1. Rigging & Inspection Considerations for Industry
Safety Team presents
Rigging & Inspection Considerations for Industry

2. Disclaimer
The following information is for presentation and demonstration purposes only, not intended for actual field application.
This is not a crane and rigging guide or manual.
This presentation is not intended to replace or add on to any regulations or guidelines set for the by the manufacturer or any regulatory agencies.
For crane operation and rigging guidelines always refer to up-to-date equipment manufacturer information, regulatory guide lines, qualified rigging manuals, and proper training.

3. Rigging Plan Basics
Responsibilities for rigging/lifting setup & execution
Load weight, gravity, # of cranes, load calculations, head room
Work area conditions, crane & rigging inspections done
Lifting equipment/gear appropriate for task
Tag lines needed for control, sling protection used
Correct communications used for the type of lift
Personnel out of the area where the lift is being performed (Safety watch)

5. Rigging Angles With a hook, maximum sling angle should be 90°
With a master link or shackle, 120° is maximum angle.
It is allowable to use a shackle in a situation where it is being side loaded, as long as the rated lifting capacity decreases by the percentage shown below.
WARNING:
Side loading of shackles is allowable only for screw pin or bolt type shackles, with the original shackle pin installed according to manufacture specifications. Always refer to the manufactures specification for the rigging equipment being used, similar product from different manufacture may have different capacity rating.

6. Eye Bolts Good working condition Must be properly engaged into threads
Do not shock load eyebolts
Do not mix SAE and Metric types
Countersink eye bolt holes
Do not overtighten, undercut, or force eyebolts into place
Un-shouldered eyebolts shall only be used for vertical loads (no side loading beyond 5 degrees from vertical).
Only shouldered eyebolts shall be used for angular loading.

7. Eye Bolts
When used in a tapped blind hole, the effective thread length shall be at least 1 1/2 times the diameter of the bolt for engagement in steel. The first 1/2 diameter length of threads do not fully engage resulting in reduced strength and should never be counted as part of the engaged length of thread. This image shows the tip of an eyebolt with a long unthreaded area nearly 1/2 thread diameter in length.
Keep in mind that when using a nut to secure an eye bolt in a through hole that the first ½ length diameter of threads dose not give full thread engagement.
Though there is hard rule as to how much thread should pass beyond the nut, a good rule of thumb would have ½ diameter of the threads extend past the nut to insure maximum nut/thread engagement with the eye bolt.
The eyebolt should not wobble or require extra force while being screwed in.

8. Eye Bolts
When tapped holes are in softer materials additional thread length must be provided to ensure sufficient strength is achieved
Minimum thread engagement for holes tapped through in various materials (ASME B18.15):
Steel - 1 thread diameter,
Cast iron, brass, bronze thread diameter,
Aluminum, magnesium, zinc, plastic - 2 thread diameters
If the threads are in a tapped blind hole, an additional 50% of thread length/depth is needed.
Keep in mind that when using a nut to secure an eye bolt in a through hole that the first ½ length diameter of threads dose not give full thread engagement.
Though there is hard rule as to how much thread should pass beyond the nut, a good rule of thumb would have ½ diameter of the threads extend past the nut to insure maximum nut/thread engagement with the eye bolt.

9. Eye Bolts Only shouldered eyebolts shall be used for angular loading.
Align eyebolts within ± 5º of the direction of pull

10. Eye Bolts
To help get the eye properly aligned with the sling angle, a shim can be added under the eyebolt shoulder. It is recommended that the shim should not be more than (1/2 turn of the eyebolt) to achieve the correct orientation.
Note: An eye bolt mounted on manufactured equipment such as an electric motor is intended and sized for lifting the motor only not an equipment assembly such as a MG set.
Do not over tighten in an attempt to get it in to proper alignment or to keep it from rotating.
Only firm hand pressure should be used to snug it down

11. Eye Bolts
Many manufacturers of electric motors warn that the eye bolt supplied on a motor is designed for lifting the motor only and not designed to lift an assembly such an MG set or motor pump assemble. An assembly of this type should be designed and fabricated with engineered lifting points on the assemble base.

12. Eye Bolts Eye bolt load capacity is reduced when loaded at an angle.
Note that eye bolts are not created equal, always use WLL and angle load information for the brand of eye bolt being used.
Proper thread engagement is also important for maximum strength.
Note that the capacity for Crosby eyebolts is different than the capacity of the Chicago eyebolts, DO NOT use the Crosby table for Chicago eyebolts.

13. Eyebolt Do not reeve sling through eye bolts or attachment points.
In this example of a 3/4” eyebolt used at 45 degrees, it has a rating of 1500 lbs.
Because the sling is reeved through each eye bolt, its effective sling angle is reduced to a load angle of around 22.5 degrees. This now increases the load to over 2,600 lbs. per sling leg.

14. Lever Hoist (Chain Fall, Come-along, etc.)
Come-a-long/Chain Fall (Hand operated)
A Come-A-Long is NOT designed for lifting.
Know your tools, read the manual and make sure it is designed for the intended task.
Pullers are only for pulling things not for lifting.
A lever hoist is designed for lifting and can also be used for pulling.
The image of the puller is a photo of the box the puller comes in, note that is says PULLER and NOT for lifting.
A lever “hoist” is designed for lifting.

