Aluminium equal leg angles

IS 3908 Scope Summary: Aluminium Equal Leg Angles

• Scope: Covers dimensions, sectional properties, and mass per unit length of aluminium equal leg angles.

• Key Parameters (from Table 1):

  • Designation: Size in mm (e.g., 25x25x3.0)
  • Mass per meter (M): kg/m
  • Sectional Area (a): cm²
  • Radius at Root (r): mm
  • Centre of Gravity (Cx, Cy): cm
  • Moments of Inertia (Ix, Iy, Iu, Iv): cm⁴
  • Radius of Gyration (Tx, Ty, Tu, Tv): cm
  • Modulus of Section (Zx, Zy): cm³

• Symbols (Clause 3.1):

• Rounding: Values must be rounded as per IS 2-1960, retaining significant digits matching specified values.

This standard facilitates design by providing detailed sectional properties for aluminium equal leg angles, essential for structural calculations.

flowchart LR
  A[Aluminium Equal Leg Angles] --> B[Designation & Size]
  A --> C[Mass per meter (M)]
  A --> D[Sectional Area (a)]
  A --> E[Moments of Inertia (Ix, Iy, Iu, Iv)]
  A --> F[Radius of Gyration (Tx, Ty, Tu, Tv)]
  A --> G[Modulus of Section (Zx, Zy)]
  A --> H[Centre of

IS 3908 - Key Definitions & Symbols (Clause 3.1 & Table 1)

The standard defines the following key symbols for Aluminium Equal Leg Angles:

Mass calculation basis: Density = 2.7 gm/cm³ (Clause 2.7).

Important formulas:

• Radius of gyration, r = √(I/a)
• Section modulus, Z = I / e
  where I = moment of inertia, e = distance to extreme fibre.

Table excerpt (ALE 25x25x3.0 example):

IS 3908: Symbols, Formulas, and Tables for Aluminium Equal Leg Angles

Key Symbols (Clause 3.1)

• a = Sectional area (cm²)
• M = Mass per unit length (kg/m)
• Ix, Iy = Moments of inertia about X-X and Y-Y axes (cm⁴)
• Iu, Iv = Moments of inertia about principal axes U-U (max) and V-V (min) (cm⁴)
• ex, ey = Distance to extreme fiber from X-X and Y-Y axes (cm)
• Zx, Zy = Section modulus about X-X and Y-Y axes (cm³)
• rx, ry, ru, rv = Radius of gyration about X-X, Y-Y, U-U, and V-V axes (cm)

Important Formulas

• Radius of gyration:
  [ r_x = \sqrt{\frac{I_x}{a}}, \quad r_y = \sqrt{\frac{I_y}{a}}, \quad r_u = \sqrt{\frac{I_u}{a}}, \quad r_v = \sqrt{\frac{I_v}{a}} ]
• Modulus of section:
  [ Z_x = \frac{I_x}{e_x}, \quad Z_y = \frac{I_y}{e_y} ]

Table 1 Highlights (Clause 5.1)

• Provides sectional properties for Aluminium Equal Leg Angles (Designation: AXAXt in mm)
• Columns include: Mass (kg/m), Area (cm²), Root radius (mm), Centre of gravity (cm), Moments of inertia (cm⁴), Radius of gyration (cm), and Section modulus (cm³).

IS 3908: Key Specifications for Aluminium Equal Leg Angles (Materials)

1. Material Density

• Aluminium density = 2.7 gm/cm³ (Clause 2.7)

2. Sectional Properties (from Table 1, Clause 5.1)

For aluminium equal leg angles (ALE AxAx t in mm), key properties include:

3. Letter Symbols (Clause 3.1)

• a = Sectional area
• M = Mass per unit length
• Ix, Iy = Moments of inertia about X-X, Y-Y
• Iu, Iv = Moments of inertia about principal axes
• Zx, Zy = Section modulus about X-X, Y-Y
• Tx, Ty, Tu, Tv = Radius of gyration about respective axes
• r = Radius at root (fillet)

4. Example: ALE 80×80×6

• Mass = 2.53 kg/m
• Area = 9.38 cm²
• Radius at root = 8 mm
• Ix = 57.59 cm⁴, Iy = 91.48 cm⁴
• Zx = 9.93 cm³, Zy = 12.93 cm³

Summary Table Snippet (ALE 80×80×6):

IS 3908: Aluminium Equal Leg Angles - Dimensions & Sectional Properties

Key Specifications (Clause 5.1 & Table 1):

Example (ALE 80×80×6):

