This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol3", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
When there is a Central Hall it should have floor space of not more than 4 square feet for each scholar, while about 3 1/2 will really be sufficient. The hall must be fully lighted, warmed, and ventilated.
A single central hall may be provided for use at separate times by two departments, so long as it be so placed as to be readily accessible from the classrooms of each.
Where outdoor space is unavailable, physical training should be given in the hall (or corridor). This should be taken into consideration when planning. Gymnastic apparatus being unsuitable for children under 14, a separate gymnasium cannot be approved.