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| ADCI Industry Informational
Update #2009-02 |
February/2009 |
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TO: ADCI General
Membership and Industry Stakeholders
The following items of
information are provided to bring your attention to
recent industry developments, initiatives,
or safety notices. If you do not wish to
receive future Industry Updates, please use the
unsubscribe option, located at the bottom of this
update. |
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ADCI UNDERWATER EXCAVATION
OPERATIONAL GUIDELINES |
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Purpose
1. Although the ADCI does not recommend the
performance of underwater tasks below the mud line, in
select instances it is required for the accomplishment
of certain underwater operations. The purpose of
this document is to identify potential hazards and
recommend safety precautions when conducting underwater
operations below the mud line (deep ditch).
2. This recommended procedure is applicable
for all sectors of the commercial diving community, both
inland and
offshore. |
| Precautions |
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| 1. When performing a
variety of tasks, divers are often required to excavate
areas, or enter excavated areas.
2. Hand jetting and
airlifting material from the natural bottom can pose a
threat of burial.
3. Extra precautions
should be taken through the performance of pre-dive
safety assessments.
4. Variations in seabed
conditions can cause changes in stability, which might
warrant a more conservative approach to operations
than the outlined recommendations of this
document.
No standard can cover all
potentialities that might be encountered. JSA's,
common sense, and extra attention to detail, by the
entire dive team, are to be considered essential
components for approaching operations of this
nature. JSA's should be updated as workprogresses,
to reflect the current
onditions. |
| Definitions |
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Ditch: an
excavation area / trench / channel created to gain
access to the working area.
Deep Ditch: any excavation or channel which
is 6 feet or deeper from natural bottom (top of
subsurface ditch) to the bottom of the subsurface
ditch.
Natural Bottom: depth of the seabed, prior to
any
excavation. |
| Responsibility |
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| The Dive Supervisor is responsible for the
welfare and safety of the dive team. The diver is
responsible for ensuring that he is performing their
tasks in a safe and responsible manner.
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| Potential Hazards Associated
with Deep Ditch Operations |
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1. Ditch wall collapses and traps
the diver and / or his umbilical.
2. Unintentional
creation of a tunnel by the diver while hand
jetting.
3. Malfunction of
jet nozzle or other component of hand jetting
tool.
4. injury to
diver or his equipment due to jet hose or water directed
from the hand jet.
5.injury to topside
personnel due to component malfunction of hand jetting
equipment.
6. Injury to
diver or damage to his equipment due to airlift
suction.
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Recommended Ways to Mitigate Potential
Hazards Associated with Deep Ditch
Operations |
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1. Situational
awareness on the part of the diver and topside
personnel:
The diver should
always inspect the condition of the ditch wall prior to
beginning regular work.
a.
Hose management / regular
communication.
b.
Diver should routinely ensure that an adequate slope to
depth ratio established and maintained. At a
minimum, it is recommended that a 3:1 ratio be
maintained. This ratio may need to be increased,
due to the instability of the bottom's
composition. For every foot excavated downward,
three feet need to be excavated in an outward
direction. Feet / meters are recommended as a
determining factor versus angle (%), as it is easier to
determine the volume of soil requiring displacement /
removal, and calculating the time to accomplish this
task.
2. Periodic and
regular physical checks need to be made by the diver on
his exact location. The diver should periodically
remove himself from the ditch and return to natural
bottom to assess any potential hazards to him, his
umbilical, or hand jet
equipment.
There are no guarantees that
equipment malfunctions will not occur during the course
of operations. Yet, routine pre-dive and post-dive
checks of all equipment and systems are the best ways to
guard against malfunction.
3. The
diver should always ensure that he is capable of
handling the force of pressure being emitted from the
jet nozzle. Proper balance, footing, and
positioning of the diver is the best way to ensure that
back or frontal spray from the jet nozzle does not
injure the diver or damage his equipment.
Sending air to the diver's pneumo and
partially activating the diver's "free flow" are
other recommended practices, while conducting deep ditch
operations. |
| Minimum Personnel
Requirements for Deep Ditch
Operations |
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On all Deep Ditch
Operations, a minimum of five (5) crew members is
required, consisting of:
- One (1) Diving
Supervisor
- One (1)
Diver
- One (1) Standby
Diver
- Two (2)
Tender / Divers
The standby
diver's equipment and thermal protection shall be equal
to that of the diver.
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| Minimum Equipment Requirements
for Deep Ditch Operations |
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Redundant jetting
equipment and a greater length of jet hose shall be
present at the dive site. In addition, the
redundant jetting equipment shall be primed and running
at an idle pressure at all times that the primary system
is in use.
NOTE: Deep
Ditch Operations are considered construction work.
Helmets are the only acceptable form of head gear for
personnel working in this type of
setting. |
| Personnel
Qualifications |
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| All
members of the dive team should be trained and
experienced for the tasks to be performed. In the
case of deep ditch operations, underwater personnel
should be properly screened to ensure that they
understand the scope of work to be performed, the
potential hazards involved, and the procedures for
rescuing a trapped or injured
diver. | |
This Information was
sent to further the communication of all industry
stakeholders. Safety is the primary concern of the
ADCI. Remember: a real time Job Safety
Analysis is important, but nothing can replace good
common sense.
Sincerely,
Phil
Newsum
Association
of Diving Contractors
International
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