Overview
EN ISO 12759-5:2021 - Fans: Efficiency classification for fans - Part 5: Jet fans defines a standardized way to classify the efficiency of jet fans. It covers all jet fan types driven by motors with an electrical input power range of 5.5 kW to 155 kW (typical size range ~500 mm to 1600 mm diameter; motors commonly rated 5.5 kW to 150 kW in line with IEC 60034-30-1). The standard is not applicable to jet fans for enclosed car parks and is intended to support manufacturers, specifiers and regulators in setting energy performance targets.
Key topics and technical requirements
- Efficiency basis: Efficiency is expressed primarily based on thrust - overall efficiency ηe(T) is fan air power (derived from inlet volume flow × dynamic pressure) divided by motor input power.
- Classification system: Jet fan efficiency is grouped into grades with identifying labels JFMEG (jet fan motor efficiency grade) and JNG (jet fan grade number).
- Reference configuration: Defines a reference axial jet fan configuration (axial fan with silencers at inlet and outlet sized 1× diameter; integral inlet devices such as bell‑mouths allowed; accessories must be recorded).
- Installation categories & tolerances: Provides guidance on using installation categories and tolerances when rating performance for real installations.
- Annexes: Informative annexes include calculation methods for jet fan efficiency (Annex A) and procedures to determine the efficiency grade (Annex B).
- Normative context: Performance testing aligns with ISO 13350; the document has no normative references but forms part of the ISO 12759 series.
Applications and users
- Who uses it: Fan manufacturers, HVAC/ventilation engineers, test laboratories, procurement teams, energy managers, and policy makers.
- Practical applications:
- Specifying and comparing jet fan models by energy performance and thrust efficiency.
- Supporting product labeling, procurement specifications, and regulatory or legislative energy-saving targets.
- Informing design decisions for open-space ventilation systems (e.g., tunnels, long passages, large industrial volumes) while explicitly excluding enclosed car-park applications.
- Benefits: Enables consistent, comparable efficiency ratings, helps reduce energy consumption, and supports compliance with minimum efficiency targets.
Related standards
Keywords: EN ISO 12759-5:2021, jet fans, fan efficiency classification, thrust-based efficiency, IEC 60034-30-1, energy saving targets, ventilation standards.
