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Containerised deck decompression chambers

James Fisher Marine Services is an industry leader in the design and manufacture of bespoke deck decompression chambers.

James Fisher Marine Services manufactures all deck decompression chambers (DDC) that comply with International Marine Contractors Association (IMCA) and Lloyd's Register, or DNV GL standards. Deck decompression chambers are available in a range of diameters and configured in different layouts, typically at least two compartments, two person systems, and range from an internal diameter of 1.4m up to 2.0m.


  • In-built gas supplies (smaller footprints)
  • Integrated dive controls (a dive spread in one 20′ container)
  • Silenced, three-phase electric high output compressors
  • Diesel back-up compressor and generator as standard
  • Recordable video and communications
  • Video of operator and occupants transmitted to dive control

Entry lock

The entry lock is used for the transfer under pressure of personnel or large equipment into the main chamber when at depth. It has a built-in breathing-system (BIBS) for the therapeutic oxygen treatment of two occupants at one time. Full communications with the operator, both electrical and sound powered phone for the event of a power loss, hyperbaric lighting and oxygen percentage analysis equipment as well as a hyperbaric fire extinguisher plus seating for two occupants.

Main lock

The main lock has a CO2 scrubber, heating mats, lighting, a medical lock for the transfer of provisions and medical supplies, beds with hyperbaric bedding, a full decompression medical kit and hyperbaric fire extinguishers.

Containerised decompression chambers

Containerised deck decompression chamber packages can be supplied in various sizes, combinations and finishes to suit any application on request. Offshore packages are in containers built to BS.EN.12079 or DVN 2.7.1 specifications. All units can be fitted out with insulation, heating, cooling and dual function packages as required.

Containerised deck decompression chambers (DDCs) specifications:

JF Subsea's decompression chamber typical specifications

1.8 Twin lock chamber:

The chamber is a twin lock decompression chamber, designed to PD 5500 standards, which is built under survey and has design approval by Lloyd's Register of Shipping.

  Technical specifications
Design code PD 5500: 2009 category 1
Design pressure 6 barg
Hydrostatic test pressure 8.3 barg
Design temperature -10° to +38°
Corrosion allowance 1mm
Main lock volume 7.2m
Entry lock volume 3.07m³


General specifications
3 x view ports
Control panel supplied with quality gauges and valves, either partition wall mounted or chamber mounted
JF Subsea medical lock with stainless steel door and pressure interlock safety system (external only)
Entry lock seat
2 x bunk beds
5 x overboard dump BIBS masks (3 x main lock and 2 x entry lock)
2 x sets of BIBS oxygen distribution inlet and dump valves and manifolds
2 x sets of BIBS treatment mix inlet and dump valves and manifolds
Hyperbaric fire extinguisher
Emergency gas scrubber
Chamber observation CCTV system
Externally mounted chamber heating system (heater mat type)
2 diver Amcom communications radio
Sound powered emergency communications telephone system
Oxygen and carbon dioxide analysers
Removable floor plates
Set of system control valve (all pressure hull gas services valved internally and externally)

20' x 9' containerised deck decompression chamber package

DDC containers can fabricated to suit any application.

  Technical specifications
Survey authority Det Norske Veritas
Certification body DNV 2.7.1
Design code BS.EN.12079:2006 - parts 1 & 2
Design temperature -20°C
Container tested in accordance with DNV 2.7.1 requirements
Supplied with lifting set in accordance with BS.EN.13414-1: 2003
1 x set container double doors
3 x personnel doors
Paint to offshore specification


General specifications
Partition wall or chamber mounted controls available
BA escape set for chamber operator
Insulated and boarded out
Air conditioning system
Fire extinguishers
Storage drawers and lockers
3 phase power supply entering container via application inlet plug
All mains power supplies run internally via trunking
2 x high frequency strip lights with maintained emergency backup facility
1 x 7 kva multi taped switchable transformer
2 x eternally mounted earth bosses