Section
2 Submersible Handling Systems
2.1 Introduction
2.1.1 Diver Handling Systems include any weight handling systems that are used
to launch and recover divers through the air/sea interface from a support ship,
diving vessel, or diving support installation. Inspection and load testing
requirements apply to diver handling operations and should not be used for general
crane applications. Diver Handling Systems may consist of a simple block and tackle
arrangement, using a davit and capstan to raise and lower a diver stage, or may
consist of a complex A-frame system that is used to launch and recover manned
tethered underwater vehicles, such as the pressurized diving bell or untethered
submersible unit.
- This section contains certification parameters for handling systems employed
in the launch and recovery of manned Diving Systems from support ships. The
methods of design and fabrication are discussed, and their required
verification scope is identified. Preventive maintenance documentation,
which is influenced by, and evolved from the basic design concepts as well
as operational documentation, is also outlined.
- Diving System handling equipment to be certified under these requirements
includes, but is not limited cranes, booms, davits, and A -frames; plus
their associated winching and rigging components. Hydraulic, electrical, and
pneumatic subsystems are also considered part of the handling system.
- All critical items, as defined in Pt 5, Ch 7, 2.2 Definitions, shall be included in the Scope of Certificate
(SOC). The SOC will also contain all items necessary to ensure compliance
with the objective and intent of certification.
- Weight handling components are typically included within the SOC for the
Diving System. When the weight handling system is portable, it must be
included within the SOC for each diving system it will be used to
support.
2.2 Definitions
2.2.1 Added Mass Effect. The mass of water particles surrounding an
object immersed in water that is accelerated with the object as the object is
accelerated through the water. When a body is accelerated in a fluid, it behaves as
though its mass is greater than it actually is due to the effect of the surrounding
fluid. This additional mass must be added to the actual body mass to account for the
change in inertia.
2.2.2 Critical Item. Any item within a system, equipment, or component
whose failure would endanger the occupants of the Diving System. These failures may
include uncontrolled dropping, shifting, or other sudden movement of the Diving
System when it is supported by the handling system.
2.2.3 Design Load. The maximum force due to the rated load plus some or
all of the following: (1) added mass effects, (2) entrained water, (3) any external
payloads, (4) drag or wind loads, and (5) dynamic loads which are derived with the
aid of the dynamic load factor.
2.2.4 Diving Ship. Any platform used to transport, launch, and retrieve
a Diving System. Ships, boats, vessels, barges, and submarines are included in this
definition. An example of a submarine support platform is one modified to carry a
Dry Deck Shelter for operations with Swimmer Delivery Vehicles.
2.2.5 Dynamic Load. The load imposed on a system due to accelerations of
gravity and ship motion. It is dependent upon the magnitude and frequency of ship
motions, ship attitude, and the location of the handling system on the ship. The
design load for the facility shall be calculated on the basis of maximum static and
dynamic loads, which may be expected under specified maximum operational limits. The
design load shall be at least twice the maximum static load.
2.2.6 Dynamic Load Factor. A calculated number given in acceleration
units, g, where g is the acceleration of gravity. The force exerted by the system on
its supports is determined by multiplying the dynamic load factor by the weight of
the system.
2.2.7 Fail-safe. Components within the handling system that are designed
to prevent uncontrolled dropping, shifting, or sudden movement of the Diving System
during a hydraulic or electrical system failure or component/equipment
malfunction.
2.2.8 Handling System. The mechanical, electrical, structural equipment
and rigging used on board a support ship to launch and recover divers or a manned
Diving System.
2.2.9 Load Bearing. Those components of the handling system that support
the loads resulting from launching and recovering of a manned Diving System.
2.2.10 Load Controlling. Those components of the handling system that
position, restrain, or control the movement of a manned Diving System. Towing is
excluded from the SOC.
2.2.11 Operational Load. The maximum weight that will be lifted during
diver handling operations. This is normally the weight of the stage plus the weight
of fully dressed divers at 150 kg each.
2.2.12 Safe Working Load (SWL) or Rated Load. The maximum weight that may
be lifted by the assembled handling system at its rated speed and under parameters
specified in the equipment specifications (e.g., hydraulic pressures, electrical
current, electrical voltages, etc.).
2.2.13 Rigging. Running rigging consists of the rope (wire rope or
synthetic line) and end fittings intended to handle the Diving System that passes
over sheaves or through rollers. Standing rigging is rope that is stationary and
provides mechanical support to the handling system.
