The sound level meters and noise dosemeters that Cirrus manufactures are designed to meet the performance criteria laid down in various standards. For example, the optimus sound level meters are designed to meet the requirements of BS EN which is also known as IEC Within these standards there are many different performance criteria that the instrument must meet along with tolerances that are allowed. It may not be possible for the instrument to meet the exact requirements all of these criteria but as long as it is within the tolerances that is acceptable. The older standards for sound level meters had different levels of tolerances with the tightest known as Type 0, with Type 1, Type 2 and Type 3 progressively looser in terms of the tolerances allowed.
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The class system in noise meters and sound level meters refers to the accuracy of the results given by the meter while measuring noise levels. The classification of sound meters has changed over the years as the standards have evolved, but is essential in place to differentiate between the performance of sound meter microphones. Below is a list the standards as they have evolved over time. It all goes back to ! If you own a Sound Level Meter and provided that it is one properly compliant with the standards, then it is required to have the standard name and Class written on the meter this can be on a start-up screen now!
Essentially, the lower the number the better the accuracy of the product. There are some applications where the classification is critical and some where it is less so. A few examples are list here. Accuracy is no simple matter with a Sound Meter as, not only does it vary with the Class of instrument, but also with the frequency of the sound being measured. The table below is a brief excerpt from the standard, which shows the acceptable tolerances at a few selected frequencies across Class 1 and Class 2.
In reality, most modern, properly compliant Sound Level Meters will perform better than this, but if you want to look specifically at a very high frequency, then you could be way out! This type of equipment is usually found in catalogues and will come with an attractive price-tag. Be warned, however, that these instruments should only ever be used if you want to check that there are no levels anywhere near the action values stated in the regulations more on that later.
You can have a look at one such meter on the Castle shop, which we sell for occasions where there is just that basic need. These meters do not, however stand up to scrutiny and can report significant errors as soon as there is a complex mix of frequencies often found in industry.
View our Sound Level Indicators. IEC is an international standard that governs the design and manufacture of this type of instrument. There are certain criteria for your sound meter to be suitable to be used as part of a noise at work assessment.
The minimum requirement is full compliance with IEC Class 2. Dosemeters are incredibly useful for assessing the exposure of mobile employees. There is no classification system for dosemeters, but because of the type of microphones used, the tolerances are actually taken from the Type 2 Sound Meter specifications. View Full Range Online. Call us on Toggle navigation. Sound Meter and Calibrator Classification The classification of sound meters has changed over the years as the standards have evolved, but is essential in place to differentiate between the performance of sound meter microphones.
The Standards Over Time Below is a list the standards as they have evolved over time. Environmental Noise Monitoring Most of the standards in use in the UK require you to use at least a Type 1 or Class 1 meter, this is generally because Class or Type 2 microphones will not measure low enough sound levels and do not measure accurately up to the higher frequencies.
Building Acoustics Due to the requirements of testing building performance at a wide range of frequencies, a Class 1 meter really should be used. Fire Alarm Noise Testing Where audible fire alarm sirens or bells are installed in commercial premises or residential properties, the should level MUST reach a required minimum.
You will often see these meters claiming IEC, even though this is now an obsolete standard! Personal Sound Exposure Meters Dosemeters, Dosimeters Dosemeters are incredibly useful for assessing the exposure of mobile employees.
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What is the Difference Between Class and Type for Sound Level Meters?
In order to get accurate and repeatable measurements, it is essential that a sound level meter meets the relevant standards. Most measurement regulations will state the standards that should be met by the equipment. There are other standards for the Calibrator, for noise dosimeters, personal sound exposure meters, octave band filters and so on. Here is a summary of the most important standards. Customer Service Chat.
Differences Between Class 1 and Class 2 Sound Meters
A sound level meter is used for acoustic sound that travels through air measurements. It is commonly a hand-held instrument with a microphone. The best type of microphone for sound level meters is the condenser microphone  , which combines precision with stability and reliability. The diaphragm of the microphone responds to changes in air pressure caused by sound waves. This movement of the diaphragm, i. While describing sound in terms of sound pressure Pascal is possible, a logarithmic conversion is usually applied and the sound pressure level is stated instead, with 0 dB SPL equal to 20 micropascals.
BS EN 60651:1994, IEC 60651:1979
Superseded By: IEC Prices subject to change without notice. About Us. Contact Us.