Plastic chairs for general office purposes
1993 Edition

Overview of Scope & Essential Specifications for Plastic Office Chairs

Applicability:

• Pertains to plastic chairs intended for general office applications.
• Encompasses material types (reinforced thermoplastics and thermosetting plastics, both filled and unfilled), dimensional criteria, strength, stability, and fire resistance testing.
• Dimensions must align with IS 3663:1991.
• Chair design may be customized per client requirements.

Core Rigidity Test: Shell Stiffness (Annex B, Section 6.2.3)

Test Arrangement (Fig. 1 Summary)

• Backrest secured on a rigid plane.
• Load applied via a rigid, rounded-edged bow.
• A rubber sheet placed between bow and backrest to evenly distribute the load.

Numerical Result Rounding

• Follow IS 2:1960 for rounding off test data.
• Maintain significant figures consistent with standard requirements.

Reference Standards

• Dimensions: IS 3663:1991
• Rounding: IS 2:1960
• Chair materials: reinforced thermoplastics/thermosetting plastics.

flowchart LR
    A[Selected Test Sample] --> B[Mounted on Rigid Surface]
    B --> C[300 N Force Applied at Point A]
    C --> D[Force via Rounded Bow + 6mm Rubber Pad]
    D --> E[Maintain Load for 4 Hours]
    E --> F[Measure Displacement]

This test confirms the chair's shell rigidity meets safety and performance standards for office use.

IS 13713: Plastic Office Chairs — Essential References & Specifications

Referenced Indian Standards (Annex A)

Principal Specifications from IS 13713

• Materials: Filled or unfilled reinforced thermoplastics and thermosetting plastics.
• Dimensions: Must comply with IS 3663:1991.
• Strength Evaluations: Static, fatigue, and impact tests as per IS 5416 (Part 1):1988.
• Testing Intensity: Usage-based Levels 4 or 5 following Table 3 of IS 5416 (Part 1).
• Fire Performance: Flammability tested by oxygen index method under IS 13360 (Part 6/Sec 6).

Important Points

• Chairs can display the Standard Mark as per Clause 8.2.
• Test outcomes must be rounded off following IS 2:1960.
• Design customization is permitted based on purchaser's preferences.

Summary Table: Strength Testing Levels (IS 5416 Part 1)

flowchart LR
    A[Plastic Chair] --> B[Materials: Thermoplastic/Thermosetting]
    B --> C[Dimension Compliance: IS 3663:1991]
    B --> D[Strength Testing per IS 5416 Part 1]
    D --> E[Static Load Test]
    D --> F[Fatigue Test]
    D --> G[Impact Test]

IS 13713 — Material Requirements for Plastic Chairs

Material Categories:

• Chairs manufactured from filled or unfilled reinforced thermoplastic and thermosetting plastics.
• Serve as environmentally friendly alternatives to traditional wood furniture.

Material Characteristics and Evaluations:

• Mechanical properties vary; reinforcement additives enhance strength.
• Flammability tested according to IS 13360 (Part 6/Sec 6):1992 via oxygen index.
• Plastic materials, like wood, release toxic gases upon combustion.

Performance Criteria (Clause 6.2.1):

• Strength assessments include static, fatigue, and impact testing per IS 5416 (Part 1):1988.
• Test intensity set at Levels 4 or 5 per Table 3 of IS 5416 (Part 1).
• No structural flaws permitted after testing.

Dimensional Compliance:

• Must adhere to IS 3663:1991 for office chair dimensions.

Key Rigidity Test Setup (Annex B, Clause 1.1)

Standards Summary Table

flowchart LR
    A[Material Selection] --> B[Plastic Type: Thermoplastic/Thermosetting]
    B --> C[Additives for Enhanced Strength]
    C --> D[Chair Manufacturing]
    D --> E[Dimensional Verification (IS 3663)]
    E --> F[Strength Testing (IS 5416)]
    F --> G[Flammability Evaluation (IS 13360)]

IS 13713: Dimensions for Office Plastic Chairs — Key Guidelines

• Dimensions: Must comply with IS 3663:1991, which specifies standard sizes for office furniture.
• Design: Customizable as per purchaser demands but must satisfy mechanical strength and stability requirements.
• Material: Utilizes filled or unfilled reinforced thermoplastics or thermosetting plastics.
• Rigidity Assessment (Annex B):
  • Load of 300 N applied at 300 mm height from seat base (Point A on backrest).
  • Load maintained for 4 hours.
  • A 6 mm thick rubber pad is placed between the loading device and backrest for load distribution.
• Marking: Optional BIS Standard Mark may be present (Clause 8.2).

