A non-return valve provided with a metal-to-metal seat, when in the closed position, shall not leak at a rate exceeding 0,50 dm3/hour when subjected to an inlet pressure up to the test pressure according to Table 3 in paragraph 5.3.
Metall-metall-tüüpi pesaga tagasilöögiklapp ei tohi suletud asendis katserõhuni (punkt 5.3, tabel 3) ulatuva sisselaskerõhu juures lekkida rohkem kui 0,50 dm3/h.