Gas piping systems that are to be supplied with gas of a specific gravity of what value or less can be sized directly from the tables provided in the international fuel gas code?

The correct choice is based on the specifications outlined in the International Fuel Gas Code for sizing gas piping systems. Specifically, gas piping systems can be sized using the provided tables when the gas being used has a specific gravity of 0.60 or less. This is important because specific gravity affects the flow and pressure characteristics of the gas.

When using tables in the code, they have been calibrated to account for the properties of gases with a specific gravity equal to or less than this value. Gases with a specific gravity higher than 0.60 would require additional calculations to ensure proper sizing to accommodate the differences in flow characteristics.

Understanding this value helps in ensuring safe design and installation practices for gas piping, ultimately impacting the efficiency and safety of the gas appliances being supplied.