Crane safety for overhead crane and gantry crane

A crane is a machine used for lifting and lowering a load and moving it horizontally, with the hoisting mechanism an integral part of the machine. Overhead cranes are used in many industries to move heavy and oversized objects that other material handling methods cannot. Overhead cranes have a railed support structure, known as a bridge, and a wheeled trolley that travels across the bridge horizontally. The other primary component of an overhead crane is the hoist, that’s attached to the trolley, and is used to perform the lifts. Several varieties of overhead cranes exist including gantry crane, semi-gantry crane, cantilever gantry crane, storage bridge and wall cranes.OSHA regulates overhead crane safety through 29 CFR 1910.179, overhead and gantry cranes. This regulation covers general requirements, design, inspection, maintenance requirements and overhead crane operation.

General Requirements

• All overhead and gantry cranes installed after August 31, 1971, must meet the specifications of the American National Standard Institute (ANSI) / American Society of Mechanical Engineers (ASME) Safety Code for Overhead and Gantry Cranes, ANSI B30.2
• Cranes can be modified and load capacity rerated as long as the modifications and associated structure is thoroughly checked for the new rated load by a qualified engineer or the equipment manufacturer
• The rated load of the crane must be plainly marked on each side of the crane. If more than one hoist is present, each hoist must have its rating shown
• Clearance must be maintained above and to the side of cranes. Walkways cannot be placed in a crane operating zone that would compromise employee safety when the crane is in operation. Parallel cranes must have adequate clearance between the two bridges if no walls or structures are between them
• Only designated personnel will be permitted to operate a crane

Design Requirements

The OSHA overhead crane safety regulation specifies design requirements on the construction of the cab and its controls as well as the cab’s lighting; foot-walks, ladders and stairways; bridge and trolley bumpers; hoist, holding, trolley and bridge brakes; electrical components; hoisting equipment; and warning devices.

Inspection Requirements

Due to the large and heavy objects often being transported by overhead cranes, routine inspections are necessary to ensure continued operation and overhead crane safety. An initial inspection of the crane (new or altered) prior to initial use is necessary. Once placed into service, overhead cranes will require two different types of inspections. Frequent inspections are done at daily to monthly intervals, while periodic inspections are completed at monthly to annual intervals. The purpose of the two inspection types is to examine critical components of the crane and to determine the extent of wear, deterioration or malfunction.

Periodic Inspections

Items to be inspected:

• Deformed, cracked or corroded members
• Loose bolts or rivets
• Cracked or worn sheaves and drums
• Worn, cracked or distorted parts, such as pins, bearings, shafts, gears, rollers, locking and clamping devices.
• Excessive wear on brake-system parts, linings, pawls and ratchets
• Inaccuracies in load, wind and other indicators
• Electric or fossil fuel motors
• Excessive wear of chain drive sprockets and excessive chain stretch
• Deteriorated electrical components, such as push buttons, limit switches or contactors.

In addition to the initial inspection, OSHA also requires that all new and altered cranes are tested. The operational testing includes the following:

• Hoisting and lowering
• Trolley travel
• Bridge travel
• Limit switches, locking and safety devices
• Trip setting of hoist limit switches
• Load test of not more than 125% of rated load

Maintenance Requirements

A preventive maintenance program based on the crane manufacturer's recommendations must be implemented. If any deteriorated components or unsafe conditions are detected during the required inspections, they must be completed before the crane is allowed to be used. Only designated personnel may perform the required maintenance and repairs. The requirements of 29 CFR 1910.147, the control of hazardous energy or lockout/tagout, should be used to de-energize the crane (See Quick Tips #170: Lockout/Tagout for more information).

Operation

The manufacturer's instructions must be followed when operating to help ensure overhead crane safety. OSHA covers their load handling requirements under 1910.179(n). It addresses the following:

• Size of load
• Attaching the load
• Moving the load
• Hoist limit switch

Crane safety tips for your cranes

Crane safety overview is for you to ensure the safety of your overhead crane, gantry crane, jib crane, workstation crane. Tips on crane safety control, safety devices, operational safety, crane inspection and maintenance, crane accidents and crane risk analysis and preventive measure, and crane factory visiting safety, etc., are for your reference.