Decompression Procedures
Introduction
This course examines the theory, methods and procedures of planned stage decompression diving. This program is designed as a stand-alone course or it may be taught in conjunction with such TDI courses as Advanced Nitrox Course, Advanced Wreck Course, or Extended Range Course. The objective of this course is to train divers how to plan and conduct a standard staged decompression dive not exceeding a maximum depth of forty five (45) msw / one hundred fifty (150) fsw unless taught in conjunction with the Extended Range Course. The most common equipment requirements, gear set-up, and decompression techniques are presented. Students are permitted to utilize Enriched Air Nitrox mixes or oxygen for decompression provided the gas mix is within their current certification level.
Student Pre-Requisites
The student must:
1. Be a minimum age of eighteen (18).
2. Have a minimum certification of Open Water Diver.
3. Show proof of twenty five (25) logged open water dives.Execution and Structure
Open Water Execution:
1. Four (4) dives are required.
2. If Advanced Nitrox is taught in conjunction with Decompression Procedures only a total of six (6) dives are required.
3. Only two (2) dives from Advanced Wreck course may be credited towards the total dives required.
Course Structure:
1. TDI allows instructors to structure courses according to the number of students participating and their skill level.
Duration:
1. The minimum number of classroom and briefing hours is six (6).Required Equipment
The following are required for this course:
1. TDI Decompression Procedures Student Manual.
2. TDI Decompression Procedures PowerPoint.
The following equipment is required for each student:
1. Primary Cylinder(s). Cylinder volume appropriate for planned dive and student gas consumption.
2. Decompression Mix Cylinder(s)
A. Cylinder volume appropriate for the planned dive and student gas consumption with submersible pressure gauge.
B. Labeled in accordance with TDI Standards.
3. Depth gauge and automatic bottom timer and I or dive computer.
4. Regulator(s)
A. Primary and alternate 2nd stage required on all primary cylinders.
B. Submersible pressure gauges are required on all primary cylinders.
5. Buoyancy Compensator(s) adequate for equipment configuration.
6. Jon-line and other rigging lines as dictated by site conditions.
7. Ascent Reel with Lift Bag /Surface Marker Buoy.
A. Adequate for maximum planned depth.
B. Minimum of eleven (11) kg / twenty five (25) lb lift bag.
8. Oxygen Analyzer (may be supplied by the Instructor).
9. Exposure Suit adequate for the open water environment.
10. Underwater Slate.
Required Skill Performance
The following open water skills must be completed by the student during open water dives:
1. Demonstrate adequate pre-dive planning
A. Limits based on personal and team gas consumption.
B. Exact dive and decompression profile.
2. Properly execute the planned dive within all pre-determined limits
A. Assembly of diver carried equipment.
B. Proper descent / ascent rates.
C. Proper staged stop procedures.
D. Monitoring of decompression status equipment (tables, computers, equipment).
3. Contingency Situations and Problem Solving (as appropriate by instructor)
A. Omitted decompression.
B. Extended bottom time profiles with increased decompression and re-calculated schedules.
C. Failure to deploy lift bag and reel.
D. Missed up-line or missed boat anchor.
E. Loss of decompression gas.
4. A safety stop of at least three (3) minutes shall be conducted on all No-Decompression dives and proper staged decompression stops whenever and wherever mandated.
5. Demonstrate the correct deployment of a lift bag using a dive reel and / or up-line.
6. Demonstrate (simulated) emergency gas sharing at a stationary depth not to exceed thirty (30) msw / one hundred (100) fsw.
7. Demonstrate emergency deployment of a backup regulator or bail-out scuba system containing bottom mix at a depth not exceeding thirty (30) msw / one hundred (100) fsw.
8. Demonstrate the proper deployment, management and use of the bottom mix, decompression mix and travel mix (if used), including but not limited to:
A. Conservative gas management.
B. Depth control to avoid descending too deep for mix.
C. Show appropriate and timely responses to instruction / signals from the instructor and demonstrate buoyancy control and awareness throughout the dive.
In order to complete this course, students must:
1. Satisfactorily complete the TDI Decompression Procedures Course written examination.
2. Complete all open water requirements safely and efficiently.
3. Demonstrate mature, sound judgment concerning dive planning and execution.
Required Subject Areas:
The TDI Decompression Procedures Manual is mandatory for use during this course but instructors may use any additional text or materials that they feel help present these topics. The following topics must be covered during this course:
1. Overview of decompression “safety stops” compared to required stops.
2. Physics
A. Pressure review.
3. Physiology
A. Mechanics of bubble formation.
B. Advantages of hyperoxic mixes for decompression.
C. Nitrogen Absorption and Elimination.
D. Carbon Dioxide Toxicity.
E. Ascent / Descent rates.
F. Hypothermia.
G. Hypothermia.
H. Psychological aspects
I. Task loading.
II. Stress.
III. Panic.
IV. Time Management.
V. Equipment.
4. Decompression Options
A. Air.
B. Nitrox.
C. Oxygen.
5. Equipment Considerations
A. Twin cylinder or single cylinder option, valve options.
B. Stage cylinder options.
C. Regulator Options.
D. Harness / BC options.
E. Computer, depth gauge, bottom timer options.
F. Ascent and navigation reels.
G. Lift bags/surface marker buoys for drifting or free decompression.
H. Jon-line or Garvin clips.
I. Proper weighting and buoyancy control during dive phase and decompression.
6. Dive Tables vs. Computers
A. Introduction and review of different models (Buhlmann, DCIEM, US Navy, etc).
B. Proper use of electronic multi-level dive computers for dive planning and decompression
I. Mix adjustable.
II. 02 integrated.
7. Dive Planning
A. Standard Operation
I. Gas requirements.
II. Oxygen limitations.
III. Nitrogen limitations.
B. Emergency planning
I. Omitted decompression.
II. Decompression sickness.
III. Equipment failure.
8. Procedures
A. Primary and Decompression Gas
I. Normal operations.
II. Failure, loss or inadequate emergency procedures.
III. Analysis and logging.
IV. Safeguards on decompression supply regulators.
V. Rigging and deployment of decompression gear.
B. Descent
I. Methods of entry, down lines or free decent.
II. Organization of equipment carried on diver.
C. Ascent
I. Variable rates.
II. Trim and compensation.
D. Fixed or Drifting Decompression Methods
I. Up-lines fixed to bottom.
II. Reels and lift bags/surface marker buoys.
III. Free drifting stages or boat supplied.
IV. Self-contained versus surface supply / rendezvous gas cylinders.
E. Support
I. From shore.
II. From descent line or fixed platform.
III. From live-aboard boat.
Graduation Requirements:
In order to complete this course, students must:
A. Satisfactorily complete the Decompression Producers written examination.
B. Complete all open water requirements safely and efficiently.
C. Demonstrate mature, sound judgement concerning dive planning and execution.
Qualifications of Graduates:Upon successful completion of this course, graduates may engage in decompression diving activities without direct supervision so long as:
1. The diving activities approximate those of training.
2. The areas of activities approximate those of training.
3. Environmental conditions approximate those of training.
Upon successful completion of this course, graduates are qualified to enroll in:
1. TDI Advanced Nitrox Course.
2. TDI Extended Range Course.
3. TDI Advanced Wreck Course.
4. TDI Entry Level Trimix.For more information please call 1-888-588-3483 or email us at fun2dive@earthlink.net
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