Consultancy report

Consultancy Report
Ref: 6386 R01
Mr M Barter and Mr P WebberJoint Occupational Safety and Health UnitSteele CloseEastleigh In accordance with our qualityassurance procedures, this report iscountersigned by: Noise measurements of
appliances and equipment
Hampshire Fire and Rescue
August 2000
ISVR Consultancy Services
Institute of Sound and Vibration Research Contents
Appendix A: The Noise at Work Regulations This report shall not be reproduced, except in full, without the prior written consent of ISVR Consultancy Services
Sound levels from fire appliances, fire-fighting equipment, and vehicles used by the fire- fighters of Hampshire Fire and Rescue were measured. Sound levels produced by tools, equipment and machines in the Vehicle Maintenance Workshop at Winnal were also measured. The main noise sources contributing to the noise exposures of firefighting and The main noise sources affecting fire-fighters were the water pumps on the Fire Appliances and particularly on the Water Carrier, the PPV fan, sirens heard inside appliance cabs when windows were open (particularly in the front seating row), and the Acme Thunderer Whistle.
Hearing protection for pump operators and PPV fan operators must be considered, and a sample calculation shows that earplugs such as the E.A.R. Classic should provide adequate Hearing protection is recommended when using most items of workshop equipment and hand Hearing protection currently provided in the HQ Compressor Room and in the Vehicle Maintenance Workshop will give satisfactory protection.
Sound levels from headsets worn by staff in the Control Room at Eastleigh were also measured, but are the subject of a separate report.
1. Introduction
The Joint Occupational Safety and Health Unit (JOSHU) commissioned ISVR Consultancy Services to measure the noise levels produced by appliances, operational and workshop equipment, and control room headsets used by Hampshire Fire and • to identify particular equipment, operations or activities which could give rise to • to provide baseline noise data enabling fire-fighters’ and other personnel’s noise exposures to be realistically estimated and assessed given various scenarios and • to identify when and where noise control or hearing protection might be required• to provide information allowing JOSHU and Hampshire Fire and Rescue to decide strategies or procedures to minimise the effects of noise on hearing, and to comply with the Noise at Work Regulations [1].
A brief outline of the requirements of the Noise at Work Regulations is given in This report covers all measurements except those for the control room headsets, which are contained in a separate report (No. 6386 R02).
Noise measurements and equipment used
Noise measurements were made on Monday 24 and Tuesday 25 July 2000 at Hampshire Fire and Rescue HQ at Eastleigh, at Eastleigh Fire Station, and at the Vehicle Maintenance Workshops at Winnal, Winchester. Measurements were carried out by Dr M C Lower of ISVR Consultancy Services with the assistance of Mr P Webber of JOSHU. The noise sources measured were operational equipment and appliances used by fire-fighters and tools and equipment used in the maintenance workshop. The items to be measured had been previously identified by JOSHU, who also arranged for the necessary equipment to be available for the measurements.
It is difficult if not impossible to define a typical daily shift and hence a typical noise exposure for either a fire-fighter or for workshop personnel. Consequently the approach adopted was to measure the noise levels from various activities and from various items of equipment to identify which of these were likely to give high noise levels. This information can then be used to estimate noise exposures given various assumptions about the amount of time spent on each activity or using each piece of The equipment used to measure noise was a Brüel & Kjær Type 2236 precision sound level meter. This was calibrated before and after each set of measurements by placing a B&K Type 4231 sound level calibrator over the sound level meter’s microphone.
The sound levels measured with the meter were A-weighted. The ‘A-weighting’ is an internationally standardised frequency weighting which approximates the frequency response of the human ear. It reduces the low sound frequencies and the very high sound frequencies to which the human ear is least sensitive, and emphasises the middle frequencies to which the ear is most sensitive. Sound levels measured with the A-weighting circuit in place are described as ‘A-weighted’, and expressed The A-weighted sound levels recorded were ‘equivalent continuous sound levels’. An equivalent continuous sound level, or ‘Leq’ for short, is the time-average level over a given period or for a given event. In this report all Leq values are average levels over typical or representative periods of working or using the equipment specified.
