The crane, believed to be one of the large tower cranes working on the expansion of the domestic terminal, was lifting a 26 tonnes- 49 metre long truss when the crane jib broke away and came down with the truss onto Air India’s operations building.

A construction worker in his late 30’s or early 40’s was pinned under the truss, it took rescue crews over an hour to free him and he died while en route to the hospital.

The main contractor, Consolidated Construction Consortium said that the area where the crane was working had been cordoned off. It also said that the crane had been inspected a week ago. The company has started an investigation into what caused the jib to collapse.

Consolidated Construction’s managing director S. Sivaramakrishnan said: “Hereafter, we will doubly ensure that safety precautions are taken,”

The warning follows two catastrophic spigot failures, one in Chicago in February 2009 and one in London in this April. The failure, which starts as a small crack is thought to be due to inadequate heat treatment.

Whilst investigations continue all spigots manufactured between 1st November 2006 and 28th February 2007 are suspected of being substandard and subject to replacement.

Manitowoc Crane care says that the K600 and K800 series mast sections are only used on its MD,MDT and MR series cranes. Each tower section has a unique PIN /identification number .The numbers for mast sections produced in this time period are in the range 80323 – 103784.

The potentially affected spigots are in the ranges 3086* to 3496* and 0037* to 0577* – the letter on the end of the reference number is irrelevant for identification.

The action required is easy for stored sections they simply need to be checked to see if they are within range and then the spigots changed, or at least checked,

For cranes in service the sections need to be checked to see if any of them are included in the list of potential affected sections. If a potentially bad section is identified, it must be pulled out of service immediately and then the spigots checked to see if any of them are within the ranges of potentially substandard spigots.

If it is not possible to dismantle a crane that has a potentially bad section within tts tower, Manitowoc crane care can help you add some factory approved re-enforcements intended to last until the end of the job or until a break in the work load. If in doubt at all contact Steve Bradby at Manitowoc cranes UK in Gawcott Buckinghamshire.

The HSE Bulletin follows:

“We are aware of two crane mast failures in which faulty mast section spigots were implicated.”

“The first of these incidents was in Chicago in February 2009. The most recent incident involved a crane in London in April 2010. Metallurgical tests undertaken on the London crane showed that the spigot failed catastrophically in brittle fracture from a small fatigue crack. The tests have shown that the failed spigot did not meet the performance characteristics specified for the component. It is believed that there was a flaw in the heat treatment process during the manufacture of the spigot. Whilst investigations continue to isolate the cause of the problem, as a precaution all spigots manufactured between 1 November 2006 and 28 Feb 2007 are suspected of being substandard and subject to the remedial action outlined in this document”
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Background:

If a tower crane mast fails and collapses there is potential for multiple fatalities. Tower crane masts or towers are constructed from a number of individual sections which are located one on top of another to achieve the required height. For the type of cranes covered by this safety notice, spigots provide a means of connecting individual mast sections together. Their condition is crucial to the integrity of the mast. Each mast section has 4 spigots. They locate within female housings on the mast section fitted above. Once assembled the batch numbers of the spigots are hidden by the female housing and cannot be read. There is no non-destructive testing which can be undertaken to check the current condition of the spigots.

The only effective means of preventing mast collapse is to identify and remove all potentially affected spigots from service or weld additional reinforcement in accordance with the specification provided by Manitowoc Cranes.

Specific details of affected cranes, sections and spigots:

We have been informed by Manitowoc Cranes that the K600 and K800 series mast sections are only used on MD,MDT and MR series cranes. K600 and K800 series mast sections manufactured between 1 November 2006 and June 2007 (when spigot stocks were exhausted) are in scope. Each mast section has a unique identification number known as a PIN number. See figure 2 for details of where to find the number. The numbers for mast sections produced in this time period are in the range 80323 – 103784.

Figure 1 gives an example of the spigot number. The potentially affected spigots are in the ranges 3086* to 3496* and 0037* to 0577* – the letter on the end of the reference number is irrelevant for identification.
Action required:

Stored Mast Sections

• Identify and record mast PIN numbers and full spigot numbers (including the letter at the end) for all K600 or K800 series mast sections. Any with spigot numbers in the range specified should be withdrawn from stock immediately and quarantined.
In use Mast Sections

• All erected Potain tower cranes should be scrutinised to identify any mast sections with PIN numbers in the specified range.