• Mass (M): 2.53 kg/m
• Area (a): 9.38 cm²
• Radius at root (r): 8.0 mm
• Centroid (Cx, Cy): 2.20 cm
• Moment of Inertia (Ix = Iy): 57.59 cm⁴
• Radius of Gyration (Tx = Ty): 2.48 cm
• Section Modulus (Zx = Zy): 9.93 cm³

Formula for Section Modulus:

[ Z_x = \frac{I_x}{e_x} \quad \text{and} \quad Z_y = \frac{I_y}{e_y} ]

Where:

• (I_x, I_y) = Moments of inertia about respective axes
• (e_x, e_y) = Distance from centroid to extreme fiber

IS 3908 - Material Requirements for Aluminium Equal Leg Angles

Key Specifications & Tables (Clause 5.1 & Table 1)

• Material Density: 2.7 gm/cm³ (Clause 2.7)
• Designation: ALE (Aluminium Equal Leg Angle) with dimensions AxAx t (mm)
• Mass per meter (M): Given in kg/m
• Sectional Area (a): cm²
• Radius at Root (r): mm
• Centre of Gravity (Cx, Cy): cm
• Moment of Inertia (Ix, Iy, Iu, Iv): cm⁴
• Radius of Gyration (Tx, Ty, Tu, Tv): cm
• Modulus of Section (Zx, Zy): cm³

Important Symbols (Clause 3.1)

Example Table Extract (ALE 80 × 80 × 6.0)

Formula for Mass per unit length

IS 3908: Packaging and Marking Key Points

Packaging (Clause 7.1)

• Equal leg angle sections must be:
  • Securely bundled.
  • Wrapped in bituminized hessian cloth or wooden boxes.
  • Alternative packaging can be mutually agreed between purchaser and manufacturer.
• Bundle weight: As agreed between purchaser and manufacturer.

Marking (Clause 8.2)

• Equal leg angles may carry the ISI Certification Mark.
• ISI Mark ensures compliance with IS 3908 under strict inspection and quality control.
• Use of ISI Mark is governed by the Indian Standards Institution (Certification Marks) Act.

Additional Specifications

• Density used for calculations: 2.7 g/cm³ (Clause 2.7).
• Units used follow the International System of Units (SI).

Summary Table for Packaging & Marking

flowchart TD
    A[Equal Leg Angles] --> B[Bundled Securely]
    B --> C{Packaging Type}
    C -->|Bituminized Hessian Cloth| D[Wrapped]
    C -->|Wooden Boxes| D
    C -->|Mutual Agreement| D
    D --> E[Bundle Weight as Agreed]
    A --> F[Marking]
    F --> G[ISI Certification Mark (Optional)]

This ensures safe transport and quality assurance per IS 3908.

IS 3908: Marking Details Summary (Clause 8.2)

• Marking: Equal leg aluminium angles may bear the ISI Certification Mark.
• ISI Mark Significance:
  • Assures compliance with IS 3908.
  • Indicates production under ISI-supervised inspection, testing, and quality control.
  • Continuous conformity checks by ISI.
• Use of ISI Mark is regulated under the Indian Standards Institution (Certification Marks) Act.

Key Specifications for Marking (from Clause 8.2)

• Marking includes:
  • Manufacturer's identification.
  • ISI Certification Mark (optional but recommended for equal leg angles).
  • Product designation (e.g., ALE 80×80×6).
  • Other details as per licensing agreements.

Reference Table: IS 3908 Aluminium Equal Leg Angles (Excerpt)

Notation (Clause 3.1)

• a = Sectional area
• M = Mass per unit length
• Jx, Iy = Moments of inertia about principal axes
• ex, ty = Distance of extreme fibre from axes
• Zx, Zy = Section modulus about axes
• r = Radius of gyration

Inspection and Quality Control - IS 3908 Key Points

1. ISI Certification Mark (Clause 8.2):

• Equal leg angles may carry the ISI mark, indicating compliance with IS 3908.
• The ISI mark ensures products are manufactured under strict inspection, testing, and quality control supervised by ISI.

2. Inspection System:

• Continuous checks by ISI for conformity.
• License for ISI mark use is governed by Indian Standards Institution rules.

3. Important Parameters & Symbols (Clause 3.1):

4. Units:

• Density used: 2.7 gm/cm³ (Clause 2.7)
• SI Units for force, energy, stress, etc., as per IS standards.

Summary Table: Key Inspection & Quality Control Points

flowchart TD
    A[Manufacturing] --> B[Inspection & Testing]
    B --> C{Conforms to IS 3908?}
    C -- Yes --> D[ISI Certification Mark]
    C -- No --> E[Reject / Rework]
    D --> F[Continuous ISI Surveillance]

This ensures quality control through systematic inspection and ISI supervision.