For some equipment the peak sound level was also measured. This level was measured without a frequency weighting.
For some items of equipment, mainly the noisier ones, tape recordings were made for further analysis. The tape recorder used was a Sony TCD D8 digital audio tape recorder connected to the line output of the sound level meter. Calibration tones were recorded from the sound level calibrator via the sound level meter onto the tape in order to give a reference sound level during subsequent analysis. The recordings were analysed in our laboratory using a B&K Type 2231 digital frequency analyser to give The measurement positions around the appliances or equipment were chosen to be typical of those occupied by personnel, generally at a defined operator’s head position or at specific distances. Care was taken to ensure the microphone was clear of any obstruction from the operator or bystanders.
Noise levels from fire appliances and fire-fighting equipment and
activities
Measured levels
The noise levels recorded are shown in Tables 1 to 13. Each table shows the average A-weighted noise level during the measurement in dB(A) Leq rounded to the nearest decibel. The final columns in each table show how long it would take to reach the First and Second Action Levels (1st AL and 2nd AL) of the Noise at Work Regulations, Peak sound levels are not shown in the tables, as in all cases where they were measured they were below the Peak Action Level of 140 dB (corresponding to a Significance and assessment of the various noise sources
Examining each table in turn leads to the following observations.
Table 1 shows the Acme Thunderer Whistle to be a very intense noise source. The
First Action Level of 85 dB(A) LEP,d would be reached in less than 25 s of use, and the Second Action Level of 90 dB(A) LEP,d after 70 seconds. We understand that the whistle will be used occasionally in emergencies when a building has to be evacuated if and when radios are not heard. In operational circumstances, occasional use can be tolerated. A signal of six short blasts on the whistle will take about six or seven seconds. If the signal is given three of four times the First Action Level will be reached, and if given 10 or 12 rimes the Second Action level will be reached, so it is possible that the whistle blower will have a daily noise exposure close to the First *Note that the times given against each noise source apply only if the specified noise source is the only significant source heard during a shift. In practice many different noise sources will contribute to anindividual’s noise exposure. Time spent working with one noisy source reduces the time available for workingwith another noisy source.
Action Level or possibly between the First and Second Action Levels, even if other sources of noise are not considered. Repeated use in training or for demonstrating signals should be minimised unless either hearing protection can be worn or unless the whistle blower is able to place fingers in his or her ears while blowing.
We understand the railway horn is rarely used and is therefore not likely to present a
risk to hearing. The Automatic Distress Signal Unit, (ADSU) while loud is unlikely
to present a risk to hearing in practice, but noise exposures can and should be minimised when these units are tested by the simple expedient of placing a hand over the sounder to muffle it – a solution already suggested by JOSHU and worth Table 2 shows noise levels in the compressor room to be high, especially during
pressure release. The compressor is used regularly to recharge the breathing apparatus cylinders. Whether someone working in the room would have a noise exposure approaching the First Action Level will depend on the time spent there.
However pairs of Racal Ultramuff and Peltor H9A are already provided within the room. These protectors will give satisfactory protection and we recommend their use Tables 3 to 8 and 11 show noise levels inside various vehicles, ranging from an
officer’s car and technician’s van to front line fire appliances. Generally with windows open and sirens operating the noise levels inside front-line appliances, particularly in the front seats, are high. For front seat passengers and the driver the First Action Level could be reached in as little as 24 minutes. However with windows and sunroofs closed it will take hours rather than minutes to reach the First Action Level even with the siren operating. The noise level in the Saxon/Volvo appliance driving on normal local roads with sirens was 89 dB(A) Leq averaged over a period of nearly 4 minutes with windows closed. Whether ventilation in the cab will be adequate in all weathers with the windows closed will need to be considered. Noise levels in the van and car with windows closed were lower.
