A control valve quotation is only as clear as the operating data behind it. If one supplier sizes for normal flow while another assumes maximum flow at a different pressure drop, their proposals may describe different duties. A well-prepared control valve datasheet gives every bidder the same starting point.
This guide explains how to organize an RFQ datasheet, using a worked example to show how flow and pressure cases belong together. For the capacity calculation that follows, see our control valve sizing guide.
What Is a Control Valve Datasheet?
A control valve datasheet records the required service and the proposed assembly. At the enquiry stage, the buyer supplies process requirements; the supplier adds selection results and equipment details. Keep those two responsibilities clear so that a proposed value is not mistaken for an approved requirement.
Emerson identifies physical details, process conditions and fluid properties as key inputs in its control valve sizing guidance. A useful enquiry combines those inputs with a consistent way to record assumptions and revisions.
Start With the Tag, Service and Revision
Give each valve its own tag number and service description. Identify the project, line reference and datasheet revision. A description such as “cooling-water flow control to exchanger” is more useful than “water valve” because it tells the reviewer what the assembly is expected to do.
Record who owns unresolved questions. If outlet pressure is still being calculated, mark it “to be confirmed” and assign an owner. An explicit open item is easier to review than an empty cell that could mean unknown, not applicable or accidentally omitted.
A Worked Operating-Case Example
The following values are invented for illustration. They are not Phileda product ratings, an approved process design or a completed valve selection.
| Required input | Minimum case | Normal case | Maximum case |
|---|---|---|---|
| Fluid | Clean water | Clean water | Clean water |
| Liquid flow, m³/h | 8 | 25 | 40 |
| Valve inlet pressure, bar(a) | 6.0 | 5.5 | 5.0 |
| Valve outlet pressure, bar(a) | 4.0 | 3.5 | 3.5 |
| Valve pressure drop, bar | 2.0 | 2.0 | 1.5 |
| Fluid temperature, °C | 25 | 25 | 25 |
Read each column as one simultaneous operating condition. The maximum case means 40 m³/h with the pressures in that same column. Combining that flow with the minimum-case inlet pressure would create a different, unsupported case.
The arithmetic check is simple: inlet pressure minus outlet pressure must equal the stated pressure drop. Passing that check does not prove the pressures are realistic. The project team must also establish where the pressure values apply and how the piping system produces them.
Keep a separate row or attachment for startup, cleaning or another operating mode when it creates a distinct duty. Do not squeeze every scenario into a single “maximum” column.
Make Units and Fluid Properties Unambiguous
Write pressure units with their reference: bar(a) and bar(g) are different inputs. Label flow as mass flow or volumetric flow. For gas volumes, state the reference temperature and pressure rather than relying on “standard flow” without a definition.
Provide the fluid information needed for the applicable calculation. Depending on service, this can include density, viscosity, vapor pressure, composition or molecular weight. The supplier should identify missing properties and the basis used for any estimated values.
Emerson’s control valve specification sheet illustrates how operating cases and fluid properties can be recorded alongside valve, actuator and accessory information.
Separate Process Duty From Mechanical Requirements
Use one section for operating cases and another for installation requirements. State pipe connections, required materials, available space and applicable project requirements. Identify design conditions separately from normal operating conditions so reviewers do not silently substitute one for the other.
A line connection size alone does not complete a control valve selection. Ask the supplier to explain the proposed body and trim combination against the supplied operating cases. Avoid adding an undocumented capacity allowance after another allowance has already been included upstream.
Specify the Complete Actuated Assembly
The enquiry should describe the available utility supply, control signal, required failure response and relevant accessories. State what should happen for each relevant loss of supply or signal, and have the responsible project team approve that requirement.
For background on the assembly choice, read our electric vs pneumatic control valve guide. Keep the actuator decision connected to the duty rather than treating it as a purchase option added after valve selection.
What Should the Supplier Return?
Request a completed selection for every operating case, including the calculated capacity requirement and predicted travel for the offered trim. Ask for the calculation basis, assumptions and any relevant service limitations. Review the returned results together rather than approving the rated capacity in isolation.
Ask the supplier to identify the proposed inherent characteristic and explain its suitability for the system. Our equal percentage vs linear guide explains why a catalog curve alone does not describe installed flow.
Review the Datasheet Before Comparing Prices
- Check that every bidder used the same revision and operating cases.
- Resolve differences in units, pressure reference and fluid assumptions.
- List technical exceptions separately from commercial exclusions.
- Distinguish buyer requirements from supplier proposals.
- Return agreed changes to the controlled datasheet before ordering.
A short clarification log can prevent an email assumption from becoming an unnoticed change in the purchased assembly. Give each question a reference, owner and resolution, then update the affected datasheet revision.
Frequently Asked Questions
Can I request a quotation before all data is available?
Yes, but identify the missing information and request that the quotation state its assumptions. Treat a budget proposal based on incomplete data differently from a selection ready for technical approval.
Should I enter a Cv value before contacting the supplier?
Include an existing calculation if available and label its basis. Ask the supplier to verify it against the offered valve and all required cases. Do not let one target coefficient replace the underlying process information.
Is maximum flow enough for the datasheet?
It leaves the other operating duties undefined. Include normal and minimum requirements, with their corresponding conditions, so the proposed selection can be reviewed across the intended range.
Can I reuse a previous project’s datasheet?
Reuse the layout, but recheck every populated field. Old tag numbers, utility assumptions and acceptance requirements are easy to carry into a new enquiry accidentally.
Prepare a Clear Enquiry for Phileda
For a Phileda control valve enquiry, provide the tagged datasheet, operating-case table and relevant installation requirements. Ask for a proposal that records assumptions, exceptions and selection results against the same revision. This creates a clearer basis for engineering review and a more useful comparison of quotations.
