What are regulations for spare fire fighting equipments on board as per SOLAS ?

Spare Charges, Additional Fire Extinguishers, and Refilling of Extinguishers:

1. For fire extinguishers of the same type, capable of being recharged on board, the spare charges should be provided as follows:

• 100% for the first 10 extinguishers and 50% for the remaining extinguishers but not more than 60 (fractions to be rounded off to next whole number).

2. For extinguishers which cannot be recharged by the crew, additional portable fire extinguishers of the same quantity, type, capacity and number as determined in paragraph a above should be provided in lieu of spare charges.

3. Instructions for recharging the extinguishers should be carried on board. Periodic refilling of the cylinders should be in accordance with the manufacturer’s recommendations.

Lacking same, refill is required when the extinguishing media starts to lose effectiveness. Partially emptied extinguishers should also be recharged. Only refills approved for the fire extinguisher in question may be used for recharging.

You may also know about hydrostatic test :

Portable fire extinguishers shall be hydrostatically tested as follows: