Water supplies and pumps

For non-residential sprinkler systems designed and installed to BS EN 12845, water supplies should
consist of either of the following.
a. Two single water supplies complying with clause 9.6.1, independent of each other.
b. Two stored water supplies meeting all of the following conditions.
i. Gravity or suction tanks should satisfy all the requirements of clause 9.6.2(b), other than
capacity.
ii. Any pump arrangements should comply with clause 10.2.
iii. In addition to meeting the requirements for inflow, either of the following should apply.
• The capacity of each tank should be at least half the specified minimum water volume
of a single full capacity tank, appropriate to the hazard.
• One tank should be at least equivalent to half the specified water volume of a single
full capacity tank, and the other shall not be less than the minimum volume of a
reduced capacity tank (see clause 9.3.4) appropriate to the hazard.
The total capacity of the water supply in (iii), including any inflow for a reduced capacity
tank, should be at least that of a single full holding capacity tank that complies with