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Crane and Hoist Safety

PUBH 3310

November 13, 2009

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Objectives

• Know hazards associated with cranes

• Become familiar with common types of

industrial and construction cranes

• Understand rigging basics, including the

importance of “sling angle”

• Be familiar with methods of controlling

crane hazards and preventing accidents

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Outline

• Crane Hazards

• Crane types – Industrial cranes

– Construction cranes

– Rigging (and “sling angle”)

• Controlling hazards – Inspections and training

– Power lines

– Equipment failure and crane stability

– Other

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Crane Hazards

• Over 250,000 cranes in operation – 125,000 in construction

– 80,000 general and maritime

• 80 fatalities per year

• One death per thousand crane

operators in their working lifetime (45

years)

• Risk to citizens and other workers

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Causes of Crane Fatalities

Electrocution 39%

Crane assembly/disassembly 12%

Crane upset/overturn 7%

Rigging failure 7%

Overloading 4%

Struck by moving load 4%

Manlifts 4%

Struck by counterweight 2%

Two-blocking 2%

Hoist limitations 2%

Other 6% A. Suruda,et al, Crane-Related Deaths in the U.S. Construction Industry, 1984-94

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Crane Types

• "Industrial cranes“ – Overhead

– Gantry

– Jib

• "Construction cranes“ – Mobile

– Tower

– Derricks

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Industrial Cranes

• Overhead Cranes – Common in industrial facilities

– Supported by overhead rails

– Components

• Bridge

• Trolley

• Hoist

– Often pendant or remote operated

– Easy to use, little training required, no

stability problems

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Industrial Cranes

• Gantry cranes – Similar to overhead

cranes, but supported by a mobile frame which travels on the ground

Small (1000 – 10,000 pound

capacity) gantry crane

Large (600 ton capacity)

gantry crane

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Industrial Cranes

• Jib cranes – Pivot mounted

boom with trolley

and hoist

Wall-mounted jib crane

Floor-mounted

jib crane

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Industrial Cranes

• Power hoist – Usually electric

or air operated

• Chain hoist (or

"chain fall") – Hand operated

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Construction Cranes

• Tower

cranes – Variable

height

“climbing

cranes”

– Used for

building

construction

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Construction Cranes

• Mobile cranes – Crawler cranes

– Truck cranes

– Hydraulic cranes

• Boom telescopes

• May have jib

• Equipped with

outriggers for stability

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Hydraulic

Cranes

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Hydraulic Cranes

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Construction cranes

• Derricks – Boom angle

changes to adjust

horizontal distance

– Often used in

shipyards, building

construction, etc. • Gin pole

• Chicago boom

• Stiff-leg

• Etc.

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Stiff-leg construction derrick

Mine-shaft rescue using a

gin pole derrick improvised

from an extension ladder

17 Hay derrick

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Rigging

• Rigging: The hardware

and equipment used to

safely attach a load to a

lifting device – Wire rope

• Usually a "core" member to

increase flexibility

– Fiber Core (FC)

– Wire Strand Core (WSC)

– Independent Wire-rope

Core (IWRC)

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Rigging

• Fittings, sheaves – Shackles

– Blocks

– Sockets

– Hooks • May have safety

latch

– Eyes

– Turnbuckles

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Rigging

• Always use rigging to connect the load to the hook

• Materials – Wire rope – Fabric – Chain

• Slings – Straight (regular) – Choker – Basket – Double, triple, etc.

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Rigging

• Sling angle – Stress on sling legs

varies with the angle

– Divide the load by the

number of sling legs,

and divide by sin of

the angle • For a two-legged sling,

2000 lb load and 60

degree, stress = 1155

lbs on the sling leg

leg

lbs1155

60sin

1

legs2

lbs2000

leg

lbs2000

30sin

1

legs2

lbs2000

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• Operators – 18 years old

– Physical exam

– Knowledge (training)

• Estimating load

weight

• Signals

• Operation

– Skill (demonstration)

Controlling Crane Hazards

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Controlling Crane Hazards

• Inspection – Frequent

• Daily, monthly • Hooks, rope, crane operation

– Periodic • At least annually • Complete inspection - wear, damage,

deterioration, operation • slings

• Testing • Records

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Preventing Crane Accidents

• Contact with energized power lines

(45% of accidents) – De-energize overhead lines

– Maintain minimum distance

• 10 feet distance for 50 kv

• Over 50 kv, add 4 inches per 10 kv

– Use proximity alarms

• Warn when energized line is near

• “No fatalities” in 25 years, according

to mfg.

– Warning signs

• I-15 construction was a good example

Sigalarm®

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Warning label

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Preventing Crane Accidents

• Under hook lifting device problems – Inspect, proper use, etc.

• Overturned cranes – Assure a level and stable base for the

crane – Comply with load charts

• Weight • Boom angle and extension • Only vertical loads

– Wind can cause a significant side load

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Load Chart

• Load charts inside the cab include Structural capacity and tipping limits for the crane

• Capacity is highest for short radius “over front” loads with outriggers extended.

Load Chart

Radi

us

Rear Over Over Side Over Front

18.8'

Boom

24'

Boom

29.8'

Boom

18.8'

Boom

24'

Boom

29.8'

Boom

18.8'

Boom

24'

Boom

29.8'

Boom

6 65,600* 65,600* 66,720*

8 57,250* 56,510* 57,250* 56,510* 61,150* 56,510*

10 50,760* 49,230* 47,060* 50,760* 49,230* 47,060* 52,520* 49,230* 47,060*

12 44,970 43,250* 41,310* 45,540* 43,250* 41,310* 46,390* 43,250* 41,310*

15 33,180 33,290 33,350 39,370 37,090 35,080 39,620 37,090 35,080

18 25,960 26,250 26,310 27,540 28,370 28,490 27,540 32,471 30,730

20 22,940 23,010 22,910 23,030 29,820 28,430

25 16,910 15,330 23,770

29 13,030 11,870 16,750

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Preventing Crane Accidents

• Dropped loads – Operating anti-two block device (upper limit switch)

– Proper rigging

– Inspection

• Boom collapse – Inspection

– Stable base

– No overloading

– No horizontal loading

• Crushing by the counter weight – Stay away from the rear of the crane

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Preventing Crane Accidents

• Proper outrigger use – Level

– Fully extended

– Stable base

• Use cribbing to

distribute the load

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Outrigger Use

Outrigger

with

cribbing

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Preventing Crane Accidents

• Rigging failure – Inspection – Proper use

• temperature, angles, etc.

• Falls – Fall protection for workers

suspended by crane "man basket" or "suspended work platform“

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Links

• Managing Mobile Crane Hazards

– http://www.elcosh.org/en/document/96/d

000104/managing-mobile-crane-

hazards.html

• Crane, Derrick, and Hoist Safety

– http://www.osha.gov/SLTC/cranehoistsafet

y/index.html