EN ISO 8233:2024 PDF

Overview

EN ISO 8233:2024 (ISO 8233:2024) specifies a standardized test method for measuring the opening, closing and running torque of manually operable thermoplastics valves used for fluid transport. Prepared by ISO/TC 138 in collaboration with CEN/TC 69, this method applies to all types of hand-operated thermoplastic valves (with or without actuators) and ensures uniform, reproducible torque measurement for design verification, quality control and compliance testing.

Key topics and technical requirements

• Scope and applicability
  • Applies to manually operable thermoplastics valves intended for transporting fluids.
  • Examples of valve types referenced include those in ISO 4437-4, ISO 16135, ISO 16136, ISO 16138, ISO 16139, ISO 16486-4, ISO 21787, EN 1555-4 and EN 12201-4.
• Torque definitions
  • Opening torque: torque needed to initiate opening from fully closed at nominal pressure (PN).
  • Closing torque: torque to complete the obturator stroke to full tightness at PN.
  • Running torque: torque required during the valve stroke under PN.
• Test conditions
  • Temperature: (23 ± 2) °C.
  • Test fluids: water, air or nitrogen. Safety note: when using air/nitrogen, use a maximum of 6 bar; for PN > 4 bar testing with water is recommended.
  • Conditioning: torque measurement not less than 24 h after manufacture; open/close valve 10 times at least 12 h before testing to ensure smooth operation.
• Pressure arrangements
  • Opening and closing pressure setups differ by valve type (e.g., ball/butterfly/gate vs diaphragm/globe) - the standard specifies upstream/downstream pressure configurations for opening and closing torque measurements.
• Apparatus and accuracy
  • Required equipment includes a pump, torque-supplying device, measuring instrument with continuous readout and maximum-value recording, and a clamping system that avoids axial or radial loading on valve components.
  • Measuring accuracy: ±2%.
• Exclusions
  • The document does not define torque changes due to long-term wear, service conditions or chemical attack. Refer to ISO/TR 10358 and ISO 8659 for endurance/chemical-aggression information.

Applications and users

• Who uses it
  • Valve manufacturers (design validation and production QC)
  • Independent test laboratories and certification bodies
  • Procurement and asset owners specifying acceptance tests
  • R&D and product development teams optimizing actuation requirements
• Practical uses
  • Type and routine testing to verify manual operability
  • Specifying actuator selection and ergonomic requirements
  • Supporting compliance and safety documentation for piping systems

Related standards

• ISO 161-1 (normative reference), ISO/TR 10358, ISO 8659
• Valve/product standards: ISO 4437-4, ISO 16135, ISO 16136, ISO 16138, ISO 16139, ISO 16486-4, ISO 21787, EN 1555-4, EN 12201-4

Keywords: EN ISO 8233:2024, ISO 8233, thermoplastics valves torque test, opening torque, closing torque, running torque, valve torque measurement, valve test method.