Which requirement must be met for the rated capacity of a regulator?

The requirement for the rated capacity of a regulator to be equal to or greater than the combined demand of all connected appliances is essential for ensuring safe and efficient operation within a gas system. This capacity ensures that the regulator can supply sufficient pressure and flow of gas to meet the peak demands of the appliances without creating unsafe conditions due to insufficient gas supply.

If the rated capacity were to be lower than the total Btu/Hr input needed, it could lead to inadequate performance or even a hazardous situation, as appliances may not receive the fuel necessary for proper operation. Consequently, choosing a regulator with a capacity that meets or exceeds the demand ensures optimal performance and safety, reducing the risk of issues such as flame instability or appliance shutdown.

While the specifics of gas type and adjustability are also important considerations when selecting a regulator, the primary concern for performance and safety remains the relationship between the regulator's rated capacity and the appliances connected to it.