Indian Standard Code IS 5391

IS 5391: Scope & Key Specifications Summary

Scope:

• Covers materials, construction, and dimensions of adjustable metal chairs for typists and telephone operators.
• Allows purchaser option for finish color (Clause 7.5).
• Final test values rounded per IS 2:1960 rules.

Key Specifications:

Referenced Standards for Materials & Testing:

• IS 5416 (Part 1 & 2): Test methods for strength and stability of chairs.
• IS 3663: Dimensions of tables and chairs for office use.
• IS 7138: Steel tubes for furniture.
• IS 110, 151: Paint specifications.
• IS 814, 1323: Welding codes.

Rounding Off Test Values:

• Follow IS 2:1960 for rounding to match the significant digits of the specified values.

flowchart TD
    A[Chair Frame] --> B{Material}
    B --> C[Mild Steel Tubular Pipe]
    B --> D[Aluminium Tubular Pipe]
    B --> E[Mild Steel Flats]
    C --> F[Wall thickness ≥ 1.25 mm, OD 25 mm]
    D --> G[Wall thickness ≥ 2 mm, OD 25 mm (square or round)]
    E --> H[Thickness ≥ 5 mm]
    A --> I[Legs ≥ 3 to prevent overturning]

This ensures structural stability and compliance with ergonomic and safety requirements for operator chairs.

IS 5391 References Summary

IS 5391 (1992) on Adjustable Metal Chairs for Typists and Operators refers to multiple Indian Standards for materials, construction, welding, finishes, and testing:

Key Notes:

• Rounding off test

IS 5391 - Materials Specifications Summary

• Aluminium Sheets (Clause 3.1):
  Must conform to alloys 31000, 52000, or 40800 in H2 condition as per IS 737:1986.

• Aluminium Tubes (Clause 3.2):
  Shall conform to IS designations 62400, 63400, or 65032 per IS 1285:1975.

• Mild Steel Sheets (Clause 3.5):
  Shall conform to IS 513:1986 or IS 1079:1988.

• Finish & Colour (Clause 7.5):
  Purchaser may select finish and colour as per requirement.

• Rounding Off (IS 2:1960):
  Test results must be rounded to the same significant figures as specified values.

Key Reference Standards for Materials:

Rounding Rule (IS 2:1960):

• Round off numerical values to the same number of significant digits as the specified value.
• Example: If specified value = 12.3 (3 significant digits), round test result to 3 significant digits.

flowchart LR
    A[Material Selection] --> B{Material Type}
    B -->|Aluminium Sheet| C[IS 737:1986]
    B -->|Aluminium Tube| D[IS 1285:1975]
    B -->|Mild Steel Sheet| E[IS 513/1079]
    F[Finish & Colour] --> G[Purchaser's Option]
    H[Test Result] --> I[Round off per IS 2:1960]

This ensures compliance with IS 5391 material requirements for adjustable metal chairs.

IS 5391: Components and Assembly of Adjustable Metal Chairs

Key Specifications:

• Assembly Methods (Clause 5.2):

  • Components must be joined by riveting, bolting, or welding.

• Components (Clause 4.0):

  • Chairs are assembled from parts specified in Clauses 4.1 to 4.3 (details of these components include metal frames, seats, backrests, etc.).

• Material (Clause 3.1):

  • Aluminium sheets must conform to IS 737:1986 with alloys 31000, 52000, or 40800 in H2 temper.

• Finish (Clause 7.5):

  • Finish color is optional and chosen by the purchaser.

Assembly Notes:

• Use standard rivet sizes or bolts as per IS standards for strength.
• Welding should ensure no distortion or weakening of the chair frame.
• Final dimensions and tolerances must comply with the standard and rounded off per IS 2:1960.

Typical Assembly Flow (Mermaid Diagram):

graph LR
A[Components (4.1 - 4.3)] --> B[Assembly]
B --> C{Joining Method}
C --> D[Riveting]
C --> E[Bolting]
C --> F[Welding]
F --> G[Final Inspection & Finishing]

This ensures a robust, ergonomic, and compliant chair structure.

IS 5391: Construction Requirements – Key Specifications

• Materials:

  • Steel Tubes: Must conform to IS 7138:1973.
  • Aluminium Sheets: Use alloys 31000, 52000, or 40800 in H2 condition as per IS 737:1986.
  • Aluminium Tubes: Should follow IS designations 62400, 63400, or 65032 of IS 1285:1975.

• Finish:

  • Clause 7.5 allows purchaser's option for color finish to suit requirements.

• Rounding Off:

  • Final test/analysis values must be rounded per IS 2:1960 rules.
  • Retain the same number of significant digits as specified values.

Summary Table of Material Standards

This ensures material quality, dimensional accuracy, and finish flexibility for adjustable metal chairs used by telephone operators.

flowchart LR
    A[Material Selection] --> B[Steel Tubes (IS 7138)]
    A --> C[Aluminium Sheets (IS 737)]
    A --> D[Aluminium Tubes (IS 1285)]
    B --> E[Mechanical Properties]
    C --> F[Alloy & Condition]
    D --> G[Designations]
    A --> H[Finish Options (Clause 7.5)]
    A --> I[Rounding off (IS 2:1960)]

IS 5391: Dimensions and Ergonomic Features for Adjustable Metal Chairs

Key Dimensions (Clause 6.2 & 6.1)

Back Rest Slope (Clause 6.1.5)

• Back Rest angle: 95° to 105°
  (Angle between vertical plane of back rest and horizontal seat plane)

Ergonomic Specifications:

• Seat and backrest dimensions per Fig. 1 (schematic not shown here)
• Effective depth and width to ensure comfort and support

Additional Notes:

• Finish color is optional (Clause 7.5)
• Measurement rounding per IS 2:1960 rules

Summary Diagram (schematic concept):

graph LR
A[Seat Horizontal Plane] --> B[Back Rest]
B -. Angle 95° to 105° .-> A
C[Overall Height ≥ 800 mm]
D[Clear Width ≥ 450 mm]

This ensures ergonomic posture and comfort for telephone operators and typists per IS 5391 standards.

