ISO 9613-1:1993

Specifies an analytical method of calculating the attenuation of sound as a result of atmospheric absorption for a variety of meteorological conditions. For pure-tone sounds, attenuation due to atmospheric absorption is specified in terms of an attenuation coefficient as a function of the frequency of the sound (50 Hz to 10 kHz), the temperature (- 20 °C to + 50 °C), the relative humidity (10 % to 100 %) and pressure (101,325 kPa) of the air. Formulae are also given for wider ranges (e.g. ultrasonic frequencies, lower pressure) and for other than pure tones.