Sheared Bolts Discovered on JLG Aerial Lift Boom Connections to Platform after Physical Inspection

Transcription

1 TN: 3514 Sheared Bolts Discovered on JLG Aerial Lift Boom Connections to Platform after Physical Inspection Priority Descriptor: Yellow /Caution Lesson ID: 2012-BNL-Aerial-0001 Originator: Brookhaven National Laboratory Date: July 30, 2012 Statement: A JLG model 860SJ aerial lift was found to have all eight of its platform rotator attachment bolts sheared in half. This condition is not obvious during a visual inspection. Although there was no risk of the platform detaching from the boom the horizontal rotation capacity of the platform was severely compromised. Discussion: On July 26, 2012, at Brookhaven National Laboratory (BNL), a contractor working on building siding outside of the National Synchrotron Light Source-II (NSLS-II) construction project was operating a leased JLG 860SJ Boom Lift and was approximately six feet off the ground when he began having difficulty in articulating the basket (platform). A DOE inspector in the area asked him to lower the basket to the ground to investigate. A NSLS-II Construction Safety Engineer in the area who had knowledge of similar issues with this type of lift examined the eight (8) 3/8-inch platform-rotator attachment bolts that surround the main center pin that holds the basket to the boom. These bolts are installed vertically, down through the platform support and threaded into the rotator s hydraulic motor, therefore all eight bolt heads appeared visually intact as expected. However, it was discovered that all eight bolts were completely sheared when the tops were able to be removed by hand. The separate center pin is the load bearing structure for the basket to boom connection; this connection was sound. All Aerial Lift activity was suspended and notifications were made to all users on site to perform necessary physical inspections before use. Inspection of site Boom Lifts (by the vendor) has been completed. Other lifts have been found with similar problems. Affected Boom Lifts have been taken out of service and those lifts found acceptable were placed back into service. Analysis: Failure of all platform-rotator attachment bolts does not result in detachment of the work basket from the boom assembly, but in lateral disengagement between the rotator power source and the work platform. Initial inspection of the failed bolts noted that corrosion had formed on the failed surface of six (6) bolts indicating that these failures occurred sometime in the past.

2 TN: 3514 The lift manufacturer has stated that these bolts can fail if they experience excessive force or contact between the platform and another object or structure and should be checked as part of manufacturer s recommended inspections. Note that friction may continue to allow horizontal rotation of the basket even if all bolts are sheared but the operator should notice a lack of normal response of the equipment. A review of the DOE Lessons Learned database cites a similar condition discovered on July 23, 2007: Lesson ID: Y-2007-OR-BJCPQA-0701, Sheared Bolts Discovered on JLG aerial lifts model 860SJ. In that incident a plastic environmental protective cover needed to be lifted up to properly see and check the bolts. Actions/Recommendations: Temporarily take all aerial lifts JLG model 860SJ out of service until they can be inspected. Physically inspect the eight (8) 3/8-inch platform-rotator attachment bolts that surround the main center pin that holds the basket to the boom. If necessary raise the environmental protective cover. Visual inspections are not sufficient because the bolts are oriented vertically and appear intact. Follow the manufacturer s guidance for inspections but it is recommended to examine the bolts prior to each use particularly if the basket struck an object or was subjected to an external lateral force. References: ORPS Report SC--BHSO-BNL-BNL Contact: S. Hoey (631) Classifier: Reviewer: M. Hauptmann (631)

3 TN: 3514 Attachment Photos JLG Model 860SJ Aerial Lift JLG Model 860SJ Aerial Lift Eight bolts as they should be surrounding the main man lift bucket attachment bolt. Note the orientation of this attachment point of the bucket to the boom is horizontal.

4 TN: 3514 Remains of the eight sheared bolts after the tops were lifted out of the holes. Tops of the sheared bolts.

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7 UK Power Networks HSS BULLETIN Issue No: NB 137 Issue Date: 10 August 2012 Type: Subject: Applicable Areas: Communication Update on the incident where Wayne Crerar lost his life at Pebmarsh on 14 June All Applicable Job Roles: Issued By: Murdo Allan Author: Nick Rogers Please consult the author if you have any queries about the information below. All UKPN and Contractors The first stage of this investigation is complete and we are now able to share some of the initial findings. Background Wayne was a member of a working party carrying out Low Voltage (LV) overhead line refurbishment work replacing main and service cables. Having replaced a section of main with Aerial Bundled Conductor (ABC) he was at a pole where services were to be connected to the ABC this was a combined High Voltage (HV) / LV construction pole. At the time of the incident Wayne was working from the platform of a Unimog Mobile Elevated Work Platform (MEWP) at 5m above ground. His colleague who was working at the house end of the services sensed movement in the service cables and turned from his work position to witness Wayne falling. There were no witnesses to how Wayne came to fall from the MEWP and no one heard any shout, or call from him during or prior to the fall. The LV services and LV conductors were not live during any of the work. The HV conductors above the LV, on the combined pole, remained live with a Proximity Limit Marker affixed to the pole in the correct location, marking the safety clearance from the HV conductors. There is no suggestion that inadvertent contact was made with the HV line. Incident Findings The MEWP had a valid statutory examination certificate which is undertaken every 6 months. On site the door of the platform was found to be open with the floor over 5 metres above ground. Forensic investigations have confirmed that the work platform door latch worked satisfactorily, and would have fastened the door closed had it been engaged. The door is also equipped with closing springs that assist the door towards the closed position. During the forensic inspection these springs were found to be broken, and not working as designed. It is the responsibility of line management to ensure that all appropriate employees are issued with this Bulletin and their understanding of the contents is checked. This Bulletin will be subject to Compliance audits after 14 days from the date of issue. Version 3.7 This printed document is valid at 10/08/12, check after this date for validity. Page 1 of 2

