CRANE CRITIQUE
CONSTRUCTION NEWS BULLETIN
BEFORE YOU LIFT Ask These 10 Pre-Lift Questions
A monthly crane and rigging informative column for all personnel directly or indirectly involved with crane safety. Each month we will attempt to explain a different technical issue pertaining to crane operations here on Guam, addressing the sometimes over-looked or misunderstood topics by management and operators alike. By Dave Barnhouse Normally, a great deal of thought and planning goes into a critical or super lift and these critical lifts are carried out with precision and are successful if the plan is carefully followed. All too often, however, the same careful planning is not present on the everyday routine smaller or simple lifts. Before performing any lift, regardless of how large or small, there is some basic information that must be known and confirmed before you begin. In most cases there is little or no planning and when things go wrong, an accident may result. I have noticed the majority of crane accidents result from lifts that are classified as routine and most likely preventable if the careful planning that is required for a critical or non-routine lift would have been implemented. There are ten questions that must be answered for any lift and could be considered a basic lift plan for standard lifts. The ten questions can be converted into a simple lift plan form. Then, require the crane operator to complete it before each and every lift. It only takes a few minutes and could prevent a costly accident. It has been shown that when a lift plan is required for every lift, the supervisors, operators and riggers catch mistakes before they happen. For example: The lift could be at a high percent of capacity. I have witnessed numerous occasions when an operator was set up for a lift, knowing the load was heavy but not actually calculating the gross load, and preparing to proceed with the lift at close to or over maximum capacity. The crew may need to move the crane a few feet to reduce the radius, significantly improving the capacity and safety of the lift. 32 | MARCH2017
Example of outrigger support checked and abated during the 10 question plan 10 Questions that should be answered include: 1. WHAT IS THE "VERIFIED" WEIGHT OF THE LOAD? It is not possible to make a safe lift when the weight of the load is not known or verified. Operators need to know this and never assume anything. There have been more than a few cranes upset because the gross load was underestimated. Smaller loads can be easily calculated, such as pre-cast concrete or a steel beam. Most loads are shipped to the work site by truck, the trucking company weight ticket is a good source for weight information. In any case, the load weight is critical and must be known and verified. 2. WHAT IS THE MAXIMUM RADIUS? The radius is defined as the distance between the center of rotation of a crane and the center of gravity of a freely suspended load, and is the single most important factor in determining a crane’s capacity. The radius must be known and www.guamcontractors.org
should be measured. At a minimum, a dry run should be performed by placing the empty hook over the pick and set locations, measuring the radius for each lift. Calculate the lift according to the farthest distance. 3. WHAT IS THE RIGGING CAPACITY AND WEIGHT? Calculate the capacity of the rigging configuration. There must be a qualified rigger making the actual connections, and capable of calculating the effect of sling angles on the rigging. A sling angle of 60 degrees, or higher, to horizontal is preferred. Calculate the actual weight of the rigging system and record it on the plan. The weight of the entire rigging system is deductible from the crane chart gross capacity. Weights should be known and estimates made on the high side.
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