Features of Sound Level Meters

Sound Level Meters (Noise Meters) often have a wide range of features and functions. Through our website we use icons and symbols to help you choose a suitable instrument. On this page is more information about each of these features and how they can be used.

	Class 1
	Class 2
	Data Logging
	Frequency Analysis
	PPE Selection
	PPE Selection with the +Version upgrade
	Weather protection available for outdoor measurements

Sound Level Meters, like all noise measurement instruments, are designed to meet International Standards. The most common of these is IEC 61672 although this may be referred to by a National Standard number such as BS EN 61672 in the UK. This standard defines how the Sound Level Meter should measure and how acurate it should be. There are many different points that have to be met to ensure that the instrument meets these standards and these include not only noise level accuracy but temperature, humidity, barometric pressure and vibration tests. These standards have levels of accuracy. The latest IEC 61672 standard (and its National variants) has Class 1 and Class 2 whilst the older standards have Type 1 and Type 2. These are very similar to each other. A Class 1 instrument is more accurate as the tolerances that are allowed are much tighter than for a Class 2 instrument. Generally Class 1 instruments are used for environmental noise applications although they are perfectly suitable for noise at work and occupational noise (provided they have the correct measurement functions). If you are working to meet a set of regulations, such as the UK Noise at Work Regulations or the OSHA Regulations, any Standards and Class that your noise meter must meet will be stated clearly and it is essential that your noise measurement instrument does meet these standards. If you have any questions about this, please let us know and we can give you some more information.

As with Class 1 instruments described above, Class 2 instruments are designed to meet standards that specify how accuractely the instrument should measure noise. A Class 2 instrument is designed to meet the same specifications as a Class 1 instrument but the tolerances allowed are wider. Typically, Occupational Noise and Noise at Work Regulations specify that a Class 2 or Type 2 Sound Level Meter is sufficient. However, do check that the instrument you are using does meet the standards and level of accuracy stated in the regulations or guidelines that you are working to. If you have any questions about this, please let us know and we can give you some more information.

In many applications where sound level meters are used, it is useful to be able to record the measurement information and then download this to software to produce reports and to analyse the measured data further. In the Cirrus sound level meters this is known as data logging. The CR:800C Series have this feature fitted as standard and they can store up to 1,300 individual measurements and over 12 days of Time History (Noise Profile) data. This is essential for environmental and community noise where the measurements are often made over a few days. It is also very useful for Noise at Work and Occupational Noise where reports of the noise are required. Data Logging can be added to the CR:260A Series by adding the +Version upgrade. This allows up to 100 measurements to be stored in the instruments memory and then downloaded to the supplied software. If you have any questions about this, please let us know and we can give you some more information.

There are many different way to use frequency analysis when measuring noise. The most common application is Octave Band Filters. These are electronic filters within a sound level meter that split up the noise into frequency bands. The number of bands depends upon the level of detail needed but the most commonly used are 1:1 and 1:3. 1:1 Octave Band Filters are often used in Noise at Work applications where there is a need to select appropriate PPE or hearing protection. The level of attentuation provided by different PPE products varies across manufacturers and designs. By measuring the noise in 1:1 Octave Bands, this inforamtion can be used to assess the protection provided by each product and this information can be used to choose appropriate hearing protection or PPE for that environment. 1:3 or Third Octave Band Filters do the same job, splitting up the noise into frequency bands, but for each 1:1 Octave Band there are three 1:3 Octave Bands. This gives more detailed information and is often used for environmental noise monitoring and analysis. If you have any questions about this, please let us know and we can give you some more information.

Sound Level Meters such as the CR:822C, CR:264A+ or CR:821C can be used to measure the noise levels using Octave Band Filters (as described above) These measurements can be downloaded to the software supplied with the instruments to aid in the selection of suitable PPE or Hearing Protection. The software supplied as a database of over 100 different hearing protection products such as Ear Defenders and Ear Plugs. Each of these has a different way in which it reduces the noise at each of the different measured frequencies. This means that some of the PPE products will be suitable for a certain noise and others may not. The software will use the Octave Band noise levels that have been measured to determine, using the information published by the manufacturer or supplier, the reduction in noise level that can be achieved with the instruments in the list. If you have any questions about this, please let us know and we can give you some more information.

The CR:264A and CR:263A Sound Level Meters can be upgraded with the +Version which allows up to 100 measurements to be stored in the instruments memory. If this +Version upgrade is added, Octave Band measurements can be downloaded into the software and then used to select PPE as described above. If you have any questions about this, please let us know and we can give you some more information.

There are many applications where measuring the noise outdoor is essential. Environmental noise monitoring usually takes place outdoors and often in conditions that are not ideal for delicate electronic equipment. To allow for these measurements to be made, a weather protected outdoor measurement kit can be used. This will contain the sound level meter and its accessories. The measurement microphone will be connected to the weatherproof kit case by a cable and the microphone will be protected from any rain or wind. An outdoor microphone will be used to protect the microphone capsule and this can be located in the most appropriate position to get good quality noise measurements whilst keeping the sound level meter in safe location. If you have any questions about this, please let us know and we can give you some more information.