Tables 5, 6, 10 and 11 show noise levels at the operator’s position at the pump bay at
the rear of the appliances. We understand that generally one firefighter will be in charge of the pumps and will need to be in the pump bay while pumps are operating.
With the Saxon/Volvo appliances the noise level is typically 94 dB(A) Leq with
pumps operating, though 98 dB(A) was measured in one instance. At 94 dB(A) an operator’s noise exposure will reach the First Action Level after one hour. Noise levels for the pump operator on the Angloco/Volvo Water Carrier were higher at
102 dB(A) Leq and the operator’s noise exposure would reach the First Action Level in under 10 minutes and the Second Action Level in just half an hour. We understand that the water carrier pumps are used for extended periods of possibly several hours particularly with agricultural fires. We consider that appliance pump operators should be provided with hearing protection and this is discussed below.
One of the Saxon /Volvo appliances was fitted with a sounder in the pump bay to
draw attention to an electronic data transmission being received in the cab.
Consideration should be given to reducing the sound level of the sounder or relocating it so that it is much further away from the pump operator. The optimum location and sound level of the sounder depends on whether it is intended to alert the pump operator or any firefighter in the vicinity. If the pump operator is provided with hearing protection this becomes less of an issue but should still be considered.
Other noise sources on vehicles do not appear to present any significant problem. The noise level of the Bronto Skylift Aerial Ladder Platform at the operator’s seat was
measured at 81 dB(A) Leq (Table 8). The noise level close to the lowered cage was approximately 85 dB(A) Leq but the position would not be occupied for long periods.
The noise levels for the operator of the HIAB fitted to the Multirole Vehicle are
below 80 dB(A) Leq and although the warning sounds are at 97 dB(A) their duration will be short and these can be discounted as a risk.
Table 12 shows noise levels from general items of fire-fighting equipment. Both the Positive Pressure Ventilator (PPV) fan and the Light Portable Pump (LPP) are
significant noise sources. The PPV fan requires an operator nearby, within a couple of metres, and this operator’s noise exposure will reach the First Action Level after about 15-30 minutes. We consider that the PPV operator should be provided with hearing protection and this is discussed below. Other firefighters may need to work in the vicinity of the PPV fan, and some will be inside the building being ventilated.
Those inside the building will be shielded from the direct fan noise to some extent.
If the LPP needs to be attended while operating, consideration should be given to the duration of the use when deciding whether hearing protection should be used. The Honda generator is not likely to present a risk to hearing.
The turnout alarm at Eastleigh Fire Station, while a high sound level in some areas,
will be operating for short periods only and is not considered to present a risk to Fire-fighters and hearing protection
We have identified sources and tasks where we consider that hearing protection for individual firefighters is likely to be required. These individuals are the pump operators on the front-line appliances and the water carrier, and the operator of the PPV fan. Any hearing protection needs to be compatible with other safety equipment, including the protective helmet, and earplugs are likely to be the practicable solution.
The presence of the helmet must also be considered. Hampshire Fire and Rescue use the Gallet helmet. This helmet covers the ears but leaves a gap between the ears and the helmet shell, and is open at the front and base around the wearer’s head and neck.
Although this helmet covers the ears, it is fairly lightweight and does not seal against the head, and will not therefore not reduce noise levels at the ear. What is more likely is that sounds from the front will enter the helmet and may be amplified by a few decibels at some frequencies so that the sound level at the ear under the helmet may be higher than if no helmet were worn. In order to test this effect we would need to borrow a helmet and carry out sound measurements in our laboratory using miniature microphones at the ears of test subjects with a range of head sizes.
