Abstract
Dry gas meters are used in physiology laboratories to measure minute ventilation. The accuracy of these meters must be known since an error, of for instance 5%, affects the subsequent calculations for oxygen consumption by the same amount. Two precalibrated DTM-325 dry gas meters (American Meter Co., Philadelphia, PA, USA) were therefore tested for accuracy against a 350 l Collins chain-compensated gasometer. Provided that at least 25 l was passed per measurement then: a. continuous flows (air saturated with water vapour) between 60 and 150 l.min-1 were measured with an error of < 1%; and b. sinusoidal flows (ambient air) between 8 and 100 l.min-1 were misread by < 1% and the error was still within 2% at 140 l.min-1. It may, therefore, be concluded that the two precalibrated dry gas meters studied are valid volume measuring devices.