2.2.17 SWL Test Load. A weight equal to SWL of the handling system.
Following the overload tests the handling system is to be operated with its SWL over
complete operating cycle to demonstrate the effective operation of the system, the
accuracy of overload and safe load indicators and the effectiveness of limit
switches, etc.
2.3 Equipment Design Criteria
2.3.1 This section provides guidelines and criteria for the design and analysis
of Diver Handling System components and associated structures designed and
constructed in accordance with these Rules.
2.4 Types of Loads
2.4.1 The initial step in designing any handling system is to determine the
design load that the system will encounter. The design load is derived from a
combination of forces under worst-case operating conditions. Components should be
sized according to the greatest design load, or combination of loadings that will be
encountered. The following loads and forces should be considered when designing
Diver Handling Systems:
- Asymmetric loads. When sizing structural members for handling systems that
employ more than one load carrying member to support their payload,
consideration should be given to factors which might cause asymmetric
loading. Such factors affecting the Diving System that would result in
asymmetric loading include, but are not limited to, the following: external
water, free surface effects in the internal tanks, a shift in ballast, and
external payloads.
- Dynamic loads. In addition to the load generated by lifting the normal rated
capacity of the handling system, dynamic forces due to wave induced motions
on the support vessel must also be considered.
- Dead loads. The dead loads consists of the masses of the structural parts of
the Diver Handling System and materials permanently attached to the
structure accelerated due to natural gravity and vessel motions in
operational and stowage conditions.
- Wind Forces. The wind loads on the projected area of the handling system
structure and on the Diving System, appropriate to the design conditions,
are to be considered.
2.5 Environmental Considerations
2.5.1 Diver Handling Systems are subjected to extremely harsh and marine
environmental factors that significantly impact the operational and maintenance
characteristics of the system. Environmental factors which should be considered in
the system design parameters are sea state, air temperature, water temperature,
precipitation (rain and snow), ice, wind velocity, currents, and the corrosive
effects of the salt water environment.
2.5.2 For the operational sea state specified, the uppermost value for the wave
heights of the significant wave or the 10th highest wave should be taken as the
design wave. The period of maximum energy of the sea spectrum should be chosen as
the design period.
2.5.3 The maximum and minimum design operating temperatures of both the air and
water must be taken into account during handling system design. This is particularly
important for hydraulic systems where hydraulic fluid may become too viscous in
extreme cold or lose its lubricating properties in extreme heat. Additionally,
extremely cold air temperatures may affect the ductility of some metals and render
structural members unsafe if not adequately designed.
2.5.4 The effect of rain, snow, sleet and ice can be dramatic on topside
equipment not designed for it. Electrical connectors, junction boxes and motors that
are not rated for harsh outside environments often fail in shipboard service. All
pivoting or sliding load bearing surfaces should either be sealed from the weather
or be designed to permit thorough inspections and be provided with an adequate
number of lubrication fittings. Waterproof grease is required for these
applications. Also, steels must have a protective coating of paint designed for a
salt air environment.
2.5.5 Side loads may be induced in the handling system by high winds. This
loading may be significant if either the Diving System or the handling system itself
has a large surface area. The prudent designer will account for possible wind
related effects in the system design.
2.5.6 In the same manner that wind affects the handling system topside, ocean currents
affect any submerged components of the Diving System. Drag effects caused by ocean
currents may be significant depending on the geometry of the Diving System and/or
any submerged portions of the handling system. Drag effects must be taken into
account in the design of the handling system.
2.5.7 Each component should be carefully reviewed for its susceptibility to corrosion, with
special attention given to those components immersed in salt water. Furthermore,
care should be taken to avoid galvanic corrosion when several different kinds of
metals are in physical contact. Galvanic series charts or tables should be consulted
when utilizing dissimilar metals.
2.6 System Considerations
2.6.1 The operation of the handling system is an integral part of the total
Diving System, and as such, is limited by the coordination of personnel on deck and
interface of the Diving System, handling system, and support vessel. For safe and
efficient launch and recovery evolutions, the following items must be considered
when developing a Diver Handling System:
- Positive Control. The motion of the Diving System during launch and recovery
operations must be under positive control at all times.
- Fail-Safe. A provision designed to automatically stop or safely control any
motion when a hydraulic or electrical failure occurs. The Diver Handling
System shall be provided with interlocks, safety devices, and protective
devices so that it will be fail-safe.
