ISO 13349-2:2022

Overview

ISO 13349-2:2022 - Fans - Vocabulary and definitions of categories - Part 2: Categories defines a standardized set of fan categories and related terminology used across the air‑moving industry. It establishes how fans are classified by pressure capability, construction suitability, transmission arrangement, inlet/outlet conditions, control method, rotation/part position and characteristic dimensions. The standard is intended to harmonize nomenclature for manufacturers, consultants and contractors and is explicitly not applicable to electrical safety.

Key topics and technical requirements

• Scope and purpose: Defines categories for fans used for all purposes; complements ISO 13349‑1 (vocabulary) and other test/dimension standards.
• Symbols and units: Lists primary symbols and SI units used in fan specifications (for example, volume flow rate qV in m³/s, fan pressure pF in Pa, power P in W, torque τ in N·m, gas density ρ in kg/m³, impeller tip speed u in m/s, rotational speed N in r/min, temperature in K or °C).
• Categorization by fan pressure:
  • Uses pressure ratio and work per unit mass to define low-, medium- and high‑pressure fans.
  • Low pressure: pressure ratio < 1.02 (pressure rise < 2 kPa for standard air).
  • Medium pressure: 1.02 < pressure ratio < 1.1 (pressure rise ≈ 2–10 kPa; reference Mach number < 0.15).
  • High pressure: pressure ratio ≥ 1.1 (pressure rise > 10 kPa).
• Table-based pressure bands: Provides discrete category codes (0–9) linked to maximum fan pressure bands (e.g., low-pressure bands from 0–2.0 kPa, medium 2.0–10 kPa, high 10–30 kPa).
• Suitability of construction: Categorizes fans by casing construction, hot‑gas suitability, smoke‑ventilation designation, and gas‑tightness - guiding thickness, stiffening and design considerations for different applications.
• Other classification axes: Transmission/driving arrangements, inlet/outlet conditions, method of fan control, direction of rotation and component positions, and characteristic dimensions. Annex A gives illustrative examples.

Practical applications - who uses this standard

• Fan manufacturers - for consistent product designations, documentation and compliance with international naming conventions.
• Consulting engineers and specification writers - to unambiguously specify required fan categories (pressure class, construction, inlet/outlet conditions).
• Contractors and system integrators - to verify compatibility between fan selection and ducting, control strategies and service conditions (temperature, gas composition).
• Test laboratories and procurement teams - to interpret performance bands and compare products across suppliers. Using ISO 13349‑2 reduces ambiguity in procurement, ensures consistent expectations for performance and construction, and aligns international communication in ventilation, industrial and HVAC projects.

Related standards

• ISO 13349‑1 (Fans - Vocabulary)
• ISO 5801 (Fans - Performance testing)
• ISO 5167‑1 (Flow measurement - pressure differential devices)
• ISO 13351 (Fans - Dimensions)

Keywords: ISO 13349-2, fan categories, fan pressure, low‑pressure fan, medium‑pressure fan, high‑pressure fan, fan construction, ventilation standards, fan nomenclature.