Orifice Meter Material Selection Criteria Design – Flow Measurement

This article is about Orifice Meter Material Selection Criteria Design for Flow Measurement of Instrumentation and Control Systems as per International Codes and standards for Commercial Buildings, Plants and Refinery Projects.

Orifice Meter Material Selection Criteria Design – Flow Measurement

Material Receiving General Checklist for Instrumentation & Control

General Requirements

1. Purchase Order and Instrument specification sheet criteria shall be confirmed and compared with instrument stainless steel tags / labels and nameplates, and shipment checked for damage, prior to acceptance of the shipment.
   Verify that all the instruments are from technically acceptable vendors (Attachment 1)
2. Paddle type orifice plates shall be used and the following minimum information shall be stamped or etched on the upstream handle See attachment “”2 & 3″” (PCCFL001, section 3.2.1 & 3.2.2 ).
   a) Orifice plate tag number
   b) Material type
   c) vent or drain hole size
   d) inlet flow side
   e) bore
   f) flange size in inches and ASME pressure rating”
3. If an Orifice meter is the selected flow element, and the orifice plate sizing dictates a meter run size less than a nominal 2 inch, use either : (PCCFL001, section 3.2.3 ).
   a. A honed fabricated meter tube with corner taps.
   b. An Integral Orifice ”
   Unless otherwise required by process service, orifice plate material shall be stainless steel minimum. Material type shall be specified in accordance with PIP PCCGN001. (PCCFL001, section 3.2.4 )
4. Orifice plates shall be fabricated in accordance with ANSI 2530/API 14.3 Part 2. (PCCFL001, section 3.2.5 )”
5. Vent or drain holes in Orifice plates shall only be used if approved by the owner.(PCCFL001, section 3.2.6 )
6. Flange type and material shall be in accordance with piping specifications. Orifice flanges shall be rated at a minimum of ASME Class 300 and shall be in accordance with ASME B16.36 and ANSI 2530/API 14.3/AGA-3/GPA-8185. (PCCFL001, section 3.2.7)
7. Orifice “flange taps” shall be used for line sizes 2 inches and larger unless otherwise approved by the owner. (PCCFL001, section 3.2.8)
8. Corner taps shall be used for line sizes less than 2 inches. (PCCFL001, section 3.2.9)
9. Orifice flange tap connections shall be 1/2 inch when used in ASME class 600 service and below unless otherwise required by piping specifications.(PCCFL001, section 3.2.10)
10. Orifice flange tap connections shall be 3/4 inch when used in ASME class 900 service unless otherwise required by piping specifications. (PCCFL001, section 3.2.11)
11. Connection type (threaded or socket weld) shall be as per piping specifications. (PCCFL001, section 3.2.12)
12. Other tap, when used, shall be per piping specifications.(PCCFL001, section 3.2.13 )
13. Orifice meters shall be installed in horizontal runs to minimize measurement inaccuracies. Vertical orifice runs shall be used only with owner’s approval. (PCCFL001, section 3.2.14.a )”
14. Orifice meter tap locations shall be as follows:
    1) For “flange tap” designated orifice meters, the taps shall be located at 1 inch (25 mm) upstream and 1 inch (25 mm) downstream from the orifice plate face including gasket thickness.
    2) For “pipe tap” designated orifice meters, the taps shall be located
    2-1/2 internal pipe diameters upstream and 8 internal pipe diameters downstream of the orifice plate face. (PCCFL001, section 3.2.14.b )

International Standard and Codes for Instrumentation Accessories

1. Turbine Meter Material Selection Criteria Design & Flow Measurement
2. Pitot Tube Design Requirement in Process Industry
3. SAES-J-002 – Technically acceptable instruments.
4. SAES-J-003 – Instrumentation Basic Design.
5. SAES-J-100 – Process Flow Metering.API 14.3 Part 2 – Manual of Petroleum Measurement Standards Chapter 14- Natural Gas Fluids Measurements, Section 3- Concentric, Square- Edged Orifice Meters, Part 2 – Specification and Installation Requirements, Fourth Edition, April 2000
6. PIP PCCFL 001 – Flow Measurement Criteria , August 2006, Process Industry Practices Process Control.

1. Attachment 1: Technically Acceptable Instruments, SAES-J-002, 23 June 2008

2. Attachment 2: Standard Orifice Plates Std Dwg. AB 036094 Sht. 1 of 2

3. Attachment 3: Standard Orifice Plates Std Dwg. AB 036094 Sht. 2 of 2

4. Attachment 4: Aramco Flow Application Guide

5. Attachment 5: ARAMCO Applications Guide with Reynolds Number