- Motion effects. The physical location of the handling system on board the
diving ship should be such that the effects of the ship's motions on the
Diving System during handling evolutions are minimized.
- Weight. The weight of the Diver Handling System should be minimized to limit
the weight added to the support vessel and the adverse effects on its sea
keeping ability.
- Shock mitigation. Dynamic motions of the support ship at-sea can cause shock
loads to the Diving System and its personnel through the handling system.
Motion compensating devices shall be considered to minimize these shock
loads.
2.7 Human Engineering and Operational Design Considerations
2.7.1 Diver Handling Systems are designed to transport personnel in a
restricted and hazardous environment under the direct supervision and control of
support personnel. A human engineering evaluation should be conducted to ensure the
ability of support personnel to control and supervise the safe and coordinated
movement of the Diving System. The following are some critical areas that should be
addressed in the evaluation:
- Hazardous exposure. Due to the nature of handling system
operations, some operations will be inherently hazardous. However, hazards
should be eliminated whenever possible. There should be a minimum of support
personnel exposed to hazards.
- There should be no diver/swimmer involvement during launch and
recovery of the Diving System.
- Coordination and control. Safe and timely operation of handling
systems requires precise control and coordination of all personnel involved.
The system arrangement should facilitate simplicity and require minimal
supervision to attain this goal.
- Communication. In addition, there must be clear communications
between Diving System handling support personnel, the support ship personnel
responsible for manoeuvring the ship and the Diving Supervisor.
- Monitoring equipment status. Control and support personnel
responsible for the operation of the handling system should have access to
monitoring devices to enable them to evaluate the status of the equipment.
This is to ensure the system is operating within its capability limits
(e.g., speed, load, pressure, temperature, etc.). These factors, along with
the observed sea state, can then be evaluated to determine their effect on
the operating parameters of the Diving System.
- Manning. Minimizing the number of personnel required to operate
and maintain the system should be considered.
2.8 Emergency Conditions and Reduced Operating Capability
2.8.1 The Diver Handling System shall be designed to minimize the effects of
component failures. An FMEA is to be conducted to determine and resolve them. The
FMEA can also be used to evaluate the system's capability to continue to operate and
safely recover Diving System personnel. All handling system components shall be
operable in sea states specified by the mission profile. In the event of a control
console failure, an alternate or backup means of system operation is required.
2.8.2 The handling system for diving bell shall include means of safe guidance
of the bell through the surface of the water, such as a moon-pool cursor or a bell
cursor tower system.
2.8.3 The handling facility shall be secured against uncontrolled pay-out as a
result of technical failure of the system. This normally implies that the facility
should be equipped with automatically applied mechanical breaking devices providing
primary and secondary protection. Furthermore the facility shall be equipped with
limit switches preventing the handling of the bell / wet bell / basket / ADS outside
the handling area.
2.9 Load Bearing Component Design
2.9.1 Design analyses must indicate forces, loads, shears, and moments for all
structural members, welds, and connections including interaction forces with the
supporting deck and ropes. Components shall be analysed considering tensile,
compressive, bending, shear, and torsional loadings. Structural members shall be
evaluated in accordance with requirements of Code for Lifting Appliances in a Marine Environment, July 2022 or equivalent structural codes. (Note when using equivalent
structural codes: the allowable stresses and safety factors used therein shall be
revised as required to meet the safety factors specified in Code for Lifting Appliances in a Marine Environment, July 2022
Ch 4, 2.17 Allowable stress – Elastic failure). Analyses for rigging gear must also be
included in the design documentation.
2.9.2 Calculations shall take into account the wet and dry weight of the Diving
System, entrained water weight, added mass effects (if applicable), crew and payload
weights, the dynamic affects due to the motion of the support ship and Diving System
at sea, and the effects of the wind forces. The support ship's motions shall be
analysed for the maximum operating sea conditions, sea state or swells specified in
the requirements documentation. The worst-case loading due to heave, roll, pitch, or
any combination thereof, shall be used in the calculations.
2.9.3 In addition to operating conditions, the Diving System is to be designed
to withstand the most severe combination of motions which can occur during transit
when the system is stowed on a vessel. In case of occurring the effects of green sea
loading on the structure should be considered
2.10 Design Factors of Safety
2.10.1 Factors of safety for Diver Handling Systems are based on LR Code for Lifting Appliances in a Marine Environment, July 2022, and are related to the material used and the operating
environment conditions. Relatively high safety factors are necessary, even though
the materials and their properties are well known, because they are used in
uncertain environments and are subjected to uncertain stresses. Material certificate
will be required in accordance with the Rules for the Manufacture, Testing and Certification of Materials, July 2022.
