#Noise mapping and dosymmetry manual

The manual also gives the calibration procedure. The SLM must be calibrated before and after each use.

#Noise mapping and dosymmetry how to

The instrument's instruction manual explains how to hold the microphone. With most SLMs it does not matter exactly how the microphone is pointed at the noise source. To take measurements, the SLM is held at arm's length at the ear height for those exposed to the noise. The SLM takes the sound pressure level at one instant in a particular location. The readout displays the sound level in decibels. These signals are then processed by the electronic circuitry of the instrument. The microphone detects the small air pressure variations associated with sound and changes them into electrical signals. The SLM consists of a microphone, electronic circuits and a readout display.

* ISLM stands for Integrating Sound Level Meter To produce noise map of an area take measurements on a grid pattern. Particularly useful if noise is highly variable it can measure equivalent sound level over a short period of time (1 minute). Measurement should be taken 1 to 3 metres from source (not directly at the source). Noise levels generated by a particular source Only useful when work can be easily divided into defined activities and noise levels are relatively stable all the time. If noise levels vary considerably, it is difficult to determine average exposure. If the worker is mobile, it may be difficult to determine a personal exposure, unless work can be easily divided into defined activities. Most accurate for personal noise exposures, and is worn by the worker. Table 1 Guidelines for Instrument SelectionДЄppropriate Instruments (in order of preference) Table 1 provides some instrument selection guidelines. The user's manual provided by the instrument manufacturer provides most of this information. It is important that you understand the calibration, operation and reading the instrument you use. The most common instruments used for measuring noise are the sound level meter (SLM), the integrating sound level meter (ISLM), and the noise dosimeter. What types of instruments are used for measuring noise? However, noise dosimetry (such as personal noise exposure measurements) is necessary if the workplace noise levels vary throughout the day or if the workers are fairly mobile. If the workplace noise remains steady, workers are stationary throughout the shift, and measurements are representative of a typical day, the noise survey data can be used to determine if there is a potential exposure to harmful noise levels and if additional measurements are required. The second step is to determine personal noise exposure levels that is, the amount of noise to which individual employees are exposed.

The initial measurements are noise surveys to determine if: Conditions during both a typical and atypical shift (noise sources, activities, shift length, etc.).The temporal pattern of noise - continuous, variable, intermittent, impulse.The sources of noise, and times when the sources are operating.The purpose of measurement: compliance with noise regulations, hearing loss prevention, noise control, community annoyance etc.The person making the measurement must understand: Before taking field measurements, it is important to determine the type of information required.