Weighing bridges (weighbridges) are critical for trade, logistics, and legal metrology, ensuring accurate weight measurements for vehicles and goods. Regular inspection and certification by a third-party or authorized agency are mandatory to comply with national/international standards.

Inspection & Certification Objectives

  • Ensure accuracy and reliability of weighbridge measurements.
  • Verify compliance with legal metrology regulations
  • Detect mechanical/electrical faults affecting performance.

Pre-Inspection Requirements

  • Documentation Review
  • Manufacturer’s specifications & installation details.
  • Previous calibration/test certificates.
  • Legal metrology approvals (if applicable).
  • Site Preparation
  • Ensure the weighbridge is clean, level, and free of debris.
  • Check for structural integrity (cracks, corrosion, foundation issues).
  • Verify load cell condition (no physical damage, proper sealing).

Inspection & Testing Process

  • Visual & Mechanical Inspection
  • Foundation & Structure:
  • Check for cracks, settlement, or corrosion.
  • Verify alignment and load distribution.
  • Load Cells & Connections:
  • Inspect for damage, moisture ingress, or loose wiring.
  • Junction Box & Cabling:
  • Ensure waterproofing and secure connections.

Functional Testing

  • Zero Load Test
  • Ensure the weighbridge returns to zero after unloading.
  • Check for drift (unstable readings when empty).
  • Span Calibration (Using Test Weights)
  • Apply known certified weights (e.g., 10T, 20T, max capacity).
  • Verify readings match within permissible error (e.g., ±0.1% to ±0.5%).
  • Eccentric Load Test (Corner Test)
  • Place test weights on different sections of the weighbridge.
  • Ensure readings are consistent across all areas (no imbalance).
  • Repeatability Test
  • Weigh the same load multiple times to confirm consistent results.
  • Material Test (Optional – For Legal Metrology)
  • Compare weighbridge readings against a pre-weighed truck (if required by authorities).

Certification & Compliance

If the weighbridge passes all tests, a certificate of conformity is issued. The certificate includes:

  • Calibration report with test results.
  • Permissible errors as per standards.
  • Next due date for re-inspection.
  • Sticker/Seal applied (for legal metrology compliance).
  • Standards & Regulations

Frequency of Inspection & Re-Certification

  • Annual/Mandatory: Required for trade-approved weighbridges.
  • Every 6 Months: High-usage or harsh environments.
  • After Repairs/Modifications: Re-calibration needed if load cells or structure are altered.