In tall buildings some of the fixtures at the lower level may be subjected to excessive pressure. The sanitary appliances and fittings in tall buildings shall not be subjected to greater than 350 kpa. This shall be achieved by one or combination of the following two methods:
a. Zoning floors by intermediate tanks:
An intermediate tank shall be provided on different floors so that plumbing fixtures are not subjected to excessive pressure.
b. Using pressure reducing valves:
The excessive pressure suffered by different fixtures shall be minimized by pressure reducing valves.
Recirculation of cooling water
Recirculation of cooling water and/or waste water from wash basin to the cistern of water closets and urinals in the lower floor may be provisioned through a separate tank. No connection between the potable water supply line and the recirculated waste water line shall be allowed with or without any nonreflex or nonreturn valves.