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IS 5384:1985 is the Indian Standard (BIS) for aluminium i-beam. This Indian Standard specifies the dimensions, mass, sectional properties, and manufacturing tolerances for a series of hot-rolled or extruded aluminium and aluminium alloy I-beams. It provides a standardized table of beam sections, designated ISALB (Indian Standard Aluminium Light Beam), intended for use in structural and general engineering applications.
Aluminium I-beam
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Structural Engineering and Structural Sections
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! The designation 'ISALB' stands for 'Indian Standard Aluminium Light Beam', followed by the nominal depth in mm.
! Aluminium's modulus of elasticity is approximately one-third that of steel, leading to significantly higher deflections under the same load and span, a critical design consideration.
! The actual mechanical properties (yield strength, ultimate strength) are determined by the specific alloy grade (e.g., 6061-T6, 6082-T6) as specified in IS 733, not by this dimensional standard.
Standard Specification for Aluminum-Alloy 6061-T6 Standard Structural Profiles
Specifies dimensions, tolerances, and properties for standard aluminium structural shapes including I-beams, using alloy 6061-T6.
EN 755-9:2016European Committee for Standardization (CEN), Europe
HighCurrent
Aluminium and aluminium alloys - Extruded rod/bar, tube and profiles - Part 9: Profiles, tolerances on dimensions and form
Defines the specific tolerances on dimensions and form for extruded aluminium alloy profiles, including I-beams.
ANSI H35.2-2017The Aluminum Association / ANSI, USA
MediumCurrent
American National Standard Dimensional Tolerances for Aluminum Mill Products
Provides a comprehensive set of standardized dimensional tolerances for all aluminium mill products, including extruded I-beams.
BS 1161:1977British Standards Institution (BSI), UK
LowWithdrawn
Specification for aluminium and aluminium alloy sections for structural purposes
Historical standard that specified dimensions and properties for aluminium sections, similar in intent to the 1985 Indian Standard.
Key Differences
≠IS 5384:1985 is a withdrawn standard, while its international counterparts (ASTM, EN) are actively maintained and updated, reflecting modern manufacturing capabilities and material science.
≠The specific I-beam designations and their corresponding dimensions (e.g., ISALB 100, ISALB 125) are unique to the Indian market and do not have direct dimensional equivalents in ASTM or EN standards, which have their own series of standard shapes.
≠Alloy designations differ. IS 5384 uses Indian standard designations like 65032 (WP) or 64430 (WP), whereas international standards use AA (e.g., 6061-T6) or EN AW (e.g., EN AW-6061 T6) nomenclature.
≠Dimensional and form tolerances in the more recent EN and ANSI standards are generally tighter and more detailed than those specified in the 1985 version of the Indian standard.
Key Similarities
≈All standards aim to standardize the dimensions, tolerances, and sectional properties of extruded aluminium I-beams to ensure predictable structural performance and interchangeability.
≈The fundamental geometric parameters defined for the I-beam cross-section are the same across all standards: overall depth, flange width, web thickness, flange thickness, and fillet radii.
≈The primary material specified or recommended is typically a 6xxx series (Al-Mg-Si) aluminium alloy in a heat-treated temper (like T6), which offers a good balance of strength, extrudability, and corrosion resistance for structural applications.
≈All standards define requirements for the same types of manufacturing tolerances, including cross-sectional dimensions, straightness, and twist, to control the quality of the finished product.
Parameter Comparison
Parameter
IS Value
International
Source
Primary Structural Alloy
IS Grade 65032 WP (Equivalent to 6061-T6)
Alloy 6061-T6
ASTM B308/B308M - 22
Tolerance on Depth (for ~100mm beam)
± 1.2 mm
± 0.85 mm
EN 755-9:2016
Tolerance on Flange Width (for ~75mm flange)
± 1.2 mm
± 0.75 mm
EN 755-9:2016
Tolerance on Wall Thickness (for ~6mm wall)
± 0.45 mm
± 0.35 mm
EN 755-9:2016
Straightness Tolerance (per meter)
1.5 mm per metre
1.0 mm per metre (0.0125 in/ft)
ANSI H35.2-2017
Twist Tolerance (per meter of length)
Max 1° per meter
Max 0.5° per meter (for width 25-100mm)
ANSI H35.2-2017
Minimum Tensile Strength (for 6061-T6 equivalent)
265 MPa (for IS 65032 WP)
260 MPa (38 ksi)
ASTM B308/B308M - 22
Minimum Yield Strength (for 6061-T6 equivalent)
245 MPa (for IS 65032 WP)
240 MPa (35 ksi)
ASTM B308/B308M - 22
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Mass of ISALB 1005.021 kg/m
Depth of ISALB 150150 mm
Flange width of ISALB 200100 mm
Web thickness of ISALB 1255.0 mm
Tolerance on depth (for D > 150 mm)+2.5 mm, -1.5 mm
Tolerance on flange width (for B <= 100 mm)± 2.0 mm
Tables & Referenced Sections
Key Tables
Table 1 - Dimensions, Sectional Area, Mass and Sectional Properties of Aluminium I-Beams
It denotes an Indian Standard Aluminium Light Beam with a nominal depth of 150 mm.
What material is used for these I-beams?+
The material must conform to a suitable wrought aluminium alloy grade specified in IS 733, such as 63400 WP (6061-T6) or 64430 WP (6082-T6).
What is the mass of an ISALB 100 beam?+
The nominal mass is 5.021 kg per metre, as per Table 1.
Can I use design properties from steel beam tables for these sections?+
No. This standard defines a unique series of sections for aluminium, and the material properties (density, modulus of elasticity, strength) are vastly different from steel.