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, Advanced Wreck, or Extended Range.

COURSE OBJECTIVES

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 150 fsw / 45 msw 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.

QUALIFICATIONS OF GRADUATES

A. 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 area of activities approximate those of training
3. Environmental conditions approximate those of training

B. 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

WHO MAY TEACH

Any active TDI Decompression Procedures, Extended Range, or Trimix Instructor may teach this course.

STUDENT - INSTRUCTOR RATIO
A. Classroom
Unlimited, so long as adequate facility, supplies and additional time are provided to insure comprehensive and complete training.

B. Open water
A maximum of four students per active TDI Instructor are allowed. The ratio should be reduced as required due to environmental or operational
constraints.

STUDENT PRE-REQUISITES

A. Minimum age 18
B. Minimum certification of diver
C. Minimum of 25 open water dives, or the equivalent at the discretion of the
instructor, in the environment in which the course is being presented

REQUIRED COURSE MINIMUMS

A. The recommended number of classroom / briefing hours is 6
B. Open water Dives 4 decompression dives with a minimum accumulated bottom time of 100 minutes

REQUIRED EQUIPMENT

The following equipment is required for each student

A. Primary Cylinder(s)
Cylinder volume appropriate for planned dive and student gas consumption.

B. Decompression Mix Cylinder(s)
1. Cylinder volume appropriate for the planned dive and student gas consumption with submersible pressure gauge
2. Labeled in accordance with TDI Standards
C. Depth gauge and automatic bottom timer and I or dive computer

D. Regulator(s)
1. Primary and alternate 2nd stage required on all primary cylinders
2. Submersible pressure gauges are required on all primary cylinders

E. Buoyancy Compensator(s) adequate for equipment configuration

F. Jon-line and other rigging lines as dictated by site conditions

G. Ascent Reel with Lift Bag /Surface Marker Buoy
1. Adequate for maximum planned depth
2. Minimum of 50 lb lift bag

H. Exposure Suit adequate for the open water environment
I. Underwater Slate

REQUIRED SUBJECT AREAS

The following topics must be covered during this course. The TDI Decompression Procedures Manual is mandatory, but instructors may use any additional text or materials that they feel help present these topics.

A. Overview of decompression “safety stops” compared to required stops

B. Physics
1. Pressure review

C. Physiology
1. Mechanics of bubble formation

2. Advantages of hyperoxic mixes for decompression

3. Nitrogen Absorption and Elimination

4. Carbon Dioxide Toxicity

5. Ascent / Descent rates

6. Hyperthermia

7. Hypothermia

8. Psychological aspects
a. Task loading
b. Stress
c. Panic
d. Time Management
e. Equipment

D. Decompression Options
1. Air
2. Nitrox
3. Oxygen

E. Equipment Considerations
1. Twin cylinder or single cylinder option, valve options
2. Stage cylinder options
3. Regulator Options
4. Harness / BC options
5. Computer, depth gauge, bottom timer options
6. Ascent and navigation reels
7. Lift bags/surface marker buoys for drifting or free decompression
8. Jon-line or Garvin clips
9. Proper weighting and buoyancy control during dive phase and decompression

F. Dive Tables vs. Computers
1. Introduction and review of different models (Buhlmann, DCIEM, US Navy, etc)
2. Proper use of electronic multi-level dive computers for dive planning and decompression
a. Mix adjustable
b. 02 integrated

G. Dive Planning
1. Standard Operation
a. Gas requirements
b. Oxygen limitations
c. Nitrogen limitations
2. Emergency planning
a. Omitted decompression
b. Decompression sickness
c. Equipment failure

H. Procedures
1. Primary and Decompression Gas
a. Normal operations
b. Failure, loss or inadequate emergency procedures
c. Analysis and logging
d. Safeguards on decompression supply regulators
e. Rigging and deployment of decompression gear
2. Descent
a. Methods of entry, down lines or free decent
b. Organization of equipment carried on diver
3. Ascent
a. Variable rates
b. Trim and compensation
4. Fixed or Drifting Decompression Methods
a. Up-lines fixed to bottom
b. Reels and lift bags/surface marker buoys
c. Free drifting stages or boat supplied.
d. Self-contained versus surface supply / rendezvous gas cylinders
5. Support
a. From shore
b. From descent line or fixed platform
c. From live-aboard boat

REQUIRED OPEN WATER SKILLS

The following open water skills must be completed by the student during open water dives.

A. Demonstrate adequate pre-dive planning
1. Limits based on personal and team gas consumption
2. Exact dive and decompression profile

B. Properly execute the planned dive within all pre-determined limits
1. Assembly of diver carried equipment
2. Proper descent / ascent rates
3. Proper staged stop procedures
4. Monitoring of decompression status equipment (tables, computers, equipment)

C. Contingency Situations & Problem Solving (as appropriate by instructor)
1. Omitted decompression
2. Extended bottom time profiles with increased decompression and re-calculated schedules.
3. Failure to deploy lift bag and reel
4. Missed up-line or missed boat anchor
5. Loss of decompression gas

D. A safety stop of at least three minutes shall be conducted on all No-Decompression dives and proper staged decompression stops whenever and wherever mandated

E. Demonstrate the correct deployment of a lift bag using a dive reel and / or up-line

F. Demonstrate (simulated) emergency gas sharing at a stationary depth not to exceed 100 fsw /30 msw

G. Demonstrate emergency deployment of a backup regulator or bail-out scuba system containing bottom mix at a depth not exceeding 100 fsw / 30 msw

H. Demonstrate the proper deployment, management and use of the bottom
mix, decompression mix and travel mix (if used), including but not limited to:
1. Conservative gas management
2. Depth control to avoid descending too deep for mix.
3. Show appropriate and timely responses to instruction / signals from the instructor and demonstrate buoyancy control and awareness throughout the dive

GRADUATION REQUIREMENTS

In order to complete this course, students must
A. Satisfactorily complete the TDI Decompression Procedures Course written examination

B. Complete all open water requirements safely and efficiently

C. Demonstrate mature, sound judgment concerning dive planning and execution

SUPPORT MATERIALS
A. TDI Student Record Folder
B. TDI Decompression Procedures Student Manual
C. TDI Decompression Procedures PowerPoint