Frequently Asked Questions

Noise Assessment according to BS 4142:2014 with the XL2

Noise Assessment according to BS 4142:2014 with the XL2
The XL2 Sound Level Meter is built for precisely measuring and recording industrial and commercial sound. The Data Explorer PC-software evaluates the recorded data in detail and calculates the Rating Level Lr. A character correction for tonality and impulsivity can be automatically added using the objective method detailed in BS 4142:2014. This provides an expert tool for rating and assessing sound of an industrial and/or commercial nature.

The assessment, according to the British standard BS 4142, is based on measuring the average sound pressure level LAeq over a representative period of time. Humans generally find that sounds with tonal or impulsive components are more disturbing than those without. The increased annoyance is considered with a penalty. The sum of the measured sound level and the individual penalties produces the rating level Lr for comparison with the applicable legal directive.

XL2 detects Impulses
The XL2 Sound Level Meter accurately records the sound levels as well as the audio data. As soon as an impulse is detected as defined by the BS4142:2014 standard or Nordtest Method NT ACOU 112, the penalty is prominently displayed on the LCD. The generated log file documents this penalty, the level difference of the impulse, and the rate of change. The tonality of the sound can be seen on the 1/3rd-octave spectrum. Given this displayed penalty and the tonality, the expert customer is able to make an on-the-spot manual calculation of the rating level Lr.

Data Explorer Software calculated Rating Level Lr
For a complete evaluation according to BS 4142, the Data Explorer PC-software is available. The reference time intervals are one hour during the day (7:00 – 23:00) and 15 minutes at night. The software calculates the number of impulsive events and the penalty for each time interval, as well as the number and duration of tonal sounds. From this, the rating levels Lr for each time interval are available for comparison with the legal limits. For example, the BS 5228-1 standard specifies limits in residential areas of 65 dB during the day and 45 dB at night. The audio recording can be played back, synchronized with the level progression on the graph, through the PC loudspeaker and thus the subjective impression can be verified.

Rating Level Assessment with XL2 Sound Level Meter
In summary, the XL2 Sound Level Meter in combination with the Data Explorer PC-software provides the professional solution for the full assessment of the rating level Lr according to the BS4142:2014 standard and Nordtest Method NT ACOU 112. The Type Approval option extends the sound level meter to the XL2-TA, a PTB-approved product. The overall measurement package is ideally suited for documenting industrial and commercial sound and generating expert reports.

To determine impulsive sounds, the XL2 Sound Level Meter requires the optional Extended Acoustic Pack and firmware V3.23 or higher. The rating level calculation is enabled by using the latest Data Explorer V1.60. The software is freely available for all users to download. Data import from the XL2 into the software is possible with the Data Explorer Option installed on the XL2 or a yearly subscription Data Explorer 365. Data Explorer can be installed on any number of PCs.



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