Hydrauliccrane (Download)
HYDRUALIC BOOM CRANE SAFETY 1 What is a Hydraulic Boom Crane? A crane with a telescoping boom 2 History of the Crane in Construction The earliest use of cranes can be dated back to the 6 th Century BC by the Greeks. Cranes have evolved throughout the history of construction as man’s needs and desires to build have changed. Early Greek Crane Medieval Crane Modern Hydraulic Crane 3 The Hydraulic Crane Most commonly used to lift or place heavy objects such as structural steel or tilt up panels Advantages of the hydraulic crane include mobility and size-to-strength ratio Hydraulic cranes use fluids and a variety of pistons to transfer forces from one point to another. Essentially, when one piston goes down another goes up. Two main factors in crane design and selection are: 1.) Must be able to lift the specified load 2.) Must be able to remain stable and not topple when the load is lifted 4 Associated Hazards Electrical Hazards Caught-In, Compressed or Crushing Hazards Struck-By Hazards Other Hazards 5 13 Common Reasons for Crane Failure ( MacCollum 1980) 1. Overloading – beyond crane cap. 2. Side pull 3. Outrigger failure 4. Hoist limitations – for conditions 5. Two-blocking 6. Killer Hooks – exceeding load capacity Crane overload Anti two Blocking system Crane Hook 6 13 Common Reasons Continued ( MacCollum 1980) 7. Boom buckling 8. Upset/Overturn 9. Unintentional turntable turning 10. Oversteer /crabbing – creating instability 11. Control confusion 12. Access/egress to work area 13. Power-line contact Boom Buckling Over Steering 7 Could This Have Been Prevented? A worker was rigging steel that was to be installed on the roof of a structure for a track to be used with an overhead crane. The 25 ft long by 25 in. tall by 14 in. wide beam weighed 1,825 lb, and was being lifted with a nylon sling located near its center. One end of the beam rose approximately 8 to 10 ft off the floor before the opposite end began to rise. The crane operator had started to lower the beam to correct the imbalance when the beam slid approximately 6 in. in the sling. At that point, the sling was cut and the beam fell, pinning the rigger to the ground and killing him. 8 Case Studies Two workers were in the process of landing two 54-sheet bundles of 3/4 inch plywood, being set on the 3rd floor deck with a crane. As the lower bundle was placed on the deck, the sheets in the top bundle began to slide out causing the entire bundle to fall onto the victim striking him in the back of the head . 1926.550 (a)19 9 Case Studies A young truck driver and his employer were electrocuted when the boom of a truck-mounted crane contacted a 7,200-volt conductor of an overhead power line. The driver had backed the truck up the steeply sloped driveway under a power line. The tip of the crane boom contacted a conductor of the overhead power line and completed a path to ground through the truck and the driver. The company president attempted to render assistance and apparently contacted the truck, completing a path to ground through his body. He died on the scene. The truck driver died a short time later. 1926.550 (a) 15( i ), (ii) 10 OSHA Regulations Crane operations primarily regulated by subpart N of OSHA regulations 1926.550 (a) 15( i )- For lines rated 50kV or below, minimum clearance between the lines and any part of the crane or load shall be 10’ 15(ii)- For lines rated over 50kV, minimum clearance between the lines and any part of the crane or load shall be 10’ plus 1’ for every 30 kV over 50kV. 15(iii)- In transit with no load and boom lowered the equipment clearance shall be a minimum of 4’ for voltages less the 50kV, 10’ for voltages 50-345kV, and 16’ for voltages up to and including 745kV 11 OSHA Regulations 19- All employees shall be kept clear of loads about to be lifted and or suspended loads (g) 6(iii)- Tag lines shall be used unless their use creates and unsafe condition (g) 6(iv)- The crane or derrick operator shall remain at the controls at all times when the crane engine is running and the platform occupied 1926.552 (a)2- Rated load capacities, recommended operating speeds, and special hazard warnings or instructions shall be posted on the cars and platforms 12 Personal Protective Equipment Hard hats Gloves ANSI 85 safety glasses Steel-toed boots Safety vests Jeans and shirts with 4” sleeves 13 Safe Work Practices Working Around Electric Power Lines Maintain at least minimum distances from power lines as required by OSHA regulations Ensure the use of a spotter for the crane operator Assume all overhead wires are energized Use tag-lines or proximity warning devices when available Be aware of inclement weather conditions 14 Safe Work Practices Know and Rehearse the Crane Signals 15 Safe Work Practices Traveling with a load No extra riders on the crane Crane boom should be lowered Avoid sudden starts and stops Always travel in the forward direction 16 Safe Work Practices Always conduct pre-operation inspections Manufacturer’s operating and maintenance manual Guarding exposed moving parts Swing clearance protection Boom stops Jib boom stops Boom angle indicator Boom hoist disconnect, automatic boom hoist shutoff Two-blocking device Powered controlled lowering Leveling indicating device Sheaves Crane Sheaves/pulleys OSHA regulations require a minimum 5BC fire extinguisher on board the crane 17 Safe Work Practices Inspection Checklist Continued Main hoist and auxiliary drums system Main boom, jib boom, boom extension Load hooks and hook blocks Hydraulic hoses, fittings, and tubing Outriggers Load rating chart Wire rope Cab—controls, gauges, glass, fire extinguisher, warning lights, horn, wipers, etc. Braking systems Turntable/crane body Counterweight Rubber tires (where applicable) OSHA-Subpart P section (a) paragraph 7 Ensure outriggers are functioning properly and free of corrosion 18 Safe Work Practices Know the capacity of the crane when extended to various lengths and at different angles. Ensure the operator has read and understands load chart located on the crane or user manual. Note that as the radius of the boom increases the maximum load decreases Know with certainty the magnitude of the load being lifted 19 THINK SAFETY WORK SAFELY 20