as possible.

Under the new CE standards, all protective ear plugs and ear defenders must inform you of their Noise Attenuation, in other words, their ability to lower the sound level heard by the operator wearing the ear protection. When you buy an item of ear protection, the manufacturer now gives details of the protection offered. This allows you to choose the ear protection to suit your circumstances of use.

I have ear plugs which give the following details:

PERFORMANCE OF THE EAR PLUG

Frequency Mean attenuation Standard Deviation Assumed Protection
Hz dB dB dB
63 24.80 7.30 17.50
125 26.10 7.80 18.30
250 26.70 7.40 19.30
500 28.90 7.00 21.90
1000 30.40 5.90 24.5
2000 32.80 4.90 27.90
4000 43.60 5.00 38.60
8000 44.40 5.50 38.90

The noise frequencies (Hz) in the chart above are the frequencies heard by the human ear ( A-weighting) and so protection at these frequencies is essential.

The above chart shows that the maximum protection given for these ear plugs is 17.50 dB at 63 Hz. i.e. the maximum noise level in which these can be used, to allow the operator to be exposed only to levels below 80 dB, is 97 dB. Levels above this require different and more efficient ear protection

The ear plugs above would not give adequate protection for the chainsaw, hedge trimmer or the strimmer.

It is clear from the above that the operators must be trained to recognise the problem of noise and take the action required in their circumstances of use.

SIGNS FOR NOISY MACHINES

New Regulations on Safety Signs are now in place. These require the employer to sign a risk where there is no better way of controlling it.

{short description of image}Generally this means that

all equipment which give noise levels, read at the ear of the operator, of between 80 and 85 dB should have a WARNING SIGN - black triangle, graphic and writing on a yellow background - with this signing, it is the choice of operator whether he wears or does not wear ear protection.



{short description of image}

all equipment which give noise levels, read at the ear of the operator, of above 85 dB should have a MANDATORY SIGN - white graphic and writing on a blue background disc - with this signing the operator MUST wear ear protection, and the employer must insist on it




The legislation asks for a detailed assessment of noise - the dB levels and the length of exposure. For a greenkeeper and groundsman, this is impracticable as choice of equipment, length of exposure etc. is wholly dependent on the growth of grass - the sunlight, heat, rain etc. and will thus vary from day to day.

ACTION PLAN:

1. buy equipment which produces a low dB noise level. - Manufacturer should be able to advise.

2. keep equipment properly oiled and serviced to maintain noise levels as low as possible.

3. place signs on the equipment accurately

4. issue and insist on the wearing of adequate ear protection for any item of equipment having a noise level of 85 dB or above. ( I would advise 80 dB)

As with all the H&S legislation, the implied threat is that claims will be made in the future against the employer by the operator. It is imperative that adequate records are kept of your assessment and the instructions and training given to your employees.

Reference: HSE Free Leaflets on Noise


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