Restriction Orifice RFQ Guide for Projects in Egypt

A clear restriction orifice request for quotation helps an engineering team compare suitable proposals without repeated technical clarification. For projects in Egypt, the RFQ should identify the process fluid, operating cases, required pressure reduction, piping information, materials and documentation requirements. These inputs allow the supplier to review whether a single-stage restriction orifice, a multistage arrangement or another flow element is appropriate.

This guide is intended for EPC teams, plant engineers, procurement departments and maintenance teams preparing a restriction orifice enquiry. Final sizing and design should be based on the confirmed process conditions and the applicable project specification.

What is a restriction orifice?

A restriction orifice is a fixed flow element installed in a pipeline to create a controlled pressure drop or limit flow. It is different from a control valve because it has no moving parts and does not actively regulate changing process conditions. It is normally selected for a defined operating duty.

A single-stage restriction orifice plate may be considered when the required pressure reduction can be handled in one stage. A multistage restriction orifice divides the pressure drop across several stages. The correct arrangement depends on the fluid, pressure ratio, flow range and project requirements.

Process data to include in the RFQ

The supplier needs a consistent set of process conditions. Where several operating cases exist, list each case separately rather than providing one combined range.

• Fluid name, composition and phase
• Minimum, normal and maximum flow rate
• Upstream pressure for each operating case
• Required downstream pressure or pressure drop
• Minimum, normal and maximum operating temperature
• Density and viscosity at the operating condition
• Vapour pressure for liquid service, where applicable
• Molecular weight, compressibility and heat-capacity information for gas service, where applicable
• Presence of solids, corrosive components or two-phase conditions

Do not use design pressure and design temperature as substitutes for the actual operating cases. Both sets of values may be required, but they serve different purposes.

Piping and mechanical information

The RFQ should identify how the restriction orifice will fit into the line and the mechanical requirements that govern the assembly.

• Line size and piping schedule
• Pipe material and flange standard
• Flange size, class, facing and material
• Required plate or body material
• Corrosion allowance, if specified
• Connection and installation arrangement
• Flow direction and available straight-pipe information
• Project tag number and line number
• Applicable project, client and industry standards

If the requirement includes mating flanges, pressure taps or a complete assembly, state this clearly. The orifice flange assembly scope should not be assumed from the words restriction orifice alone.

Questions that affect single-stage or multistage selection

The required pressure drop is not the only selection factor. The review should also consider the behaviour of the fluid as pressure changes through the device.

• Is the service liquid, gas, steam or a mixed phase?
• Could the liquid flash or cavitate at any operating case?
• Could gas velocity or acoustic noise become a concern?
• Is the duty continuous, intermittent or start-up only?
• Are several operating cases expected?
• Is a maximum allowable pressure drop per stage defined?
• Are there limits on face-to-face length or available installation space?

These questions help the engineering review determine whether the pressure reduction should be distributed across multiple stages. The final recommendation should be supported by the confirmed data rather than by a general rule based only on line size.

Documents and inspection requirements

Document requirements should be agreed before quotation because they can affect scope, cost and delivery planning. The RFQ may request:

• General arrangement drawing
• Calculation or sizing report
• Material certificates
• Inspection and test plan
• Welding and non-destructive examination records when applicable
• Pressure test records when applicable
• Installation, operation and maintenance manual
• Data book format and document submission schedule

Restriction orifice RFQ checklist

1. Confirm the fluid and every operating case.
2. State upstream pressure, downstream pressure and temperature for each case.
3. Provide the required flow units and property basis.
4. Attach the line list, piping class or relevant datasheet.
5. Define line size, schedule, flange details and materials.
6. Identify the preferred installation and supply scope.
7. List applicable standards and client specifications.
8. State inspection, testing and documentation requirements.
9. Include tag numbers and required quantities.
10. Identify any space, noise, vibration or maintenance constraints.

Common RFQ gaps that delay review

Enquiries often require clarification when they provide only line size, flow and a total pressure drop. Missing fluid properties can prevent a reliable review, especially for compressible or flashing service. Another common issue is mixing normal operating data with design limits without labelling them.

Avoid asking for a final bore size before supplying the process basis. The bore and stage arrangement are outputs of the engineering review, not substitutes for the input data.

Frequently asked questions

Can one restriction orifice cover several operating cases?

It may be possible, but each case must be reviewed. A fixed restriction cannot actively adjust like a control valve, so the expected behaviour at minimum, normal and maximum flow should be checked.

When should a multistage restriction orifice be reviewed?

A multistage arrangement should be reviewed when the pressure reduction, fluid behaviour, velocity, noise or cavitation risk makes a single pressure-drop stage unsuitable. The decision depends on the confirmed process data.

What should an Egypt project RFQ say about location?

State the project site, delivery destination, applicable client specifications and documentation requirements. Location alone does not replace the technical process and piping data.

Send a complete enquiry

Globe United can review restriction orifice enquiries when the operating cases, piping details and required documentation are provided. Use the contact page to send the datasheet, line information and project requirements. You can also review the wider regional coverage on the markets we serve page.