3. ADVERTENCIAS DE SEGURIDAD
3.3 Normas de empleo
Some cranes are suitable for sub-sea lifting, however not all. The crane manufacturer must be contacted for written conformation of suitability of sub-sea lifting before the crane is used.
14.18.3.1
Load Charts
Sub-sea capacity charts must be posted in the operators cabin and the rated capacity indicator must be programmed for sub-sea duties.
14.18.3.2
Crane Maintenance
The crane maintenance during sub-sea operations will be inline with the crane manufacturers recommendations.
14.18.3.3
Rope Maintenance
Spin resistant multistrand ropes have a characteristic of developing large numbers of internal wire breaks, long before external signs of deterioration become apparent. This characteristic becomes even more pronounced when the rope is frequently immersed or sprayed with sea water, as this leads to severe internal fretting wear.
1. All sheaves and guide rollers in contact with the moving rope must be given regular visual checks for surface wear, and lubricated to make sure that they run freely. This operation must be carried out at appropriate intervals (generally not exceeding more than one week during sub sea operations).
2. The rope must be maintained in a well lubricated condition using appropriate marine grade rope lubricants (as recommended by the rope manufacturer). The maintenance of internal lubricant is especially important for multistrand ropes, due to the way they are constructed.
3. A surface dressing must be applied at appropriate intervals from the winch drum to the hook, commensurate with the depth to which the hook is to be deployed during sub-sea lifting operations. Application of the surface dressing maybe by whatever application method is convenient.
4. In order to make sure that the inner layers of the rope remain well lubricated, use an effective pressure lubricator, an effective lubricator is one that will not only convey fresh lubricant to the core of the rope but will also displace trapped water. This generally requires high pressure application of a heavy grade of lubricant, from the winch drum to the hook, commensurate with the depth to which the hook will be deployed. This shall be carried out at intervals not exceeding six months. The lubricant must be an appropriate heavy marine grade, as recommended by the manufacturer of the lubricator, and approved by the rope manufacturer.
14.18.3.4 Crane Inspection
The routine crane inspection during sub-sea lifting operations will be inline with the crane manufacturers recommendations.
14.18.3.5 Rope Inspection
During sub-sea lifting operations all accessible rope and associated equipment shall be checked visually each day. Particular attention to the end termination and the part of the rope entering the end termination.
A visual inspection of the rope, from the winch drum to the hook commensurate with the depth to which the hook will be deployed, must be carried out at weekly intervals during sub-sea lifting operations. At the same time, because multistrand rope tend to suffer internal damage, local reductions in diameter or lay distortions shall be treated with the utmost suspicion as they are likely to indicate serious internal degradation. Any anomalies shall be reported immediately and lifting operations stopped.
At intervals not exceeding 12 months, the rope shall be replaced.
When a rope is not in service, corrosion can take place, particularly within the rope where sea water may have been trapped by any external dressing. This means it is necessary to subject the rope to appropriate inspection and tests, before putting it back into service.
For crane ropes not in use, when the period of non-use exceeds one month, the wire rope and termination shall be subjected to external visual inspection to identify any corrosion or damage over the entire length of rope, including the end termination.
14.18.3.6 Crane/Rope records
Full records shall be kept for the crane involved in sub-sea lifting operations. This crane record, shall be part of the records of the crane’s planned maintenance programme, the records shall contain details of all daily, weekly inspections and maintenance carried out on the crane.
Full records shall be kept for each rope involved in sub-sea lifting operations, from its first installation to discard. The records shall contain the following information:-
1. At installation, details of the installed rope must include: a. date, length installed and name of rope manufacturer; b. minimum breaking load and certificated test strength; c. diameter, construction, wire grade and surface treatment; 2. Confirmation of daily and weekly inspections.
3. A record of lubrication (date, lubricant used and application method). 4. A record of inspections, maintenance and testing, needs to include:
a. results of six monthly inspection; b. details of any length removed; c. details of the NDT, if applicable;
d. details of pressure lubrication, if applicable; e. details of re-termination;
f. results of the functional tests.
14.19 Mobile Crane Operations
Only crane operators who have been adequately trained, and has adequate experience and fully complies with the competency requirements of the Lifting Equipment Management Manual (LEMM) appendix 1.
14.19.1 Documents
The following documents must be present on mobile cranes: 1. Crane manual.
2. The current certificate of examination.
3. The safe working load charts in English or Bahasa Malay. 4. Crane operators daily inspection log book.
5. Registration document.
6. The current certificate of examination for all lifting equipment belonging to the crane. 7. Mill certificates for all ropes fitted to the crane.
8. MPI reports of the Hooks / Hook blocks.
14.19.2 Load Charts
Where the crane has numerous load charts (e.g. for different boom and fly jib configurations), the charts must be kept in a book, folder or envelope in the operator’s cabin. Lifting must not take place unless the load charts are in the crane cabin. Although the crane’s load capacity indictor system may appear to be operating correctly, the load charts must be available to verify that the crane is not being overloaded.
The lifting capacities specified on a load chart must never be exceeded, except during testing of the crane by the third party surveyor under controlled conditions.
The lifting capacity of a crane is limited by:
a. structural strength when the working radius is small; and b. stability when the working radius is greater.
The load charts on most cranes have a bold line or shaded area dividing the chart into two segments. The divided segments show the crane operator, which capacities are, limited by structural strength, and which are limited by stability. Ratings above the bold line are based on structural strength, while the ratings below the bold line are based on the stability of the crane. If a crane is overloaded in the structural area of the load chart, a structural or mechanical component of the crane may fail. However, if the crane is overloaded in the stability area of the load chart, the crane may overturn.