IS 5391: Surface Treatment and Finishing Key Points

• Pre-treatment (Clause 7.1):

  • Remove dents, burrs, and sharp edges.
  • Pickle, scrub, and rinse all components to eliminate grease, rust, and scale.

• Phosphating (Clause 7.2):

  • Apply immediately after pickling.
  • Use phosphate coating conforming to Class C of IS 3618:1966.
  • Follow application process as per IS 6005:1970.

• Putty and Primers:

  • Use putty conforming to IS 110:1983 for filling surfaces.
  • Aluminium primer must conform to IS 2074:1979.

• Finish Colour (Clause 7.5):

  • Purchaser may select finish colour as per requirements.

• Rounding off (General):

  • Follow IS 2:1960 for rounding test/analysis values.

• Additional Finishing:

  • French polish (if applicable) should conform to IS 348:1968.

Summary Table of Surface Treatment Standards

flowchart TD
    A[Start: Steel Parts] --> B[Remove dents, burrs, sharp edges]
    B --> C[Pickling, scrubbing, rinsing]
    C --> D[Phosphating treatment (IS 3618:1966 Class C)]
    D --> E[Apply Putty (IS 110:1983)]
    E --> F[Apply Aluminium Primer (IS 2074:1979)]
    F --> G

IS 5391: Strength and Stability Tests for Adjustable Metal Chairs

Strength Requirements (Clause 8.1)

• Test as per IS 5416 (Part 1):1988.
• Chair must withstand sustained and impact loads.
• Load distribution must be uniform on all supports without excessive strain.
• Typical test load: Usually a static load of around 1000 N to 1500 N applied on seat and backrest (refer IS 5416 for exact values).

Stability Requirements (Clause 8.2)

• Test as per IS 5416 (Part 2):1988.
• Chair must not overturn under sudden weight shifts.
• Stability test involves applying a horizontal force at the seat or backrest to check overturning moment.

Design Specifications (Clause 5.1)

• Structural design must ensure:
  • Uniform load distribution.
  • No overturning under normal use.

Rounding Off (Clause 7.5)

• Final test values rounded as per IS 2:1960 rules.

Summary Table (Typical Test Parameters from IS 5416)

flowchart LR
    A[Load Application] --> B[Uniform Distribution on Supports]
    B --> C{Excessive Strain?}
    C -- No --> D[Pass Strength Test]
    C -- Yes --> E[Fail Strength Test]
    A --> F[Horizontal Force for Stability]
    F --> G{Chair Overturns?}
    G -- No --> H[Pass Stability Test]
    G -- Yes --> I[Fail Stability Test]

Note: Refer IS 5416 (Part 1 & 2) for detailed test procedures and exact load values.

IS 5391: Packing and Transit - Key Points

The standard does not provide explicit formulas or detailed tables for packing and transit but emphasizes:

• Packing: All chair components must be packed to prevent any damage during transit.
• Stability Testing: Chairs must comply with stability requirements as per IS 5416 (Part 2): 1988.
• Surface Treatment: Mild steel parts require phosphating (Class C, IS 3618:1966) after pickling to enhance corrosion resistance before packing.
• Finish Selection: Purchasers may select finishes/colors as per Clause 7.5.

Practical Recommendations (Engineering Knowledge):

• Use shock-absorbent materials (foam, bubble wrap) inside packaging.
• Secure parts to avoid movement.
• Mark packages with handling instructions.
• Ensure moisture-proof wrapping to prevent corrosion.

Reference Table (Sample Packing Materials):

flowchart LR
    A[Pickling] --> B[Phosphating Treatment (IS 3618)]
    B --> C[Surface Finishing (Putty & Primer)]
    C --> D[Packing with protective materials]
    D --> E[Transit & Handling]

Summary: Ensure corrosion protection, secure packing to avoid damage, and stability per IS 5416.

IS 5391 - Marking of Adjustable Metal Chairs

• Clause 10.1: Chairs shall be marked with a suitable mark identifying the manufacturer.
• Clause 10.1.1: Chairs may also bear the Standard Mark of BIS, indicating compliance with the standard under BIS supervision.
• The Standard Mark assures:
  • Production under defined inspection, testing, and quality control.
  • Continuous conformity checks by BIS.
• Marking typically includes:
  • Manufacturer's name or trademark.
  • BIS Standard Mark (optional but recommended).
• Finish and color can be selected by the purchaser (Clause 7.5).
• Marking ensures traceability and quality assurance.

Additional Notes:

• Marking must comply with IS 2:1960 for rounding off numerical values.
• Refer to BIS for licensing conditions to use the Standard Mark.

flowchart LR
    A[Chair] --> B[Manufacturer's Mark]
    A --> C[Optional BIS Standard Mark]
    B --> D[Traceability]
    C --> E[Quality Assurance]

This marking system ensures product authenticity and adherence to IS 5391 quality norms.