Following are the requirements of a fixed CO2 systems, as per the SOLAS -

1. The pipes for conveying system shall be provided with control valve so marked as to indicate clearly the space to which the pipe is led
2. The provision shall be made to prevent inadvertent release of the medium into space
3. The pipes may pass through accommodation areas provided that they are of substantial thickness and that tightness is verified with a pressure test at a head not less than 5N/mm2
4. Means shall be provided to give an audible indication of the release in which persons normally work
5. The alarm shall operate for the length of the time needed to evacuate the space but in no case less than 20seconds before the medium is released
6. Control of the system shall be readily accessible and simple to operate. Clear instructions shall be displayed
7. For cargo spaces the quantity of the carbon di oxide available shall be sufficient enough to give minimum volume of the free gas equal to 30% of the gross volume of the largest cargo space protected on the ship
8. For machinery space the quantity of carbon dioxide carried shall be sufficient enough to give minimum volume of free gas equal to 40% of the gross volume of largest machinery space so protected. This volume excludes the part of the casing above the level at which the horizontal area of the casing is 40% or less of the horizontal area of the space concerned taken midway between the tank top and the lowest part of the casing or 35% of the gross volume of the largest machinery space protected including casing
9. The volume of free carbon di oxide shall be calculated at 0.56m3/kg.
10. For machinery space the fixed piping system shall be such that 85% of the gas can be discharged into the space within 2 minutes
11. Two separate controls shall be provided to release including activation of the alarm.