5.4.1        Lifelines

A lifeline system shall:

The above are recommended minimum requirements. The HIRA should determine if a higher strength lifeline system is needed in order to ensure the security of the diver (e.g., potential pressure differentials, strong underwater currents, underwater encumbrances, etc.), or if a larger diameter is desirable to improve handling by the surface team.

In order for the lifeline system to have a rated breaking strength of 5kN, it is necessary that all loaded components (lifeline, connecting components, and harness) be rated to at least this breaking strength.

5.4.2        Shot-lines

A shot line is a weighted line with a surface float used to guide the diver between the surface and the bottom and as a tangible reference for speed of ascent and descent. As such the weight must be sufficient to prevent the divers on the line from lifting it off the bottom and the float must have sufficient buoyancy to prevent the weight of the divers dragging it below the surface if their buoyancy control is compromised. The line must be thick enough to offer a comfortable grip to allow a diver to remain in place for decompression stops, and for the surface team to comfortably deploy and recover the shot -line. A diameter of 15 to 25mm is recommended unless there is a good reason to deviate.

Additional weight or an anchor may be desirable to prevent drift.

A shot line must be used when the diver is not lowered to the underwater working place by means of a diving bell or similar device, unless the use of a shot line is impractical.

Whenever a shot line is not used, a boat must be kept ready for rescue purposes if the possibility exists that the diver may surface away from the control point in the course of a dive. Special consideration must be given when more than one diver may surface away from the control point.

A buddy line is used for securely connecting two divers to each other during a dive.

Buddy lines must conform to the following standards:

5.4.4        Depth measuring devices

All divers must use depth measuring devices, provided that surface-supplied divers' diving depth must be measured by pneumofathometer from the surface.

5.4.5        Communications

Effective communications are essential to ensure that all personnel directly involved in operations are made fully aware of the work being undertaken and that during operations all parties are kept aware of the status of any unusual situation.

Communications between the diving team and any other relevant personnel (such as marine crew) are important to the safe and efficient operation.

5.4.5.1        Language during operations

In an emergency, personnel tend to revert to their own language. If team members do not speak the same language, this can cause an obvious hazard. The dive plan should state the language to be used during the project, and all team members will need to be able to speak to each other fluently and clearly at all times, particularly during emergencies.

5.4.5.2        Communications between supervisor and divers

The diving contractor must provide an effective means of direct, two-way communication between the divers and the diving supervisor of a diving operation. Where voice communications are required, the following shall be provided:

In addition to the primary communication system between the diver and the diving supervisor, an emergency signal system shall also be in effect.

All voice communications should be recorded, and the recording kept for a period of at least 48 hours. If an incident occurs during the dive, the communication record must be retained for any subsequent investigation. All such voice recordings must be made available to an inspector for inspection purposes.

5.4.5.3        Communications between supervisor and persons other than the divers

The diving contractor must ensure that an effective means of communication is in place between the diving supervisor and any other person that may assist in the diving operation, e.g. winch operators, crane operators, RCN supervisors, etc.

To ensure effective communication, the diving team should have access to the communications system and services of any installation or vessel on which operations are based. This includes all available media, e.g. word of mouth, reports, telephone, telex, fax, radio, etc.

Communication with the level 2 Designated Medical Practitioner may be needed in the course of a diving operation, especially in the case of an accident or other medical emergency. The diving contractor must lay down clear protocols and procedures in the operations manual in consultation with the Designated Medical Practitioner. Care should be taken to ensure that medical information is provided to the dive team when needed.

A wet diving bell (also called an "open bell is a compartment at ambient pressure by means of which the divers can be transported to and from the underwater work site, which allows the divers to access the surrounding environment and which is capable of being used as a refuge during diving operations.

A basket or wet bell, used in support of surface-supplied diving, needs to be able to carry at least two divers in an un-cramped position. It must be fitted with a chain or gate at the entry and exit point to prevent the divers falling out, and with suitable hand holds for the divers. Additional lifting points should be fitted to permit emergency recovery of the diving basket or wet bell.

Diving with closed diving bells is covered in the Offshore Code of Practice.

5.4.7        Man-riding Launch and Recovery Systems (LARS)

Because of the variety of diving systems, support locations and deployment systems, it is not possible to define every launch/recovery procedure.

A safe launch/recovery procedure must exist and it should be understood by all members of both the diving team and any other support crews. The procedure should progress in smooth, logical steps and be designed so that all personnel involved in the operation are fully aware of the situation at all times.

Particular safety standards will need to be applied when using lifting equipment to carry personnel, because serious injury may result from falling, Such handling systems should be designed with a suitable minimum safety factor on the load.

Alternative design factors may be considered if based on detailed analysis, such as computer modelling, etc.

The device used to lower the divers) into the water shall remain available throughout the dive for the immediate recovery of the diver in the event of an emergency if required.

The person responsible for giving directions to the operator in charge of the hoisting device shall be identified in the dive plan (this is usually given either by the diver, the diver's tender, or the diving supervisor). The signal to stop may be given by anyone.

All lifting equipment should be examined by a competent person before the equipment is used for the first time, after installation at another site and after any major alteration or repair. Regular examination every six months is also recommended. Any additional testing specified should be at the discretion of the competent person.

Any lifting cable or wire should be provided with a test certificate confirming its Safe Working Load (SWL). The SWL should never be exceeded during operations and should include the deployment device, the number of divers to be deployed (with all their equipment) and any components that hang from the lifting cable (including cable weight in air). The condition and integrity of the cable should be checked at six monthly intervals, or more frequently as circumstances dictate.

The lifting and lowering winch should be rated by the manufacturer for a safe working load at least equal to the weight of the deployment device plus divers in air plus any additional components. An overload test of the winch's lifting and braking capacity should be undertaken after:

Both hydraulic and pneumatic winches will need suitable braking systems, providing primary and secondary protection. They are not to be fitted with a pawl and ratchet gear in which the pawl has to be disengaged before lowering.

Particular selection criteria will need to be used for man-carrying lift wires, including wires intended for secondary or back-up lifting. These wires will need to have a suitable safety factor, be non-rotating, and be as compact as possible to minimise the space requirements of their operating winches.