Table of Contents

  1. Scope
  2. Codes and Standards
  3. Environmental Conditions
  4. Design and Construction Details
  5. Nameplate
  6. Inspection and Testing
  7. Requirements for Transport and Storage
  8. Documentation
  9. Notes

1. Scope

This specification/requisition covers the minimum technical requirements for the design, manufacturing, testing, supply and documentation of orifice plates.

It is the responsibility of the vendor to ensure that the equipment is suitable for the service conditions stated in this requisition.

2. Codes and Standards

The orifice plates shall comply with the requirements of this requisition, the relevant data sheets and of other applicable specifications, codes, standards, attachment II, etc. as stated below.

Order of priority of given requirements: national and/or local requirements shall govern in case they are more stringent than this requisition.

DIN 50049 Edition * : Material testing certificates
ISO 5167 Edition * : Measurement of flow by means of orifice plates, nozzles and venturi tubes inserted in circu­lar cross section conduits running full.
* Edition * : Pipe flanges and fittings.

3. Environmental Conditions

Location : ***  
Temperature : normal : *°C
  maximum: *°C
  minimum : *°C
Relative humidity:    
  min/max : **
Rainfall: design:  
  intensity: * mm/h
Wind : max. velocity: * km/h


4. Design and Construction Details

All orifice plates shall be suitable for outdoor service in a petrochemical plant, which is located in * area.

Piping and process data are detailed per item on the instrument specification sheets in attachment II.

Further details shall be as per ISO 5167.

The pressure rating of the complete assembly, shall be equal or better than the flange rating.

The materials of the orifice plate and the flange rating/facing shall be as specified per individual item (preferably AISI 316SS).

The standard type orifice plate shall be concentric square edge plate in accordance with standard drawing.

The vendor is responsible for sizing the orifice plate conform ISO standard 5167 and shall submit calculations for review (see attach­ment II).

The design and machining shall avoid sharp corners and notches on the assembly.

Flange facing shall be smooth finished with a roughness in the range of 3.2 Ra to 6.3 Ra regardless of gasket type.

5. Nameplate

The following items shall be permanently marked on the upstream face of the orifice plate handle or on a stainless steel nameplate.

- "Upstream"
- Rating and facing
- Line size
- Measured bore (d) radius (r)
- Plate material
- Orifice tag number
- Type of orifice plate

6. Inspection and Testing

All equipment shall be given complete visual inspection and check of measures.

Vendor shall submit his standard test and inspection procedure in his proposal.

Inspection shall be made at the place of manufacture by the purchaser prior to shipment.

Acceptance of shop tests shall not constitute a waiver of requirements to meet field tests under specified operating conditions, nor does inspection relieve the vendor of his responsibilities in any way whatsoever.

Vendor shall supply material certificates in accordance with DIN 50049.3.1.B.

7. Requirements for Transport and Storage

For protection during transport and field storage, equipment shall be provided with suitable packing to protect against rough handling.

Individually packing shall show the number and Company requisition number stamped or painted on the outside.

The equipment shall be packed securely for domestic or export shipment as specified. Lifting points or lugs shall be clearly marked. The equipment shall be properly identified with item and serial numbers. All material shipped separately shall be identified with securely fixed and corrosion resistant metal tags indicating the item and serial number for which it is intended.

8. Documentation

Vendor shall submit documents and drawings in accordance with the requirements as specified in attachment I, "Vendor Furnished Documents".

9. Notes

  1. Vendor shall submit all data which is marked with a single asterisk (*) on attachment II.
  2. Vendors quotation shall include orifice plate calculations for all items on attachment II according to ISO-5167.