The relationship between stair dimensions and rate of energy expenditure was investigated in order to decide a maximum allowable pitch for domestic stairs.

Three experimental stairs were used to produce various dimensional combinations of tread going and riser height; three young male subjects climbed up and down the stairs at a constant vertical speed, and their heart rate was used as a measure of the energy requirements. Its relationship with the oxygen consumption was established in advance by a treadmill walking test. A continuous climbing-up of a highrise office building also provided data on the change of heart rate during stair use.

A careful examination of the obtained data suggests no definite maximum pitch for domestic stairs; the hypothesis that there exists a pitch limitation due to energy expenditure is applicable only to public ones where a walking speed is imposed by other users. The present study gives a conclusion that other factors such as safety or usability decide necessary dimensions for domestic stairs.

* Part of this paper was published in the Transactions of the Architectural Institute of Japan in Japanese (Uno & Kose, 1984), and a shorter version is to be presented at the International Conference on Building Use and Safety Technology, in Los Angeles, Ca. , March 1985.
^*1 Senior Researcher
Building Design and Use Division Environment, Design & Fire Department