LOS ANGELES UNIFIED SCHOOL DISTRICT THE SCHOOL REPAIR AND CONSTRUCTION PROGRAM The Safety Sheet January 27, 2004 This edition of the Safety Sheet addresses Crane Safety Awareness, and is intended to provide an overview of crane safety. It is not a comprehensive review of operating practices and regulations relative to crane operations its intent is to provide an individual with basic tools and knowledge to be able to determine what looks right, and what doesn t, but more important when to ask questions. LAUSD SAFETY SHEET 012704 OWNER CONTROLLED INSURANCE PROGRAM Aon Risk Services Construction Services Group Aon Risk Services Inc. of Southern California Insurance Services License No. 0530733 707 Wilshire Boulevard, Suite 6000, Los Angeles, CA 90017 telephone: (213) 630-3200 facsimile: (213) 689-4358
Crane Safety Awareness 11/05/03 crane safety awareness 1 The First Rule of Material Handling: 11/05/03 crane safety awareness 2
Keep people out from under the load. 11/05/03 crane safety awareness 3 Question: What s the difference between a crane and a boom truck? 11/05/03 crane safety awareness 4
Answer: None as far as the physics, regulations, and mechanisms of incidents are concerned. Many people make the mistake of thinking that a boom truck is safer because it s a little crane on a truck. 11/05/03 crane safety awareness 5 Lattice Boom Truck Crane 11/05/03 crane safety awareness 6
Hydraulic Truck Crane 11/05/03 crane safety awareness 7 Hydraulic Rough Terrain Crane 11/05/03 crane safety awareness 8
Boom Truck 11/05/03 crane safety awareness 9 Rigging What is the load? How much does it weigh? Where are the pick points? Where is the center of gravity? Do you have the right rigging? 11/05/03 crane safety awareness 10
Lifting links 3 most common types of rigging: Wire rope slings Nylon slings Chain slings Chain ain t chain think grade A8 alloy. 11/05/03 crane safety awareness 11 Wire Rope Pocket Chart (similar charts exist for nylon and chain slings) 11/05/03 crane safety awareness 12
TOP: Flemish Eye with pressed metal sleeve BOTTOM: Hand Tuck, no sleeve 11/05/03 crane safety awareness 13 Caution: Think of a 3 or 4 leg bridle as a 2 leg bridle with 1 or 2 ornaments. The third or third & fourth legs typically only serve to balance the load. It s an imperfect world - not all legs share the load equally due to variables like sling length, load deflection, and distance between attachment points. 11/05/03 crane safety awareness 14
11/05/03 crane safety awareness 15 When a rated load really isn t: Do you know that shackle strength depends where the load is applied? Same goes for eye bolts and lifting lugs. As much as 75% of the rated load strength can be lost due to the angle that the load is applied to the device. 11/05/03 crane safety awareness 16
Red thread is dead This shows the red thread on a damaged edge, and how it is woven into the sling. 11/05/03 crane safety awareness 17 Broken wires = remove from service Every wire in a wire rope acts as part of a team. With each broken wire, the rope grows weaker... 11/05/03 crane safety awareness 18
Time to trash this one, too! This part of a sling eye was almost completely severed, but it was still in use. 11/05/03 crane safety awareness 19 Damaged goods. This 2-leg sling was overloaded. The eye on the left has birdcaged. The eye on the right has stretched. 11/05/03 crane safety awareness 20
Lookin good! Dead end of load line properly secured. Safety latch on hook in place and working. Load centered in hook. Straight line between load line and center point of load in hook. 11/05/03 crane safety awareness 21 A swing for you... Loads swing when they are first hoisted. This is caused by: The boom deflecting under load, The boom/hook not being centered over the load, Asymmetrical rigging Watch out for pinch points created by deflection. 11/05/03 crane safety awareness 22
Cranes OK, you ve: analyzed your load, done your rigging calculations, and inspected your rigging. Think you re ready to pick? 11/05/03 crane safety awareness 23 Questions to answer: Did you get the right crane? What is the farthest radius that the load will be handled at? How high does it have to be lifted to / from / over? Don t forget the length of your rigging 11/05/03 crane safety awareness 24
Look in the charts for a working range diagram Did you think about quadrants? Did you figure the load right? Everything below / beyond the sheave (typically) 11/05/03 crane safety awareness 25 Don t forget the paperwork! The crane is here. Does it have current paperwork? Are the manuals / charts there? How about inspection records daily, periodic, annual quadrennial 11/05/03 crane safety awareness 26
If you re in the City of Los Angeles, does the Operator have a Hoisting License? 11/05/03 crane safety awareness 27 Chart examples: 11/05/03 crane safety awareness 28
This is a Working Range Diagram: It was marked up to see how far in on a roof a crane could reach. It must be used with the appropriate load chart. ALL cranes have them. Check the manuals. >The manuals had better be there... 11/05/03 crane safety awareness 29 This is a Quadrant Diagram: All cranes have them. Capacity is not always the same in every quadrant. Once again, READ THE MANUAL! 11/05/03 crane safety awareness 30
Operators are often overlooked! How much seat time has the operator had in this crane, in this configuration, and in this type of lift? Can he/she read the charts? Can he/she set the crane up properly? PLEASE, don t take operator qualifications lightly. A few questions never hurt 11/05/03 crane safety awareness 31 How about a quick visual inspection? 11/05/03 crane safety awareness 32
