Methods of sampling of helmets

IS 9695: Scope - Key Sampling & Inspection Specifications

Scope:
IS 9695 specifies sampling and inspection criteria for helmets, focusing on material, workmanship, weight, peripheral vision, and other safety features.

Sampling for Material, Size, Construction, Workmanship & Finish (Clause 4.4)

Sampling for Weight, Peripheral Vision, and Other Safety Features (Clause 4.5)

• Samples for Clause 4.5 are selected randomly from helmets already passing Clause 4.4 inspection.

Summary

• Two-stage sampling for workmanship and finish with acceptance/rejection criteria.
• Separate sampling scale for functional tests (weight, vision, retention, etc.).
• Ensures quality control before safety feature testing.

If needed, I can provide formulas or

IS 9695: Key Definitions & Sampling Tables

Definitions (Clause 2.0)

• The standard defines terms related to material quality, size, workmanship, finish, weight, and peripheral vision for the product under inspection.
• These terms ensure uniform understanding for inspection and acceptance criteria.

Sampling & Inspection (Clauses 4.4 & 4.5)

Table 1: Sampling for Material, Size, Construction, Workmanship, Finish (Clause 4.4)

Table 2: Sampling for Weight, Peripheral Vision, etc. (Clause 4.5)

Usage:

• Use Table 1 for detailed quality checks on workmanship and finish.
• Use Table 2 for weight and peripheral vision checks.
• Follow acceptance/rejection numbers strictly for lot acceptance.

This

IS 9695: Process Control - Key Points

1. Statistical Quality Control (Clause 3.3)

• Use Statistical Quality Control (SQC) techniques for effective process control.
• Refer to IS 397 (Part I & II) for detailed SQC methods.

2. Rejection Number (Clause 2.8)

• Rejection Number: Minimum defective count in a sample to reject the lot.

3. Sampling for Lot Inspection (Clause 4.5)

4. Quality Control Importance (Clause 2.1)

• Proper quality control reduces product quality fluctuations.
• Both process control and lot inspection are recommended.

Summary Formula/Concept:

• Lot Acceptance: Accept lot if defective count < Rejection Number.
• Sample size depends on lot size (see table).

flowchart LR
    A[Start Production] --> B[Apply SQC Techniques]
    B --> C{Sample Lot?}
    C -->|Yes| D[Select Sample Size per Table]
    D --> E[Inspect Sample]
    E --> F{Defectives < Rejection Number?}
    F -->|Yes| G[Accept Lot]
    F -->|No| H[Reject Lot]
    C -->|No| I[Continue Production]

References: IS 397 (Part I & II), IS 2-1960 (Rounding rules)

IS 9695: Lot Inspection Key Points

1. Sampling for Material, Size, Construction, Workmanship & Finish (Clause 4.4)

• Acceptance Number: Maximum allowable defectives to accept the lot.
• Rejection Number: Minimum defectives to reject the lot (Clause 2.8).

2. Sampling for Weight, Peripheral Vision, etc. (Clause 4.5)

3. Process Control (Clause 3.3.1)

• Inspection/test data at manufacture can be supplied for purchaser’s acceptance judgment.

Summary Diagram:

flowchart TD
    A[Start: Identify Lot Size] --> B{Lot Size ≤ 50?}
    B -- Yes --> C[Sample 8 (First), Cum. 8]
    B -- No --> D{

IS 9695: Inspection of Each Lot — Key Formulas & Tables

1. Sampling for Material, Size, Construction, Workmanship & Finish (Clause 4.4)

• Acceptance Number = Max allowable defectives to accept the lot.
• Rejection Number = Minimum defectives to reject the lot (Clause 2.8).

2. Sampling for Weight, Peripheral Vision, etc. (Clause 4.5)

3. Additional Notes

• Inspection data from process control tests (Clause 3.3.1) may be submitted to assist acceptance.
• Sampling is done in two stages (First & Second) with cumulative sample

IS 9695: Scale of Sampling & Acceptance Criteria

1. Sampling for Material, Size, Construction, Workmanship, Finish (Clause 4.4)

• Double sampling plan: Inspect first sample; if acceptance number exceeded, inspect second sample.
• Acceptance: If defects ≤ acceptance number, lot accepted.
• Rejection: If defects ≥ rejection number, lot rejected.

2. Sampling for Weight, Peripheral Vision, Protection, etc. (Clause 4.5)

• Samples selected only from helmets passed in Clause 4.4 inspection.
• Applies to tests like weight, vision, retention strength, ventilation, flexibility, etc.

Summary:

• Use Table 1 for material, size

IS 9695: Scale of Sampling & Criteria Summary

1. Scale of Sampling for Weight, Peripheral Vision, Extent of Protection, etc. (Clause 4.5, Table 2)

• Samples are selected randomly from helmets already accepted in material, size, workmanship (Clause 4.4.1).
• Inspection covers weight, peripheral vision, protection extent, retention system strength, head clearance, depth of fit, chin strap attachment, lamp bracket, cable clip, ventilation gap, flexibility of peak and brim.

