IPE-EP-5-3-18

IPE Engineering Practice IPE-EP-5-3-18

Document number: IPE-EP-5-3-18 · Section: 5 — Piping

CoInafsletcatilo nA Prouinbta E nEgningeeirninege Prriancgtic Pesractices Flue Gas Block and Bypass Valves 9.2.3 Bimetallic welds shall be located where the design temperature is less than 500°F. Bimetallic welds shall be made in the shop by the valve manufacturer. 9.2.4 Bimetallic welds are required, such as in cold wall designs, the entire weld shall be internal to the valve using a stub fabricated from the same material as the body, unless an alternative design has been approved by the Owner’s Engineer. 9.2.5 All corner fillet welds shall be ground to a smooth concave geometry. 9.2.6 Attachment welds for nozzles, clips, etc., shall be clear of all main seam welds by 3 times the body thickness or 2 inches, whichever is greater. 9.2.7 Valves fabricated using AISI Type 304 stainless steel and operating at 1100°F and above shall have the ferrite levels of all weldments controlled. The weldments shall have a ferrite content of 3% to 10%. 9.2.8 The ends of weld end valves shall be beveled to match the adjoining pipe/duct wall thickness specified on the Data Sheet, see EP 5–3–18 DS. Unless otherwise approved by the Owner’s Engineer, the valve ends shall be beveled with 1/3 of the pipe/duct thickness on the inside, 2/3 of the pipe/duct thickness on the outside, and a 1/8 inch wide land. 9.2.9 The ends of welded end valves shall have the wall thickness mismatch with the adjacent pipe/ duct tapered three to one on the outside diameter. 9.2.10 The end dimensions of welded end valves shall meet the following tolerances: 1) Inside Diameter: ”1/8 inch of the duct/pipe inside diameter specified on the Data Sheet. 2) Weld bevel diameter: ”1/16 inch of the diameter calculated based on the pipe/duct inside diameter and wall thickness specified on the Data Sheet. This tolerance is not additive to the ID tolerance above. 3) The difference between major and minor outside diameters (out–of–roundness tolerance) shall be 5% maximum. 9.2.11 Welded overlays shall be applied in a minimum of two layers. Preheat, per the electrode manufacturer’s recommendations, shall be included as part of the welding procedure specification (WPS) used for valve fabrication. Any portion of the weld overlay that does not meet the minimum following requirements shall be ground down to good metal and rewelded. 1) (*)Unless otherwise specified by the Owner’s Engineer, a crack free weld overlay is not required and the weld overlay cracks that are deemed acceptable must meet the following criteria: • There shall be no intersecting cracks. • Cracks shall be no closer than 2 inches. • Cracks shall be no wider than 0.01 inch. A piece of 2 gage piano wire (0.011 inch diameter) may be used as a no–go gage to measure the crack width. 2) A liquid penetrant examination shall be done on the completed overlay surface (after surface finishing on parts that require finishing). There shall be no voids, sub–surface horizontal cracks, slag pockets, etc. under the overlay surface. Acceptance criteria shall be per ASME B31.3.

CoInafsletcatilo nA Prouinbta E nEgningeeirninege Prriancgtic Pesractices Flue Gas Block and Bypass Valves 9) (*)Specify the media temperature for normal and other operating cases. 10) (*)Specify the molecular weight for normal and other operating cases. 11) (*)Specify the upstream pressure for normal and other operating cases. 12) (*)Specify the downstream pressure for normal and other operating cases. 13) (*)Specify the flow rate of the media and units for normal and other operating cases. 14) (*)Specify the flow direction. 15) (*)Specify the maximum leakage rates as a percentage of maximum specified flow rate when the valve is open, for normal and other operating conditions. Specify man–safe if required. 16) (*)Specify the total, cumulative time of the operating condition over the expected life of the valve. 17) (*)Specify if use of seal air is permissible. 18) (*)Specify if damper seats must close when the valve is open, see Paragraph 8.9.2. This is required with sickle dampers. The closing seat design shall be used for hot wall valves only. 19) (*)Specify actuator type, (e.g. electric, pneumatic, electro–hydraulic). 20) (*)State yes if an existing actuator is to be reused and attach actuator details. 21) (*)Specify maximum valve closing time. 22) (*)Specify how the actuator is to be supported. 23) (*)Specify the minimum Cv for butterfly valves. 24) Specify the internal material of construction. If a different grade of stainless steel is required than specified in this Practice, so specify (e.g. “Use Type 347H”). See Paragraph 7.1. 25) Specify the body and bonnet material of construction. See Paragraph 7.1. 26) (*)Specify the minimum thickness and type of insulating refractory for a cold wall valve. This would normally be the refractory thickness in the adjoining pipe or duct. Specify if a dual layer lining with a hex–mesh is required in areas subject to erosion. 27) (*)Specify the thickness (1 or 3/4 inch) and type of refractory in a hexmesh erosion resistant lining and type of hexmesh installation (e.g. 3/4 inch, 1 inch, raised bar). 28) (*)Specify the refractory ID of the adjoining pipe or dimensions for rectangular duct (height by width). 29) (*)For the upstream end, specify: flange size, face, and class for flanged end; pipe outer diameter or duct dimensions (height by width) and thickness or NPS and schedule for weld– end; “add w/ C.S. stub end” if a stub end is required. Attach design details for special flanges required to match existing. 30) (*)Specify the downstream end the same as line 31. 31) (*)Provide details of required purge arrangement. 32) (*)Specify flange class for auxiliary connections into the valve body. 33) (*)Specify if there are geometry limitations to the valve (e.g. for replacement valves) such as length and/or diameter. Attach a sketch if necessary. 34) (*)Specify if source inspection of material is required. 35) (*)State if a leak test is required. 36) (*)Specify if a Finite Element Analysis is required, see paragraph 6.2.2. 37) (*)Specify the loads acting on the upstream end of the valve. Check if this is an estimated load that will be revised based on actual valve dimensions and weight. 38) (*)Optionally, also specify loads acting on the downstream end of the valve, in the same manner the loads on the upstream end are specified.

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