The Pro Rigger by Mike Parnell of ITI

Rigging Training Workshop - Rigging Selection

Rig from the bottom up. Select the correct rigging for the load below using the Master Rigger's Reference Card panels at the right. Answers can be found below.

Happy trails to all my crane and rigging friends,

Mike Parnell
ITI-Field Services

P.S.  This article was originally published in The Professional Rigger Newsletter - Rigging Selection.

Answers:

Rigging Training Workshop - Find CG by Test Lift

With four quick lifts, raising the load only a few inches, a rigger can confirm:

a) The load's estimated weight
b) The load's approximate center-of-gravity (CG)
c) The approximate load at each pick point

Find the approximate weight and the location of the CG of the load in the diagram. Answers provided below.

Happy trails to all my crane and rigging friends,

Mike Parnell
ITI-Field Services

P.S.  This article was originally published in The Professional Rigger Newsletter - Find CG by Test Lift.

 

Answers:

Rigging Training Workshop: 2-Hook Pick

Any time 2-hook pick is made, the crew needs to determine the weight carried by each hook, based on the center-of-gravity (CG) of the load. Review the schematic below and then evaluate the Master Rigger's Reference Card Panel 9 and the Journeyman Rigger's Reference Card Panel 2.

Workshop Assignment: First find the load's CG, then determine the weight being carried by the 30 and 10 ton hooks respectively. Answer the questions listed, and then check your work against the answers listed below. Have fun!

 

1. The CG is ___ ft. from the west end.
2. The portion of the assembly lifted by the 30 ton hook block is ___ lbs.

 

Master Rigger's Reference Card Panel 9:

 

Journeyman Rigger's Reference Card Panel 2:

 

Happy trails to all my crane and rigging friends,

Mike Parnell
ITI-Field Services

P.S.  This article was originally published in The Professional Rigger Newsletter - 2-Hook Pick.

Answers:

Rigging Crossword Puzzle

A sincere "Thank You" to our steadfast readers and supporters, who over the years have been entertained by the Professional Rigger. We thought that a fun way to kick off the year would be with a crane and rigging-oriented crossword puzzle. Thanks for letting us test your rigging brain cells.

(This puzzle is part of Mike's Rigging Mysteries, available through iti.com/bookstore). Enjoy! Answers below.

 

Happy trails to all my crane and rigging friends,

Mike Parnell
ITI-Field Services

P.S.  This article was originally published in The Professional Rigger Newsletter - Rigging Crossword Puzzle.

 

Answers:

Rigging Training Workshop: Determine CG

A crew must load out a short bridge column which will be used in a creek bed to support one end of a light bridge deck. The crew rigged the precast column at two locations about 20 feet apart. Using two cranes, they have decided to determine the location of the column's center-of-gravity so that they can load the column onto an over-the-road trailer. By properly placing the column onto the trailer, the resulting axle loading allows the tractor trailer to not exceed any travel limits.

Use Panel 2 of the Journeyman Rigger's Reference Card to help solve the question about the column's CG. Instead of using Run1 and Run2, consider replacing them with Weight1 and Weight2, to arrive at the percent distribution, times the total span of 20 feet. To double-check your work, remember "Short Stout, Long Light". Translated, that means that the CG is a short distance from the stout (heavier) end, and a long distance from the light end.

Journeyman Rigger's Reference Card Panel 2



Assignment: Estimate the location of the column's center-of-gravity from the "head-end". (Answer below)

The CG is ______ ft from the head end.

 

Happy trails to all my crane and rigging friends,

Mike Parnell
ITI-Field Services

P.S.  This article was originally published in The Professional Rigger Newsletter - Crane & Rigging Quiz.

 

Answer:

The R's of Rigging Managment

The R’s of Rigging Management

Review:  Be methodical in your approach to any rigging task.

Research:  Be a student of your profession.  Load and rigging data – Don’t start until you get it; don’t stop until you get all of it.

Responsibility:  Be willing to give it and receive it.

Reinforcement:  Show support for those who work for you and those you work for.

