| Product Material | Valve body and disc should be manufactured from clearly identified PVC-U, CPVC, or another specified thermoplastic grade. Elastomer material should be stated separately. | Material datasheet, batch traceability, resin or compound declaration, and product drawings. | Accept only when the material grade is suitable for the intended fluid, temperature, pressure, and chemical exposure. | Pass when documented |
| Nominal Size Range | Common commercial availability is approximately DN50–DN600, with larger sizes requiring project-specific confirmation. | Dimensional drawing, face-to-face standard, flange drilling details, and available size list. | Confirm compatibility with the existing piping system and actuator mounting arrangement. | Project dependent |
| Pressure Rating | Many PVC butterfly valves are rated around PN6, PN10, or PN16, depending on size, temperature, material, and design. | Pressure-temperature chart, rated working pressure statement, and applicable design standard. | Do not evaluate the pressure class without checking temperature derating and the complete valve assembly. | Required |
| Lead Time for Standard Items | Approximately 15–30 working days after drawing approval and payment confirmation is a practical benchmark for standard configurations. | Formal quotation, production schedule, capacity statement, and recent delivery records with customer details removed. | Shorter lead times are credible only when the required size, seal material, connection type, and quantity are already available. | 15–30 working days |
| Lead Time for Customized Items | Approximately 30–60 working days is common when special materials, non-standard drilling, custom actuators, or new tooling are required. | Engineering timeline, drawing-approval workflow, tooling plan, and milestone schedule. | Include approval time, testing time, packing, and export documentation in the purchase schedule. | 30–60 working days |
| MOQ for Samples | One to five pieces is a reasonable benchmark for technical evaluation or pre-production sampling. | Sample quotation, sample inspection plan, and sample-to-production consistency statement. | A low sample MOQ reduces qualification risk but does not replace full production inspection. | 1–5 pieces |
| MOQ for Standard Production | Approximately 10–50 pieces per size and configuration is a common purchasing range; actual MOQ depends on tooling and inventory. | MOQ schedule by size, packing quantity, and configuration. | Compare MOQ with annual demand and avoid mixing different materials or seal specifications under one quantity commitment. | 10–50 pieces |
| Shell Pressure Test | Use a documented hydrostatic shell test based on the applicable valve standard; 1.5 times the rated pressure is a commonly specified reference value. | Pressure-test procedure, calibrated gauge records, test duration, test medium, and signed inspection report. | Test pressure, duration, and acceptance criteria must be stated rather than described only as “tested.” | Mandatory evidence |
| Seat Leakage Test | Seat testing should follow the selected standard and valve direction. A commonly used reference is approximately 1.1 times the rated pressure for certain resilient-seat test procedures. | Seat-test method, allowable leakage class, test direction, pressure, duration, and recorded results. | Specify whether the requirement is zero visible leakage, a defined leakage rate, or a standard leakage class. | Mandatory evidence |
| Pressure-Test Coverage | Every finished valve should be tested, or the supplier must provide a clearly justified sampling plan accepted by the buyer. | Serial or batch number, inspection lot, test date, operator identification, and final inspection release. | Individual test records provide stronger traceability than a generic certificate covering an entire shipment. | 100% preferred |
| 100,000-Cycle Service Test | For automated service, require a documented 100,000-cycle endurance test using the specified pressure, temperature, torque, actuator, and media conditions. | Endurance-test report, test-rig description, cycle definition, pre-test and post-test leakage results, and torque measurements. | 100,000 cycles is a project requirement, not a universal performance claim for every PVC butterfly valve. | Verify by test |
| Operating Torque Data | Supplier should provide breakaway, running, and end-of-stroke torque values across the specified pressure range. | Torque chart, calculation method, test results, safety factor, and actuator sizing sheet. | Incorrect torque data can lead to actuator failure, stem damage, or incomplete shutoff. | Required for automation |
| Temperature Suitability | PVC-U is commonly selected for moderate-temperature service; the exact limit depends on material, pressure, media, and design. Temperature derating is essential. | Pressure-temperature chart, material operating limits, and chemical compatibility table. | Do not use a nominal pressure rating at temperatures outside the supplier’s published operating range. | Check application |
| Connection Compatibility | Flanged, wafer, lugged, socket, or other connection types must match the piping standard and installation space. | Connection drawings, flange standard, bolt-hole information, gasket requirements, and installation instructions. | Dimensional mismatch is a frequent cause of otherwise avoidable installation delays. | Required |
| Quality Management | A documented quality system with inspection procedures, nonconformance control, calibration management, and batch traceability should be available. | Quality manual extract, inspection plan, calibration certificates, corrective-action records, and audit responses. | Certification alone is insufficient without product-specific inspection evidence. | Audit preferred |
| Warranty and After-Sales Support | A written warranty should define coverage, exclusions, claim documentation, response time, and replacement procedure. | Warranty terms, service-level commitment, spare-parts list, and technical support contact process. | Prefer suppliers that can support installation, actuator sizing, troubleshooting, and replacement parts. | Documented terms |
| Overall Supplier Decision | Approve only when material, pressure rating, lead time, MOQ, pressure testing, torque data, and endurance requirements are all aligned with the project specification. | Completed technical questionnaire, quotation comparison, sample inspection report, and signed quality agreement. | Use a weighted score rather than selecting solely on unit price. | Approved after verification |