Spec:The personal noise dose meter is test equipment to evaluate the noise condition of working environment by measuring the accumulated noise exposure.

DOSE is a parameter used to quantify noise exposure measured in a period, during turns of % noise exposure relative to 90dBA for 8 hours. 
i.e. 100% DOSE = 90dBA for 8 hours 
This is known as the Criterion. Other criterion are available such as 100% DOSE = 85dBA for 8 hours to meet legislation in different countries. 
If the person stayed in this environment for 4 hours, he would receive 50%DOSE. 
Also if the noise level was say 93dBA, 3dB higher, a 100% DOSE would be accumulated in only 4 hours, The above example is for a dose meter with 3dB Exchange Rate, where a 3dB increase in sound level corresponds to a doubling energy. A dose meter with 5dB Exchange Rate is also, available where the sound must increase by 5dB to double the dose as required to meet noise legislation in some countries.

The Noise Dose Meter measure the frequency weighted noise exposures and peak sound levels simultaneously.
* Simple operation, including direct read–out of results.
* Eight built–in standard dose measurement setups : OSHA80, OSHA90, MSHA-80, MSHA-90, DOD, ACGIH, ISO85 and ISO90.
* Nine user – defined measurement setups.
* A single sound level meter (SLM) setup.
* A single sound level meter (SLM) setup.
* 50 dose (DATA) result stores.
* Download of setups from PC to the meter.
* Keypad lock protects meter against accidental operation.
* Timers support pre–selection of measurement time and duration.
* Use USB data output to connect with PC.
* Provide Bluetooth data output choice.
The meter is ideal for quick on–site surveys and for monitoring personal noise exposure in accordance with European ISO or USA OSHA, MSHA, DOD AND ACGIH standards.
The meter is two overlapping measurement ranges : 60 – 130 & 70 – 140dB, A & C RMS weightings, Linear & C Peak weightings, Fast & Slow time weightings, and energy exchange rates (Q) of 3, 4, 5 & 6. In dose measurement mode, it display % dose, % dose projected for an 8 hour period, peak level and measurement duration.
For countries that are subject to European Union regulations or the equivalent ISO standards,  the  meter  measure  the  daily  sound  exposure  level  (LAeq,8hr,Pa2h according to IEC 61252, which is identical with the L EX,8h  required by ISO 1999), while for USA OSHA/MSHA regulations they measure the Time Weighted Average level (TWA).
When used as a sound level meter it display sound level, time–averaged (L Aeq) sound level, peak and sound exposure level (SEL).
The meter is automatic run timing facilities controlled by the built–in clock and time–history recording capabilities. Sampling times can be specified between 1s and 1 hour, while storage is 120000 data points.
The meter is able to measure and save up to five specified Ln values (Statistical noise levels). Run duration, start and stop times preset, and other setting via the meter keys or software.