IPE-EP-5-10-1

IPE Engineering Practice IPE-EP-5-10-1

Document number: IPE-EP-5-10-1 · Section: 5 — Piping

Supplemental Requirements for Piping in HF-Service (Phillips) 5.5 The hardness of welds and heat–affected zones in HF service piping and flanges shall be less than or equal to BHN–200. Contractor’s welding procedures shall include hardness testing to assure hardness control can be achieved meeting these requirements. All carbon steel buttwelds shall be welded using uphill progression. 5.6 Evaluation of welds shall be according to the ASME B 31.3 Piping Code and EP 5–5–1 5.7 Process piping in HF service shall not be smaller than NPS 1. Vents and drains on lines, pumps, heat exchangers, etc., shall not be smaller than NPS 3/4. NPS 1 and smaller pipe and fittings shall use threaded connections. Threaded connections shall not be seal welded. 5.8 All threaded connections (elbows, tees, reducers, plugs, etc.), excluding thermowells (see paragraph 5.17), shall be made with ASME Class 3000 forged steel fittings. All threaded pipe shall be installed using heavy duty industrial grade (extra dense) Teflon tape (Federal Process Co.––formerly John Crane––Thred Tape or equal). No other type of pipe joint compound shall be used. 5.9 All bolting shall be ASTM A–193 Grade B–7 or B–7M continuous threaded stud bolts with carbon steel hex nuts, ASTM A–194 Class 2H, see EP 5–2–2. 5.10 Gaskets used with ASME B16.5 raised face flanges shall be Monel–Teflon spiral–wound gaskets fabricated to the dimension in ASME B 16.20. (Flexitallic Style CG and GCI or Lamons Spira–Seal; others require qualification). For new construction, teflon inner rings are required. For existing equipment, teflon inner rings are recommended. Filler material shall be Teflon (Virgin Teflon is recommended). 5.11 (*)All HF service piping shall be installed above grade and shall be self–draining to the necessary low point bleeders. Low points in piping shall be limited insofar as possible to locations at equipment such as pumps, heat exchangers, vessels, control valves, etc., to minimize the number of low point bleeders. 5.12 The acid relief header shall be self–draining to the Acid Relief Neutralizer. There shall be no low points or pockets in the header. 5.13 All piping in the HF Alkylation Unit shall be designed and constructed so that: 1) Process control valve assemblies are located at grade level as often as is practical. 2) Drain valves are located a minimum distance from the line or item to be drained. 3) No vent or drain bleed valve discharges directly onto any piping, structure, vessel, or other item which would cause splattering of the discharged material. Discharge side of drain valves should be at least 12 inches above grade concrete or platform plating or grating. 4) All screwed block, vent, drain, bypass, and trycock valves may be rotated a full 360° to remove or tighten without interference from other piping, vessels, platforms, support legs or structures. 5.14 All plugs used in HF acid service piping shall be solid steel, three inches in overall length, machined preferably from hexagonal bar stock, although round bar stock is acceptable. Hollow plugs or pipe caps are unacceptable. All plug threads shall be wrapped with heavy–duty industrial grade (extra dense) Teflon tape (Federal Process Company–formerly John Crane– Thred–Tape or equal). 5.15 The edges of all piping flanges, manway flanges, valves and valve bonnet flanges, etc., in HF service shall be painted with one coat of Valspar Corporation Hydrofluoric Acid Detecting Paint No. 220–Y–7 for detecting HF leaks.

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