Rigidity Test Setup Summary

Reference Standards:

• IS 3663:1991 for detailed dimensional data.
• Strength and stability tests per IS 686 and IS 5416.

flowchart LR
    A[Seat Base] -->|300 mm| B[Point A on Backrest]
    B -->|Apply 300 N Force| C[Backrest]
    C --> D[6 mm Rubber Pad]
    D --> E[Rigid Bow with Rounded Edges]

The standard guarantees ergonomic design and safety compliance for office plastic chairs.

IS 13713 — Design Requirements Overview (Clause 6.2.3 & Annex B)

Principal Rigidity Test:

• Test Configuration:

  • Chair specimen secured on a rigid flat surface.
  • Force applied at Point A, located 300 mm above the lowest seat point along the backrest’s vertical axis.
  • Force magnitude: 300 N, directed backward, parallel to the mounting surface.
  • A 6 mm thick rubber sheet with a minimum 10 mm overhang surrounds the rigid bow to distribute the force evenly.

• Duration: Force sustained for 4 continuous hours.

• Acceptance: Displacement of Point A after load application is measured; minimal movement signifies sufficient rigidity.

Strength Evaluations (Clause 6.2.1):

• Static, fatigue, and impact tests conducted as per IS 5416 (Part 1):1988.
• Test intensity selected according to usage level, either Level 4 or 5 (refer Table 3 in IS 5416).
• Post-test, chairs must be free of structural damage.

Dimensional Compliance:

• Chairs must conform to IS 3663:1991 dimensions.

Rigidity Test Setup Summary

flowchart LR
    A[Specimen Mounted on Rigid Surface] --> B[Mark Point A at 300 mm Height]
    B --> C[Apply 300 N Force Backwards at Point A]
    C --> D[Insert 6 mm Rubber Sheet Between Bow and Backrest]
    D --> E[Maintain Force for 4 Hours]
    E --> F[Measure Displacement at Point A]
    F --> G{Is Displacement Within Limits?}
    G -- Yes --> H[Pass Rigidity Test]
    G -- No --> I[Fail Rigidity Test]

Note: Chair design flexibility is allowed; materials include reinforced thermoplastic or thermosetting plastics. Fire resistance and material toxicity considerations are also incorporated.

IS 13713 — Performance Specifications Summary

1. Mechanical Performance Tests (Clause 6.2.1)

• Includes static, fatigue, and impact assessments in line with IS 5416 (Part 1):1988.
• Testing level depends on expected usage intensity, Level 4 or 5, as detailed in Table 3 of IS 5416 Part 1.
• Acceptance demands absence of structural failures after testing.

2. Sampling and Evaluation (Clause 6.1)

• Samples selected randomly as per Clause 6.1.
• Final values are rounded off following IS 2:1960.

3. Materials and Dimensional Standards

• Chairs must be fabricated using reinforced thermoplastic or thermosetting plastics.
• Dimensions must adhere to IS 3663:1991.

Reference Table: IS 5416 (Part 1):1988 Test Levels for Office Chairs

Testing Workflow Diagram

flowchart TD
    A[Select Samples (Clause 6.1)] --> B[Static Loading Test]
    B --> C[Fatigue Loading Test]
    C --> D[Impact Resistance Test]
    D --> E{Any Structural Damage?}
    E -- No --> F[Performance Criteria Met]
    E -- Yes --> G[Sample Rejected]

Note: For detailed load magnitudes and cycles, review Table 3 of IS 5416 (Part 1):1988.

IS 13713: Sampling and Testing Protocols (Clauses 6.1 & 6.2)

• Sampling (6.1.1): Random sampling must be conducted as per IS 5416 (Part 1):1988 to ensure representative test specimens.

• Strength Testing (6.2.1): Includes static, fatigue, and impact tests following IS 5416 (Part 1):1988 procedures. Test intensity (Level 4 or 5) is determined based on anticipated usage (see Table 3 in IS 5416 Part 1). Acceptance requires no structural damage post-testing.

• Stability Testing (6.2.2): Performed according to IS 5416 (Part 2):1988 to guarantee the chair does not tip over.

Reference Table Excerpt (IS 5416 Part 1:1988 Table 3)

Testing Process Flow

flowchart TD
    A[Random Sampling per IS 5416 Part 1] --> B[Strength Tests]
    B --> B1[Static Load]
    B --> B2[Fatigue Load]
    B --> B3[Impact Test]
    B --> C{No Structural Defects?}
    C -- Yes --> D[Pass Tests]
    C -- No --> E[Fail Tests]
    D --> F[Stability Test per IS 5416 Part 2]
    F --> G{Chair Stability Confirmed?}
    G -- Yes --> H[Stability Passed]
    G -- No --> I[Stability Failed]

Refer to IS 5416 (Parts 1 & 2):1988 along with IS 13713 for detailed procedures and load specifications.

