Section 2 Life Support and Safety
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Construction & Classification of Submersibles & Diving Systems, July 2022 - Part 7 Hyperbaric Rescue Facilities - Chapter 1 Hyperbaric Evacuation Systems - Section 2 Life Support and Safety

Section 2 Life Support and Safety

Parent topic: Chapter 1 Hyperbaric Evacuation Systems

2.1 General

2.1.1 An additional/ emergency life support package shall be provided for connection to the hyperbaric evacuation unit (HEU). The contractor shall ensure that the equipment is properly maintained and ready for use at all times during saturation diving operations.

2.1.2 The Life Support Package (LSP) shall be kept at a suitable location from where it can reach the HEU within reasonable time. Risk analysis shall be performed for verification. Compatibility of the LSP to the HEU shall be verified.

2.1.3  Procedures for use of the LSP shall be included in the contingency plan and shall be available with the LSP and inside the HEU.

2.1.4 Relevant emergency procedures shall be available in the HEU chamber, the HEU control and with the LSP.

2.1.5 Means should be provided to maintain all the occupants in thermal balance and in a safe and breathable atmosphere throughout the environmental operational envelope for air temperature, sea temperature and humidity with the maximum and minimum number of divers likely to be carried. In determining the duration and amount of life-support necessary consideration should be given to the geographical and environmental conditions, the O2 and gas consumption and CO2 generation under such conditions, the heat input or removal and the emergency services that may be available for the decompression of the divers. Gas losses as a result of using toilet facilities which discharge to outside the hyperbaric evacuation unit and medical lock operation should be taken into account in determining the amount of gases required. The effects of hypothermia and hyperthermia should be considered and the effectiveness of the arrangements provided should be established as far as is reasonable and practicable under all conditions envisaged. However in no such case should the duration of the unit’s autonomous life-support endurance be less than 72 hours.

2.1.6 In addition to any controls and equipment fitted externally, compression chambers should be provided with adequate controls within for supplying and maintaining the appropriate breathing mixtures to the occupants, at any depth down to the maximum operating depth. The persons operating the chamber, whether they are within or outside it, should be provided with adequate controls to provide life support. As far as practicable, the controls shall be capable of operation without a diver having to release his/her safety harness.

2.1.7 Two separate distribution systems should be provided for supplying oxygen to the compression chamber. Components in the system should be suitable for oxygen service.

2.1.8 Adequate equipment should be provided and suitably situated to maintain oxygen and carbon dioxide levels and thermal balance within acceptable limits for the life support duration.

2.1.9 In addition to any instrumentation necessary to be provided outside the compression chamber suitable instrumentation should be provided within the chamber for monitoring the partial pressures of oxygen and carbon dioxide and be capable of operation for the duration of the available life-support period.

2.1.10 Where it is intended that divers may be decompressed within the hyperbaric evacuation unit, provision should be made for the necessary equipment and gases including therapeutic mixtures, to enable the decompression process to be carried out safely.

2.1.11 An adequate supply of food and water should be provided within the evacuation chamber. In determining in particular the amount of water to be provided, consideration should be given to the area of operation and the environmental conditions envisaged.

2.1.12 A breathing system should be provided with masks which exhausts to the external environment sufficient for all the occupants under pressure.

2.1.13 Provision should be made external to the hyperbaric evacuation unit and in a readily accessible place for the emergency service connections as per IMCA D-051. Any supplementary connections required by the end user should be mounted on a separate plate to the 12 emergency connectors in order to minimise any possible confusion. The connections should be clearly and permanently marked and be suitably protected.

2.1.14 In hyperbaric evacuation units designed to pass through fires the breathing gas bottles and piping systems and other essential equipment should be adequately protected. In addition thermal insulation should be non-toxic and suitable for this purpose.

2.1.15 First Aid equipment, sickness bags, paper towels, waste disposal bags and all necessary operational instructions for equipment within the compression chamber should be available within the chamber, on board the parent vessel and ashore.

2.2 Gas and Power Supplies

2.2.1 Any capsule/chamber designed for escape/rescue should be self-contained and carry sufficient provisions, fuel, breathing gas and power supplies to enable the full diving complement to exist for a minimum period of 72 hours, without outside assistance. The chamber should be mounted in and connected to a properly equipped lifeboat, which complies with the requirements of the relevant National Regulations.

2.2.2 The consumables such as fuel, gas and power supplies are to be kept fully charged whilst the complex is manned and under pressure. The power supplies should be sufficient for heating, cooling, scrubbing the atmosphere and for systems providing communication with HEU as designated in the Specification with both minimum and maximum number of persons on board.

2.2.3 All electrical equipment and installation including the power supply arrangements should be designed for the environment in which they will be required to be operated and designed to minimise the risk of electrical capacity depletion as result of fault, fire or explosion, electric shock, the emission of toxic gases and of galvanic action. Electrical equipment within the compression chamber should be designed for hyperbaric use, high humidity levels and marine application.

2.2.4 Power supplies required for the operation of life-support systems and other essential services should be sufficient for the life-support duration. The battery charging arrangements should be designed to prevent overcharging under normal or fault conditions. The battery storage compartment should be provided with means to prevent over-pressurisation and any gas released should be vented to a safe place.

2.2.5 Each compression chamber should be provided with a source of lighting sufficient for the life-support time and be of such luminosity to allow the occupants to read gauges and operate essential systems within the chamber.

2.3 Safety harness

2.3.1 For the safety of personnel a safety harness is to be provided for each person of the full diving complement.

Copyright 2022 Clasifications Register Group Limited, International Maritime Organization, International Labour Organization or Maritime and Coastguard Agency. All rights reserved. Clasifications Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as 'Clasifications Register'. Clasifications Register assumes no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant Clasifications Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.