•Any erected cranes with the relevant mast sections should be taken out of use immediately and arrangements should be made to:

- Either dismantle the crane sufficiently to view spigot numbers on all relevant mast sections. Record all spigot serial numbers and, where they are in the potentially affected range, take the mast section out of service and quarantine.

- Or weld additional sections in accordance with the specification provided by Manitowoc Cranes. This work will need to be undertaken following a safe system of work and to an assured quality standard. Welds must be inspected and non- destructively tested on completion. Arrangements must be made for documented competent person weekly inspection of the welds and at least monthly non destructive testing for the entire time the crane remains erected. Manitowoc Cranes can advise.

•Whichever option is selected, the work must be managed rigorously to ensure the safety of anyone who might be affected. Safe systems of work, safe access and competence are key elements.

•Please retain mast sections for further possible investigation by HSE. We will not be able to complete investigations if we do not have further supplies of spigots to test.
Recommendations

•It is recommended that you identify both mast section serial numbers and spigot batch numbers for your entire inventory of mast sections for Potain MD, MDT and MR Tower Cranes. As investigations into the defect progress, we may need to ask for more cranes to be removed from service. It will be easier to take proportionate action if you can identify where potentially defective spigots have been used.

•It is recommended that you retain photographic evidence of the checks you undertake.

Relevant legal documents:

•Health and Safety at Work etc Act 1974, Sections 2 and 3
•Lifting Operations and Lifting Equipment Regulations 1998, Regulation 4
•Work at Height Regulations 2005, Regulation 6
References:
•Manitowoc Crane Care Service Bulletin T10-019a dated 11 June 2010
For general advice on tower cranes work see
•Strategic Forum for Construction Plant Safety Group – guidance on tower cranes [3]
•Construction Plant-hire Association Tower Cranes Technical Information Notes [4]
Further information:

Email: Stephen.Bradby@Manitowoc.com
Post: Manitowoc Crane Group (UK) Ltd
Manitowoc House, Network 421,
Radclive Road, Gawcott, Buckingham. MK18 4FD.

The workload on the job site is demanding, but the MCi 85 has performed perfectly, even when working around the clock. Main contractor and development company on the project is Wave Silver Tower Pvt Ltd, which took delivery of the crane in December 2009.

Vineet Jayee, deputy purchasing manager at Wave Silver Tower Pvt Ltd, said lift capacity and precision were key elements on the project.

“This is an important project, and we needed a crane that not only has the necessary lift capacity, but also can transport loads carefully and precisely within a confined area,” he said. “We thoroughly compared the Potain and another crane. The Potain was superior, and its quality is outstanding. We also like that the cranes are manufactured in India. When we purchased the crane, we wanted quick after-sales service— and we haven’t been disappointed. While Potain cranes may cost a little more, the crane and service are first class.”

A Potain MCi 85 tower crane at work on the Wave 1st Silver Tower development in Noida, India.

The MCi 85 crane, built at Manitowoc’s factory in Pune, India, is lifting loads at heights of 60 m and working in close proximity to other buildings. There is also a Metro line construction taking place just 20 m away. Project congestion prompted Wave Silver Tower Pvt Ltd. to seek the precise control of Potain’s mechanisms for hoisting, slewing and trolleying. The company rigged the crane with 45 m of jib (short of the available 50 m maximum) and limited its slewing to 180 degrees. On the project, the crane is lifting sand, steel bars, shuttering plates and concrete, and loads weigh 2 t to 3 t each.

Subhash Jha, deputy project manager for Wave Silver Tower Pte Ltd., said the company turned to two of its most experienced operators for this job.

“Because of the close control needed on the project and its high profile, we selected two of our most experienced operators along with two crane assistants,” he said. “Both operators have over 10 years of experience and are part of the 341-strong workforce on this site.”