IS 13713 — Summary of Strength, Stability, and Rigidity Evaluations

1. Strength Tests (Clause 6.2.1)

• Static, fatigue, and impact tests conducted as per IS 5416 (Part 1):1988.
• Test levels 4 or 5 applied depending on use case (refer Table 3 in IS 5416 Part 1).
• No structural damage permissible after testing.

2. Stability Testing (Clause 6.2.2)

• Stability test carried out as per IS 5416 (Part 2):1988.
• Chair must remain stable and not overturn during testing.

3. Rigidity Test (Clause 6.2.3, Annex B)

• Backrest rigidity assessed by applying a specified load.
• Maximum permissible displacement at load application point is 75 mm.

Reference Table (Excerpt from IS 5416 Part 1:1988 Table 3)

Testing Flow Chart

flowchart TD
    A[Selected Test Sample] --> B[Strength Tests (IS 5416 Part 1)]
    B -->|Pass| C[Stability Test (IS 5416 Part 2)]
    C -->|Pass| D[Rigidity Test (Annex B)]
    D -->|Pass| E[Sample Approved]
    B -->|Fail| F[Sample Rejected]
    C -->|Fail| F
    D -->|Fail| F

Refer to IS 5416 Parts 1 and 2 for detailed load values and testing methods.

Key Points on Strength Testing as per IS 13713 (Clause 6.2.1)

• Test Types:

  • Static loading
  • Fatigue cycling
  • Impact resistance Conducted according to IS 5416 (Part 1):1988.

• Test Levels:

  • Usage-based Levels 4 or 5 as per Table 3 of IS 5416 (Part 1).
  • Higher levels correspond to greater loads or higher cycle counts.

• Acceptance Criteria:

  • No permanent structural damage after testing.

• Stability Testing (Clause 6.2.2):

  • Performed according to IS 5416 (Part 2):1988.
  • Chair must not overturn.

• Shell Rigidity (Annex B):

  • Ensures deformation remains within acceptable limits.

Typical Strength Test Parameters (IS 5416 Part 1)

Strength Testing Flowchart

flowchart TD
    A[Prepare Test Sample] --> B[Static Load Test]
    B --> C{Passed?}
    C -- Yes --> D[Fatigue Test]
    C -- No --> E[Reject Sample]
    D --> F{Passed?}
    F -- Yes --> G[Impact Test]
    F -- No --> E
    G --> H{Passed?}
    H -- Yes --> I[Sample Accepted]
    H -- No --> E

Refer to Table 3 of IS 5416 (Part 1):1988 for detailed parameters.

IS 13713 — Stability Testing Summary

• Stability testing follows IS 5416 (Part 2):1988.
• The chair must resist overturning under prescribed load applications.
• Test samples are selected as per Clause 6.1.

Key Elements from IS 5416 (Part 2)

• Load is applied at designated points such as armrests or seat edges.
• Load magnitude is typically 1.5 times the design load.
• The chair should neither tip over nor slide during testing.
• The test simulates realistic tipping scenarios.

Typical Stability Test Setup

Summary

• Ensures user safety by preventing chair tipping.
• If the chair fails, design modifications to base size or weight distribution are required.

flowchart LR
    A[Start Stability Test] --> B[Apply Load at Specified Point]
    B --> C{Does Chair Overturn?}
    C -- No --> D[Pass Stability]
    C -- Yes --> E[Fail - Redesign Needed]

Consult IS 5416 (Part 2) Tables 2 and 3 for precise load and test details.

IS 13713 — Backrest Rigidity Test (Clause 6.2.3 & Annex B)

Test Setup (Annex B-1)

• The backrest is firmly attached to a rigid, flat surface.
• Point A is marked at 300 mm above the lowest seat point along the backrest axis.
• A force of 300 N is applied backward, parallel to the mounting surface.
• The load is delivered through a rigid bow with rounded edges.
• A 6 mm thick rubber pad, extending at least 10 mm beyond the bow edges, is placed between the bow and backrest.
• The force is maintained continuously for 4 hours.

Acceptance Criteria

• Maximum allowable displacement of Point A is 75 mm from its original position.

Rigidity Test Parameters Summary

Simplified Test Diagram

flowchart LR
    A[Backrest Mounted Rigidly]
    B[Mark Point A at 300 mm Height]
    C[Apply 300 N Force Backwards]
    D[6 mm Rubber Pad Inserted]
    E[Rigid Bow with Rounded Edges]

    A --> B
    B --> E
    E --> D
    D --> C

This test verifies that the backrest maintains structural integrity under prolonged load without excessive deformation.