Basic things to look for: Hydraulic oil leaks at any cylinder or hydraulic hose Does the boom look straight? Rust on the boom If it doesn t look right, call in your resources! 11/05/03 crane safety awareness 33 Commit to memory: Three key points to remember: As radius increases, capacity decreases As boom length increases, capacity decreases As boom angle increases, capacity increases 11/05/03 crane safety awareness 34
Location is everything. Where will you put the crane? Are there power lines in the area? ABSOLUTELY, POSITIVELY, WITHOUT A DOUBT, YOU NEED AT LEAST 10 MINIMUM CLEARANCE BETWEEN THE RIG AND THE POWER LINES. What are the ground conditions? 11/05/03 crane safety awareness 35 The Operator said it s OK it s only cable but the sign on the pole said HIGH VOLTAGE! 11/05/03 crane safety awareness 36
Very, very, very important: The crane will suppor the load as long as, and only if, the ground will support the crane and the load. 11/05/03 crane safety awareness 37 Outrigger pads- who needs em? Lets take a 35-ton crane with a 30,000# load set up on all 4 outriggers, say that s 100,000# Let s see what happens under each of the outrigger floats and what kind of forces are put on the supporting ground or pavement: 11/05/03 crane safety awareness 38
The pounds are everywhere... On a 24 dia. float, that s 25,000#, or 7,961 psf, or 55.3 psi. With a 2 x 2 pad, it drops to 6,250 psf. That s 43.4 psi. With a 3 x 3 pad, how about 2,778 psf and just 19.3 psi. 11/05/03 crane safety awareness 39 Did it get you thinking? Did the preceding slide make you think about concrete pumps, too. If so, good. If not, think about it a little more. 11/05/03 crane safety awareness 40
Crawlers need support, too! The same principles of weight distribution apply to crawler cranes, too. Crawlers have 4 high load points - they are located at the corners, and distribution varies as the crane rotates - just like an outrigger equipped crane. 11/05/03 crane safety awareness 41 What no support can do... Ground settled 3 under left front corner Mats were not used 11/05/03 crane safety awareness 42
Human error... Outrigger beams were out Floats were not put on rams Rams were not extended Rig wasn t stable 11/05/03 crane safety awareness 43 Charts, charts, charts. Is the crane properly set up for the load chart you are using (on rubber / outriggers and for the applicable outrigger extension)? Are quadrants a consideration? You re either on outriggers, or you re not. No in-between here. Determine if you are, or aren t, and follow the appropriate load chart. READ THE MANUAL! 11/05/03 crane safety awareness 44
This is good setup! Outriggers have all the weight. Outriggers evenly extended. Tires are clear of the ground. Level. Blocking under outriggers. 11/05/03 crane safety awareness 45 Maybe not so good... Three of the four outriggers look like they are fully extended. The far left outrigger does not appear to be extended at all. The only load chart that applies to a situation like this is the chart for 0% outrigger extension. This crane has such charts. The short outrigger governs chart selection. In this case, 3 out of 4 ain t good. Load may have been too heavy, or boom lowered too low. 11/05/03 crane safety awareness 46
An educated guess says... The outside outriggers aren t extended, but this crane does have charts for 0% outrigger extension an educated guess is that the load exceeded capacity. 11/05/03 crane safety awareness 47 More points to ponder... Is the swing radius protected? Are there power lines in the area? Yes, this was covered before - but we don t want you to forget to look for them. Does everyone know their part? Who is going to signal? 11/05/03 crane safety awareness 48
THE Hand Signal Chart 11/05/03 crane safety awareness 49 Would you believe? In some cases, just the weight of the boom and jib can make a crane unstable when rotating if the outriggers are not out and set. Consult the manual for stability notes and restrictions. 11/05/03 crane safety awareness 50
Rust and Booms Don t Mix: 11/05/03 crane safety awareness 51 Trouble This is trouble waiting to happen. Does anyone know the capacity of a barrel with 2 holes burned in it? Didn t think so... 11/05/03 crane safety awareness 52
General note: If it looks like it s home-made, it probably is. If it s home-made, chances are there s no engineering behind it, and it shouldn t be on the jobsite. 11/05/03 crane safety awareness 53 Lifting Modulars Pictures and comments on what appeared to be a good lift. 11/05/03 crane safety awareness 54
This specialized lifting beam was observed on a lift in Covina. Notice that there is a six-leg sling used to minimize stresses on the lifting beam. The beam is wider than the modular so that the slings do not impart forces on the side of the modular. 11/05/03 crane safety awareness 55 The lift is made using a basket hitch. That means the floor is bearing all of the weight. The modular manufacturer should be able to provide lifting points and a rigging plan but not a lift plan. The Contractor and Crane Company are responsible for the lift plan and rigging plan. 11/05/03 crane safety awareness 56
Conclusion: The ultimate burden for a safe lift is on the General Contractor. They should be able to show you via charts, diagrams, calculations, and/or a lift plan, that the lift will work, and they should be able to explain it in plain terms. 11/05/03 crane safety awareness 57 Suggested Reading: The following pocket-sized publications are widely used and recognized in the industry: Mobile Craning Today This is the source for the diagrams on pages 6-9. Bob s Rigging and Crane Handbook 11/05/03 crane safety awareness 58