LA ENCUESTA A JÓVENES
1. MEDIO AMBIENTE Y ESCUELA
11.4
Requirements
11.4.1 Crane Suitability
It shall be noted that mobile cranes are particularly sensitive to external influences such as environmental effects, vessel movements, and dynamic loading. There are several types of mobile cranes initially designed for land-based operations, which can be considered for lifting operations offshore. Not all, however, are equally suitable, e.g., a wheel-mounted crane, will not be suitable, because of tyre floatation effects and shorter wheelbase. It is not as stable as a tracked/crawler crane for the same duty and/or operating conditions. The suitability of a mobile crane for use on a marine vessel shall therefore be carefully appraised according to service requirements, type of marine vessel and operational requirements.
Mobile cranes require to be certified in accordance with the latest revision of BSP-72-Procedure- 012 “Procedure for Lifting Equipment Inspection and Certification” (PLIC). It shall be noted that the certification and load-testing of the mobile crane, shall include verification that tie downs, supports, ballast counterweight and load radius configuration conform to the crane manufactures or an authority experienced in crane design and stability of craft specifications. Certification and load-testing of the mobile crane must be undertaken after the crane has been mounted on the marine vessel and prior to utilisation in Brunei; the certification and load-testing of the mobile crane requires to be undertaken by a third party surveyor from a classification society and witnessed by BSP’s Technical Authority.
Subsequent certification of the mobile crane shall be at the time intervals detailed in BSP-72- Procedure-012, PLIC 002 table 2, witnessing of these certifications by BSP’s Technical Authority is not required.
11.4.2 Types of Mobile Cranes
Crane, Powered Mobile Crawler Jib Crane, Powered Mobile Wheeled Jib
Mobile cranes that feature all hydraulic power transmission, integrated control systems, enclosed gear drives and brakes are preferred opposed to mechanically driven cranes using open gear drives and open brakes/clutches.
TABLE 1 outlines in general terms, the prospective suitability of various types of mobile cranes for use on barges.
TABLE 1
Monohull
TYPE OF MOBILE CRANE & MODE OF USE Sea lifts Inboard lifts Wheel mount - free lifting/travelling on tyres NP NP
Wheel mount - free on outriggers NP NP
Wheel mount - outriggers tied-down POSS POSS
Wheel mount - fixed chassis YES YES
Crawler crane - free lifting / travelling on tracks POSS POSS
Crawler crane - tied-down YES YES
NP Not Permitted YES Preferred option
POSS Possible option, where a risk assessment has been performed that shows that the risks are as low as reasonably practicable (ALARP). Refer to Appendix 14 for BSP’s risk matrix.
The risk assessment shall be appraised by the contractor and the executing department and submitted to BSP’s Technical Authority for review.
Other factors for consideration when selecting mobile cranes for use offshore are as follows: Cranes, which operate with outriggers deployed, shall have the facility to withstand any
high pressure generated in the outrigger's hydraulic system, arising from dynamic lifting operations.
Booms shall have adequate torsional stiffness, rigidity and lateral stability for the service specified. Box section booms of the type used on ram luffing/telescoping cranes are not considered suitable.
Mobile cranes fixed, tied-down or pedestal mounted shall still be considered as mobile cranes.
Note: -
All other types of mobile cranes on marine vessels, which are not included in the classification society register of lifting gear, or are not covered by this standard, will be considered by BSP's Technical Authority on a case-by-case basis. They shall be strictly appraised in accordance with this section.
11.4.2.1
Fixed Mobile Cranes
Fixed mobile crane is a crane, which is securely fastened to a marine vessel so the crane is restrained from tipping.
Example:
1. Crane upper works mounted on a pedestal, which is securely fastened to the deck. 2. Crane upper works still mounted on the chassis, with crawlers removed, which is
securely fastened to the deck.
11.4.2.2
Deck Mounted Cranes
A deck mounted crane is a mobile crane that still has their tracks or tyres attached, but which, is anchored or restrained on a marine vessel and is subjected to tipping forces.
Example:
1. Crane with the chassis anchored with tie-downs to the deck.
2. Crane working on a timbered area of a marine vessel with travel restrained by side constraints and end stops. When not working, the crane chassis is anchored with tie- downs to the deck and the boom lowered onto a boom rest.
3. Securing arrangements must comply with vessel’s “cargo securing manual” requirements if applicable. Refer to IMO (International Maritime Organisation) cargo and securing guidelines for further information.
11.4.3 Crane Age
Mobile cranes considered for use on a marine vessel shall fully meet the lifetime time limits stated in the latest revision of BSP-72-Procedure-012 “Procedure for Lifting Equipment Inspection and Certification” (PLIC).