- Structural and machinery components
- For launch and recovery systems, the stress factors (F)
for all structural and machinery components shall be according to
Table 4.2.6 Stress factor, F
of Code for Lifting Appliances in a Marine Environment, July 2022.
- For underwater applications, the factor of safety shall
be 3 on material yield or 5 on material ultimate tensile strength;
whichever is greater. The above factors of safety shall be based on
the design load.
- Rigging and Fittings
- Factors of safety for wire and synthetic rope are given
in Table 7.2.1 Factors of Safety for Rigging. These factors
shall be based on the design load of the Diver Handling System and
the specified nominal breaking strength for wire rope or average
breaking strength for synthetic rope.
- If galvanized wire rope is used, reduce the nominal
breaking strength by 10 per cent to account for the effects of
galvanizing.
Note If
drawn galvanized wire is used, no reduction in breaking strength
is necessary.
- Rope break test. Each rope is to have a certificate of
break indicating the load at which the test sample broke.
2.10.2 When used with wire or synthetic rope, the factor of safety for fittings
shall be equal to or greater than the commercial rating for the Diving System design
load. The main lifting wire shall be calculated using a safety factor of at least
8.0 related to the maximum safe working load.
Table 7.2.1 Factors of Safety for Rigging
| Material
Application
|
Critical
Component
|
Noncritical
component
|
D/d
Ratio1
|
| Wire
rope standing rigging
|
5
|
5
|
-
|
| Wire rope running rigging
|
5
|
6
|
18:1
|
| Rotation
resistant wire rope
|
|
|
|
| -Standard construction
|
72
|
6
|
34:1
|
| -Formed
through a die
|
6
|
5
|
18:1
|
| Synthetic rope3
|
|
|
|
|
|
- Braided
|
7
|
5
|
8:1
|
|
|
-Twisted/Plaited
|
7
|
5
|
10:1
|
|
|
- Aramid
(Kevlar)
|
6
|
5
|
20:1
|
Note 1. Ratio of sheave or drum diameter (D) to wire rope or synthetic line diameter
(d).
Note 2. This factor of safety is used for rotation resistant wire rope supporting a
free hanging load. If a guideline system is used that does not allow the load to
rotate, this factor of safety can be reduced to 6. Under no circumstances shall the
factor of safety for ropes be less than 6 for manned lift systems.
Note 3. When wet, the safety factor for nylon rope shall be applied to the breaking
strength minus 15 per cent unless a suitable marine overlay finish is used.
2.11 Design and Testing Requirements
2.11.3 Design analyses for Diver Handling Systems must be based on LR Code for Lifting Appliances in a Marine Environment, July 2022 and on recognized engineering analytical methods and standards.
Loads imposed by the environmental conditions specified in the requirements
documentation must be included in the analyses. The design of all load bearing and
load controlling elements must be within the Scope of Certificate of diving
equipment.
2.11.4 All elements of the handling system that support the weight of the Diving System when
occupied by personnel shall be designed, fabricated, and maintained in accordance
with the following requirements:
2.11.5 All new Diver Handling Systems must be tested prior to initial
certification and operational use. In addition, all modified or extensively repaired
handling systems shall be inspected and tested as required in Pt 5, Ch 7, 2.11 Design and Testing Requirements 2.11.11. These tests are intended to confirm the adequacy
of the design, the operational characteristics, and the validity of the operating
procedures. For modified or repaired systems, the purpose of these tests is to
verify the adequacy of the work performed, and to ensure the handling system
continues to meet its design and certification criteria.
2.11.6 All Diver Handling Systems shall have static, dynamic, and rated load
tests conducted on the following occasions: after being installed on a diving ship,
upon completion of an overhaul, and at intervals not to exceed 5 years. In addition,
a static load test, dynamic load test, rated load test, and/or no -load test shall
be accomplished, as required, after repair or replacement of system components in
accordance with Pt 5, Ch 7, 2.11 Design and Testing Requirements 2.11.12.
2.11.7 The main handling facility shall be operable even if essential components such as a
power source or a winch motor is out of action.
