Crane Inspection Preparation

By John Davis PE
Director Crane Certification Association of America(CCAA)

Crane certification requires that the crane be placed temporarily out of service. This usually creates a significant cost to the owner. Therefore, it is incumbent on the surveyor to be organized and efficient so that the cost can be minimized. Part of the responsibility of the surveyor is to appraise the client of the conditions and limitations of the process so that the client can plan accordingly. Then the inspector must prepare himself to accomplish the task. The following elements should be part of the preparation.

1. An estimate of the time required for test/inspection will help the client plan. The surveyor should be able to estimate the time required with the understanding that if the crane is not maintained well or if extra testing is required for auxiliary equipment, the inspection will take longer.

2. The client should be advised of the work area required for the test/inspection. The crane must be operated through its full operational range and the boom must be lowered and extended for inspection. Similarly, bridge and track gantry cranes must be operated throughout their range.

3. The crane should be presented to the surveyor in clean well-maintained condition. It should be configured with the full compliment of boom and accessory equipment that the client wishes to be certified. The surveyor should discuss the crane description and limitations sections of the certificate so that the owner can make informed decisions about the crane configuration.

4. The surveyor must be able to study the load chart(s) and owner’s manual for the particular crane before the actual inspection/test date to determine test limitations and special inspection requirements required by the manufacturer. With this information he can add to his checklists as necessary and properly design the load tests. If the surveyor has previously inspected the particular crane, a review of his records may provide all the required information.

5. In order to plan for sufficient test loads, the surveyor must have access to the load charts for the crane. Using the load chart(s) the surveyor can arrange for the minimum number of weights that will test the crane’s structural integrity, stability and provide for testing line pull and accessory equipment such as jibs and extensions. Again, prior records may provide all required information.

6. The surveyor should not inspect/test a crane without having the client’s operator or mechanic available. The surveyor’s job is to inspect and test, so the operation and adjustments should be left to the client’s personnel both for operational as well as liability reasons. If the surveyor is required to operate the crane he should have a hold harmless clause in the contract, so that if the crane fails and causes damage during testing the surveyor is protected from litigation to some extent.

7. It is always wise to review the test/inspection procedure as well as the certification process with the client before the work commences. This will usually generate any questions about the process and details can be worked out before they become problems.

8. The documents that will be provided to the client should be fully explained before hand. The client should be advised of the limitations and time constraints of the compliance certificate, deficiency report, check lists, and material certifications.

One of the best ways to present the foregoing information is in the form of a comprehensive written description, which includes the elements noted above. Depending on the surveyor’s scope of work, a few versions of this “Crane Inspection Preparation” can be developed which will cover all the different cranes in his client base, can be copied repeatedly, and sent out in advance to the client.

The actual inspection/test should be conducted in a well-planned, efficient manner. This maximizes the surveyor’s effectiveness and presents a professional impression to the client and his personnel. The surveyor should be fully equipped to do the job, having the correct tools and gauges.

The “static” inspection should begin with verification of the data plate information as to make, model and serial number, as well as a brief review of any special inspection requirements given in the owner’s manual. Then follows the visual, static inspection of hook, block, reeving, drum, controls, safety devices, draw works, carrier and any accessory equipment in methodical order that best suits the surveyor. The idea is to get all the static inspection done that is practical before starting up the crane.

After completing the “static” inspection, the surveyor should verify operation of all controls, let out and inspect the amount of reeving required for the type of inspection, lower and inspect the boom, gauge the sheaves and grooved drums, check pins and operating components for wear, check safety devices and operator aids for function, check brake, clutch and pressure adjustments, including carrier components as applicable.

A partial load functional test is required by most authorities for all periodic inspections. This is conducted to determine that all operating mechanisms are functioning as they should. This test can also be used to do a rated load stability test using a relatively light load. With a little planning it can also be used to verify rated line pull, load indicator accuracy, and boom elevation function. Some jurisdictions require an overload test which should be done following the partial load test. (See the CCAA Recommended Load Test Procedure.)

Following the load test, the structural components must be carefully inspected for damage, distortion, paint dislocation, loose fasteners, or any other evidence of existing or impending structural deficiencies. During this inspection, hook bearings, slew bearing fasteners, and structural components under the carrier and at the outriggers should be carefully viewed. The surveyor should always be sensitive to any change in characteristics, as a result of rated condition testing, such as excessive clutch/brake temperatures, engine power loss, malfunctioning hydraulic system components, and unusual noises or vibration.

After reviewing and completing all check lists, a deficiency or inspection report should be prepared and reviewed with the client’s representative. The surveyor should cite the standards that were not met and indicate the level of correction that will be acceptable. The client should be advised if an inspection of corrections is required or if documentary evidence will suffice. The surveyor should advise the client of any time limits for correction that apply.

One of the best customer relations methods is proper planning that saves the client expense, confusion, and worry. Good planning is also one of the best safeguards against undeserved lawsuits and devastating liability. Inspectors will serve themselves and their clients well if they use a comprehensive planning system.

The purpose of CCAA is to promote crane safety, improve the certification profession and address the subject of crane safety in governmental forums.

