ISO 13348:2025

Overview

ISO 13348:2025 - "Fans - Tolerances, methods of conversion and technical data presentation" specifies how fan performance is to be reported, converted and tolerated. It applies to fans of all types except low‑volume household fans (ceiling, table, extractor fans) and excludes jet fans (refer to ISO 13350). The standard establishes performance tolerances, conversion rules (air and sound), and a consistent technical data presentation to improve contract clarity and catalogue consistency for manufacturers, purchasers and designers.

Key phrases: ISO 13348:2025, fans tolerances, technical data presentation, performance tolerances, fan testing, conversion methods, efficiency scaling.

Key topics and requirements

• Scope and limits

  • Applies to fans up to a typical upper limit of fan work per unit mass (normally 25 kJ/kg, ~30 kPa at mean density 1.2 kg/m3); higher values require supplier–user agreement.
  • Excludes household low‑volume fans and jet fans (ISO 13350).

• Installation categories

  • Uses the five installation categories from ISO 5801: A, B, C, D and E (A = free inlet/outlet; B = free inlet/ducted outlet; C = ducted inlet/free outlet; D = ducted inlet/ducted outlet; E = free inlet and outlet without a partition). Performance reporting must state the installation category because it strongly affects fan behavior.

• Performance tolerances

  • Defines tolerance regimes for purpose‑designed fans and for series‑produced fans (including certified ratings programmes).
  • Provides guidance on purchaser and supplier information requirements, tolerance grades and contractual testing procedures (air performance, power, efficiency and sound).

• Methods of conversion

  • Rules for converting test data using similarity and fan laws, including interpolation, extrapolation and scaling procedures.
  • Efficiency scaling procedures applicable to centrifugal and axial fans within specified specific speed ranges (see Table 4); mixed‑flow fan behavior currently lacks experimental confirmation.
  • Sound power conversion and prediction methods with stated conditions and limits.

• Technical data presentation

  • Standardized requirements for fan performance charts, essential and optional data (air, sound, electrical, mechanical), marking and documentation.
  • Annexes include documentation, marking and a scaling method (Annex D).

Practical applications and users

ISO 13348:2025 is essential for:

• Fan manufacturers preparing catalogue data or contractual performance guarantees
• Specifiers, system designers and HVAC engineers ensuring agreed performance in different installations
• Test laboratories and certification bodies applying standardized tolerances and conversion methods
• Procurement teams and end users drafting performance clauses to reduce disputes

Using ISO 13348:2025 improves accuracy in fan selection, reduces warranty disputes, and enables reliable performance comparisons across suppliers.

Related standards

• ISO 5801 - Installation categories and test methods reference
• ISO 13350 - Jet fans (where applicable)
• AMCA certified ratings programme rules (referenced for certified series‑produced fans)