BSAC’s Accelerated Decompression Procedures (ADP) course is a great way to extend your nitrox diving skills, by learning to use oxygen-rich mixes to improve the efficiency of decompression. It encourages you to make informed choices about your diving.

It is a stand-alone course that also complements the Twin-set Diver course.

Using oxygen-rich decompression gases has changed the way I dive and has enhanced my overall diving experience. I can now extend my dive times knowing that I can do accelerated decompression stops more safely.

- Simon Fitt-Stirling, Mid Herts Divers

Accelerated Decompression Procedures (ADP) introduces a qualified nitrox diver to the use of oxygen-rich decompression mixes to achieve optimum off-gassing at deco stops, and promotes self-reliance within buddy diving.

To enrol on the Accelerated Decompression Procedures Diver course you must have already successfully completed a BSAC Sport Diver course with a 35m depth certification and nitrox training (or have equivalent certification from another recognised training agency). You also need to have successfully demonstrated buoyancy and trim to Gold standard (+ 0.5 m).

You should also have 20 or more logged dives as a Sports Diver, including depth experience to 30m.

You will learn to plan and conduct dives using nitrox mixes with up to 80 per cent oxygen as a deco gas, using a stage cylinder, and you will practise the skills needed to become a more self-reliant diver.

You will develop your knowledge of accelerated decompression diving, including:

  • Diving physics and physiology
  • Kit configuration to achieve redundancy and self-reliance
  • Using the BSAC Ox-stop tables
  • Practical stage-cylinder diving techniques, including regulator switching, and run-time management
  • Dive profile planning for more adventurous diving, including gas selection and run-time schedules

The Accelerated Decompression Procedures course includes four theory sessions, a dry practical session, and a dive-planning session. It also includes a sheltered-water lesson, and two open-water dives with a total duration of no less than 60 minutes (to a maximum depth of 35m or within your qualification), to ensure that you have plenty of in-water time to practise the skills and discipline needed for accelerated decompression diving.

This is a continually assessed course during which students must reach the required performance standards.

An Accelerated Decompression Procedures diver is competent to plan and conduct open-circuit dives with mandatory decompression using back gas of up to 36 per cent nitrox on BSAC tables, or 50 per cent nitrox using a multi-mix programmable dive computer, and deco gases of up to 80 per cent nitrox, to accelerate decompression, within the depth limits of their diver certification.

An Advanced Twin-set Diver is defined as a qualified Sports Diver who has successfully completed Twin-set Diver and Accelerated Decompression Procedures. They can plan and conduct dives to an extended maximum depth as defined by the current maximum air or nitrox depth limit recommended by BSAC, currently 40m, using breathing gases that they are certified for.

You could do this course at a regional event or local club. Not all clubs run ADP courses, so please check if you are interested.

Alternatively, book your place on a scheduled ADP course online now.

Not a BSAC member? You can do this course by joining BSAC directly or joining via a local club. Find a club.

Students will be given a pack of supporting learning materials. You will need full open-water dive kit suitable for local conditions with either a single or a twin-cylinder configuration and an oxygen-clean deco gas (stage) cylinder with a minimum capacity of three litres and dedicated oxygen-clean regulator. You will also need additional redundant buoyancy provision – such as a drysuit and BC, or a double-bladder BC – and an appropriate configuration of long second-stage hoses.

Your next steps – developing your skills

After completing Accelerated Decompression Procedures and consolidating your skills, your options for diving significantly expand.



Not yet a BSAC member?

You can do this course by joining BSAC directly or joining your local club.

If you need a hand send your postcode to and we'll help you find the right scuba club for you. Or if you fancy a chat call us 0151 350 6226 (Mon - Fri, 9 - 5:30).

Website by NetXtra