11.4.4 Crane Capacity
The capacity charts displayed in the operators cab shall clearly show the maximum crane list the crane can safely operate at. The charts will reflect the type of crane mounting and operating conditions i.e. static or dynamic lifting.
1. Capacity chart’s supplied for a fixed mobile crane shall be based on structural strength. 2. Capacity chart’s for a deck-mounted crane shall be based on stability (tipping).
It is preferable to have crane capacity charts based on allowable crane list supplied by the crane manufacturer.
Where this is not possible, an authority experienced in crane design and stability of craft shall provide capacity charts and the maximum amount of crane list the charts are applicable for. The capacity charts shall be confirmed and approved by the marine vessel’s Classification Society, Naval Architect or Warranty Surveyor.
The crane’s load indicator shall be recalibrated to reflect the cranes reduced capacity charts.
11.4.5 Crane Stability for Deck Mounted Cranes
The minimum stability margin for a deck-mounted crane shall be 1.33 X the safe working load. Stability testing of the deck-mounted crane shall be carried out if the crane has been de-rated from its land-based duties to achieve a stability margin of 33%.
11.4.6 Crane Inspection
The mobile crane shall be inspected, load testing and certified in accordance with the latest revision of BSP-72-Procedure-012 “Procedure for Lifting Equipment Inspection and Certification” (PLIC). The certification and load-testing of the mobile crane shall be undertaken after the crane has been mounted on the marine vessel and prior to utilisation in Brunei; this certification and load-testing of the mobile crane shall be undertaken by a third party surveyor from a classification society and witnessed by BSP’s Technical Authority.
Subsequent inspections and load tests of the mobile crane shall be at the time intervals detailed in
BSP-72-Procedure-012, PLIC 002 table 2, witnessing of these inspections and load tests by BSP’s Technical Authority is not required.
The following must be ascertained prior to inspection and load testing:
The crane’s allowable rated capacity whilst working on the marine vessel (taking account of the capacity charts obtained in accordance with 11.4.5).
The limiting weather and sea state specified in 11.5.
In conjunction with BSP-72-Procedure-012, PLIC 002 the certification of the crane shall include the following additional areas, verification that ties downs, supports, ballast counterweight and load radius configuration conform to the crane manufactures or an authority experienced in crane design and stability of craft specifications.
The rated capacity indicator has been recalibrated to reflect the crane list capacity chart displayed in crane operators cabin.
11.5
Weather Criteria and Mobile Offshore Unit (MOU) Stability
11.5.1 Weather Criteria And Mobile Offshore Unit Stability
The weather criteria and maximum MOU movement for all mobile cranes on marine vessel operations shall be as follows: -
Maximum wind speed : 20 knots steady wind measured at 10 metres above the sea.
Significant wave height : of not more than 2 metres, and a 3° roll and 2 deg pitch of the vessel. (on site conditions NOT weather forecast data)
Maximum list : as advised by the crane manufacturer or the
authority experienced in crane design and stability of craft.
The master of the marine vessel or attending marine vessel shall demonstrate that the above weather criteria are met at all times during lifting operations. The contractor shall liaise with the CSR on site who in turn, will liaise with the Marine Department of Brunei Shell Petroleum (SMR) to confirm the sea state values.
In all cases when the above sea state values are exceeded the mobile crane shall have the boom lowered onto the boom rest. Crane activities can only resume when the sea states fall below the above stated values.
11.6
Mobile Cranes Tied-Down, Free Lifting and Travelling With Load
11.6.1 Vessel deck Strength
The vessel’s Classification Society or Naval Architect shall verify that the vessel’s deck is strong enough, under all operating conditions and the cranes operating area for the use of the proposed mobile crane.
11.6.2 Mobile cranes tied-down
Mobile crane’s operating on a marine vessel, require to be tied-down or fixed at dedicated locations on the deck. The location of the tie-down points on the crane/marine vessel and, the method of fixing via welding, bolting, turnbuckles etc., shall be agreed between the marine vessel’s Classification Society or Naval Architect and the crane manufacturer/supplier. The crane supplier shall verify that the method used to fasten or restrain the crane to the deck is strong enough, under all operating conditions to prevent the crane from breaking off the deck or moving on the marine vessel.
The supplier shall provide a critical assessment of the strength and failure mode sequence of the tie-down points and of the crane’s primary load path elements including as appropriate; boom, A-frame, bedplate, car body, chassis, outriggers, hydraulic rams (luffing and outriggers), slew bearing and fasteners and all primary load carrying pins. The calculations of all forces transmitted to the marine vessel’s structure and the sequence of failure report in conjunction with the lift programme that the mobile crane is intended to be used for, shall be assessed and approved by the marine vessel’s Classification Society, Naval Architect or a BSP recognised warranty surveyor. The crane supplier shall provide copies of the approved calculations and the sequence of failure report to BSP’s Technical Authority for review.