2.11.8 An alternative handling system shall be provided and shall comprise a dedicated
system ready for immediate use, with the capability to bring the device back to the
surface and into position to be connected to the chamber complex in the event of the
main handling facility being out of action.
2.11.9 The alternative handling system shall comply with the same requirements for load
strength as the main handling system.
2.11.10 Guide wire equipment may, in addition to functioning as an alternative handling
facility, ensure a controlled movement of the device in the water and may also
provide an arrangement for stopping the device in the event of failure in the
primary lifting wire.
2.11.11 Test procedures for all load tests and System Operational Tests shall be submitted to
LR for review and approval.
2.11.12 The following paragraphs identify the requirements for conducting static, dynamic,
operational and rated load (SWL) tests. In addition, maintenance testing
requirements after completing maintenance tasks are also addressed.
- No Load Test. No load tests are conducted to evaluate the functioning of the
Diver Handling System. The Diver Handling System shall be operated through
its full range of motions and directions. Check for unusual noise,
vibration, or overheating in machinery and control components. Also check
for proper operation of all indicator lights and gages.
- Static Load Test. A static load test physically verifies the structural
integrity of the fully assembled Diver Handling System. Test loads may be
applied with certified test weights or by mechanical devices with calibrated
load measuring gages.
- The static test load shall be held for a minimum of ten
minutes by the brake without power to the system. (See
Controlled Work Package for testing procedures) No evidence of
structural or rigging component deformation is allowed.
- Upon completion of the static load test, the critical load bearing
components and strength welds of the handling system shall be
inspected to verify there is no permanent set, deformation,
cracking, or other damage to any part of the structure, foundations,
machinery, and reeving components. For initial certification, or if
load bearing component repair or modification work was accomplished,
the level of inspection shall be as specified on the drawings or in
separate specifications to include MT or PT as applicable.
- End fittings on ropes included in the test shall be inspected for
slippage and damage.
- Verify the system will hold the static load for one minute without
power to the system.
- The static load test shall be conducted when the support ship is
pier-side and experiencing no significant motion. The handling
system shall be tested in the position of maximum loading.
- Dynamic Load Test. A dynamic load test demonstrates the capability of the
Diver Handling System brakes.
- The dynamic load test shall be stopped at least three times in each
direction to ensure proper brake operation. No speed is specified;
however, the maximum speed attainable with the test load shall be
used.
- During the dynamic load test, the handling system brakes shall be
checked for any signs of binding, abnormal noise or vibration, and
overheating. As a minimum, the following equipment parameters shall
be recorded during the test: motor amperage, hydraulic fluid
temperatures and pressures (including main loop, servo, and
replenishing pressures), and operating speeds. In general, the
following shall be verified and noted: smooth operation, and proper
stopping and holding of the test weight.
- Upon completion of the dynamic load test, the handling system shall
be inspected for any indications of the following: warping or
permanent deformation; leaking hydraulic fluid from any component or
connections; wear patterns on sheaves, ropes, and gear trains; and
proper drum spooling.
- The dynamic load test shall be conducted when the support ship is
pier side and experiencing no significant motion.
- Operational Load Test. An operational load test demonstrates the capability
of the Diver Handling System to operate under the dynamic conditions of the
support ship's motions at sea. The test shall demonstrate the handling
system's overload capabilities and the adequacy of fail-safe components
throughout its complete operating range. Care must be taken to ensure
specific operating limits of the components being tested are not
exceeded.
- Test loads shall be moved through one complete cycle of the handling
system, with all limits of its operating modes (raising, lowering,
traversing, travelling, rotating, etc.) included in the test. The
handling system, with the test load, shall be stopped at least three
times in each direction to ensure proper brake operation.
- During the operational load test, the handling system shall be
checked for any signs of binding, abnormal noise or vibration, and
overheating. As a minimum, the following equipment parameters shall
be recorded during the test: motor amperage, hydraulic fluid
temperatures and pressures (including main loop, servo, and
replenishing pressures), operating speeds for all modes of
operations (i.e., booming out, booming in, and/or raising and
lowering, etc.). In general, the following shall be verified and
noted: smooth operation, and proper stopping and holding of the test
weight.
- Upon completion of the operational load test, the handling system
shall be inspected for any indications of the following: warping or
permanent deformation; leaking hydraulic fluid from any component or
connections; wear patterns on sheaves, ropes, and gear trains; and
proper drum spooling.
