This standard establishes the water supply systems used to feed the specific fire extinguishing systems that use this extinguishing agent, such as those treated in the following UNE standards: UNE 23-501 to UNE 23-507 - Fixed water spray systems. UNE 23-521 to UNE 23-525 - Low expansion foam extinguishing systems. UNE 23-590 to UNE 23-597 - Automatic water sprinkler systems.