Methods of test for strength and stability of settees and benches, Part 2: Stability

IS 12674 Part 2: Scope Summary & Key Specifications

Scope (Clause 2.0):
Defines the application of the standard for seating articles, focusing on test methods and load application.

Key Points on Load Application (Clause 4.1 & 4.3)

• Load Application: Loads or forces are applied at specified points on seating articles.
• Template Setup:
  • Template positioned at 90° angle (Fig. 3).
  • Placed on the bench as per Fig. 2.
  • Mark loading points for seat and back loads (A, B, C) in millimeters.

Typical Loading Points (Fig. 1 Template)

Test Report Requirements (Clause 8.1)

• Article details tested.
• Whether overturning occurred.
• Deviations from test procedures.

Additional Notes

• The standard mark ensures compliance and quality per BIS.
• Indian Standards are periodically reviewed and updated.

flowchart TD
    A[Setup Template at 90°] --> B[Place on Bench]
    B --> C[Mark Loading Points A, B, C]
    C --> D[Apply Loads as per Mark]
    D --> E[Test Article]
    E --> F[Prepare Test Report]

For exact dimensions and detailed test procedures, refer to Figures 1, 2, and 3 in IS 12674 Part 2:1989.

IS 12674 Part 2: Definitions & Key Specifications

• Scope (Clause 1.1):
  Method to determine stability of settees & benches seating 2–4 persons.

• Definitions (Clause 2.0):
  Establishes terms related to loading points and stability testing.

• Loading Application (Clause 4.1 & 4.3):

  • Loads applied at specific points marked using a template set at 90° (Fig. 1).
  • Template helps mark seat load (A & C) and back load (B) points accurately on the furniture.
  • All dimensions in millimeters.

Key Points for Stability Testing:

Template Setup Summary:

graph LR
    A[Template] -->|Set at 90°| B[Mark Loading Points]
    B --> C{Load Types}
    C -->|A| D[Seat Load - Settees]
    C -->|B| E[Back Load]
    C -->|C| F[Seat Load - Benches]

This ensures consistent and repeatable load application for stability tests per IS 12674 Part 2.

IS 12674 Part 2: General Requirements for Tests

Key Points from Clauses:

• Clause 2.1:

  • Test objective: Verify ability to withstand overturning.

• Clause 3 / 7.1:

  • Article passes if:
    • It does not overturn during the test.
    • Meets the product specification requirements.

• Clause 4.1:

  • Specifies means of applying required loads or forces during tests (details in the standard).

• Clause 8.1 (Test Report Requirements):
  Test report must include:

  • Details of the article tested.
  • Whether overturning occurred.
  • Any deviations from test procedures.

Summary Table for Test Acceptance Criteria

Additional Notes:

• The Standard Mark indicates compliance with BIS quality and testing.
• Testing ensures stability and safety against overturning under specified loads.
• Follow load application methods strictly to ensure valid results.

flowchart TD
    A[Test Setup] --> B[Apply Required Loads (Clause 4.1)]
    B --> C{Does Article Overturn?}
    C -- No --> D[Check Product Specs]
    C -- Yes --> E[Fail Test]
    D -- Meets Specs --> F[Pass Test]
    D -- Does Not Meet Specs --> E

This flowchart illustrates the test decision process based on overturning and product specs.

For detailed load application methods and product-specific criteria, refer to the full IS 12674 Part 2 document.

IS 12674 Part 2: Test Equipment and Setup - Key Points

1. Test Loading Accuracy (Clause 3.1.1)

• All loads/forces must be measured with ±5% accuracy.
• For practical conversion:
  [ 10 \text{ N} \approx 1 \text{ kgf} ]

2. Test Setup (Clause 4.3)

• Use a template fixed at 90° to mark loading points (Fig. 1).
• Place the specimen on the bench as per Fig. 2.
• Mark loading points A, B, C corresponding to:
  • A: seat load (settees)
  • B: back load
  • C: seat load (benches)

3. Overturning Resistance (Clause 2.1)

• Tests evaluate the ability to withstand overturning under applied loads.

Summary Table: Load Points & Setup

Diagram: Template Setup (Simplified)

graph LR
  Template["90° Template"] -->|Mark loading points| Bench["Test Bench"]
  Bench --> LoadA["Load A (Seat - settees)"]
  Bench --> LoadB["Load B (Back load)"]
  Bench --> LoadC["Load C (Seat - benches)"]

Note: Refer to IS 12674 Part 2 Fig. 1 & 2 for exact dimensions and positioning.

IS 12674 Part 2: Determination of Seat Loading Points

Key Specifications:

• Local Loading Pad: Rigid cylinder, 100 mm diameter, flat face with 12 mm radius on front edge (Clause 4.6).
• Loading pads must pivot vertically; horizontal pivoting if design allows.

