Which statement about 5-inch coupling pressure ratings is true?

• A. 140 psi max non-locking, 170 psi max locking; tested at 200 psi for 5 minutes
• B. 160 psi max non-locking, 190 psi max locking; tested at 210 psi for 5 minutes
• C. 150 psi max non-locking, 180 psi max locking; tested at 200 psi for 5 minutes
• D. 150 psi max non-locking, 180 psi max locking; tested at 200 psi for 5 minutes

Answer: (D)

Understand that pressure ratings for a 5-inch coupling differ by whether the coupling is non-locking or locking. The non-locking version must withstand a lower maximum pressure than the locking version because the locking mechanism provides a secure connection that resists separation under pressure. The standard values are 150 psi for non-locking and 180 psi for locking, with a proof test conducted at 200 psi for 5 minutes to confirm the assembly remains intact and leak-free under over-pressure conditions. This is why the statement matching those exact numbers is correct. The other options mix up the rating values or the test pressure/duration, which don’t align with the established specifications.