The facilities regulations § 36

§ 36 Firewater supply

All facilities with accommodation shall have a sufficient supply of firewater to combat fires and suppress gas explosions if this can result in lower explosion pressure, cf. Section 37.
Manned facilities shall have firewater supply from fire pumps or other independent supply to ensure sufficient capacity at all times, regardless of whether parts of the supply are out of service.
Simpler facilities with emergency quarters shall have a firewater supply from a fire pump or other equivalently reliable supply.
Simpler facilities without emergency quarters shall have an adequate supply of firewater or passive shielding so that the personnel by evacuation can be protected from fires that can occur.
The firewater system shall be designed such that a pressure stroke does not make the system or parts of it inoperative.
On facilities where firewater is supplied from fire pumps, the pumps shall start up automatically in the event of a pressure drop in the fire main and fire and gas detection. Fire pumps shall also be capable of being manually activated from the central control room and at the propulsion unit. Propulsion units for fire pumps shall be equipped with two independent starting arrangements. Automatic disconnection functions shall be as few as possible.
Firewater piping shall be designed and placed such that a sufficient supply of firewater is ensured to any area on the facility.
Section last changed: 01 January 2021

Sufficient capacity as mentioned in the second subsection, means the capacity necessary to supply all firefighting equipment in the facility's largest fire area plus the largest of the adjacent areas. A pump start-up failure does not need to be used as a basis for capacity calculations for the largest fire area plus the largest adjacent area at the same time as a pump is out of operation for a short period (less than 24 hours). On simpler facilities without emergency quarters, the supply can come from a dedicated water reservoir, from seawater pumps or other available water supply. Simpler facilities without their own fire water supply should have deluge systems that can be supplied from the drilling facility if this can be exposed to fires that can occur on the simpler facility.
For simpler facilities with fire water supply, the associated power supply can come from a power source which is placed on the facility, provided that it is protected against the fires that can occur.
In order to fulfil the other requirements as mentioned in this section, the standard NORSOK S-001 Chapter 21 should be used, with the following addition: for hydraulic calculations, a recognised method shall be used.
For mobile facilities that are not production facilities, and that are registered in a national ship register, DNV-OS-A301 Chapter 2, Paragraphs 3, 6 and 7 can be used as an alternative.
Chemicals added to firewater shall be tested and assessed as mentioned in Section 62 of the Activities Regulations.