NFPA (Fluid) T3.5.26 R2-2000 (R2019)
Hydraulic valve – Pressure rating supplement to NFPA/T2.6.1 R2-2000, Fluid power components – Method for verifying the fatigue and establishing the burst pressure ratings of the pressure containing envelope of a metal fluid power hydraulic valve
standard by National Fluid Power Association, 03/15/2000