Colour Fastness Evaluation (IS 13713 Clause 6.2.4)

• The chair’s plastic shell is tested following IS 686:1985 for colour fastness to daylight.
• The minimum acceptable rating on the grey scale is 3 (where 1 denotes poor and 5 excellent).

Colour Fastness Scale (IS 686:1985)

• Testing involves exposing the material to natural or simulated daylight for a set duration.
• Colour change is compared against a grey scale to quantify fading.

Related Tests for Context

Summary

• Chairs must achieve a minimum colour fastness rating of 3.
• Ensures plastic components retain acceptable appearance under daylight exposure.

flowchart TD
    A[Plastic Shell Sample] --> B[Colour Fastness Test per IS 686]
    B --> C{Rating ≥ 3?}
    C -- Yes --> D[Pass: Acceptable Colour Fastness]
    C -- No --> E[Fail: Unacceptable Fading]

This guarantees that office chairs maintain colour quality over their service life.

IS 13713 — Flammability Determination Using Oxygen Index

Key Requirement

• Minimum Oxygen Index (OI) value: 17.
• Testing performed as per IS 13360 (Part 6/Sec 6):1992, which defines the oxygen index method for plastics.

Oxygen Index Explanation

• Oxygen Index is the lowest oxygen concentration (percentage) that supports material combustion.
• A higher OI value reflects superior flame retardancy.

Test Principle (IS 13360 Part 6/Sec 6)

• A vertical plastic sample is exposed to a controlled oxygen-nitrogen atmosphere.
• Oxygen concentration is varied to identify the minimal oxygen level sustaining combustion.

Typical Oxygen Index Values by Material

Practical Notes

• All chair plastic parts must meet or exceed OI of 17.
• Packaging must safeguard components during transit to maintain integrity.
• This test ensures compliance with fire safety standards for plastic furniture materials.

flowchart LR
    A[Prepare Sample] --> B[Clamp Vertically]
    B --> C[Introduce Oxygen-Nitrogen Gas Mix]
    C --> D[Ignite Sample]
    D --> E{Does Sample Continue Burning?}
    E -- Yes --> F[Lower Oxygen Concentration]
    E -- No --> G[Increase Oxygen Concentration]
    F --> E
    G --> E
    E --> H[Determine Minimum Oxygen Concentration = Oxygen Index]

References:

• IS 13713 Clause 6.2.5
• IS 13360 (Part 6/Sec 6):1992 for detailed test method.

IS 13713 — Guidelines for Marking Plastic Chairs

Marking Specifications (Clause 8)

• Clause 8.1: All chairs must bear a clear mark identifying the manufacturer.

• Clause 8.2: Chairs may optionally display the Standard Mark indicating compliance with IS 13713.

Additional Considerations

• Marking must be durable and easily readable throughout the product’s lifespan.
• Marks facilitate traceability and quality assurance.
• The standard does not prescribe a specific format for marking; it is a mandatory identification feature.

Related Standards (Annex A)

• IS 3663:1991 — Office chair dimensions
• IS 686:1985 — Colour fastness testing
• IS 13360 (Part 6/Sec 6):1992 — Plastic flammability testing

Marking Summary Table

flowchart TD
    A[Plastic Chair] --> B[Apply Manufacturer’s Mark]
    B --> C{Include Standard Mark?}
    C -->|Yes| D[Add Standard Mark]
    C -->|No| E[Manufacturer Mark Only]
    D & E --> F[Ensure Marking Durability]

In summary, IS 13713 requires permanent manufacturer identification on plastic office chairs, with optional inclusion of the Standard Mark for compliance.

IS 13713 — Packaging Specifications and Protective Measures

1. Packaging Requirements:

• All chair components must be packaged to prevent damage during transportation (Clause 6.2.5).
• Packaging should provide protection against mechanical shocks and environmental exposure.

2. Flammability Compliance:

• Materials must comply with oxygen index flammability standards (OI ≥ 17) as per IS 13360 (Part 6/Sec 6):1992.

3. Packaging Materials and Protection:

• Use cushioning elements such as 6 mm thick rubber sheets with at least 10 mm projections to protect surfaces.
• Packaging must support load tests, such as the 300 N backrest force applied during rigidity testing, without causing damage.

Packaging and Testing Parameters Summary

Conceptual Packaging Protection Diagram

flowchart LR
    A[Chair Component] --> B[6 mm Thick Rubber Sheet]
    B --> C[Rigid Bow for Load Application]
    C --> D[Packaging Box]
    D --> E[Transportation]

    style B fill:#f9f,stroke:#333,stroke-width:2px
    style C fill:#bbf,stroke:#333,stroke-width:2px

Note: Packaging must ensure both mechanical protection and adherence to fire safety standards as specified in IS 13713 and related codes such as IS 13360.