IPE-EP-5-6-5

IPE Engineering Practice IPE-EP-5-6-5

Document number: IPE-EP-5-6-5 · Section: 5 — Piping

CoInafsletcatilo nA Prouinbta E nEgningeeirninege Prriancgtic Pesractices Piping for Instruments 12.2 Design and installation requirements for Control Valve Manifolds shall be in accordance with API 550, Part I, Section 6 except as modified by this Practice. A typical Control Valve Manifold is shown in Figure 4. 12.3 Control valves and actuators shall normally be installed in horizontal lines as follows: 1) Globe valve - actuator above the line and valve stem vertical. 2) Angle valve - actuator above the line and valve stem vertical. 3) Rotary valve, noncryogenic service - valve shaft horizontal with actuator above the line and actuator stem vertical. 4) Rotary valve, cryogenic service - valve shaft vertical with actuator stem horizontal. 5) Rotary valve, rolling diaphragm actuator - valve shaft horizontal with actuator stem horizontal. 12.4 Clearance shall be provided above and below control valves for maintenance. Valves installed at a location other than grade shall be accessible from a permanently installed platform for maintenance. 12.5 (*)Block and bypass valves shall be installed with all control valves, except that, when approved by the Owner’s Engineer, they may be omitted in applications where a process shutdown can be tolerated. General installation requirements are shown in Figure 4. 12.6 (*)The minimum block and bypass valve size shall be per API 550, Section 6. Control valve manifold configurations shall be in accordance with ISA 75.06, unless otherwise specified by the Owner’s Engineer. 12.7 (*)Block and bypass valves for control valves and protective system shutdown valves NPS 6 and larger shall be installed as specified by the Owner’s Engineer. 12.8 (*)Valves installed in bypass lines NPS 4 and smaller shall be globe valves. Valves installed in bypass lines NPS 6 and larger shall be globe or gate valves as specified by the Owner’s Engineer. Consideration shall be given to whether the bypass valve needs to be a globe valve for control purposed in the event the control valve is out of commission for any reason. 12.9 Bypass valves in Let–Down Stations shall be sized per EP 3–7–2 to minimize the downstream overpressure protection requirements for the failure of the control station. The need for a bypass should be evaluated in these situations and other alternatives as given in EP 3–7–2 should be considered. 12.10 Block and bypass valves shall conform to the upstream line rating. 12.11 Bypass valves on control valves in protective system shutdown services shall be car sealed closed (CSC) and shall be identified with a permanent sign, as shown below. The sign shall conform to ANSI Z35.1, have black letters on a yellow background, and have the following message: CAUTION THIS VALVE TO BE USED ONLY FOR CHECKING PROTECTIVE SYSTEMS 12.12 Bypass valves on control valves 1/2–inch size and smaller shall have a flow coefficient equal to but not greater than twice that of the control valve and shall be needle or globe–type.

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