Load Measuring Pins from Water Weights

Load Pins

Load measuring pins are designed for many diverse applications as direct replacements for clevis or pivot pins. They have many advantages over other load sensors in that they do not normally require any change to the mechanical structure being monitored. Load pins are typically used in ropes, chains, sheaves, shackles, bearing blocks and pivots.


Different options include:
Special anti-rotation/loacking plates
Internal greaseways
Plug/Socket breakdown at pin
Second redundancy gauge bridge
Internal signal amplifier
Single shear pins

Installation Notes
Various factors influence the performance of a load pin when it is put into service. The majority of load pins are designed to fit existing structures so that each design is dependent on the size and constraints of that structure.

A rigid support structure is required to minimize the bending forces imparted on to the pin. The pin works by sensing the shear stress, and any bending stresses within the pin will degrade its overall accuracy. The fit of the pin within its mating holes is important in the overall performance. Bearing stresses, and overall proportions are always taken into consideration with the design of a new pin.

Before installation note the Direction of Load arrow on the end of the pin. The key consideration in the performance of any load pin is that there is no change in the geometry, the loading structure or loading conditions throughout the range (0 -100%). If these conditions are achieved then a high performance can be expected. Even minimal bending of the structure, changes in bearing areas or bending of the load pin (if highly loaded) will have an effect on performance however repeatability is unlikely to be affected.

Calibration

Load pins are normally calibrated in half or full blocks in a traceable compression test machine. When a load pin shackle is supplied, we would normally calibrate the total shackle assembly in tension. We endeavor to match the loading conditions that would be experienced in service but it would be unrealistic to totally simulate the on-site structure for every load pin manufactured. It is for this reason that for optimum system accuracy, a calibration in the final assembly is recommended.

For more details on our line of instrumented load pins visit:http://www.waterweightsinc.com/en/Downloadable-PDFs.html

Deck Loading for Structural Verification

Water Weights provides specialist products, services and project management for structural testing. This includes verification of structural integrity of buildings, testing of bridges, elevators, loading ramps, gangways and decks.

Our range of flexidams and mattress bags allows uniform surface loadings to be applied. Advantages over traditional solid weights include ease of handling and positioning on site, very low carriage costs and gradual application of load (often over a period of several days). Loading is measured by means of a calibrated flowmeter to give accuracy of +1/-2%. By using our simple manifold arrangement several units can be filled simultaneously.

Specific examples of applications include:

Roll on, roll off ferry ramps have been tested ranging from 70 to 600 tonnes

Ballasting arrangements for ship's conversion up to 300 tonnes

General floor testing applications to verify structural integrity on renovation; change of use or suspected structural damage. Examples include, 130 tonnes to an educational establishment and 40 tonnes to an historical monument.

Passenger and freight elevator load testing

Listening to Crane Structures

Cranes have traditionally been certified for their “fitness for purpose” by the application of a test load. Typically, the structure’s resilience to withstand the stresses imposed by the Proof Load (a load that surpasses the generally applied load) illustrates that all defects that are within the structure are sub-critical. By the periodic application of such load tests owners can content themselves that because the crane passed the previous test, then there must be some redundancy within the system that will permit the continued safe operation until the next scheduled test.

In other industries, such as in pressure systems this methodology has been enhanced by coupling the traditional “load test” other technologies. Imes in conjunction with Water Weights pioneered a process on cranes which listens to the structural behavior of the material while in the loaded condition. The technique utilizes highly sensitive instrumentation with the ability to “hear” localized yielding, which therefore allows identification of initiating and propagating defects. Such is the sensitivity that the technique boasts listening to even the active corrosion on the material under test.

Acoustic Emission is defined as excerpted from ASTM E610-82 as “The class of phenomena whereby transient elastic stress waves generated by the rapid release of energy from localized sources within a material.” The term AE is referred not only to the phenomena, but also to the non-destructive technique. Typical sources are cracking, plastic deformation, phase transformation and it is very sensitive to the initiation and propagation of discontinuities.

The technology of this non-destructive technique can be utilized for testing the integrity of crane structures (booms and slew rings) as part of a Condition Based Maintenance Program. Tried and tested, the application was pioneered by Imes Group.

The system utilizes the unique application of a load with Water Weights (a trading division of Imes) during the load application. In conjunction with the applied load, the method measures structural performance by “listening” for the telltale “creaks” and “groans” that emanate from the highly stressed regions during gradual application of the test load.

This activity can be located to a position on the crane structure and additionally ranked for its intensity such that a qualitative assessment of damage severity is made.

The operator can monitor in real time the acquired data and determine location of Acoustic Emission activity and how this varies with time and or load. Each wave has a unique signature composed of counts, amplitude, rise time, duration, energy and relative time of arrival. Full analysis of the emissions can be used to determine the characteristics of the source emissions and help characterize the flaws. The processed data can then be displayed as required by the operator. As the system has the capability of capturing the full waveform then the data file can be run as required and full post-test analysis can be undertaken either on or off site.