On some mobile cranes, there maybe numerous load charts for differing boom and counterweight configurations. The load charts maybe complex and include numerous conditions that must be complied with to ensure the crane can safely lift a load. Two important factors that are often overlooked when reading load charts are:
a. The need to subtract the mass of the hook block and lifting slings from the gross capacity of the crane at the particular radius, unless otherwise noted on the load chart. For example, if the load chart states the crane can lift 20 tonnes at a given radius, but the hook and lifting gear have a combined mass of one tonne, the load to be lifted cannot be greater than 19 tonnes. This issue becomes critical for heavier hook blocks and lifting gear (e.g. spreader beams).
b. The need to subtract the mass of the fly jib from the capacity of the main hook when lifting from the main hook on the main boom with a fly jib attached to the boom head, unless this is allowed for and noted on the load chart. Capacities of the main boom are generally based on the fly jib being removed.
If this issue is ignored, the likelihood of the crane overturning can be very high.
14.19.3 Sitting of Cranes
1. The ground or foundation, temporary supporting structures, packing or anchor points must be of sufficient strength and stability for the maximum loading to be imposed. 2. Settlement and deflection of ground support or structures must also be taken into
account.
3. Cranes must not be sited on soft or waterlogged ground unless adequate precautions have been taken to provide support to each wheel/outrigger.
4. Dynamic loads, which might arise during operations must be estimated and calculations must include a 25% margin to allow for unpredictable effects.
5. Mobile crane shall not be used during wind conditions above 15 m/s or above the crane supplier’s recommendations, whichever is the lower. A wind anemometer shall be fitted to the boom tip alternatively a hand-held anemometer can be used in the area of the lift. 6. Sitting of cranes on sloping ground must be avoided. Where necessary the crane shall be
levelled using outriggers or other means to give a level and stable working platform. 7. Mobile cranes must be positioned so that the risk of injury from collision with other plant
is minimised. This issue is particularly important where mobile cranes are set up on public roads. Another way to minimise the risk of injury from collision with other mobile plant and vehicles is to increase the visibility of mobile cranes. One way to increase the visibility of a crane is to permanently mark the crane’s outriggers with high visibility hazard striping (i.e. ‘zebra striping’). The outrigger beams and/or hydraulic cylinders shall be marked with the hazard striping.
The striping must:
a. Be at an angle 30-60 degrees to the horizontal; b. Be 40-150 mm wide; and
c. Consist of two contrasting colours, black and yellow.
8. For cranes sited in flowing water careful investigation must be made of any potential for scouring effect. Constant checks must be made during operations to monitor the situation. The possibility of cranes being trapped by rising water must not be overlooked and cranes must be moved to safe positions as necessary.
9. Checks must be made to ensure that cranes are not sited above or adjacent to excavations or inadequately compacted ground, which shall be liable to subside.
10. Particular care must be taken when cranes are sited in the proximity of hazards including other cranes.
11. Prior to the commencement of any lifting operations, the temporary closure of roads and access required for crane operations must be notified to all parties likely to be affected by the closures.
12. Cranes must not be operated unless all personnel including third parties and members of the public are cleared from the radius of the crane’s boom and loads with a safety margin of 5 metres. The barriers maybe made from red/white marking tape.
13. The operation of any crane within 15 metres height or reach from the nearest point of contact (typically the boom, jib or cab) with live overhead electric cables or conductors is strictly prohibited.
14. Mobile cranes must not be operated where the operating radius of the boom overlaps with that of another crane unless:
a. There is a clear over-riding business requirement and
b. There is no alternative sitting or equipment that can be used and
c. The operators and banksmen of both cranes are supervised by a single supervisor in accordance with the written lift plan.
15. Where there is a danger of any part of the crane fouling any overhead or nearby obstruction e.g. bridges, gantries, pipe work, scaffolding, buildings or walls, the operator must work only under the direction of a banksman so positioned as to have a clear view of the crane and the obstruction.
16. Adequate clearance must be allowed between any part of a crane and the nearest obstruction to prevent contact with, and/or the trapping of personnel when the crane is slewed.
17. Where it is not possible to allow such a clearance, no access must be allowed whilst lifting operations are in progress.
14.19.4 Preparation
1. Preparations for lifting operations must be in accordance with manufacturers recommendations and the lift plan.
2. Load indicators, overload cut-outs, limit switches and all other safety devices must be function tested before operation of a crane.
3. Visual load/radius indicators and rated capacity indicators must be checked after assembly, boom length change or any other factor, which might affect correct and safe operation.
4. Outriggers must be fully extended properly supported and if required by manufacturers pinned in position.
5. Jacks and outriggers must be correctly fitted with feet to provide a firm base for the crane. Prior to operations, the crane must be jacked in accordance with manufacturer's recommendations.
6. Counterweights of the correct weight must be correctly fitted prior to operation. Additional counter-weighting must be fitted as necessary to suit load requirements and any boom or jib extension.
7. On wheeled cranes with pneumatic tyres particular care must be taken to ensure tyres are inflated to correct pressures as recommended by the crane manufacturers.
8. Ensure that a pennant (stinger) of a minimum length of 2 metres and fitted with a swivel scissor action self latching type hook, with trigger release handle is used, except for heavy lifts. (see fig 16A)