- The operational load test shall be conducted when the support ship
is pier side and experiencing no significant motion.
- Rated Load (SWL) Test. A rated load test demonstrates the capability of the
Diver Handling System to operate with its intended load at its rated speed.
It also verifies that all hydraulic and electrical components operate within
their specified operating limits. Test loads shall be moved completely
through the handling system's full operating range, and within limits of all
operating modes (raising, lowering, traversing, travelling, rotating, etc.).
The system shall be capable of hoisting the Diving System at the system's
rated speed when the hoist wire rope or synthetic line is on the outermost
layer of the drum. The test load shall be run through at least three cycles
to demonstrate proper operation. Each cycle is to be run at the specified
normal operational speed of the handling system.
- Maintenance Testing Requirements. Conducting the full range of
load tests (i.e., static, dynamic, and rated load tests) is not always
necessary after completing corrective maintenance actions or some repair
tasks. Table 7.2.2 Maintenance Testing Requirements – Load Bearing Components identifies the tests
required after performing various tasks on structural, rigging, or machinery
components. Some handling systems have unique components and may require
additional or modified testing. The test documents for those tests shall be
submitted to LR for review and approval on a case basis. The system
drawings/specifications should be consulted for further testing
requirements. The tests specified in Table 7.2.2 Maintenance Testing Requirements – Load Bearing Components and the applicable tests
specified by a drawing or specification shall be conducted for each
maintenance task identified. If there is a conflict between the tests
specified in Table 7.2.2 Maintenance Testing Requirements – Load Bearing Components and the test specified by
the applicable drawing or specification, then the requirements of this
document take precedence, unless specifically authorized by LR.
- After each installation on board, the handling system is to be tested with
the static test load. In addition, a dynamic load test (braking test) is to
be carried out as well.
- A test is to be performed to ensure that the mating, release, transfer,
lowering and raising of the diving bell proceed smoothly and safely under
normal and emergency operating conditions.
- A test is to be performed to verify that the mating device can be released
and the diving bell transported only when the trunk is not under
pressure.
- A functional test is to be performed to demonstrate that the hyperbaric
evacuation system is able to convey divers under pressure from the ship or
floating structure to a safe position where they can be monitored and
supplied.
Table 7.2.2 Maintenance Testing Requirements – Load Bearing Components
| Maintenance
Task
|
Test
Requirements
|
| 1. Drum or sheave repair,
replacement, or modification
|
Static load
test1
|
|
|
Dynamic load
test
|
|
|
Rated load test
|
| 2. Hook2 repair,
replacement, or modification
|
Static load test
|
| 3. Main lift rope(s)
replacement (wire rope or synthetic line)
|
Pell
test3
|
|
|
No-load test
|
| 4. Coupling , shaft, or
bearing repair or replacement
|
Dynamic load
test
|
|
|
Rated load test
|
| 5.Non-load bearing
shafts or bearing repair or replacement
|
No-load test
|
| 6. Gear repair and
replacement (load bearing or load controlling only)
|
Static load
test1
|
|
|
Dynamic load
test
|
|
|
Rated load test
|
| 7. Gear bearing oil-seal
replacement
|
No-load test
|
| 8. Hydraulic cylinder
repair and replacement (when the cylinder is used to support the
weight of the Deep Submerged Vehicle, as in the case of an
A-frame and elevator)
|
Static load
test1
|
|
|
Dynamic load
test
|
|
|
Rated load test
|
Note 1. Only the repaired, replaced, or modified component needs to be statically load
tested. If the affected component can be rigged such that the test load can be
applied to it only, then that test would suffice for the static load test.
Note 2. "Hook" in this document is a generic term for the interface device between the
Diving System and the handling system.
Note 3. All wire rope end fitting installations must be pull-tested to the static test
load of the handling system, or to 40 per cent of the nominal breaking strength of
the wire rope. All synthetic line eye splices shall be proof tested to the static
test load of the handling system.
2.12 Hydraulic and Pneumatic System Requirements
2.13 System Design
2.13.1 Hydraulic and pneumatic systems and components shall be designed to
operate the rated load at the rated speed when the differential pressure across the
actuator is not more than two-thirds of the maximum operating pressure. This will
ensure the handling system will operate efficiently under dynamic conditions at sea
as well as when undergoing load testing.
2.13.2 Hydraulic and pneumatic systems and components shall be designed such
that they are fail-safe and the brake on any winches, cranes, or elevators shall set
and stop motion if there is a loss of power.
