How are these sections designated in drawings?

They are designated by the prefix 'ISL' followed by the longer leg dimension, shorter leg dimension, and thickness (e.g., ISL 150 x 90 x 10).

Are the material properties covered in IS 1864?

No, IS 1864 only covers dimensions and sectional properties. Material properties for shipbuilding steel are covered by IS 3039.

Can ISL sections be substituted with ISA (Standard Angles)?

Not directly without redesign, as L-sections (ISL) have distinct leg proportions and properties specifically designed to act as efficient hull stiffeners.

IS 1864

: 1979

Hot-rolled steel L-sections for shipbuilding

CurrentSpecializedSpecificationBIMStructural Engineering · Structural Engineering and Structural Sections

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This standard specifies the dimensions, mass, and sectional properties of hot-rolled steel L-sections intended primarily for structural use in shipbuilding.

Hot-rolled steel L-sections for shipbuilding

Quick Reference Values

designation prefixISL (Indian Standard L-Section)

standard supply length6 to 15 m

mass tolerance per piece± 4.0%

mass tolerance per lot± 2.5%

Practical Notes

L-sections covered here are optimized for use as stiffeners in ship hulls and decks, offering a better weight-to-stiffness ratio for marine applications compared to standard equal angles.

Material compliance must strictly follow marine grades (e.g., IS 3039) and classification society rules, as this code only dictates geometric properties.

When modeling in BIM (like Tekla or AVEVA Marine), ensure you select the 'ISL' library rather than standard 'ISA' (Indian Standard Angle) to get the correct center of gravity and root radii.