BS EN 15714-3:2022 is a European standard that specifies the basic requirements for pneumatic part-turn valve actuators, encompassing both double acting and single acting types, used in on-off and modulating control duties. This standard provides comprehensive guidelines, recommendations, and methods for the design, testing, and application of these actuators, ensuring their safe and efficient operation across various industrial settings.
1. Scope and Application:
The standard applies to pneumatic part-turn actuators that transmit torque to valves for less than one revolution. It excludes actuators that are integral parts of control valves and those designed for permanent immersion in fresh or seawater. The requirements outlined are intended to serve as a basis for negotiations between purchasers and manufacturers/suppliers when different conditions of use are needed.
2. Classification and Designation:
Actuators are classified based on their duty (on-off or modulating) and action (double acting or single acting). Double acting actuators require motive energy for both travel directions, whereas single acting actuators use external power in one direction and stored energy (typically from a mechanical spring) for the return stroke. The standard also specifies the standard angular stroke for part-turn actuators as 90°, with tolerances and adjustment ranges detailed for different configurations.
3. Motive Energy and Performance:
The operating medium for these actuators is primarily compressed air, with specific quality requirements regarding humidity and particle content. The standard defines the pressure limits, including nominal supply pressure, maximum allowable pressure, and design pressure for pressurized parts. Actuator performance data such as minimum moving pressure, operating time, and displacement volume are also specified to ensure consistent operation.
4. Safety and Design Requirements:
Safety is a paramount concern in the design of these actuators. The standard mandates provisions to prevent excessive pressure build-up within spring enclosures and ensures safe assembly/disassembly procedures. Actuator attachments must comply with EN ISO 5211, and the design must account for endurance, leakage, and environmental conditions such as ambient temperature, enclosure protection, and corrosion resistance. Specific corrosion categories are defined based on the operating environment, guiding manufacturers in selecting appropriate materials and surface treatments.
5. Pressure Connections and Fail-Safe Mechanisms:
The standard details the requirements for pressure connections, including dimensions, identification, and mounting interfaces for both remotely mounted and directly mounted pilot valves. For single acting actuators, provisions are made to avoid excessive pressure in the spring enclosure during operation. Fail-safe directions are clearly indicated for single acting actuators to ensure predictable behavior in case of supply pressure loss.
6. Conformity Assessment and Marking:
Compliance with the standard is demonstrated through type tests and production process control. Type tests confirm all requirements stated in the standard, while production verifications ensure ongoing compliance. Each actuator must bear permanent markings indicating manufacturer details, model number, serial number, maximum allowable pressure, ambient temperature range, fail-safe direction, and other relevant information.
7. Documentation and Selection Guidelines:
Manufacturers must provide comprehensive documentation, including installation, commissioning, operating, and maintenance instructions. Annex B of the standard offers detailed guidelines for selecting the appropriate actuator based on valve characteristics, operating conditions, safety factors, and environmental considerations. This ensures that actuators are correctly sized and equipped with necessary ancillary devices for their intended application.
In summary, BS EN 15714-3:2022 provides a robust framework for the design, testing, and application of pneumatic part-turn valve actuators, ensuring their safety, reliability, and efficiency in industrial settings.
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