To calculate the effect of earplugs we have analysed the noise spectra of various noise sources from our tape recordings. The spectra are shown in Figures 1 to 3. We have used these spectra together with the manufacturer’s noise attenuation data to calculate the effective noise level if ear plugs were worn. The earplugs selected for of this example calculation are the yellow foam ‘E.A.R. Classic’ manufactured by AEARO and widely available. The attenuation data used is the ‘assumed protection’, that is the mean noise reduction minus one standard deviation. Statistically this is the attenuation attained by 84% of wearers, whereas the mean is the attenuation achieved The E.A.R. plugs would reduce noise levels at the ear to effectively 79 dB(A) Leq for the Angloco Water Carrier pump, 72 dB(A) for the PPV fan, and below 70 dB(A) for the Saxon appliance pump. Even allowing for some amplification of sound when a helmet is worn, say 5 or 6 dB, these plugs properly fitted should ensure that noise exposures of the pump and PPV operators are unlikely to reach the First Action Level.
Often people unused to wearing hearing protection are wary that they will have difficulty hearing warning sounds or radio messages if they start to wear the protection. In high noise levels hearing protection reduces both the wanted signal’s sound level and the background noise level together within each frequency band, so the wanted signal will still be audible above the background noise, and communication and audibility of signals should not be degraded. In fact there is published evidence that there may even be a slight improvement in audibility of wanted signals and speech messages when hearing protection is worn.
There is one adverse effect on communication: a person will speak more quietly when wearing hearing protection, because the background noise does not appear to be as loud as it really is, whereas their own voice, heard by conduction of sound through the head as well as through the air, is still relatively loud. The tendency to speak too quietly can be overcome by training and awareness.
Noise levels from tools and equipment in the Workshop
Measured levels
The A-weighted noise level recorded from each tool or item of equipment at the operator’s position during normal operation is shown in Table 14. The final item in this table is a measurement of the sound level in an enclosed space, the pump testing bay. A fire appliance is reversed into this bay and the pumps connected by hoses to a water reservoir for testing. The pumps are the noise source and the noise level is Peak sound levels are not shown in the tables. Where peak levels were measured they were below the Peak Action Level of 140 dB specified in the Noise at Work Regulations and corresponding to a sound pressure of 200 Pa.
Assessment
The use of particular tools and equipment within the workshop is highly unpredictable. Consequently noise exposures for individual staff are likely to vary considerably from day to day and from person to person. While an operator might only use a particular machine for a short period, he may use many noisy machines in the course of a day, and the noise exposure accumulates. In such circumstances the practical approach is to identify machines, tools or areas where hearing protection should be worn, whether the machine is to be used for short or long periods. We would recommend that the tools and equipment which produce noise levels in excess of 90 dB(A) Leq as indicated in Table 14 should be used with hearing protection and signed accordingly. It was noted that many machines already have hearing protection It is generally difficult to reduce noise levels from workshop machines and hand tools at source without interfering with the work being carried out.
The pump testing bay can be used for periods of 20 minutes up to a few hours depending on the adjustments and work necessary on the pumps. This area should be designated as a hearing protection zone.
The Peltor earmuffs or E.A.R. earplugs provided will provide satisfactory noise attenuation, though compared to earplugs, the earmuffs have two advantages, they are more hygienic when hands are dirty or oily, and easier to fit and remove 5. Conclusions
Noise sources which will contribute significantly to fire-fighters’ noise exposures are: • The pumps of the Angloco Water Carrier, 102 dB(A) Leq at the operator’s • The pumps of the Saxon Front-Line Fire Appliances, 94 dB(A) Leq at the operator• The Positive Pressure Ventilator fan, 97 dB(A) to 102 dB(A) Leq at 1m to 3 m• The Acme Thunderer Whistle, 116 dB(A) Leq by the blower’s ear.
Earplugs worn under the helmet are should be provided if feasible for the pump and PPV operators. The effect of the Gallet helmet on noise levels at the ear was not determined, but there could be some amplification of sound from some directions.
We would recommend the effect of the helmet on noise levels at the ear be Noise levels were high in the front seats in the cabs of Front Line Fire Appliances when sirens were operating and windows or sun roof open. The First Action Level could be reached in just over twenty minutes. Closing the windows reduced noise levels and extended the time taken to reach the First Action Level to between 2 and 3 Noise levels of the Bronto Skylift Aerial Ladder Platform or the HIAB crane on the Multirole Vehicle are such that noise exposures of operators will not normally reach the First Action Level from these sources alone.
