According to the National Fuel Gas Code, what is the maximum pressure drop allowance for gas piping?

The maximum pressure drop allowance for gas piping, as specified by the National Fuel Gas Code, is indeed 0.50 inches of water column (W.C.). This standard is set to ensure safe and efficient gas supply throughout a piping system.

Maintaining an allowable pressure drop ensures that all appliances connected to the gas supply receive adequate gas pressure for proper operation. If the pressure drop exceeds this limit, it may result in insufficient gas pressure at the appliances, potentially leading to poor performance, incomplete combustion, or safety hazards.

In comparison, the values lower than this allowance would not meet the standard for maximum pressure drop, indicating that they permit less drop than the recommended allowance. The option for 1.5 inches W.C. significantly exceeds the acceptable limit, which could lead to operational inefficiencies or safety issues in a gas system. Thus, 0.50 inches W.C. is the accepted maximum for effective gas-piping design, ensuring a balance between safety and system performance.