Outdoor Environmental Noise Monitoring

Outdoor Environmental Noise Monitoring

Environmental noise is a major issue in most countries, especially in heavily populated or industrialised areas. The link between exposure to noise and hearing damage has been known for more than 50 years now. Its sources and adverse effects on our well-being are varied and can range from sleep disturbances to increased stress levels, potentially leading to more major problems such as heart disease. In order for environmental noise monitoring to be effective you will, therefore, need to take into account a number of diverse issues by monitoring noise levels for longer periods and in a variety of different ways.

Industrial noise monitoring, for example, is a much more exact science as it involves the assessment of specific noise levels and the decision asenvironmental noise monitoring kit to corresponding legislative and/or action levels. Environmental noise is very different because the level of annoyance or nuisance can be highly subjective and will elicit diverse reactions from different people.

Typical sources of environmental noise include:

Industrial sites.
Power stations.
Construction work.
Road traffic.
Animals (e.g. dogs barking).
Aircraft noise.
Entertainment venues.

Claims against your company for noise-induced hearing loss may be made many years in the future. The only serious defense is correctly-measured noise data, made logically, and on regular basis. The key thing to establish here is how loud the noise is and how long people are exposed. Noise is accurately measured with a compliant sound level meter or personal noise exposure meter in decibels, expressed as (dB). An ‘A weighting’ also expressed as ‘dB(A)’ is used to measure average noise levels, and a ‘C weighting’ or ‘dB(C)’, is used to measure peak, impact or impulsive noises.

To calculate personal exposure, you will need to measure the sound pressure level at the different places the person works and for the different tasks carried out during a working day.  An average is calculated from these values and the time spent in each place or at each task.

But what if the noise values you wish to measure are situated outside and over a long period? Rain or even heavy fog, can make using a normal sound level meter outside for long periods impractical, as moisture can damage the microphone capsule and, in extreme conditions, the instrument itself.

Some applications require you to measure for perhaps a few hours, half a day or overnight to get adequate data to monitor a noise issue, while other applications require longer term measurements on a semi permanent basis.

Pulsar WK1 Short-term outdoor Monitoring Kit

Please note: The WK1 short term outdoor kit is only intended for measurements that are for relatively short periods i.e. up to a day or overnight. If you require a system for longer measurements you should choose the WK2 long term outdoor kit.

To reduce cost, the pre-amplifier and microphone from the sound level meter itself are fitted within the ‘waterproof’ mounting system complete with windshield and bird-spikes. The windshield system provides protection from the elements whilst the bird-spikes are needed to avoid birds perching on the windshield and affecting your noise measurements. This unit can then be mounted on a standard camera tripod.

The 10 metre cable coming from the microphone assembly is connected to the extremely robust weatherproof carry case which protects the instrument, power supply and accessories.

The Lightweight Outdoor Microphone unit is designed to provide weather protection to a Preamplifier and Microphone Capsule (supplied with the Sound Level Meter). This allows Sound Level Meters to be used for short term outdoor measurements. Please note that the unit does not provide weather protection for the Sound Level Meter. Precautions should be taken to ensure that the Sound Level Meter is not exposed to adverse weather conditions.

Pulsar WK2 Long-term Outdoor Monitoring Kit

The full outdoor noise measurement device microphone system consists of an integral tripod and microphone assembly which hermetically seals the pre-amplifier and associated circuitry. This is to prevent humidity affecting the circuitry and introducing impedance and therefore measurement errors, so the WK2 system will work in conditions of up to 99% humidity to full performance.

The microphone windshield /bird spike assembly employs the same weatherproofing techniques normally used for permanent airport monitors. The adjustable tripod legs of the sealed unit can level the system to any surface and the ‘hook’ system* can be used to attach the assembly to a nearby permanent fixture or add extra weight to the assembly. This ‘tripod and microphone’ assembly can be easily transported using its tubular carry case.

*The WK2 has a hook system at the top of the tripod legs to allow this to be chained down. The hook is on a standard 20mm conduit thread so that all the standard electrical fittings can be utilised to fasten the system in place. Some users mount the microphone on a vertical threaded conduit tube to place it at a special height.

FEATURES

Quickly converts selected Pulsar sound level meters into an environmental noise monitor.
Very robust weatherproof carrying case (lockable).
Cost effective.
WK1 for shorter measurements.
Heavy duty WK2 for longer term noise measurements.
Bird spikes to protect the windshield.
Rechargeable power pack which lasts up to 5 days.
Complete waterproofed outdoor microphone system with WK2.

The WK:2 outdoor system is designed to be used as part of a portable semi-permanent acoustic measurement system. It is powered by the Sound Level Meter or data logger to which it is connected via the screened and waterproof cable. The microphone system in its standard form is not equipped with a separate rainshield, relying instead on a windshield to prevent rain reaching the microphone capsule membrane.

The capsule height can be set to be between 1,2 and 1,5 metres, the two internationally agreed microphone heights for various outdoor measurements. It should be noted that this will bring the birdspikes to a height at which they could cause danger to the user. Care should be taken therefore when using the birdspikes and persons should be protected from this danger.

The WK:2 is supplied with a windshield to reduce wind noise and to protect the capsule from adverse weather conditions. The top of the windshield carries the bird-spikes which prevent birds from landing on top of the unit, thus causing extraneous noise as well as soiling the windshield. The unit is also supplied with an integral tripod allowing the unit to be used as supplied.

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