Load Charts & Rated Capacity

The load chart is your primary reference for safe lifting operations. Every side boom tractor has a load chart specific to that machine configuration. Understanding how to read and apply the load chart correctly is critical for preventing overload and tip-over incidents.

Never exceed the rated capacity. The load chart represents the maximum safe working load under ideal conditions. Real-world conditions may require additional derating.

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Understanding the Load Chart

A side boom tractor load chart typically shows:

  • Working Radius – Horizontal distance from machine centerline to the load center
  • Boom Angle – Angle of the boom from horizontal
  • Rated Capacity – Maximum safe working load at each configuration
  • Counterweight Configuration – If adjustable counterweights are fitted

Key Principles

  • Capacity decreases as working radius increases
  • Capacity increases with steeper boom angles (shorter radius)
  • The rated capacity includes the weight of the hook block and rigging
  • Ground conditions and slopes affect the actual safe working load

Calculating the Load

To determine if a lift is within capacity, you must know:

  1. Weight of the load (pipe section weight)
  2. Weight of rigging gear (slings, shackles, spreader bars)
  3. Working radius (measured or calculated)
  4. Boom angle (read from the indicator)
Total Load = Pipe Weight + Rigging Weight

This total must not exceed the rated capacity at the working radius.

⚠️ Derating Factors

The rated capacity may need to be reduced for:

  • Wind – High winds can destabilize the load and machine
  • Ground Conditions – Soft or uneven ground reduces stability
  • Slope – Operating on slopes affects the tipping line
  • Dynamic Loading – Sudden movements, swinging loads
  • Temperature – Extreme cold affects hydraulics and steel

✅ Load Chart Best Practices

  • Always verify the load chart is specific to your machine configuration
  • Never rely on memory – always reference the chart before each lift
  • Include rigging weight in your load calculations
  • Apply derating factors for non-ideal conditions
  • If in doubt, consult your Lifting Supervisor

❌ Common Errors

  • Estimating load weight instead of verifying
  • Ignoring rigging weight in capacity calculations
  • Using the wrong load chart for the machine configuration
  • Not accounting for radius change during the lift
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