An analysis has been made of draft failure with residential heating units operating at low rates of combustion during mild, calm weather. It has been shown that under these conditions the relation between chimney draft andhouse pressures becomes important in determining when venting failure will occur. A simple equation expressing this relation has been developed. It shows that draft failure will occur if the mean flue gas temperature in the chimney falls below a value that depends on the neutral zone level.
This paper describes part of a research on the influence of environment on physiological reactions and thermal comfort. Experimental rooms and apparatus are described and the imperfections in some of the instrumental methods - especially in respect to the measurement of air change by tracer substances - are noted. A brief description of a method to measure air change is givenin which CO2 is used. The importance of limiting the rate of air change in rooms heated by fires - as a means to save heat - is stressed.