Require:  Demand thoroughness of yourself and others for each rigging assignment.  Show by example, not by lip service.  Require continuing education for everyone.

Reserve:  Be cautious in making decisions.  Hold your judgment until all of the available information is known.

Resist:  Resist the temptation to make decisions for people who need to make them as part of their learning process.  Be patient.

Respond:  Respond quickly to those who are seeking answers or help.  Be wise in how to lend assistance.

Reward:  Be liberal in your praise and compliments.  Let others know when a job has been done well.  Be consistent in your praise of things done, i.e. equal praise for equal jobs.

Happy Rigging, Mike Parnell.

This is an article from The Professional Rigger newsletter, 1988. To download this issue of The Professional Rigger, click The R's of Rigging Managment.

7 Best Practices for Blocking & Cribbing after Rigging a Load

When stabilizing a load after rigging and moving it to a specified location, the rigger should ensure it is well blocked before the rigging is removed.

1. Select wood blocking that is straight and uniform. Preferably the rigger should use a hardwood like hickory or oak.
2. When creating a “Lincoln Log Stack” the height of any blocking stack should not exceed 2 times its width. With large loads, three stacks (cross laid) or four should be used to provide stability. The load’s center-of-gravity should be well contained within the stacks’ boundary.
3. A load edge like a dozer blade should rest cross-grain on the wood immediately underneath it. If it rests in-line with the grain of the wood, it can split the wood causing a collapse.
4. To create additional stability between stacks, long timbers can be used to “inter-tie” the stacks.
5. Wedges should be used to fill gaps under curved load surfaces in order to distribute the weight and avoid point loading on a stack’s corner, causing instability.
6. A flat table of blocking can be laid on the top layer of a cribbing stack. The blocking should be cross-grain to the load’s bearing surface.

   

7. The ground surface that supports the blocking should be firm and level before building a cribbing stack.

From ASME B30.1 Jacks

1-1.9.5.4 Blocking

(a) While jacking, blocking should follow the load up or down to serve as an arresting device if the load falls.

(b) Wedges or shims should be used as necessary to ensure the load is completely supported at its blocking points.

(c) Blocking should never be taller than twice the width of the blocking base.

(d) Blocking shall be of sufficient thickness, width, and length to prevent shifting, toppling, or excessive settlement of the load.

(e) Blocking shall be of sufficient strength to prevent crushing, bending failure or shear failure, and to adequately transmit the load’s weight to the supporting surface.

 

Happy trails my rigging friends,

Mike Parnell, ITI – Field Services

Horizontal Rigging - When Rolling a Load...

As we begin to plan to move a load horizontally, using a set of industrial rollers, we should consider some options that can help ensure a success.

 

1. Identify the weight and center-of-gravity of the load.

 

2. Select a set of 3 rollers and “surround” the center-of-gravity at hard points underneath the load. When using three, we have continual pressure to the rollers’ bearing points, like a 3-leg milking stool. If the floor is uneven (undulations) and four rollers are in use, it is common for one roller to disengage causing diagonal loading of two rollers.

 

3. If a single roller is near one end of the load, and the other two are opposing it on the other side of the center-of-gravity, the single roller is typically used as the “steering” roller. The shorter the “wheel-base” is, the more maneuverable the load. A long wheel-base causes challenges when turning corners. Think about the wheel-base underneath a school bus. With a short wheel-base, it can turn 90deg corners easily and efficiently.

 

4. Ensure that each industrial roller has the necessary rated capacity to bear the amount of load intended for it.

 

Happy trails my rigging friends,

 

Mike

 

Mike Parnell, ITI – Field Services

ACRP 2010 Annual Conference Recap

The ACRP (Association of Crane & Rigging Professionals) met in Shreveport, LA during May 11-13, 2010. A series of in-depth presentations were made on the most current updates to the ASME volumes, including ITI's Devon Beasley's discussion about ASME B30.2 Overhead Cranes and B30.5 Mobile Cranes. A special highlight of the series was offered by Paul Sweeney, Chair of B30.1 Jacks, Industrial Rollers, Air Casters and Telescopic Hydraulic Gantry Systems. Mr. Sweeney is in charge of crane and rigging engineering group at Electric Boat - General Dynamics' shipyard in Groton, CT.

