Pressure, Rated Discharge (RDP)
ISO-13631 and API-618 define the
Rated Discharge Pressure as the "highest pressure required to meet
the conditions specified by the purchaser for the intended service".
Rated Discharge Pressure is conditional
upon the Maximum
Allowable Working Pressure based on the guidelines in ISO-13631 and
API-618. The
maximum allowable working pressure shall exceed the RDP by at least 10%
or 25 psi (1.7 bar), whichever is greater.
Ariel provides a design maximum
RDP for each cylinder based upon the MAWP as per the guidelines within
ISO-13631 and API-618. The
MAWP for Ariel cylinders will be 10% or 25 psi (1.7 bar) above the cylinder
nameplate RDP.
Ariel does allow for operation
above the cylinder RDP provided there is ample room for the pressure relief
valve range and for a high pressure shutdown device. Typically,
when the operating pressure is above the RDP, a pilot operated relief
valve must be used (rather than a spring operated relief valve). The
relief valve must be set no higher than the cylinder MAWP.
Ariel
Corporation Application Manual
15 March 2010