Most items of equipment, machinery and hand tools used in the Vehicle Maintenance Workshop produce high noise levels. These items are identified in this report. Since it is not possible to predict the amount of time that any individual will use each machine or tool. We recommend that hearing protection should be worn when using the designated machines, as noise control by other means would be difficult.
6. References
Statutory Instruments 1989 No. 1790; Health and Safety. The Noise at Work Regulations 1989. HMSO ISBN 0 11 097790 4.
Council of the European Community, 1986; Council Directive of 12 May 1986 on the protection of workers from the risks related to exposure to noise at work (86/188/EEC). Official Journal of the European Communities No L137, Health and Safety Executive, 1998; Reducing Noise at Work. Guidance on the Noise at Work Regulations 1989. HSE Publication number L108. HSE Books.
Health and Safety Executive; Introducing the Noise at Work Regulations HSE Personal alarm and alerting equipment
Compressor room
Notes: Compressor room is approx 3.6 m x 4.2 m, with block work walls and acoustic-tiled ceiling. Racal Ultramuff and ARCO/Peltor H9A earmuffs were available.
Inside Operational Equipment Technician’s (OET’s) van - Ford
Transit - Registration V525 FCR
Whelan Siren Speaker SA 340 STS fitted inside engine compartment onpassenger side.
Inside officer’s car: Ford Mondeo (Registration R433 YRV)
Front line fire appliance: Volvo FL6-14 chassis with Saxon
bodywork (Registration P963 JTR)
3 min 50 son localroads withsirensTotal trip 7m 04s,includingabove 3min 50 swithsirens,thenreturningviamotorwaywithoutsirens Front line fire appliance: Volvo FL6-14 chassis with Saxon
bodywork (Registration N324 HBK)
Front line appliance: Volvo FL6-14 chassis with Saxon bodywork
based at Eastleigh Fire Station (Registration not noted)
Aerial Ladder Platform: Angloco / Volvo vehicle (Registration
R359 TRV) with Bronto Skylift type F32 HDT
Angloco / Iveco Multi-role vehicle (MRV) (Registration P913 KPX)
fitted with HIAB 071AW crane
Angloco / Volvo FL7 Water Carrier (Registration No M267 XOT)
Fire appliance: Dennis (Registration A36 OPX)
Fire-fighting and general equipment
Turnout Alarm - Eastleigh Fire Station
Workshop equipment and operations.
One-third octave band centre frequency, Hz Noise spectrum of the pump on the Angloco Water Carrier at the
pump operator’s position
One-third octave band centre frequency, Hz Noise spectrum of the PPV fan at 3 metres distance behind and to
One-third octave band centre frequency, Hz Noise spectrum of the pump on a Saxon appliance at the pump
operator’s position
Appendix A
The Noise at Work Regulations, 1989.
Current limits for occupational noise in the UK are set by the Noise at Work Regulations 1989 [1]. The Noise at Work Regulations are the UK’s national implementation of European Directive 86/188/EEC [2]. Similar regulations apply throughout the European Union.
The Noise at Work Regulations specify that the employer shall reduce the risk of damage to the hearing of his employees from exposure to noise to the lowest level reasonably practicable (Regulation 6). In addition the regulations specify various Action Levels.
The First Action Level is a personal daily noise exposure, or ‘LEP,d’ of 85 dB(A). An employer must measure the noise exposures if they are likely to approach or exceed the First Action Level. If the action level is exceeded the employer has a duty to provide employees with information on noise and its effects and to make hearing protectors available for employees who wish to use them. In the Noise at Work Regulations the symbol LEP,d is used The Second Action Level is a personal daily exposure of 90 dB(A). At or above this Action Level the employer must provide ear protection and employees are obliged to wear it. The regulations also state that, above the Second Action Level, the reduction in noise exposure should be achieved by means other than hearing protectors where reasonably practicable.
