Pump down the volume
New legislation and a public less tolerant of environmental noise mean that water companies must introduce noise control measures wherever possible. Alan Carter reports on a project in Derby that shows the way ahead.
In recent years, attention has increasingly focused on the detrimental effects of noise pollution. This is further emphasised with the rapidly growing amount of literature available, highlighting how noise pollution can be responsible for a wide range of detrimental health problems.
In 1996, the European Commission's Green Paper, Future Noise Policy, stated that an estimated 20% of EU citizens were exposed to noise levels that scientists and health experts considered unacceptable. Levels at which most people become annoyed, sleep is disturbed and health could be at risk.
While levels of environmental noise in the UK do not generally reach intensities that could damage hearing, which can be the case when investigating workplace noise, research indicates that there can be significant detrimental health issues from people being regularly affected by high noise levels within the environment. Research also indicates that the effects on health can range from annoyance, to disturbed sleep and increased levels of stress.
To combat the detrimental effects of environmental noise, the EC proposed a directive relative to the Assessment and Management of Environmental Noise (Environmental Noise Directive), which focuses principally on road, rail and air traffic and industry. The proposal complements existing EU legislation.
The directive was adopted in the form of Directive 2002/49/EC European Noise Directive and was subsequently adopted in the UK under The Environmental Noise (England) Regulations 2006, The Environmental Noise (Scotland) Regulations 2006 and The Environmental Noise (Wales) Regulations 2006.
The key tenants of the legislation are the assessment and management of environmental noise from road, rail, air traffic and industry.
The legislation requires that:
- All member states produce strategic noise maps for rail, road, railways and industrial agglomerations. These maps will be used to assess the number of people "annoyed" and sleep disturbed throughout Europe
- Members of the public are informed and consulted about noise exposure, its effects and the measures which will be considered to address noise issues
- Action plans to reduce noise and maintain environmental noise quality, where it is good are drawn up
- A long-term EU noise strategy is produced with the objective of reducing the number of people affected by noise in the long term
While noise at work applications are measurable against defined measurement criteria, it is often more difficult to assess the impact environmental noise has on individuals and the wider community. Not only do individuals perceive noise differently, they can also respond differently to the same noise under different conditions.
Noise levels that are considered acceptable in a work environment may be considered unacceptable in a residential setting. Also, a noise level that may be acceptable during the day may be unacceptable at night, and this can further be exacerbated by changing weather and wind conditions.
Major water utilities and contractors, such as Norwest Holst, are already addressing such noise-related issues.
Norwest Holst was involved recently in installing two pumps to provide standby/emergency facilities for pumping water from sources in the Derby area into the Derwent Valley aqueduct. The pumps were needed to supplement water available from the Derwent Valley reservoirs and to protect the supply to locations farther down the aqueduct.
It was intended that the pumps would only ever operate continuously in the case of water supply difficulties and occasionally for limited periods for servicing. Despite this, an environmental noise assessment in line with BS4142:1997 was commissioned to assess the impact of the pumps on background noise levels particularly at night time.
It is important when tackling and addressing these types of environmental noise issues that specialists in the field are consulted to assist with the analysis, diagnosis and provision of suitable noise control measures for both industrial and environmental applications.
After researching the market, Norwest Holst called in noise control specialist Wakefield Acoustics. Following the completion of an initial noise assessment it was deemed that a reduction in noise levels of at least 15dB(A) would be required to ensure any risk of increased noise levels to local residents was eliminated.
The solution was to supply bespoke designed and purpose-built acoustic enclosures on to the pre-installed vertical pumps. The enclosures comprised of a hot dip galvanised framework and pre-galvanised acoustic panels and a forced air ventilation system. The enclosure was made fully demountable for major access/maintenance and all panels over 25kg incorporated lifting points as standard.
Following installation of the acoustic enclosures, a post installation noise assessment was done which recorded noise levels that had been reduced by 17dBA, significantly higher than the original specification.
Norwest Holst opted to use Wakefield Acoustics' services because of its experience in providing noise control solutions. It offers a range of applications within the water and wastewater sector throughout the UK, working closely with manufacturers, contractors and directly with water authorities, providing noise control solutions for applications such as sludge dewatering, aeration, filtration, fluid handling and odour control.
Patrick McGee, of Norwest Holst, says: "We are pleased with the work undertaken by Wakefield Acoustics. We achieved more than the noise reduction required and the project was completed and installed against a tight timescale."
Alan Carter is technical sales manager at Wakefield Acoustics. T: 01274 872277