The 15-story Wave 1st Silver Tower is located in a premier commercial square of Noida called Sector 18, Atta Market. The crane will remain on site until the project finishes in February 2011.

When complete, the Wave 1st Silver Tower will have four floors dedicated to retail and 11 dedicated to offices, each floor covering 1,850 m2. The contemporary design includes several aesthetic features including an elevated atrium, green landscaped pedestrian area and energy efficient external façade. Internally, column-free spaces allow for personalized office designs.

Potain’s MCi 85 is suited for city center projects like the Wave 1st Silver Tower. It is easy to assemble in downtown locations and has excellent lift abilities at all lengths of the jib. The crane has a free-standing height of 34.5 m and a maximum capacity of 5 t. At its maximum jib length of 50 m, the crane has a 1.3 t lift capacity.

The new crane is currently being tested at Liebherr with a number of different equipment attachments, and machines are scheduled for delivery at the end of the year.

The court agreed on the bankruptcy of the companies while Spierings Kranen will remain in business although it is shedding a large number of its 140 employees. Production sales and product support will continue, with particular focus on the current order book, new sales, and product support for the company’s 700 plus crane population.

Spierings laid off 17 people last year but the cutbacks were not sufficient to carry the group through the current market slowdown. It has recently been working on a radical new model, the City Boy for which the company has already booked 10 orders.

Owner Leo Spierings, who founded the company in 1987, said he was very disappointed to have had to initiate such a severe restructuring of the business and was particularly upset over the personnel losses. However he says that he is optimistic that the company will be able to re-employ most, if not all of the staff once the market returns to health.

It seems that the accident had occurred around eight weeks ago and thankfully no one was hurt. McNally’s was understandably not keen initially to have photographs of one of its cranes published while sitting on its backside.

However the company, which has a solid reputation for doing things right and a correspondingly good safety record, also appreciated the benefits to the industry as a whole to publish the details so that others might learn from the errors that caused the accident as well as ensuring that the facts are understood and tht they accompany the pictures, which were clearly being circulated without the relevant information.

The response from the company was so comprehensive and open that we felt it best to simply publish the information exactly as we have received.

“This incident occurred when the Terex-Demag AC100 was being moved, partially rigged, across a crane hard-stand. The boom was telescoped in, the lifting gear removed and the superstructure was slewed over the rear of the carrier as is normal practice for moving a crane when partially rigged.

Normal practice would dictate that the operator should further proceed as follows:

a) Slew pin engagement, the Terex pin is manually engaged and requires the superstructure to be slewed slowly in each direction to ensure that it is fully inserted.

b) Activation of the slewing brake, this device acts on the slew motor.

c) Superstructure engine switched off, this constitutes good practice.

The operator deployed the slew-pin mechanism but did not slew the superstructure to ensure the pin had dropped fully into place, neither did he check (when dismounting from the cab) that the pin was fully engaged. (this can be seen from the access ladder!) The slewing brake was not activated!

A heavy elastic band had been placed on the control levers to de-activate the “dead-man” switches – these are designed to activate the slewing brake when released.

The superstructure engine was left running – were this switched off the slewing brake would have automatically engaged.

The crane was being shunted on the hardstand (under the control of our crane supervisor) when the superstructure began to slew beyond the carrier centre-line; as the crane slewed out the momentum increased until the crane fell onto its’ own counterweight.

All our lifting operations are carried out with a crane supervisor in attendance, we sign off lift plans and pre-lift check-lists, the operator had more than 20 years experience. With all these measures in place a potentially fatal incident occurred because humans, not robots, drive cranes. Most accidents can be categorised as lack of experience or making too many assumptions – the latter would prove that negligence is a more serious issue than inexperience.

Following the incident we banned all partially rigged crane movements for machines of 130 onnes capacity or less, we issued a safety alert to all staff and have agreed to share the investigation results with Renewables UK (BWEA) “Lessons Learned Database”.

We treat all incidents in the same manner, the investigation results are used to strengthen our procedures and, more importantly, the information is conveyed to our front line staff; we do not and have not, scoffed at the misfortune of other crane owners – this scenario awaits us all and we will gladly share this information if it prevents a reoccurrence elsewhere.”