DCIEM Decompression Algorithm
DOC. 10055-DraftA (2021-07-21)
3
DCIEM Decompression Algorithm
P1
P2
P3
P4
Pa
Controlling
Controlling
Compartment 1
Ambient
Compartment 2 Compartment 3 Compartment 4
What is DCIEM?
The DCIEM 1983 decompression model is a serial, 4 compartment decompression model
used by many naval, governmental, commercial, and scientific divers around the world.
In the DCIEM model, only the first tissue compartment is exposed to ambient pressure.
Tissue tension diffuses into each adjacent tissue compartment, and critical supersaturation
ratios in the first two compartments control decompression requirements.
Caution
This document is not a complete reference or a substitute for professional
training. Read your dive computer’s operating instructions prior to use and
never dive beyond your training.
What you don’t know can hurt you.
The DCIEM model was developed by the Canadian Defense and Civil Institute of
Environmental Medicine, now renamed Defense and Research Development Canada
(DRDC Toronto). The model has been extensively tested with working divers in cold
water using Doppler ultrasonic bubble monitoring. While the model was not designed to
be bubble-free, it is comparatively well validated and considered by many experts to be
safer than other decompression models.
Shearwater has worked closely with DRDC Toronto to ensure our DCIEM algorithm
implementation is true to their model. We would like to give credit and thanks to DRDC
for their work on developing the DCIEM decompression model but note that they are not
responsible for our implementation of the algorithm.
For more information about the DCIEM model and its rigorous validation we recommend
the book “
Deeper Into Diving, 2nd edition”
by John Lippmann & Dr. Simon Mitchell.