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IS 1252:1991 is the Indian Standard (BIS) for hot rolled steel bulb angles dimensions. This standard covers the dimensions, mass, and sectional properties of hot rolled steel bulb angles. These sections feature a bulbous protrusion at the toe of one leg, providing high strength-to-weight ratio for use primarily as stiffeners in shipbuilding and large plated structures.
Hot rolled steel bulb angles Dimensions
Overview
Status
Current
Usage level
Specialized
Domain
Structural Engineering — 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
! Ensure exact profile dimensions are mapped correctly in BIM/detailing software (like Tekla), as bulb angles are asymmetrical and orientation is critical.
! This code purely defines geometry and mass properties; material grades and testing requirements must be specified via IS 2062 or relevant marine material standards.
Defines dimensions and properties for hot-rolled unequal flange bulb angles, the same product type as IS 1252.
ISO 657-19:2022ISO, International Organization for Standardization
MediumCurrent
Hot-rolled steel sections — Part 19: Bulb flats — Dimensions and sectional properties
Covers bulb flats for shipbuilding, which serve a similar purpose but are geometrically different (flat vs. angle).
EN 10067:1997CEN, European Committee for Standardization
MediumCurrent
Hot rolled bulb flats. Dimensions and tolerances on shape, dimensions and mass
European standard for bulb flats used as stiffeners in shipbuilding, a functional but not a geometric equivalent.
JIS G 3129:2018JISC, Japanese Industrial Standards Committee
MediumCurrent
Hot-rolled steel sections for shipbuilding
Japanese standard covering various shipbuilding profiles, including bulb plates (flats), but not bulb angles.
Key Differences
≠The primary geometric profile is different. IS 1252 specifies 'bulb angles' (an L-shaped section with a bulb on one leg), whereas most modern international standards like EN 10067 and ISO 657-19 focus on 'bulb flats' (a rectangular section with a bulb on one edge).
≠Dimensional range varies. IS 1252 covers depths from 100 mm to 180 mm. In contrast, EN 10067 for bulb flats covers a much wider range, from 80 mm up to 430 mm in height.
≠Tolerances on dimensions and form are not harmonized. For example, the tolerance on depth for a 100mm section in IS 1252 is ±2.5 mm, while for a 100mm bulb flat in EN 10067 it is ±2.0 mm.
≠Sectional properties and designations differ. A 100 mm deep Indian section is designated 'BA 100' (Bulb Angle) with a mass of 11.9 kg/m, while a 100 mm European section is 'BP 100' (Bulb Plate/Flat) with a mass of 10.2 kg/m.
Key Similarities
≈The intended primary application for sections under both IS 1252 and its international counterparts is as longitudinal stiffeners in ship hull construction.
≈All standards apply to sections produced through the hot-rolling manufacturing process.
≈The standards primarily define geometry, dimensions, and mass. They do not specify the material's mechanical or chemical properties, instead referencing separate material standards (e.g., IS 2062 for India, EN 10025 for Europe).
≈Both the Indian and international standards define a similar set of key dimensional parameters, including overall depth/height, web/flange thickness, and bulb geometry, which are critical for structural design.
Parameter Comparison
Parameter
IS Value
International
Source
Profile Shape
Bulb Angle (asymmetrical L-shape with bulb)
Bulb Flat (symmetrical flat bar with bulb)
EN 10067:1997
Section Designation (100mm section)
BA 100
BP 100
EN 10067:1997
Mass per Meter (for ~100mm deep section)
11.9 kg/m (for BA 100)
13.56 kg/m (for No 10 bulb angle)
GOST 21937-76
Web Thickness (for ~100mm deep section)
7.0 mm (for BA 100)
7.0 mm (for No 10 bulb angle)
GOST 21937-76
Flange Width (for ~100mm deep section)
65 mm (for BA 100)
75 mm (for No 10 bulb angle)
GOST 21937-76
Tolerance on Depth/Height (for ~100mm section)
± 2.5 mm
± 2.0 mm
EN 10067:1997
Largest Section Depth Available
180 mm (BA 180)
430 mm (BP 430)
EN 10067:1997
⚠ Verify details from original standards before use
Key Values2
Quick Reference Values
Standard delivery length6m to 12m
Tolerance on cutting length+100 mm / -0 mm
Tables & Referenced Sections
Key Tables
Table 1 - Dimensions, Sectional Properties and Mass of Hot Rolled Steel Bulb Angles