Three employees were injured in separate rigging accidents over a two month period. In the first incident, an employee was struck in the head by a metal pulley when the nylon sling it was attached to broke under tension. In the second incident, an employee was struck by a falling 2,000 pound concrete form that broke loose from its rigging during a crane lift. In the third incident, an employee was fatally struck on the head by a drilling pipe that came loose from its rigging during a lift. The document outlines 10 rules for rigging safety including knowing load weights, rigging capacities, center of gravity, sling angles, inspections, and using tag lines and signal persons.

1. Rigging Safety
johnanewquist@gmail.com

2. Hit by Pulley
• Event Date: 07/27/2010
• Inspection: 314807090
• Employee #1 was struck in the head by a metal
pulley when the nylon sling to which it was
connected broke.
• The pulley was being used to drag felled trees.
• When the rigging was put under tension, the
nylon sling broke, releasing the pulley, hitting the
employee in the head.
• 50 M

3. Struck by Form
• Event Date: 04/21/2010
• Inspection: 314374182
• An employee was struck by a falling 20'
column form weighing approximately 2,000
pounds that broke loose from its rigging while
being moved by crane from one location to
another location on the construction site.
• 27 M

4. Pipe Fell
• Event Date: 04/29/2010
• Inspection: 314409277
• On 4/29/10 , an employee was struck on the head by a
drilling pipe which resulted in fatal injuries.
• The employee rigged a 20 foot section of pipe and as it
was being lifted by the operator, the pipe came loose
from the rigging and fell approximately 10 to 15 feet
onto the head of the employee.
• The employee died as a result of his injuries.
• 50 M Fatality
•

5. 10 Rules for Rigging Safety #1
• Know the weight of the load
• Concrete slab
• Steel Beam
• Concrete form
• Tree

6. Bulk Density
• Building material Unit weight
• Aluminum 171 pounds per cubic foot
• Cast Iron 450 pounds per cubic foot
• Cement 94 pounds per cubic foot
• Concrete 150 pounds per cubic foot
• Crushed Stone 2,500 pounds per cubic yard
• Gravel 2,700 pounds per cubic yard

7. 10 Rules for Rigging Safety #2
• Know the center of gravity of the load.

8. Center of Gravity
A load is stable when:
– The hook is directly above the center of gravity of the
load
Estimate the center of gravity
Lift the load just enough to clear the ground
If the hook is not over the center of gravity the hook
will travel to the center of gravity
CG?

9. Center of Gravity
If necessary, set the load down and adjust the
rigging
If the load tips more than 3°, the rigging should be
adjusted
The longer the sling legs, the more stable the load
will be B
The longer set of sling
legs (B) will improve load
A stability

10. How Would You Rig This?
What would you need in the
way of rigging materials?

11. How Would You Rig This?
Would it matter if
the tank were full
or empty?

12. 10 Rules for Rigging Safety #3
• Know the rated capacity
of slings and hardware.

13. 10 Rules for Rigging Safety #4
• Inspect all rigging
before use.

14. Rigging equipment for material handling
• Synthetic webbing (nylon, polyester, and
polypropylene)
• Remove from service immediately if:
– Acid or caustic burns
– Melting or charring of any
part of the sling surface
– Snags, punctures, tears
or cuts
– Broken or worn stitches
– Distortion of fittings

15. 10 Rules for Rigging Safety #5
• Allow for D/d ratio on all wire rope slings.

16. Rigging equipment for material handling
D/d Ratio
D - is diameter around
which sling is bent.
D
d - is diameter of the
sling.
d

17. 10 Rules for Rigging Safety #6
• Protect sling from sharp
surfaces
• Dekalb accident
• Photo is an example

18. Rigging Protection From
Cutting or Slipping
Softeners, padding or use of blocking..

19. 10 Rules for Rigging Safety #7
• Proper calculation of increased tension caused
by sling angles (on all rigging components!).

20. How horizontal angle
affects slings capacity
500 LBS
500 LBS
1000 LBS 1000 LBS
90 60° 45° 30°
1000 LBS 1000 LBS 1000 LBS 1000 LBS
Note: A good operating practice is to keep sling angles from
going below 60 degrees

21. 10 Rules for Rigging Safety #8
• Keep personnel clear
from lift area.
• 1926.953(d) requires
taglines on any load
“where hazards to
employees exist” in
order to keep the loads
under control

22. 10 Rules for Rigging Safety #9
• Calculate reductions
when using choker hitch

23. Wire Rope Sling Choker Adjustments

24. 10 Rules for Rigging Safety #10
• Know the proper crane signals
• A signal person is required
when:
• The point of operation is not in
full view of the operator
(1926.1419(a)).
• The operator’s view is
obstructed in the direction the
equipment is traveling.
• Either the operator or the
person handling the load
determines that a signal
person is needed because of
site-specific safety concerns.

25. Questions