Lifecycle Playbooks
Stage 01 · FEED / detailed engineering
Valve Design & Specification
Specification is where 80% of lifetime valve cost is locked in. This playbook sequences the selection decisions - type, material, pressure class, standard, trim - so the datasheet that reaches procurement is buildable, testable and priced right the first time.
For: Process, piping and mechanical engineers fixing the valve list
You are here if
- The P&ID is frozen and every valve tag now needs a type, material and standard
- A fluid is corrosive, cryogenic or sour and the default material is in doubt
- The piping class dictates a spec but the service pushes against its limits
Where this stage goes wrong
- Material chosen on habit (SS 316 everywhere) rather than the fluid's real compatibility
- Valve type selected for purchase price, not total cost across cycling and maintenance
- Standards cited that conflict (design standard vs testing standard vs piping class)
- Trim left unspecified, defaulting at the vendor and failing early in service
The Playbook
- 1Fix the service conditionsDocument fluid, concentration, temperature, pressure, cycling duty and any H2S/chloride/oxygen flags per tag before touching a catalog.
- 2Select the valve type for the functionIsolation, throttling, non-return or overpressure - use the type capability data, not vendor preference, to shortlist.
- 3Select body material against the fluidCheck the compatibility rating for the exact fluid; step up the alloy only where the rating demands it.
- 4Confirm the temperature envelopeVerify the grade's min/max service temperature covers upset and startup conditions, not just normal operation.
- 5Specify trim explicitlySeat, stem, disc and hard-facing per the duty - cycling and throttling services need hard-faced trim called out on the datasheet.
- 6Cite the governing standardsDesign, pressure-temperature, testing and fire-safety standards must be consistent with each other and the piping class.
- 7Close the datasheetEnd connections, operation (manual/actuated), documentation requirements and inspection level complete the tag.
Stage deliverables
Completed valve datasheet per tagMaterial selection basis noteStandards compliance list per tag
Tools for this stage
Service Selection AtlasValve type + standard by fluidCompatibility AtlasMaterial vs fluid ratingsTemperature EnvelopeGrade min/max service temperaturesTrim Selection GuideSeats, stems and hard-facing by gradeStandards ApplicabilityWhich standard governs which typeSelection MistakesWhat NOT to specify, by fluidSpecification DebtThe cost of copying instead of engineering
Reviewed by Process Engineering, Vajra Industrial SolutionsDiscipline: Valve Service SpecificationLast reviewed: 20 June 2026
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