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IS 3141 : 2018Centrifugal Fans - Specification

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ISO 5801 · ISO 14694 · ANSI/AMCA 205
CurrentSpecializedSpecificationBIMMEP · HVAC and Air Conditioning
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OverviewValues5InternationalTablesFAQ3Related

IS 3141:2018 is the Indian Standard (BIS) for centrifugal fans - specification. This standard specifies the design, construction, material, and performance requirements for centrifugal fans used in HVAC and industrial applications. It sets the baseline for aerodynamic testing, dynamic balancing, and acoustic limits to ensure efficient and reliable ventilation.

Specifies requirements for the design, construction, performance, and testing of centrifugal fans.

Overview

Status
Current
Usage level
Specialized
Domain
MEP — HVAC and Air Conditioning
Type
Specification
International equivalents
ISO 5801:2017 · International Organization for Standardization (ISO), SwitzerlandISO 14694:2003 · International Organization for Standardization (ISO), SwitzerlandANSI/AMCA 205-16 · Air Movement and Control Association International (AMCA), USAISO 12759:2010 · International Organization for Standardization (ISO), Switzerland
Typically used with
IS 4894IS 14207IS 10431IS 325
Also on InfraLens for IS 3141
5Key values2Tables3FAQs

BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.

Practical Notes
! Fan performance curves must be derated for altitude and temperature, as standard data is based on standard air density (1.2 kg/m³).
! Always specify the fan discharge arrangement and rotation direction as per the standard nomenclature (e.g., CW 90, CCW 360) to avoid installation clashes.
! Dynamic balancing of the impeller is critical; ensure the manufacturer provides a balancing certificate to Grade G 6.3 or better to minimize vibrations.
Frequently referenced clauses
Cl. 4Terminology and ClassificationCl. 5Material SpecificationsCl. 6Construction Details (Impeller, Casing, Shaft)Cl. 8Performance RequirementsCl. 9Dynamic Balancing and Vibration limits
Pulled from IS 3141:2018. Browse the full clause & table index below in Tables & Referenced Sections.
mild steelgalvanized steelaluminumstainless steel

