제  목 : Bell run and bell lock-out times, and bell run times
  일  자 : 1998년 09월
  제공처 : Internet

 Bell run and bell lock-out times, and bell run times in relation to habitats
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    CONTENTS

    ㅇ Introduction
    ㅇ General
    ㅇ Two-man bells
    ㅇ Three-man bells
    ㅇ Habitats
    ㅇ Further reading

   

 1.This diving information sheet is part of a series of information sheets
 providing guidance on diving at work. It replaces the following diving safety
 memorandum: DSM 2/1992. The remaining DSMs have either been replaced by other
 diving information sheets, or will be cancelled when the Diving at Work
 Regulations come into force on 1 April 1998.

 2.This information sheet sets down clear guidance on:

    1.bell run and bell lock-out times for two and three-man diving bells; and
    2.bell run times in relation to work carried out in habitats.

 It is important to recognise that the various bell run and lock-out
 times set out in this sheet are, unless stated otherwise, to be
 regarded as maxima and will need to be reduced for very heavy work.

 3. Bell run and bell lock-out times are interpreted as follows:

    1.Bell run times The maximum bell run time is calculated from initial bell
      lock-off until the final lock-on to the diving system and the divers are
      ready to transfer. If, after the initial bell lock-off, the bell is
      returned to the system for any reason, no adjustment should be made to
      extend the bell run beyond 8 hours after the initial lock-off.
    2.Bell lock-out times Lock-out time in the water is the elapsed time from
      when the diver is totally submerged after exiting the bell until the
      diver is back in the bell.

 

 4. In order to ensure safe and efficient operations, it is important that
 diving personnel work with a time routine which allows them to develop a
 regular work and sleep pattern, and with a minimum rest period of 12 hours (ie
 not diving or carrying out pre or post-dive checks). Therefore, when bell
 diving operations are carried out around the clock, and on a continuous basis,
 they should be planned so that no diver takes part in a 6-hour lock-out
 operation or an 8-hour bell run more than once within a pre-planned 24-hour
 period.

 5.The practice of 'ratcheting', ie cycling the whole dive team in less
 than 24 hours, and then immediately recommencing the cycle to gain
 work time, should not be used.

 6.Reference is made in this information sheet to 'planned' bell run and
 lock-out times. This has deliberately been included, as diving operations
 should be organised in such a way that the time necessary to carry out certain
 tasks is assessed in advance by the project team. Diving supervisors should
 make a clear note in the diving operations record, before the operation
 starts, as to how long they feel the bell run and lock-outs will take. It will
 therefore serve as a guide to them, the divers, other members of the diving
 team, client representatives and others.

 7. When divers are involved in tiring physical work, diving supervisors must
 appreciate that it may be appropriate for them to return to the bell for a
 short rest and to take refreshment before finishing their task. They should
 only do so with the consent of the diving supervisor, but such consent should
 in most, if not all, cases be given. This applies to all diving bell
 operations. The diving supervisor must ensure that the divers are offered a
 refreshment break of at least 15 minutes within 3 hours of the initial
 lock-out. If the diver agrees to forego such a break, then a timed entry
 should be made in the diving operations record and subsequently signed by the
 diver and diving supervisor.

 

 8. The total bell run time should be planned not to exceed 8 hours. The
 lock-out time in the water of divers from a two-man bell can be flexible
 within the total bell run time, up to a maximum of 4 hours. It may exceed this
 time, under exceptional circumstances, by a further maximum period of 30
 minutes if it is necessary to complete a 'critical task', but then only with
 the agreement of the two divers and the diving supervisor. In this case their
 agreement should be recorded in the diving operations record.

 

 9.The total bell run time for a three-man bell (containing three divers)
 should be planned not to exceed 8 hours. If two divers lock-out simultaneously
 from the bell, then the lock-out shall be for a maximum of 6 hours (provided
 that the bell man remains in the bell, except in an emergency, throughout the
 bell run). They should be organised in such a way that each diver has a dry
 dive, acting as standby diver/tender in the bell every third bell run.

 10. On occasions, in advance of a bell run, a diving supervisor may judge that
 three divers will need to lock-out during the course of the dive. In this
 situation, as part of the pre-planning, the supervisor may organise lock-outs
 in the water on a flexible basis, within a maximum bell run time of 8 hours,
 so that each lock-out does not exceed 4 hours. Under exceptional
 circumstances, a 4-hour lock-out in the water may be extended by up to a
 maximum 30 minutes if it is necessary to complete a 'critical task', but then
 only with the agreement of the two divers and the diving supervisor. In this
 case their agreement should be recorded in the diving operations record.

 

 11. The work carried out in the dry in a habitat is generally concerned with
 the welding of pipes or structural members, and is very different from the
 work carried out by divers in the water.

 12. The total bell run time should be planned not to exceed 8 hours. Once in
 the habitat, the divers need to assess the work that has to be carried out,
 set it up, carry it out, and then leave the habitat in a suitable condition
 for the next team. Recent assessment of several dozen habitat dives has
 indicated that such work can usually be completed within the planned 8-hour
 bell run. However it is appreciated that practical and technical problems can
 occur, eg the requirement, for technical reasons, for root and hot pass welds
 to be completed by a diver before passing on to the next team.

 

    a.Commercial diving projects offshore. The Diving at Work Regulations 1997.
      Approved Code of Practice L103 HSE Books 1998 ISBN 0 7176 1494 8
    b.Commercial diving projects inland/inshore. The Diving at Work Regulations
      1997. Approved Code of Practice L104 HSE Books 1998 ISBN 0 7176 1495 6
    c.Recreational diving projects. The Diving at Work Regulations 1997.
      Approved Code of Practice L105 HSE Books 1998 ISBN 0 7176 1496 4
    d.Media diving projects. The Diving at Work Regulations 1997. Approved Code
      of Practice L106 HSE Books 1998 ISBN 0 7176 1497 2
    e.Scientific and archaeological diving projects. The Diving at Work
      Regulations 1997. Approved Code of Practice L107 HSE Books 1998 ISBN 0
      7176 1498 0
    f.The Diving at Work Regulations 1997 SI 1997/2776 The Stationery Office
      1997 ISBN 0 11 065170 7

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 Fax: 01787313995

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