2. Sampling & Acceptance Criteria for Materials, Size, Construction (Clause 4.4 & 4.4.1)

• Uses a double sampling plan (Table 1 in the code).
• First sample inspected; lot accepted/rejected based on defect count vs acceptance/rejection numbers.
• If inconclusive, a second sample of equal size is inspected, and combined results decide acceptance.

Key Notes:

• Sampling ensures quality control for critical helmet safety parameters.
• Random selection minimizes bias.
• Double sampling balances inspection effort and reliability.

flowchart TD
    A[Start: Lot Received] --> B[Select First Sample (size per Table 1)]
    B --> C{Defectives ≤ Acceptance No.?}
    C -- Yes --> D[Accept Lot]
    C -- No --> E{Defectives ≥ Rejection No.?}
    E -- Yes --> F[Reject Lot]
    E -- No --> G[Select Second Sample (same size)]
    G --> H[Inspect Second Sample]
    H --> I{Combined Defectives ≤ Acceptance No.?}
    I -- Yes --> D
    I -- No --> F

This flowchart illustrates the double sampling plan for materials, size, and workmanship inspection.

For detailed acceptance/rejection numbers and sample sizes, refer to Table 1 in IS 9695.

IS 9695: Scale of Sampling & Criteria for Safety Performance Tests

1. Scale of Sampling for Weight, Peripheral Vision, etc. (Clause 4.5, Table 2)

• Samples are randomly selected from helmets already passing Clause 4.4 inspection.
• Applies to: Weight, Peripheral Vision, Extent of Protection, Strength of Retention System, Head Clearance, Depth of Fit, Chin Strap Attachment, Lamp Bracket, Cable Clip, Ventilation Gap, Flexibility of Peak and Brim.

2. Scale of Sampling for Material, Size, Construction, Workmanship, Finish (Clause 4.4, Table 1)

• Double sampling plan: If first sample fails, second sample is taken.
• Acceptance/Rejection numbers define

IS 9695: Sampling for Small Lots

Key Tables & Specifications

1. Sampling for Materials, Size, Construction, Workmanship, and Finish (Clause 4.4, Table 1)

• Double Sampling Plan: Inspect first sample; if acceptance/rejection criteria are not met, inspect second sample.

2. Sampling for Weight, Peripheral Vision, etc. (Clause 4.5, Table 2)

Definitions

• Lot: Total quantity of helmets offered for inspection.
• Sample: Group of items drawn from the lot for inspection.

Summary

• Use Table 1 for detailed quality attributes with a double sampling plan.
• Use Table 2 for specific requirements like

IS 9695: Testing Sequence for Medium Lots (26 to 500 helmets)

Sampling Sizes

Sampling for Material, Size, Construction, Workmanship & Finish

Testing Sequence (Table 3, Clause 4.6.2)

Notes on Shock Absorption Test Conditions

• Condition (a): 50±5℃ for 4 hours (oven)
• Condition (b): -10±2℃ for 4 hours (refrigerator)
• **Condition (c

IS 9695: Testing for Large Lots - Key Specifications

Sampling & Testing for Large Lots (Clauses 4.4, 4.5, 4.6.2)

1. Sample Size for Material, Size, Construction, Workmanship & Finish (Table 1, Clause 4.4)

• Second sample sizes and acceptance/rejection numbers increase cumulatively if the first sample is inconclusive.

2. Sample Size for Weight, Peripheral Vision, etc. (Table 2, Clause 4.5)

3. Testing Sequence & Lot Conformity (Clause 4.6.2)

• For lots 26 to 500 helmets, perform one test per requirement.
• Use sequence of tests (Table 3, not provided) to minimize sample size.
• Lot is accepted if all test results are satisfactory.
• Lot is rejected if any test fails.

Definitions

• Acceptance Number: Max allowable defective samples to accept the lot.
• Rejection Number: Minimum defective samples to reject the lot.

Summary Formula for Lot Acceptance

• If number of defectives ≤ Acceptance Number → Accept lot
• If number of defectives ≥ Rejection Number → Reject lot

flowchart TD
    A

Here are the key formulas, tables, and specifications for Reporting and Documentation as per IS 9695:

1. Sampling & Inspection (Clause 4.4 & 4.5)

Table 1: Scale of Sampling for Material, Size, Construction, Workmanship, and Finish

Second sampling doubles sample size and adjusts acceptance/rejection numbers accordingly.

Table 2: Sampling for Weight, Peripheral Vision, etc. (Clause 4.5)

2. Testing Sequence (Clause 4.6.2)