International Equivalents

Similar International Standards
ISO 5801:2017International Organization for Standardization (ISO), Switzerland
HighCurrent
Fans — Performance testing using standardized airways
Defines the core aerodynamic performance testing methodology referenced within IS 3141.
ISO 14694:2003International Organization for Standardization (ISO), Switzerland
HighCurrent
Industrial fans — Specifications for balance quality and vibration levels
Covers mechanical integrity aspects like balancing and vibration, which are key parts of the IS specification.
ANSI/AMCA 205-16Air Movement and Control Association International (AMCA), USA
MediumCurrent
Energy Efficiency Classification for Fans
Introduces the Fan Energy Index (FEI), a concept conceptually similar to the efficiency grades in IS 3141.
ISO 12759:2010International Organization for Standardization (ISO), Switzerland
HighCurrent
Fans — Efficiency classification for fans
Provides a framework for fan efficiency grades (FEG), which is the basis for the efficiency requirements in the IS code.
Key Differences
≠IS 3141 is a comprehensive 'specification' standard, combining construction, performance, testing, and marking, whereas international standards (ISO, AMCA) are typically modular, with separate documents for testing, balancing, safety, and efficiency.
≠IS 3141 explicitly references other Indian Standards for materials (e.g., IS 2062 for steel) and procedures, making it specific to the Indian regulatory and industrial ecosystem.
≠IS 3141:2018 introduces its own 'Minimum Fan Motor Efficiency Grade' (MFMEG) system, which, while based on ISO 12759 principles, has specific values and application criteria tailored for India, differing from the AMCA 'Fan Energy Index' (FEI).
≠Marking requirements in IS 3141 mandate the inclusion of the BIS (Bureau of Indian Standards) Certification Mark, a national requirement not found in global standards.
Key Similarities
≈The methodology for aerodynamic performance testing in IS 3141 is based on IS 3588, which is technically harmonized with ISO 5801 and AMCA 210, using standardized test airways.
≈The requirements for impeller and fan assembly balancing are derived from the same fundamental principles, referencing balance quality grades from ISO 1940-1 (adopted as IS 11723-1), which is also the basis for ISO 14694.
≈Fundamental definitions of fan performance parameters such as static pressure, total pressure, fan power, and efficiency are aligned with international vocabulary as defined in ISO 13349.
≈The classification of fan installation types for testing purposes (Category A: free inlet/outlet, Category B: free inlet/ducted outlet, etc.) is directly adopted from the framework established in ISO 5801.
≈Both IS 3141:2018 and its contemporary international counterparts place a strong emphasis on energy efficiency as a primary performance metric for fans.
Parameter Comparison
ParameterIS ValueInternationalSource
Impeller Balance QualityGrade G 6.3 as per IS 11723 (Part 1) / ISO 1940-1 for standard applications.Recommends Grade G 6.3 as a typical value for most industrial fans, with other grades for specific duties.ISO 14694:2003
Vibration Severity (Assembled Fan)Limits specified as per IS 14457 (Part 1) / ISO 10816-1, e.g., 2.8 mm/s RMS for rigid-support fans up to 15 kW.Specifies limits based on fan type and support rigidity, e.g., 2.8 mm/s or 4.5 mm/s RMS are common acceptable levels.ISO 14694:2003
Aerodynamic Performance Test MethodAs per IS 3588 (Methods of testing of industrial fans).Performance testing using standardized airways.ISO 5801:2017
Efficiency MetricMinimum Fan Motor Efficiency Grade (MFMEG), e.g., MFMEG50, MFMEG55.Fan Efficiency Grade (FEG) or Fan Energy Index (FEI), with a minimum FEI of 1.00 in many regulated markets.ISO 12759:2010 / ANSI/AMCA 205-16
Acoustic Test Method ReferenceReference to IS 6451 (Sound power level determination).Reference to ISO 13347 series, which in turn specifies methods from the ISO 3740 series (e.g., ISO 3744).ISO 13347-2:2004
Performance Tolerance (Power)Absorbed power shall not exceed the rated value by more than 5% at the duty point.For Class 2 tolerance, power input shall not exceed the rated value by more than 7% at the rated flow rate.ISO 13348:2008
⚠ Verify details from original standards before use

Key Values5

Quick Reference Values
air volume tolerance± 5%
static pressure tolerance± 5%
typical dynamic balancing gradeG 6.3
recommended motor margin below 10kW15%
recommended motor margin above 10kW10%
Key Formulas
Q1/Q2 = N1/N2 — Fan Law for flow rate vs speed
P1/P2 = (N1/N2)² — Fan Law for pressure vs speed
kW1/kW2 = (N1/N2)³ — Fan Law for power vs speed
η = (Q × ΔP) / P_motor — Fan Efficiency

Tables & Referenced Sections

Key Tables
Table 1 - Minimum Thickness of Casing and Impeller Plates
Table 2 - Tolerances on Fan Performance
Key Clauses
Clause 4 - Terminology and Classification
Clause 5 - Material Specifications
Clause 6 - Construction Details (Impeller, Casing, Shaft)
Clause 8 - Performance Requirements
Clause 9 - Dynamic Balancing and Vibration limits

Related Resources on InfraLens

Cross-Referenced Codes
IS 4894:2018Rigid PVC Sheets
→
IS 14207:1994Guidelines for Canal Lining with Geomembranes
→
IS 10431:1982Criteria for Design of Aqueducts and Other Cr...
→
IS 325:1996Three Phase Induction Motors
→

Frequently Asked Questions3

What is the acceptable tolerance for air delivery?+
± 5% of the specified air volume flow rate.
Which IS code outlines the testing procedure for these fans?+
IS 4894 is used for the performance testing of centrifugal fans.
What balancing grade is required for the impeller?+
The impeller should be dynamically balanced to Grade G 6.3 as per IS 14207.

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