15. Swivel Hoist Ring
When using a swivel hoist ring, apply the proper torque to the bolt to ensure the hoist ring and bolt will achieve its rated capacity in any allowed position used.
Whenever a bolt-on device is used it is always best to consult with the device manufacturer, or a qualified engineer to ensure the device’s attachment bolts are the right grade for the application, installed, and then tightened correctly.

16. Sling Load Angle Factor
To Calculate Load Angle Factor:
NOTE: The number of legs used for sling load calculation is not to exceed 3 legs, even when 4 or more legs are rigged. L
= Load Angle Factor (LAF) H
LAF x Load Weight = Total Sling Load
Total Sling Load
= Load Per Sling Leg
Number of Slings

17. Sling Angles
Sling Angle Degrees
Load Angle Factor 90 1 85
1.004 80
1.015 75
1.035 70
1.064 65
1.104 60
1.155 55
1.221 50
1.305 45
1.414 40
1.555 35
1.742 30 2 25
2.364 20
2.924 15
3.861 10
5.747 5
11.49
When the sling angle can be measured, use a LAF table for your rigging configuration.
Always round the measured value down if it is not on a listed number.
Example: Angle of measure is 34°, round down to 30°. This gives a slightly higher sling load, but will increase your margin for error in the calculations.
Always round your weight calculation up but your horizontal sling angle down.
This method of rounding will increase your margin in your rigging of error or the safety factor.
In normal rounding to the nearest number could cause to calculate you load to light.

18. Sling Angle Factor
Below are some visual reverences to sling angles and there effect.

19. Sling Angle Factor
When three or more sling legs are used, the sling angle is measured perpendicular to the centerline of the load line and hook, not in the plane of the adjacent sling.
Note:
It is possible under a verity of conditions that the load on the each slings legs may not be equal.
Careful consideration must be given to where the load weight is distributed and how it affects the true load on each sling.

20. Sling Angle Factor
When using a choker hitch with multiple sling legs, the sling leg and choke angle must both be factored in to sling load calculations.
In an example like the one shown here there are multiple factors that must be considered for calculating sling load.
* The choke angle of the sling
* The horizontal angle between the sling legs
* The possible reduction in sling strength do the a sharp or small corners on the load
Devices like spreader bars and strong back can be used to reduce or eliminate some of the forces.

21. Sling Angle
DO NOT use a horizontal sling angle less than 60° on an inverted basket.
When rigging a sling in an inverted basket, the horizontal sling angle must be greater than 60°, to minimize the possibility of the sling shifting on the hook.
The shallow angle on the sling will allow to sling to shift in the hook, which could result in loss of load control

22. Sling Angle
The preferred method when two sling leg are used, is to use two slings that terminate at the hook, providing the best possible load control and stability.
 When additional sling legs are needed, a master link and shackle may needed to prevent sling bunching on the hook and to even out sling load distribution.

23. Sling Angle DO NOT Wrap the sling around the hook in any manner
Neither of the methods is desirable means of achieving load control or reducing sling length.
The first method puts a load on the hook in a manner the hook was not designed to accommodate.
In the second method the sling wrap typically lay one on top of the other which can cause pinching of the fiber on the lower part of the sling.

24. D/d Ratio
D/d – Is the ratio between the curvature of the part being rigged D and the diameter of the sling being used d
This ratio is important in because it effects both the load carrying capacity of the sling and its ability to resist damage
An excessively small D/d ratio with wire rope and chain sling will be permanently damaged the sling.
The D/d ratio for wire 6 x 19 rope is 25/1.
Other sling type have different D/d ratings, such as 6/1 for chain slings or 5/1 for grommet slings
NOTE:
Different types and grades of wire rope have can have different D/d ratios.

25. D/d? Flat Web Slings
Flat web slings have no diameter and therefore no D/d ratio.
All web sling manufacturers recommend some form of edge protection be used between web slings and load edges to protect the sling against damage, such as cutting.
Some manufacturers suggests that at minimum the edge radius of the load contact point should be at least the thickness of the sling at the point of contact.
If the sling is 3/16” thick webbing, the contact radius should be 3/16” or greater.
If the sling is 2 or more ply’s in thickness, it is the total thickness of all the ply's at the contact point of the sling and load that constitutes the sling thickness.
A chamfered edge is not the same as a radius, it still has sharp edges.
The WSTDA is not specific about contact radius for web slings.

26. Sling Protection
All slings types must be protected from sharp edges of a load, and any other damaging forces.
Many types of protection are available and can be improvised, below are some examples
Note:
Things like cardboard, rages, and old gloves are not suitable protection.

27. Sling Strength Loss
Shown here are test results from two different sling manufacturers, showing the loss of ultimate strength of the sling do the various sizes of edge cut in a 2 inch wide single ply sling.

28. Sling Strength Loss To help put things in perspective:
The red wire represent 12 randomly spaced wire on a wire rope sling, this equates to about 10-1/2 % of the wires in the sling.
The image below represents the cross section of a 1 inch wide by .147 inch thick web sling, the blue area is about 10-1/2 of the sling fabric a cut of about ..015” deep, this is about the thickness of two business cards.
The image below is about what the sling cross section would look like in your hand.