Pressure gauge connection size should be at least what size?

Pressure gauge connection size should be at least what size?

• A. 1/4 inch
• B. 3/8 inch
• C. 1/2 inch
• D. 5/16 inch

Answer: (A)

The key idea is that the pressure gauge port on a residential sprinkler system must be able to accept a standard gauge, and the smallest acceptable size is 1/4 inch NPT. This size is chosen because it fits the common pressure gauges and fittings used on test valves and risers, making it easy to install, read, and maintain without adding unnecessary flow restrictions or leak paths. If you used a smaller port, standard gauges wouldn’t fit and readings could be unreliable. You can use a larger port if desired, but the requirement sets the minimum at 1/4 inch.

The key idea is that the pressure gauge port on a residential sprinkler system must be able to accept a standard gauge, and the smallest acceptable size is 1/4 inch NPT. This size is chosen because it fits the common pressure gauges and fittings used on test valves and risers, making it easy to install, read, and maintain without adding unnecessary flow restrictions or leak paths. If you used a smaller port, standard gauges wouldn’t fit and readings could be unreliable. You can use a larger port if desired, but the requirement sets the minimum at 1/4 inch.