Tom DeSoo of Slingmax/I&I Sling presented a terrific overview of ASME B30.9 Slings with a review of inspection and removal criteria. Also, The Crosby Group's Danny Bishop provided attendees with the updates to ASME B30.10 Hooks and ASME B30.26 Rigging Hardware, during the technical session series.

A very informative session was provided by Michael Greenwood of Samson Ropes, which outlined the expanded usage of synthetic rope slings developed using Dyneema fibers, commonly known as HMPE (high-modulus polyethylene). These slings help in the super-lift category around the world, particularly in the offshore construction industry.

Mike Parnell of ITI presented three short topics on Positive Connections, Accident Causation and Engineered Sling Protection. The Crosby Group hosted a 2-hour tour of their Longview, TX forging plant where much of their shackle and load binder manufacturing is performed.

The General Assembly voted to issue letters of endorsement to the American Society of Mechanical Engineers in support of the development of new chapters or volumes for three subjects; Lift Planning, Wire Rope and Strand Jacks.

The 2011 ACRP meeting is slated for Milwaukee, WI (May 10-13) with a host of technical sessions, including a tour of the Manitowoc Crane manufacturing facility. To become a member of ACRP and to participate in next year's event visit www.acrp.net.

4 Points for Connecting Rigging Blocks and Lines for a Suspended Work Platform

4 Things to Consider When Connecting Rigging Blocks and Lines for a Suspended Work Platform (adjacent to the face of a building or structure)

Working with a crew this week was a reminder about how easy it is to get rigging hardware fouled and lose a finger trying to free it. We were rigging up the vertical lines needed to support a self-powered work platform. The hoist used to lift the lines hooked into either a block shackle or thimbled wire rope eye, depending on the line being rigged. Once hoisted to the upper connection point, a shackle pin passed through the suspended shackle or eye. Slowly the hoist hook was lowered to allow the lines to be supported by the upper rigging. When the work platform tasks were completed, the rigging process would be reversed in order to get the suspension rigging and lines back down to the ground.

This transfer process can go well or disastrously depending on the attention to details. The following are just a few helpful hints that can lower the risks associated with transferring tensioned rigging. Though the actual load weight may be less than 1,000 lbs, its dropping can cause injury, death or significant equipment damage.

1. While hoisting the rigging (blocks and lines) for connection, using a locking style hoist hook can help avoid hook fouling. The standard hook tip can snag on objects, suspended lines or rigging blocks and hardware during the lifting and positioning process.

2. Using an oblong master link as the transfer hardware provides a large arching curve at each end for connection. Picture a rigging block being hung to accommodate a 2-part line to a suspended platform. Its upper connector is a swivel shackle. If a master link is pre-placed into the block shackle, it can serve as an easy-to-access rigging suspension point. A master link will rotate 20-30 degrees left/right in the block shackle bow, allowing for best final alignment.

3. Consider using a short chain sling (2'-4') with a locking style hook at each end, to "jump" between the upper dedicated suspension point and the hoisted rigging. These are easy to connect/disconnect and eliminate the need for handling shackles/pins over open spaces. Remember, the chain sling and all rigging need to be rated for the maximum intended load of the work platform, its occupants, tools and materials.

4. Caution should be exercised when de-rigging. The hoist hook needs to be properly seated before it takes tension. While de-tensioning, if a suspension shackle has been unloaded using the hoist, it should be removed with great care. Fingers can be lost if the hoist is "adjusted" up or down during the removal process. Sounds obvious, doesn't it? If there is one person dealing with the connection and one person working the hoist, there are two brains at work, which might not be synchronized. Communication is absolutely critical during the entire rigging activity, but even more so when installing or disconnecting rigging hardware.

Plan, communicate, execute, communicate, review and communicate. Did I mention communication?

Well, lots more could be said but I won't.

As Roy Rogers would say, "Happy Trails" to my rigging friends.

-Mike Parnell, ITI