9. The type of supervision for a mixed installation is established as follows:(a) by establishing the most rigid type of supervision with respect to different types of stationary engines in simultaneous operation and according to Schedule C;
(b) by the computation of ratios between the total capacity of each type of stationary engine and their respective maximum capacity, as indicated in Schedule C for the type of supervision established under paragraph a; however, low-pressure refrigerating apparatus from Group A1 or B1 whose capacity exceeds 1,200 kW, high-pressure refrigerating apparatus from Group A1 or B1 using a compressor of the centrifugal type whose capacity exceeds 1,200 kW, steam engines and turbines whose capacity exceeds 250 kW may not have an influence on the type of supervision for an installation;
(c) by the sum of these ratio;
(d) if this sum is inferior or equal to the whole, the type of supervision for the installation is the same as the type established in paragraph a; and
(e) if this sum is greater than the whole, the type of supervision for the installation becomes the type immediately more restrictive than that established in paragraph a.