Periodic monitoring utilizing this method during load testing will give an indication of the condition of the crane detecting any growing discontinuities. The exercise would greatly enhance the load test and should be conducted in conjunction with future tests to verify the cranes integrity and develop a trend history.
for more info visit: www.waterweightsinc.com


About Imes:
Imes delivers knowledge-based solutions that, in partnership with its clients, produce radical improvement in the management of full life cycle costs, performance and safety of their assets. Imes provides inspection, in-service support, reliability, measurement and specialist engineering products, systems and services to construction, defense, heavy process, marine and shipping and the oil and gas industries in over 60 countries.
for more info: visit www.imes-group.com

INSPECTION CERTIFICATE –ASSET OR LIABILITY

INSPECTION CERTIFICATE –ASSET OR LIABILITY
By: John W. Davis, PE

Crane surveyors (inspectors, certifiers) are usually required to provide some record of the inspection/testing that they perform. This record is usually in the form of a certificate testifying as to the condition of the crane. The information contained on the certificate may be either an asset or a liability to the surveyor.

On the asset side, the certificate can clearly define the scope of the inspection/testing and state the limitations involved, thereby specifying the limits of responsibility for the surveyor. On the liability side, an incomplete or inaccurate certificate leaves the surveyor subject to assumptions about the thoroughness of the inspection and, subsequently subject to potential lawsuits. Some jurisdictions, such as Federal Maritime, specify the form of the certificate, but many, maybe most, areas of the nation leave it to the surveyor to develop his own. Even if the form is specified or supplied, there are usually items or spaces on the form that allow adequate definitions and limitations to be noted. However, it is vital that the surveyor use such forms carefully and thoroughly.

The following elements, while not exhaustive, may help the surveyor create an asset rather than a liability.

1. Identification information. The owner or user must be identified accurately so that there is no doubt about the recipient of the certificate. It’s equally important to accurately specify the make, model, and serial number of the crane so that the certificate only applies to one crane. Many surveyors fail to accurately define the configuration of the crane as presented to them. The boom length, extensions, jib, auxiliary winches, counterweight and carrier that are subjected to inspection must be specified in order to limit the scope of the surveyor’s exposure to liability.

2. Inspection criteria. It is important, if the certificate does not specify the criteria or authority, to include a clear description of the authority or basis of the inspection. In many cases, the jurisdictional authority such as a state OSHA may be definitive. Frequently, however, an ANSI B30 standard may be the criterion along with the OSHA regulation. In some circumstances, the criteria could be the surveyor’s own check list. In any case, the criteria must be
defined so that there are no assumptions about the authority for the inspection

3. Tests performed. Completeness suggests that all tests be noted on the certificate so that there is no doubt as to the thoroughness of the survey. Most authorities that specify tests express or imply that “such other tests as the surveyor deems appropriate” should be done. Therefore, the certificate should include notation of all tests such as no load, partial load, full load proof, line pull, and any tests done to accessories such as jibs and auxiliary hoists. If proof tests are not required, the surveyor is wise to use the partial load functional test at an authorized radius for the load and line pull tests for diagnostic purposes, thus demonstrating due diligence (this applies to mobile cranes).

4. Limitations/Comments. This is the space to note any caveats or disclaimers. Such topics as single line limitation, no jib or extensions, less than full counterweight, or special accessories can be noted. If a regulatory body has granted a variance from a rule, it could be noted here. If the crane is authorized to pick “on rubber” but is not used and wasn’t tested in that mode, that exception should be noted in the comments space. Any limitation of the authorized operational capacity of the crane should be noted here.

5. Certification statement. The authority of reference, compliance verification, date of inspection/certification and the surveyor’s qualification should be included in this section. Forms required by regulatory bodies usually have this section pretty well laid out so that all these elements are detailed. It
is most important that the authoritative regulation or standard be specified so that the surveyor is not held to inappropriate criteria. The statement should indicate that the crane “…meets the inspection/testing requirements…” of the noted authority. In conclusion, it is most important to demonstrate due diligence and a reasonable standard of care in order to make the certificate an asset rather than a liability. Due diligence means that the surveyor has used the methods and practices that a reasonably competent practitioner would employ for the task, and reasonable standard of care means that the surveyor has exercised the level of care that is typically expected in the industry. The certificate may be the only indication that these standards were met if the quality of the inspection is ever questioned. Make sure your certificate is an asset, not a liability.

Wedge Socket Load Indicating System

When developing new load monitoring and measurement systems for use in lifting applications, innovation and reliability of design are paramount to Water Weights. This focus has led to the introduction of our wedge-socket crane load indicating systems.

These systems have been designed to replace the standard wire rope dead-end. Requiring no modification to the existing wire rope reeving of the crane, simply replace the existing wedge socket with our modified version for the same sized wire rope. The result is no loss of headroom or functionality to the crane.

Available in both radio-telemetry and cabled configurations, our systems give clients maximum flexibility in choice. Together with our parts of line option, the system can be used on cranes where the parts of line alter from job to job, without having to recalibrate the load indicating system. Other available options include solar power, data logging, set points, tape printer and serial I/O.

Water Weights’ wedge-socket systems are ordered based on the wedge-socket wire rope size, not crane capacity or parts of line. Selection of the appropriate systems therefore straightforward and uncomplicated.