ISO 14694:2003

Overview

ISO 14694:2003 - "Industrial fans: Specifications for balance quality and vibration levels" defines balance and vibration limits for most industrial fans (excluding small air‑circulation fans such as ceiling and table fans). It applies to fans with installed power below 300 kW (or when driven by commercially available standard motors up to 355 kW) and establishes test and documentation practices for balance quality and vibration severity. The standard focuses on the fan itself - not foundation design, installation practices or vibration effects on people, equipment or processes.

Key topics and technical requirements

• Scope and applicability
  • Covers rigid‑rotor fans used in HVAC, process, mine/tunnel ventilation and power‑generation applications.
  • Fans >300 kW use ISO 10816-3; mixed‑power installations require purchaser/manufacturer agreement.
• Balance quality
  • Defines balance quality grades and links permissible residual unbalance to ISO 1940‑1 methods.
  • Balancing procedures include single‑ and multi‑plane methods; Annexes discuss balancing‑machine assembly practices.
• Vibration measurement
  • Allows displacement, velocity or acceleration metrics; velocity (mm/s) is the preferred parameter.
  • Reports may be r.m.s., peak or peak‑to‑peak to accommodate global practices.
  • Distinguishes test conditions: factory tests (filter‑in) vs in‑situ tests (filter‑out) to reflect differences in support and aerodynamic duty.
  • Emphasizes bearing measurements as primary test points for routine quality grading.
• Vibration limits & categories
  • Defines BV (Balance and Vibration) categories and workshop vs in‑service limits (see Clauses 6–8).
  • Measurement instruments and calibration requirements are specified (Clause 10).
• Documentation
  • Specifies required records for balancing, vibration tests and certificates (Clause 11).
• Informative guidance
  • Annexes cover vibration theory, sources, supports, bearing reactions, condition monitoring and suggested relaxations.

Applications and users

ISO 14694 is practical for:

• Fan manufacturers performing factory balancing and acceptance testing.
• Purchasers and specifiers who need contractual vibration and balance requirements.
• Test laboratories and commissioning teams conducting workshop or in‑situ vibration tests.
• Maintenance and condition‑monitoring engineers using vibration data for troubleshooting and lifecycle planning.
• Designers of fan systems who need the residual vibration data to inform ducting and support design (while foundation design itself remains out of scope).

Related standards

• ISO 1940‑1 - balance quality tolerances for rigid rotors
• ISO 10816‑3 - vibration evaluation for larger machines (>300 kW)
• ISO 14695 - method of measurement of fan vibration
• ISO 5801 and ISO 13348 series - related fan performance and specification standards

Keywords: ISO 14694, industrial fans, fan balance, vibration levels, vibration measurement, balance quality grade, BV categories, fan testing, condition monitoring.