8 UK Power Networks HSS BULLETIN At this stage it is not possible to be sure when this damage occurred or the extent to which it may have contributed to the incident, if at all. However as a precaution all similar design working platforms have been checked by the manufacturer (Versalift) and where required modifications made. Until these checks have been completed by Versalift these vehicles have been withdrawn from service. Harness & Lanyard The P&P MEWP full body harness and Mini Max retractable fall arrest lanyard which were being worn by Wayne at the time of the incident have now been formally examined by specialists from the Health and Safety Laboratories and observed by a representative of UKPN. No major fault was found with any of the equipment and therefore no concerns were raised during the examinations to suggest the equipment not being fit for purpose. There were a few scuffs visible on the webbing, but the lack of any major degradation indicated that the equipment had not been subjected to any type of fall arrest. Further Work being undertaken In addition to the work around the MEWPs we have appointed human factors and ergonomics specialists to looking at the equipment we use and the human factors associated with working at height. It is possible that the circumstances of this incident may never be fully understood, and we are continuing to co-operate with the Health and Safety Executive who are also carrying out an investigation. In the meantime I would like to remind everybody that: It is essential that anybody who is planning to use a MEWP completes the pre-use checks (form HSS a), in particular if the MEWP bucket is fitted with an access door or movable guard rails check that they close properly and that the latch or locking mechanism keeps them closed. Using a MEWP is one of the safest methods of working at height provided all the control measures are in place. It is essential that anybody using a MEWP wears an appropriate harness and fall arrest device and the fall arrest device is clipped onto the anchor point of the bucket. Further information on work at height arrangements can be found in the Health, Safety and Environmental Handbook, Section 5. It is the responsibility of line management to ensure that all appropriate employees are issued with this Bulletin and their understanding of the contents is checked. This Bulletin will be subject to Compliance audits after 14 days from the date of issue. Version 3.7 This printed document is valid at 10/08/12, check after this date for validity. Page 2 of 2

9 SavOx Chemical Oxygen Self-Rescuer Fast escape in case of hazardous concentrations of toxic gases or oxygen deficiency The Chemical Oxygen Self-Rescuer SavOx is a self-contained respiratory protective escape device. It is ideal for all escape applications wherever toxic gases, particles or oxygen deficiency must be expected suddenly. With its small size and low weight the SavOx can be carried along constantly on the person ensuring the escape set is always within hands reach. MSA EUROPE Phone: +49 (30) contact@msa-europe.com Because every life has a purpose...

10 SavOx Chemical Oxygen Self-Rescuer Class K30 S, EN i 1 Important Notice: Don the device in a standing position with the device worn on the belt Opening the Container Push the locking lever in the direction of the arrow until the seal breaks and locking device falls off 6 Inserting the Mouthpiece Place mouthpiece into mouth with flange of mouthpiece between teeth and lips Bite down on the two lugs Exhale into the device (so the breathing bag is inflated) Note: It might be necessary to unfold the breathingbag by hand 2 Removing the Device Grasp container cover with one hand Pull out the device by the neck strap with the other hand Discard container cover 7 Fitting the Nose Clip Grasp nose clip by rubber pads, pull nose pads apart and fit them onto nose 3 Donning the Neck Strap Take off the protective helmet, if used Place the neck strap around the neck (do not adjust neck strap!) Put the protective helmet on 8 Removing and Fitting the Goggle Note: Goggle is on the right side of the neck strap Grasp the goggle strap and pull to remove the goggle from neck strap Fit the goggle Tighten goggle straps Note: The valve of the bag must be visible on the front of the bag 4 Detaching the Device Detach device from mouthpiece bung 5 Activating the Device Grasp breathing tube at the mouthpiece Fully extend the breathing tube to activate the starter (a drop in pull resistance indicates the starter is initiated)! 9 10 Adjusting the Neck Strap Adjust neck strap (ensure that the head is able to move freely) Tying the Waist Belt Tie waist belt and tighten with a bow ATTENTION: There is an ignition risk if this procedure is not followed. The starter MUST be initiated at the beginning of use when the device is donned. MSA EUROPE Phone: +49 (30) contact@msa-europe.com Because every life has a purpose...

11 Standard for excavator exclusion zones Zone 1 Zone 2 Machine operator sight line Zone 1 Only enter this zone if you cannot approach from the excavator operator line of sight. Always signal the plant operator and receive a positive response before entering zone 1. Zone 2 Keep out of zone 2. Where specific activities have been planned with a Safe System of Work implemented and controlled, an exception may be authorised. Machine operator sight line This is the safest zone for approaching an excavator as it provides the greatest chance of being seen by the operator. Before approaching an excavator, always make eye contact with the operator and indicate that you wish to approach. Wait for the operator to ground the excavator s bucket, apply the safety lever and switch the engine off. Only approach once the operator has indicated it is safe to do so. If in doubt, stay out of a machine s working area. Things to remember For operators Power down and turn off engine when anyone approaches the excavator Remove the keys when the excavator is left unattended Only release the Dead Man s Handle when fully in control of the excavator Consider that your clothing may get in the way of controls For all of us Be aware of your actions when beckoning others Don t walk, stand, park or drive within the radius of excavators (zones 1 and 2) Make eye contact with the excavator operator before entering any zone Always follow these standard rules around excavator