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1.0 INTRODUCTION
Construction sites are often communities within themselves consisting of a variety of activities with numerous pieces of equipment and tools in use simultaneously. An important piece and one of the most expensive pieces of equipment in use on most construction sites is the crane. Statistics indicate that a significant number of construction injuries and fatalities are crane related accidents that also cost hundreds of thousands of dollars in equipment damage and other related costs. An example of the tremendous loss potential occurred a few years ago when two cranes, working in tandem, while traveling, dropped their load onto a sports stadium under construction and some other construction equipment. Although no personal injuries were experienced, the cost due to equipment damage and the project delays was extremely high. For instance, the cost of one 150-200 ton mobile crawler crane alone is in excess of $800,000.00, and, depending upon capacity and added components, can sell for more than $1,000,000.00. Construction delays and investigative costs can easily run the cost into the millions of dollars.
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MODERN RINGER CRANE
500 TON CAPACITY | Over the past few decades, there has been a significant increase in the cost of cranes due in part to improved engineering design and specific job site requirements.
Today, manufacturers design and build stronger and lighter cranes in response to specific industry needs. Speed, utility, capacity, and reach (radius) have been improved to the point that the crane has become an indispensable workhorse for construction. Therefore, a more thorough understanding of cranes, their capabilities and limitations is critically important for everyone involved in construction today. The crane can perform safely and economically when operated within the design parameters set by the manufacturer.
Due to significant advances in lifting technology, crane operators, site supervisors, safety professionals, and OSHA compliance officers need to keep abreast of modern crane technology and changes in operating procedures to help them recognize problems before potentially unsafe conditions lead to accidents that result in injuries and/or fatalities, as well as equipment damages.
With these factors in mind, the need for a better understanding of crane operations and the implementation of appropriate maintenance schedules is evident in preventing accidents.
A recent study by Don Dickie, a recognized crane authority with the Construction Safety Association of Ontario, indicates that although mechanical failures represent only 11% of the causes of crane accidents, they usually result in the major accidents involving injuries, fatalities, substantial material costs, and usually spectacular media coverage. Studies and analyses of crane accidents involving mechanical failure show they are frequently due to a lack of preventive maintenance or adequate training and/or experience on the part of the personnel involved. It is important that not only crane operators but also other personnel working with cranes receive training in crane operations. Cranes and associated rigging equipment must be inspected regularly to identify any existing or potentially unsafe conditions. In addition, preventive maintenance must be performed as required by the crane manufacturer and/or the supplier to ensure safe crane operation. The inspections performed by OSHA compliance officers and/or other safety professionals also can play an important role by identifying hazards as well as safe crane operations.
This report addresses major issues related to the crane itself and provide some basic information on crane capacities and inspection criteria for OSHA compliance officers. Since it would be difficult for a single report to fully address all types of cranes available in today's market, two types of cranes typically found on construction sites are discussed in this report. Some of the issues encountered during inspections cover the following three areas:
- Basic Crane Operations – Lifting principles/mechanics and some operational criteria.
- Typical Crane inspection Checklist – Listing of critical items and components recommended for periodic inspection.
- Regulations – Federal OSHA regulations and applicable ASME/ANSI and PCSA standards.
This report also contains general guidelines for crane inspections, as well as some suggested operational considerations and inspection items recognized by a number of construction companies.
Cranes are designed for both general use and for specific purposes. Similar to the vast automobile industry, crane manufacturers produce similar models or types of cranes for the same purpose, often with different sizes of the same model of crane. Each type, model, or size of crane manufactured, may have different operating controls and require specialized operator training, individualized inspection criteria, and different preventive maintenance schedules.
Two commonly used cranes, a hydraulic rough terrain crane and a crawler lattice boom friction crane, are shown as examples for developing this document. There are several significant differences between these two cranes, primarily in boom hoist and load line controls. The somewhat smooth operation of the boom control adjustments on the hydraulic cranes may suggest falsely to the novice operator or inspector that it is a simple crane to operate. On the other hand, the lattice boom friction cranes' movement in its boom, or its adjustment in load position tend to be a little jerky requiring more skill and experience to operate smoothly. Another clear difference between the two types of cranes is their load charts. Due to the fixed boom length, the lattice boom friction crane has a somewhat simplified load chart. This requires extensive motion control and an anticipation of boom movement to accurately lift or place loads. Conversely, the hydraulic crane's load charts are more extensive or complicated due to the variations in boom length thus requiring more training in the multiple charts available. The differences between these two types of cranes are significant enough to require specific training on each type of crane. Crane operators cannot be expected to be totally knowledgeable and proficient in the operation of the many diverse types of cranes available today. They cannot be expected to move from one type of crane to another without adequate education and training on the specifics of each piece of equipment.
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