2.13.3 Additionally, the following requirements shall also be met:
- The maximum operating pressure shall not exceed pump or
compressor and motor manufacturer's continuous ratings.
- Pump or compressor drive electric motor current shall not
exceed nameplate rating at the design load.
2.13.4 In the case of cross hauling, such equipment shall fulfil the same
requirements for strength as the rest of the handling system.
2.13.5 Umbilical shall be handled by a system compatible with the system
handling the diving bell. Bell and guide-wire winches used for dry transfer into a
habitat shall include a heave compensation / constant tension system.
2.13.6 Records shall be maintained of umbilical and wire cut-backs,
re-termination, end-for-ending and replacements.
2.13.7 Where direct visual monitoring of the winch drums from the winch control
station is not practical, TV monitoring shall be fitted.
2.13.8 Primary and emergency lighting in all critical handling areas shall be
provided.
2.13.9 As a minimum, the following documents shall be submitted for review and
approval:
- Design analyses and calculations that provide the basis for the system
design, including all assumptions governing the design. The analyses must
include the following when results of computer calculations are submitted:
input data, summaries of input and program assumptions, output data, and
summaries of conclusions drawn from the output data.
- Plan showing manufacturer’s ratings, braking capabilities and power drive
requirements for hydraulic equipment.
- Plan showing details on emergency source of power.
- Hydraulic schematic that shows:
- Relief valve settings.
- Material specifications, size, and pressure ratings of all pipe
fittings, valves, flexible hoses, pumps, filters, and
accumulators.
- Testing and cleaning requirements.
- Drawings and design calculations, or a Certificate of Compliance (COC) from
the manufacturer is required for each hydraulic or pneumatic cylinder to
identify its burst pressure.
- Testing procedures.
2.14 Relief and Counter-Balance Valves
2.14.1 Relief valves and counter-balance valves require special attention and
shall meet the requirements of this section. The safety of Diving System personnel
depend on the proper operation of these valves. Relief valves are used in motion
compensation circuits as well as for protecting the hydraulic system from over
pressurization. Counter-balance valves are used to stop the Diving System from
moving uncontrollably in the event of a sudden loss of system pressure.
2.14.2 The following shall be accomplished for all new relief valves and
counter-balance valves, and existing relief and counterbalance valves that have been
subjected to repairs, modifications or corrosion that would affect the structural
integrity of the valve. Prior to system operational use, they shall be:
- Cleaned,
- Seat tightness tested, and
- Have their cracking pressure verified.
Note Seat tightness testing and cracking pressure verification may be
accomplished after installation while the system is being adjusted.
2.14.3 The duration of seat tightness tests conducted in a shop or on a test
bench shall be not less than 5 minutes.
2.14.4 The duration of seat tightness tests conducted in the as-installed
configuration shall be based on the time necessary for the minimum leakage to be
detected at the point of observation or monitoring.
2.14.5 Acceptance criteria for seat tightness testing shall be zero leakage or
that allowed in the manufacturer's specifications or approved test documents.
2.14.6 The seat tightness test shall be conducted at a pressure equal to the
maximum allowable working pressure.
2.14.7 System fluid is the preferred test medium for seat tightness testing.
2.14.8 Cracking pressures shall be verified in accordance with system drawings
or manufacturer's specifications. The actual cracking pressure and date verified
shall be etched or stamped on a metal or plastic tag and affixed to the
component.
2.14.9 Operating characteristics of relief valves and counter-balance valves
shall be verified by either test bench methods or when adjusting the system during
installation or maintenance.
2.15 Construction
2.15.1 The handling system must be provided with suitable means for preventing
any excessive rotating of the diving bell (e.g. nonspin rope).
2.15.2 The use of fibre ropes is permitted only in special cases with the prior
consent of LR.
2.15.3 Precautions are to be taken to prevent the diving bell from jarring
against the ship’s hull or handling gear.
2.15.4 All interchangeable components such as blocks, hooks, shackles,
masterlinks, etc. are to conform to recognised standards and must be selected with
the FS=5 as a minimum factor of safety to ultimate load based on SWL, or the FS=3.33
as a minimum factor of safety to ultimate load based on design load, whichever
results in higher required ultimate load.
2.15.5 The driving power of the handling system must be sufficient to lift the
static test load specified in these rules. The strength of the mechanical brake must
be sufficient to hold the dynamic test load specified in these rules.
