Air quality is a basic requirement for the survival of miners in distress while waiting for rescue in a MRC (mine refuge chamber). The use of air purifying devices is an effective supplement for removing harmful gas in a MRC. Scholars have paid much attention to the structure of air purifying devices and purifying agents for MRCs, but research on the number and layout of purifying devices in MRC has attracted little attention. To determine a reasonable number and layout of purifying devices in a MRC, theoretical analysis was conducted on the relationship between harmful gas concentration and the number, as well as the operating parameters, of devices in the chamber. A configuration calculation formula for purifying devices in MRCs was thus obtained. By conducting five experiments in a MRC with capacity of 50 people, the influence of the number and layout of purifying devices in the chamber, on the CO2 concentration distribution, was studied. The results show that, when the number of personnel is constant, the final concentration of harmful gas in the MRC is only related to the air volume from the air purifying devices and the efficiency of the air purifying devices. When using air purifying devices to remove CO2 in the MRC, the maximum CO2 concentration difference between different measuring points was less than 0.15%. With increasing number of purifying devices, the harmful gas concentration decreases, and the distribution of harmful gas is more uniform. When using two purifying devices, one at either end of the MRC, the harmful gas concentration was more uniform than when both devices were located in parallel at one end. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.