An atmospheric diving suit or ADS is a small one-man articulated submersible similar in shape to a suit of armor. The ADS is equipped with elaborate pressure joints to allow articulation while maintaining an internal pressure of one atmosphere.
The ADS can be used for very deep dives of up to 2300 feet (700m) for many hours, and eliminates the majority of physiological dangers associated with deep diving. There is no need for the occupant to decompress, there is no need for special gas mixtures, and there is no danger of decompression sickness or nitrogen narcosis. Divers do not even need to be skilled swimmers.
The traditional approach to offshore maintenance, construction and inspection work has been to use either ROVs or divers.
An ROV equipped with video and still cameras, water jetting and/or wire brush cleaning tools can be used for platform inspection. An ROV has the advantage of high speed in the water column, practically unlimited depth capability and the ability to make long horizontal excursions. The disadvantages of the ROV include poor access to structures, limited visual acuity, and limited spatial NDT tools and equipment for remote operation.
Divers offer the advantage of much improved access to structures, much improved visual acuity and a wide range of off the shelf hand held NDT inspection tools available. Marine growth cleaning for divers is achieved quickly and efficiently using water or grit blasting equipment. The disadvantages of diving include depth or decompression limitations, limited vertical and horizontal excursion capability, and in the case of saturation diving, very high equipment and operating costs coupled with extended decompression time.
The modern atmospheric diving systems (ADS) available today in many ways combine the advantages of ROVs and divers. The ADS is capable of using a range of hand-held diver tools with little or no modifications. Marine growth cleaning is done in the same way as with divers using high pressure, surface supplied, water jets. Decompression considerations are eliminated and horizontal excursion capability is comparable to that of an ROV and vertical excursion is unlimited.
The Atmospheric Diving System (ADS) training course is intended to train pilots in the safe operation and maintenance of the ADS and to provide a sufficient amount of experience and knowledge to qualify the pilot to undertake field operations.
The program provides a safe and supervised environment where pilots can be directed and corrected in technique and understanding. The duration of the course allows students to identify individual constraints in operating the suit and develop personalized corrective action. During the course structures and framework will be added to simulate the real working environment. In a training course specific to a job, training will simulate the real tasks that will be encountered during operations.
AODC 022 Code of practice for the operation of manned submersible craft.
Students must have demonstrated the ability to fit within the ADS and perform all necessary movements including the following:
Student candidates that are unable to meet the above criteria will not be allowed into the ADS pilot training program.
Theory covers top level understanding relevant to the physical operations of the ADS and the understanding of resources available to assist in ADS understanding. An extrapolation of information is conducted during the class by the instructor. All technical information can be found within the hard copy manuals which are followed during the in class modules.
During the practical dive sessions the pilot trainee is expected to perform a number of tasks that reflect situations and operations that may be encountered in the field. Pilots require approximately 20 hours to learn basic skills and become proficient with suit life support and flying functions to allow them to focus on the work tasks. Students are introduced to the tooling with emphasis on job preparation, planning, and tool modification required for use with the ADS.
Examples of typical tasks which will be completed by students are; sizing up and buoyancy set up, overall operating procedures in water exercise, emergency procedures in water exercise, flying in and around structures, giving a set of life support system readings while hovering, thru-water communications protocols and many more.
During open water dive sessions the pilot trainee is expected to perform a number of tasks that reflect situations and operations that may be encountered in the field.
Tools applicable to these tasks are provided within the course. Courses directly leading to real operations will request the actual tools to be used in the operation be present during the course. Courses may be tailored for military sub-rescue, salvage, inspection and NDT, or typical oilfield construction.
Specific training in using tooling effectively involves a significant amount of preparation. Students are introduced to the tooling with emphasis on job preparation, planning, and tool modification required for use with the ADS.
The following are examples of typical tasks which will be completed by students and tracked within the course:
All personnel will have successfully completed a training course specifying the type and extent of that training (Pilot, Supervisor, Technician). This should be signed by the Examining Supervisors. Upon completion of their training, they will have a competent working knowledge of the following subjects:
- Thermal protection
- Gas partial pressures
- Gas mixtures
- Effects of high/low oxygen, carbon dioxide, carbon monoxide on human systems
- The body’s requirements – oxygen, food and water.
- Atmospheric monitoring.
- Cleanliness in gas systems, particularly in relation to oxygen.
- Colour coding and marking of gas cylinders.
- Carbon dioxide removal.
- Material compatibility with oxygen.
- Trim – centre of gravity and centre of buoyancy.
- Payload effects.
- Stability when submerged and in emergency conditions.
- Water density, layering.
- Pressure effects.
- Ballast systems.
- Propulsion systems, thrusters.
- Control of vertical, lateral and forward movement.
- Fires and fire extinguishing methods.
- Life-support, toxic hazards.
- Loss of communications.
- Loss of power and sensors.
- Emergency communications.
- Emergency planning.
- Physical and mental effects of a prolonged period underwater when subject to sensory and thermal deprivation.
- Chain of command, liaison, handovers.
- Familiarization with codes of practice, certification requirements and relevant government regulations.
- Operational planning.
- Interface with other underwater activities/operations.
- Hull shape
- Depth rating
- Materials of construction
- Safety systems
To be familiar with the system’s equipment, all personnel should be conversant with the items listed below. Depending on job description, technicians will require more detailed knowledge than others.
- Compasses (gyro and magnetic), including compass errors.
- Depth gauge
- Currents and tides
- Velocity triangles
- Visibility and mid-water problems.
- General seamanship.
- Transponders, pingers and sonars.
- Hard wire digital system
- VHF systems
- Emergency signals
- Batteries and other relevant primary sources.
- Umbilical systems.
- Circuit protection, electrical faults and their effects.
- Fault detection and elimination.
- Emergency power sources
- Hydraulic and Pneumatic Systems
- Compensated systems
Time allocation of this course is as follows (per student):
a) Minimum 20 hours each of bottom dive time (pilot/dive).
b) Minimum 12 hours of supervisory training.
Thanks to Ian Milliner for contributing to this web page.