15. In the case of a boiler, coiled tube boiler or thermal liquid boiler, with the exception of electric boilers, the capacity in kilowatts is established by dividing by 3.6 × 106 the difference between the total quantity of heat in joules contained in the fluid which enters the boiler and the total quantity of heat contained in the fluid leaving the boiler per hour. In the case of an electric boiler, the capacity in kilowatts is equal to the maximum number of kilowatts supplied to the boiler.
R.R.Q., 1981, c. M-6, r. 1, s. 15.