CRANE CRITIQUE
CONSTRUCTION NEWS BULLETIN
MOBILE CRANE BOOM INSPECTIONS
LATTICE AND HYDRAULIC BOOMS
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 overlooked or misunderstood topics by management and operators alike. By Dave Barnhouse Telescopic and lattice booms must be regularly inspected for two reasons: To prevent damage and/or excessive wear and destruction from the collapse of the boom, the second reason is to maintain regulatory compliance under the federal OSHA law. Boom inspections of mobile cranes require an up-close and personal approach. The inspector must have access for complete visual inspection and close enough to see the entire boom in close detail or perform NDT on any suspect components. If the boom cannot be lowered to the ground, an aerial lift may be needed. The crane’s load chart should be consulted before attempting to lower the boom to the horizontal, as some cranes configured with long booms cannot attain low angles without tipping. Only after access to the entire boom from base to tip is available, the boom inspection can begin. A visual inspection of all booms is required before operating the equipment by a competent person. A comprehensive inspection is required annually by a qualified person and must be documented, maintained and retained for a minimum of 12 months. A well-documented and thorough inspection is a relatively inexpensive way of ensuring the health and well-being of everyone at a worksite along with protecting the hundreds of thousands of dollars invested in the crane. Proper boom inspections require an up-close and personal approach, with the inspector close enough to clearly see the boom in detail. Telescopic boom inspection Telescoping crane booms differ from lattice boom cranes greatly and require just as much, if not more, scrutiny. Many 14 | SEPTEMBER2018
Lattice boom of Black Construction’s 250 ton Kobelco Crawler, lowered for inspection, on the GIAA expansion project of the components are inspected in the same manner as lattice booms – boom tip, operator aides and safety devices – but the boom itself has major differences. Telescoping booms are made up of multiple sections that become progressively lighter and smaller in size the further they scope out from the crane. Through a system of hydraulic cylinders in conjunction with roller chains or wire rope, each section will slide out as the boom is lengthened. The boom may be equipped with the latch and pin system, enabling lighter component weights, and adding to gross capacity of the crane. This type of boom is not telescoped or retracted while in lifting mode with a load on the hook. The boom hinge pins are a good place to start the inspection, no gaps or play, lubricated if applicable, boom cylinder and www.guamcontractors.org
pins, no gaps or play where they attach, and the cylinder should be free of leaks and damage. Inspect each boom section closely for any structural damage, with the boom fully extended. If an inspection reveals structural damage, nicks, corrosion, gouges, bent components, broken welds or any type of deformation, the damage needs to be recorded, and the crane is to be tagged out until the manufacturer has been consulted and/or the damaged repaired. Any deformation in this type of boom can lead to a collapse, even without a load on the crane. Closely inspect all wear pads. These prevent metal on metal contact and excessive movement on each section, making inspection of wear and/or need of adjustments very critical. Recommendation should be made to contacted replace if worn. There should be a light coat of Like Us On Facebook