2.15.6 Before assembly all interchangeable components are to be subjected to
individual component load testing.
2.15.7 The rupture strength of ropes is to be verified by a full tensile
breaking test.
2.16 Plans, Documents and Calculations
2.16.1 Design stress analysis, based on recognized engineering analytical
methods and including environmental conditions, load plans indicating loads, shears,
moments and forces for all rope members, strength welds, and connections including
interaction forces with the supporting deck are to be submitted. (When the results
of computer calculations are submitted, input data, summaries of input and program
assumptions, output data, and summaries of conclusions drawn from the output data
are to be included as part of the design analysis). In addition, the following
analyses are to be submitted as applicable to the particular design features:
- Foundation stress analysis;
- Electric load and electric fault analysis including power source and power
requirements;
- Standard wiring practice and details, including such items as cables, wires,
conduit sizes and their support, cable splicing, watertight and explosion
proof connections;
- Strain gage measurements may be required for novel designs or in association
with acceptance of computer data.
2.16.2 As a minimum, the following documentation shall be submitted:
- Design analyses and calculations that provide the basis for the system
design, including all assumptions governing the design. The analyses must
include the following when results of computer calculations are submitted:
input data, summaries of input and program assumptions, output data, and
summaries of conclusions drawn from the output data.
- General arrangements showing equipment locations and the rated capacity of
the system.
- Details showing sizes, sections, and locations of all structural
members.
- Details of all reeving components showing sizes, safe working loads,
materials, manufacturer, and part number. For synthetic rope: length, size,
material, construction, average breaking strength, manufacturer, and
specification (if applicable). For wire rope: length, size, construction,
preformed or non-preformed, lay, finish, grade (IPS, EIPS, or traction
steel), core type, lubrication, and manufacturer.
- Foundation and support arrangements.
- Structural material specifications.
- Drawings must show all welding proposed for the principal parts of the
structure. The welding process, filler metal, and joint design are to be
shown on detail drawings or in separate specifications.
- The areas to be non-destructively inspected and methods of inspection are to
be shown on the drawings, or in separate specifications.
- NDT methods;
- Winch drum details.
- Type and size of bolts.
- Reeving diagram.
- Testing requirements and procedures.
- List of all materials and fittings, for all components. p) A description of
the system with details of operating conditions
- Installation drawings.
- Construction drawings of:
- Transferable equipment,
- Lifting equipment,
- Mating equipment,
- Substructure of handling gear, including winches.
- Detailed drawings of interchangeable components and fittings.
- Drawings of mechanical equipment items such a winches, drives etc.
- Piping and instrumentation diagrams of the hydraulic or pneumatic system as
applicable.
- Control system diagrams and descriptions of safety equipment.
- Details of ratings and protection class of equipment.
- Details of hoisting and guide ropes.
- General arrangements showing equipment locations, indicating safe working
loads for each system component and rated capacity for the system;
- Material specifications;
- Dimensioned weld joint details;
- Type and size of rivets, bolts, and foundations;
- Foundation and support arrangements;
- Hydraulic piping systems, materials, sizes, details of fittings, and valves
and overpressure protective devices;
- Electrical systems, cable, and wiring types and sizes, nominal
characteristics and overcurrent protection settings of all electrical
protections;
- Rope sizes and data indicating material, construction, quality, and breaking
strength;
- Manufacturer’s ratings, braking capabilities, and power drive requirements
for electrical, hydraulic, and mechanical equipment;
- Details of emergency source of power;
- A schematic or logic diagram giving the sequence of handling
operations;
- Operating procedures;
- Procedures for operating normal and emergency electric, pneumatic and
hydraulic power supplies;
- List of degrees of enclosure of all electrical components;
- List of materials, fittings, contacts and support for all components;
- Electric feeder list;
- Motors and battery characteristics.
- Operation check-off list (to include list of equipment requiring maintenance
or inspection prior to each operation and verification of the existence of
appropriately updated maintenance;
- System description;
- Electrical system description;
- Hydraulic system description;
- Pneumatic system description;
- Sea state capabilities;
- Maximum dynamic loads;
- Handling operating procedures;
- Liaison with support vessel;
- Emergency procedures developed from system analysis for situations such as
power failure, break in lifting cable, break in umbilical cord, loss of
communication, etc.;
- Special restrictions based on uniqueness of design and operating
conditions.
|