metal folding chairs - Specification
1983 Edition

Overview of Scope and Primary Standards

Scope:

• Specifies metal folding chairs focusing on quality assurance, safety, and marking requirements.
• Details material, manufacturing, and finishing prerequisites.
• Mandates protective caps on chair legs to avoid floor marking and slipping (Clause 3.2.1).
• Requires purchasers to supply technical details during order placement (Clause 0.3).

Marking (Clause 10.1.1):

• Chairs may carry the ISI Certification Mark confirming adherence to standards and quality control.
• Use of ISI mark is regulated by the Indian Standards Institution (Certification Marks) Act.

Units & Terminology:

• All dimensions use SI units.
• Important units include:
  • Length: metre (m)
  • Mass: kilogram (kg)
  • Force: newton (N) = kg·m/s²
  • Pressure/Stress: pascal (Pa) = N/m²
  • Energy: joule (J) = N·m
  • Power: watt (W) = J/s

Materials & Fabrication:

• Chair legs must have end caps made of metal, plastic, or rubber to protect floors and prevent sliding.
• Caps should be designed to reduce cutting or shearing during use.

Key Material Requirements and Relevant Standards

Tube Ends & Caps (Clause 3.2.1)

• Bottom ends of chair legs to have caps of metal, plastic, rubber, or similar materials.
• Caps must prevent floor marking and resist slipping.
• Caps and tube ends fabricated to minimize cutting or shearing.
• Rear leg top ends may be plugged or capped similarly.

Steel Sheets

• Mild steel sheets must comply with:
  • IS 1513-1973 (Grade O)
  • IS 1079-1973 (Grade O)

Welding Consumables

• Filler rods and wires for gas welding as per IS specifications.
• Covered electrodes for metal arc welding of structural steel according to IS standards.

Paint and Coating Tests

• Flexibility and adhesion tests on mild steel plates (150×50 mm, 0.315 mm thick) per IS 101-1964.
• Paint films must exhibit no cracking or damage under 10× magnification.

Units and Definitions

Overview of Components and Construction Methods

• Chairs to be constructed from components as detailed in Clauses 3.2 through 3.5.
• Bottom ends of chair legs equipped with caps (metal/plastic/rubber) that do not mark floors, resist sliding, and reduce cutting or shearing during use.
• Rear leg top ends may be plugged or capped similarly.

Materials and Welding

• Use filler rods and wires for gas welding adhering to IS standards.
• Employ covered electrodes for metal arc welding as specified.
• Steel tubes for furniture must meet IS standards.
• Cold-rolled and hot-rolled carbon steel sheets/strips used must comply with IS specifications.

Marking

• Chairs may display the ISI Certification Mark, confirming quality and conformity.

Units & Definitions

Assembly Procedures as per IS 3763

• Chair components are assembled using riveting, bolting, or welding techniques (Clause 4.2).

Standards Referenced for Assembly

Tube End Caps

• Bottom ends should have protective caps preventing floor damage and sliding.
• Caps must minimize cutting or shearing during use.
• Rear leg top ends may also be plugged or capped.

Assembly Diagram

graph LR
A[Chair Parts] --> B[Riveting]
A --> C[Bolting]
A --> D[Welding]
D --> D1[Arc Welding (IS 814, IS 10232)]
D --> D2[Gas Welding (IS 816)]
D --> D3[Resistance Spot Welding (IS 11239)]
D --> D4[TIG Welding (IS 13354)]

Dimensions and Tolerance Limits

• Overall dimensional tolerance is ±5 mm (Clause 5.3).
• Measurements are in millimetres.
• Reference dimensions are detailed in Clauses 5.1.1 to 5.1.3, including seat height, width, and depth.
• Tube ends must have caps to prevent floor marking and sliding (Clause 3.2.1).

Table of Dimensions and Tolerances

Notes

• Dimensions should be rounded following IS rounding conventions.
• Protective caps must minimize damage during use.
• For exact chair dimensions, refer to IS 3763 Clauses 5.1.1 to 5.1.3.

Surface Treatment and Corrosion Protection Standards

Phosphating

• Phosphating treatment must conform to IS 3618-1966 (Class C).
• Application per IS 6005-1970.
• Establishes a corrosion-resistant phosphate layer on mild steel parts.

Paint and Primer

• Use aluminium red oxide primer as per IS 5660-1970.
• Putty/filler materials per IS 110-1968.
• Various IS standards apply for paints and enamels suitable for brushing, spraying, stoving, and finishing.

Quality Tests

• Flexibility and adhesion test on mild steel plates (150×50 mm, 0.315 mm thick) as per IS 101-1964 Clause 16.
• Paint films must show no cracking or detachment under 10× magnification.
• Corrosion resistance test on mild steel panels (150×100 mm, 1.25 mm thick) per IS 101-1964 Clause 18.
• No corrosion should appear after condensation testing.

Summary Table of Finishing Requirements

Testing Requirements Overview

Rounding Off Test Results

• Test results must be rounded according to IS 2-1960.
• Maintain the same number of significant digits as the standard values.

Flexibility and Adhesion Test (Clause 7.3)

• Use mild steel plate samples sized 150×50 mm, thickness 0.315 mm.
• Test per IS 101-1964 Clause 16.
• Paint coatings must exhibit no damage, cracking, or detachment under 10× magnification.

Marking

• Metal folding chairs may bear the ISI Certification Mark, denoting compliance and ongoing quality assurance.

Units and Symbols (SI Units)

Sample Size for Flexibility and Adhesion Test

Details Buyers Must Provide When Ordering

• Specify the exact colour and finish desired.
• Indicate preferred construction or finishing methods if multiple options are acceptable.
• Confirm compliance with corrosion protection testing per IS 101-1964 using mild steel panels (150×100 mm, 1.25 mm thick).
• State if ISI Certification Marking is required on the metal folding chairs (Clause 10.1.1).

Summary Table of Purchaser Information

Notes

• Corrosion test panel size: 150×100×1.25 mm.
• Test standard: IS 101-1964.
• No corrosion signs permitted after testing.

Packaging Guidelines for Metal Folding Chairs

• All components must be packed securely to prevent damage during transportation (Clause 9.1).
• Tube ends must have protective caps (metal/plastic/rubber) that avoid floor marking, resist slipping, and reduce cutting or shearing during transit (Clause 3.2.1).
• Rear leg top ends may be plugged or capped similarly.
• Chairs may carry the ISI Certification Mark to confirm quality and inspection compliance (Clause 10.1.1).

Packaging Summary

Additional Considerations

• Packaging should provide mechanical protection and facilitate handling.
• Use durable materials for end caps to safeguard both the chair and flooring during delivery.

Marking Requirements for Metal Folding Chairs

• All metal folding chairs must bear a manufacturer’s identification mark (Clause 10.1).
• Chairs may optionally display the ISI Certification Mark indicating conformity with Indian Standards and ongoing quality monitoring (Clause 10.1.1).

ISI Certification Mark Details

• Governed by the Indian Standards Institution (Certification Marks) Act.
• Signifies compliance through continuous inspection and testing.
• Usage license granted by ISI under specified conditions.

Marking Summary Table

Additional Notes

• Protective caps on chair legs must prevent floor marking and resist sliding (Clause 3.2.1).
• Marking format and placement are at the manufacturer’s discretion, provided identification is clear.