Section 10 Instrumentation

10.1.1 Monitoring systems for the small manned submersibles will be generally based upon individual sensory units, rather than continuous automatic analysis systems.

10.1.2 Instrumentation must be adequate for maintenance of a safe and breathable atmosphere.

10.1.3 Atmospheric monitoring instruments should have a back-up unit, but not necessarily of the same type.

10.1.4  Each manned compartment should be provided with means of testing the atmosphere therein.

10.1.5 All instruments and gauges should be capable of withstanding the pressure, temperature, vibration, shock, humidity likely to be encountered.

10.1.6 Pressure gauges should be fitted showing the pressure drop across pressure reducing valves, together with the pressure within all gas storage cylinders, or within the discharge rail where two or more cylinders are on line.

10.1.7 All connections to pressure gauges and other instrumentation should be provided with suitable isolating valves.

10.2.1 Where applicable it is recommended that an oxygen monitor with a continuous read out should be provided. Simple analysers of the chemical gas absorption type should be carried on board. See also Pt 6 Electrical Installations and Control Engineering Systems for degree of monitoring and control.

10.2.2 If the instruments are battery powered spare batteries should be carried.

10.3.1 Where applicable it is recommended that a carbon dioxide monitor with a continuous read out should be provided. Simple analysers of the chemical gas absorption type should be carried on board. See also Pt 6 Electrical Installations and Control Engineering Systems for degree of monitoring and control.

10.3.2 The response time can be several minutes since a rapid accumulation of CO2 is not envisaged.

10.4.1 These gases may be monitored by a wide band toxic contamination level indicator or simple analysers of the chemical gas absorption type. Consideration should be given to monitoring carbon monoxide when the dive operation duration exceeds a few days.

10.5.1 Tests and calibrations should be carried out on a regular basis. Care should be taken that items with a limited shelf life are in date. The procedures should be as simple as possible in order to permit quick and accurate calibration.

10.6.1 Most craft do not have sufficient power to heat the crew compartment(s) and if an emergency situation prevents the craft from surfacing it will be necessary to provide thermal protection for the crew. Sufficient space is to be allocated within the submersible craft to stow thermal survival suits or bags for each crew member.

10.6.2 The autonomous submersible craft will normally have ample power reserves to provide air conditioning in the crew compartments and will probably have sufficient space to fit insulation material to the inside of the pressure hull throughout the crew compartments. However, it is recommended that thermal survival suits or bags are carried on board for use in emergency.

10.6.3 In one man submersible craft the provision of thermal protection creates a problem, as often there is insufficient space to stow thermal clothing, or to put it on, and the design of the craft may only allow the occupant to cover the upper half of his body. In these craft it is usually impractical to wear thermal clothing at all times, because the occupant is too hot during normal work. Possibilities for thermal protection include wearing leggings etc. to cover the lower half of the body and providing protection for the upper part of the body by building in a thermal top into which the occupant could zip himself.