All crane tie-down welds to be subjected to 100% volumetric and surface inspection methods prior to utilisation in Brunei. The crane tie-down welds shall be subject to 100% visual inspection every six months and 100% volumetric and surface inspection annually.
11.6.3 Mobile cranes free lifting
Because of the particularly large and random motions of monohull marine vessel’s arising from wave action, the use of mobile cranes for free lifting shall not be BSP’s preferred option.
However, where cranes are required to free lift, the crane must work on a timbered area and have travel restrained by side constraints and end stops. When not working, the crane chassis is required to be anchored with tie-downs to the deck and the boom lowered on to a boom rest. Where cranes are required to free lift, particularly when the motion of the marine vessel can cause the load to pendulum and adversely affect the stability of the crane. A risk assessment shall be performed that shows that the risks are as low as reasonably practicable (ALARP). Refer to
Appendix 14 for BSP’s risk matrix.
BSP's Technical Authority shall carefully consider free lifting on a case-by-case basis, only after approval has been granted by BSP’s Technical Authority shall work commence. The supplier shall provide a critical assessment of the cranes stability, based on the weather criteria and maximum MOU movement detailed in Para 11.5. The calculations of all forces transmitted to the marine vessel’s structure and the critical assessment, shall be assessed and approved by the marine vessel’s Classification Society, Naval Architect or a BSP recognised warranty surveyor.
The crane supplier shall provide copies of the approved calculations and the critical assessment report to BSP’s Technical Authority for review.
All crane tie-down welds to be subjected to 100% volumetric and surface inspection methods prior to utilisation in Brunei. The crane tie-down welds shall be subject to 100% visual inspection every six months and 100% volumetric and surface inspection annually.
The supplier shall ensure that the provision of any mats, bearers etc. used to spread these forces are positively and effectively secured to the deck of the marine vessel. Any mats/bearers used to carry the load across the deck of the barge shall not deviate, move, spread or cause any de-stabilising effects under any operating condition and, under any forces arising from a), b), c), d), e) and f) below.
The deck structure of the marine vessel and any mats/bearers used, shall be adequate to support all forces generated by the operation and test loading of the crane including:
a. The maximum force that would cause the crane to tip. b. Tractive forces i.e., forces to propel/travel the crane.
c. Braking forces when arresting travelling and/or slewing and, decelerating the load hoist and boom.
d. Dynamic forces including any forces arising from offleads/sideleads e. Forces generated by steering and spragging of the crane.
f. Forces induced by any motion of the barge.
11.6.4 Mobile cranes travelling with load
Because of the particularly large and random motions of monohull marine vessel’s arising from wave action, the use of mobile cranes travelling with load shall not be BSP’s preferred option. However, where cranes are required to travel with the load, they must fully meet the requirements of 11.6.3 and be shown to be ALARP. Refer to Appendix 14 for BSP’s risk matrix.
BSP's Technical Authority shall carefully consider cranes travelling with load on a case-by-case basis, only after approval has been granted by BSP’s Technical Authority shall work commence. On wheel mounted cranes, the effects of tyre floatation will add to the pendulum problem. Wheel mounted cranes shall not be considered suitable and are therefore not permitted. (refer table 1).
11.6.5 Mobile cranes used for basket transfer
11.6.6 Procedures
The contractor shall provide a procedure for the safe use of the mobile crane on the marine vessel. The procedure shall be forwarded to BSP’s Technical Authority for review and approval.
11.7
Documentation
11.7.1 Records
Records shall be maintained by the Competent Authorised Person for the crane, tie-downs and any other associated equipment, and are sufficient to enable the condition of the crane, tie-downs and associated equipment to be determined and its fitness for further operation to be properly addressed.
The records shall include the following as a minimum: -
1. Test certificates, records of thorough examinations and inspections, including ropes, carried out on the crane.
2. Copies of the crane maintenance schedules and maintenance records, NDT reports and previous certificates of inspections.
3. Copies of the manufacturer's certificate of tests stating specified and actual breaking load and the rope construction for all the ropes fitted to the crane.
4. The crane log of daily, weekly and monthly inspections.
5. Records of significant repairs and modifications to the crane including renewal of major parts and confirmation of completion including signatures of responsible persons.
6. Records of any defects, incidents, shock loadings, however they occur, dangerous occurrences reportable accidents.
7. Hours worked
It is not important in which format the records are kept. Whatever method is used shall be adequate to ensure that the records allow a relevant coherent history of the crane to be readily retrieved. The records shall be clearly identifiable with the crane to which they refer.
11.8
Periodic Checks
11.8.1 General
The Chief engineer shall ensure that the checks given in 11.8.2 to 11.8.3 have been carried out.