There is a third action level, known as the Peak Action Level. The Peak Action Level is an instantaneous level of 200 Pa (200 pascals pressure, or 200 N/m2 or 140 dB re 20 µPa) and must never be exceeded without protection, no matter how short the exposure may be.
It is important at this stage to distinguish between noise levels and noise exposures. Noise exposures depend both on noise levels and on the duration of the noise. A high level noise for a short time will give the same noise exposure as a lower level noise for a longer time, if the total sound energies of the two noises are the same. Like noise levels, noise exposures are generally A-weighted and expressed in dB(A). The symbol ‘LEP,d’ is commonly used to denote the ‘personal daily noise exposure’ of an individual at work. The noise exposure is numerically equal to the average noise level for a standard 8-hour shift.
For example, a person working for a total of eight hours a day in a steady noise level of 75 dB(A) Leq will have a noise exposure of 75 dB(A) LEP,d. If he or she stays in the noise level for a lesser time the exposure is reduced, for example, four hours a day in an average noise level of 75 dB(A) Leq will give an exposure of 72 dB(A) LEP,d. Conversely, working overtime will increase the noise exposure, for example 16 hours a day in a noise level of 75 dB(A) Leq will give an exposure of 78 dB(A) LEP,d.
In guidance notes published by the Health and Safety Executive [3] it is stated that there is “a quantifiable risk” of hearing damage from noise exposures between 85 dB(A) and 90 dB(A), and a “residual though small” risk below 85 dB(A).
A summary of the employer’s and the employees’ responsibilities under the Noise at Work Regulations are summarised in the tables below.
Summary of employers’ duties under the Noise at Work Regulations
Action required
≥ 90 dB(A)
Level ‡
General duty to reduce risk
Risk of hearing damage to be reduced to the lowest level reasonably
practicable (Reg 6)
Assessment of noise exposure
Noise assessments to be made by a competent person
(Reg 4)Record of assessments to be kept until a new one is made (Reg 5) Noise Reduction
Reduce exposure to noise as far as is reasonably practicable by means
other than ear protectors (Reg 7)
Provision of information to workers
Provide adequate information, instruction and training about risks to
hearing, what employees should do to minimise risk, how they canobtain ear protectors if they are exposed to between 85 and 90 dB(A),and their obligations under the Regulations (Reg 11) Mark ear protection zones with notices, so far as reasonably practicable (Reg 9)
Ear protectors
Ensure so far as is practicable that protectors are:
provided to employees who ask for them (Reg 8(1)) Ensure so far as reasonably practicable that all who go into a marked ear protection zone use ear protectors
(Reg 9(1)(b))
Maintenance and use of equipment
Ensure so far as is practicable that: all equipment provided under the
Regulations is used, except for the ear protectors provided between 85and 90 dB(A) (Reg 10(1)(a))Ensure all equipment is maintained (Reg 10(1)(b)) Notes:
‡ All the actions indicated at 90 dB(A) are also required where the peak sound pressure is at or above 200 Pa
(140 dB re 20 µPa).
* This requirement applies to all who enter the zones, even if they do not stay long enough to receive anexposure of 90 dB(A) LEP,d (Acknowledgement: Table adapted from HSE Leaflet IND(G)75) [4] Summary of employees’ duties under the Noise at Work Regulations
Level ‡
Use of equipment
So far as practicable:
use ear protectors (Reg 10(2))
use any other protective equipment (Reg 10(2)) report any defects discovered to employer (Reg 10(2)) ‡ All the actions indicated at 90 dB(A) are also required where the peak sound pressure is at
or above 200 Pa (140 dB re 20 µPa).
(Acknowledgement: Table adapted from HSE Leaflet IND(G)75) [4]

Source: http://www.hantsfire.gov.uk/so-8-1-7-equipment.pdf