Loading Point Template (Clause 4.3):

• Consists of two shaped members fastened by a pivot, forming a 90° angle.
• Template mass: 20 kg, applied through the seat loading point.
• Designed to sink into upholstery under moderate load, simulating realistic seating pressure.

Procedure to Determine Seat Loading Points:

1. Place template on seat centerline, as far rearward as possible.
2. Apply load; push back portion into the backrest, levering seat portion forward.
3. Adjust until template shape matches seat contour.
4. Mark loading point on seat.
5. Repeat for other seats.
6. Use the marked points to position the template at 90° on a bench.
7. Mark final loading points from the template.

Diagram Concept (Simplified):

graph LR
A[Seat Loading Arm (20 kg)] -->|Load applied| B(Loading Point Template)
B --> C{Pivot at one end}
C --> D[Two shaped members at 90°]
D --> E[Template sinks into upholstery]
E --> F[Mark loading points on seat]

This ensures accurate seat loading points for durability and comfort testing.

IS 12674 Part 2: Stability Tests for Settees and Benches

Key Concept:

• Stability = Ability to withstand overturning (Clause 2.1).

General Test Procedure (Clause 1.1):

• Applies to settees/benches seating 2 to 4 persons.
• Stability tested by applying forces/moments to simulate overturning.

Typical Stability Test Method:

1. Apply a horizontal force (F) at a specified height (h) from the floor (usually seat height or backrest height).
2. Calculate the overturning moment:
   [ M_o = F \times h ]
3. Compare with the restoring moment due to weight (W) of the bench and occupants acting at the center of gravity (distance d from pivot):
   [ M_r = W \times d ]
4. Bench is stable if:
   [ M_r \geq M_o ]

Typical Specifications:

Summary:

• Ensure bench resists overturning moments by applying horizontal forces.
• Measure weight and center of gravity for restoring moment.
• Stability test confirms safety against tipping.

graph LR
A[Applied Force (F)] --> B[Overturning Moment (M_o = F × h)]
C[Weight (W)] --> D[Restoring Moment (M_r = W × d)]
B --> E{Is M_r ≥ M_o?}
E -- Yes --> F[Stable]
E -- No --> G[Unstable]

For detailed test setup and force magnitudes, refer to full IS 12674 Part 2 document.

IS 12674 Part 2 — Interpretation of Results: Key Points

Loading Forces & Positions (Clause 4.5)

• Vertical Force on Seat: 250 N applied 100 mm lateral to fore-aft centerline, 175–250 mm forward from rear seat edge.
• Vertical Force on Arm: 350 N applied 37.5 mm inside outer edge of arm at most adverse position.
• Horizontal Force on Armrest: 20 N outward at upper surface, aligned with vertical arm force side with stopped feet.

Test Setup (Clause 4.3 & Fig. 3)

• Use loading template at 90° angle.
• Mark loading points per Fig. 3 (scale: 1 square = 20x20 mm).
• Position article with stops against legs/base on one side.

Interpretation of Results (Clause 7 & 8.1)

• Report must include:
  • Article details.
  • Whether overturning occurred.
  • Deviations from test procedure.
• Evaluate structural integrity under applied loads.
• Check for permanent deformation, failure, or instability.

Summary Table of Forces

Diagram: Loading Positions on Chair Seat & Arm

graph LR
    A[Rear Edge of Seat] -->|175-250 mm| B(Vertical Seat Load 250 N)
    B --> C[100 mm lateral from centerline]
    D[Outer Edge of Arm] -->|37.5 mm inside| E(Vertical Arm Load 350 N)
    E --> F(Horizontal Arm Load 20 N outward)

Note: Ensure test setup and force application strictly follow IS 12674 Part 2 for valid interpretation and certification.

IS 12674 Part 2 — Test Report Key Points (Clause 8.1)

The Test Report for seating articles must include:

• a) Article Details: Description and identification of the seating article tested.
• b) Overturning Status: Whether the article overturned during the test (Clause 2.1 defines overturning as the article's inability to withstand overturning).
• c) Deviations: Any deviations from the standard test procedures must be clearly noted.

Pass Criteria (Clause 7.1)

• The article passes if:
  • It does not overturn during testing.
  • It meets all requirements of the relevant product specification.

Summary Table for Test Report Content

Additional Notes

• The Standard Mark usage is regulated by BIS under the Bureau of Indian Standards Act, 1986.
• Continuous quality control and inspection are mandatory for Standard Mark products.
• Ensure the latest amendments of the standard are referred.

flowchart TD
    A[Start Test] --> B{Article Overturned?}
    B -- No --> C[Check Product Specs]
    B -- Yes --> D[Fail Test]
    C -- Meets Specs --> E[Pass Test]
    C -- Does Not Meet Specs --> D

This flowchart shows the test decision process based on overturning and specification compliance.