Noise meter handles dangerous environments

Edited by the Engineeringtalk editorial team Apr 17, 2008

The Protector Software can present logged noise exposures, making it much easier to visualise the variation with time of the measured noise levels.

Bruel and Kjaer's 'intrinsically safe' version of its Type 4445E noise dose meter handles measurements, in potentially explosive environments.

The 4445E can be enhanced with Bruel and Kjaer's Protector Software for use on a PC, which offers users a range of post-measurement facilities, including data comparisons and statistical analyses.

Statistical analysis of noise levels establishes a general 'picture' of the noise situation, showing how much the noise level varies and whether excessive exposures stem from a generally high noise level or a few isolated incidents.

This makes the meter ideal for use in many different work environments, such as factories, chemical plants or construction sites.

The Protector Software also can present logged noise exposures, making it much easier to visualise the variation with time of the measured noise levels.

The data logging tool allows users to make numerous measurements over an extended period of time and add a time stamp to each data point.

This set of time history data reveals a variety of information, including frequency and times when noise levels are excessive, making it possible to link noise problems to specific processes or events throughout the day.

It also allows users to decide whether excessive measured values should be discarded from the record and whether further investigation is needed.

The timer feature allows an entire week's worth of measurements to be set up, eliminating the user's need to personally attend to each measurement.

The user has only to enter the date and time for the measurements to begin, before switching the noise dose meter on.

The instrument can then be left unattended, until switched off, once the required period of measurement has finished.

Since 2003, all noise dose meters used within hazardous or volatile atmospheres must have the ATEX (Intrinsically Safe) approval.

Bruel and Kjaer's model meets the requirements associated with ATEX certification code EEx ia I M1 and EEx ia IIC T4 II 1 G, making it suitable for use in dangerous areas such as mines, printing works, petrochemical plants and other areas that require the use of Ex-rated instruments.

Damage caused to workers' hearing by long-term exposure to high levels of noise is the primary cause of occupational hearing loss, yet many are still unaware of the potential for damage.

Noise dose meters such as the Bruel and Kjaer Type 4445E are valuable tools in the fight against noise-induced hearing loss.

A noise dose meter is worn with the microphone fastened close to the ear.

It measures the sound pressure level and calculates the so-called noise "dose" received by the individual during the day.

The noise dose is expressed as the equivalent average sound level for an eight-hour period (reference duration) and this level must be below the limit specified in the relevant occupational health regulation.

Often an 87dB limit is used.