The Safe Use of Outrigger Pads for Equipment Stability

The Safe Use of Outrigger Pads for Equipment Stability

Written by Jeff Steiner on September 16, 2019. Posted in Worksite Safety.

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An outrigger pad is a safety tool that can be used with any equipment that has outriggers, down jacks, or stabilizers. It is essential for stability when equipment like cranes lifts loads or personnel aloft. This article provides an overview of outrigger pads, their safe usage, and the types of pads available today.

The Basics

Outrigger pads are placed on the ground under the equipment’s outrigger, shoe, float, or foot. The size and thickness of the pads to be used should be selected based on equipment type, soil conditions at the work site, and the type of lift being performed.

Without an outrigger pad, the point of contact between an outrigger and the ground is very small. The high pressure at this point can cause the ground underneath to shift, displace or collapse. If this happens, the equipment may shift or tip the load, leading to the equipment toppling over. About half of crane lifting accidents are due to the improper use of outriggers.

Stability Factors

Outrigger pads help stabilize equipment to prevent ground shifting and toppling. Stability depends on the equipment’s footprint and center of mass. The footprint is the total area enclosed by the support structure of the equipment, while the center of mass is the balance point if the equipment were set on a single point. It will topple if the center of mass is at the edge of or outside the footprint.

There are two main ways to provide extra stability. The first is using a counterweight to shift the center of mass back over the footprint. The second is expanding the footprint using an extendable outrigger system.

All cranes have counterweights, but these are limited by transportation and setup considerations. The ground can only sustain so much pressure before displacing or collapsing. Even if a crane can be transported to a work location, ground conditions may not be stable enough to set up and hold the crane. Hence, retractable outriggers are essential for extending the footprint. Using outrigger pads under these outriggers will further expand the point of contact with the ground, displacing the pressure from the equipment through the pad.

Key Safety Points

As with any safety tools, outrigger systems and pads must be used according to manufacturers’ instructions. Keep the following six points in mind:

1. Proper Setup and Leveling: Proper setup and leveling are essential. Follow the manufacturer’s chart for allowable level and grade percentage. Incorrect levels reduce lifting capacity.
2. Soil Conditions: Acquire recent soil conditions for the work area to determine the appropriate outrigger pad. OSHA 29 CFR 1926.1402 requires ground conditions to be firm, drained, and graded adequately.
3. Utility Clears: Check current locates and identify utilities overhead and underground. Maintain proper clearances, especially around overhead power lines.
4. Bridging Gaps: Do not use outrigger pads to bridge gaps or span voids.
5. Lift Capacity: Know the equipment's maximum lift capacity, which includes understanding the load chart and lifting rigging. Employ qualified personnel and conduct thorough job briefings.
6. Understanding Systems: Different pieces of equipment have different outrigger systems. Learn how to set up each system correctly.

A Rule of Thumb

A known ground-bearing capacity may not always be available. In such cases, an outrigger pad should be at least three times the square surface area of the outrigger shoe or float for Grade A soil conditions. As soil conditions worsen, create a larger footprint using pads and cribbing. After setup, perform a dry run with a spotter to ensure pads are not shifting, sliding, or sinking. If issues arise, stop and make adjustments.

Types of Outrigger Pads

Outrigger pads come in various lengths, widths, thicknesses, and shapes. Large square outrigger pads have a large surface area but are harder to move. Round outrigger pads can be rolled into position easily but have less surface area.

Materials

Three primary materials are recommended for critical lifts or loads above 10,000 pounds: American custom composite, premium birch, and American steel. Each has unique strengths, with American custom composite offering 3,000 psi and a lifetime value, premium birch being durable with a decade-long lifespan, and American steel being robust and long-lasting.

Conclusion

Outrigger pads should be inspected before each use. After setup, conduct a dry run with a spotter to inspect the outriggers and pads, ensuring the equipment is level before proceeding with the job. For more information on high-quality outrigger pads, Check now.