Plumbing codes place strict constraints on plumbing installations in the interest of public health. Following are typical basic provisions:
All buildings must be provided with potable water in quantities adequate for the needs of their occupants. Plumbing fixtures, devices, and appurtenances should be supplied with water in sufficient volume and at pressures adequate to enable them to function properly. The pipes conveying the water should be of sufficient size to provide the required water without undue pressure reduction and without undue noise under all normal conditions of use.
The plumbing system should be designed and adjusted to use the minimum quantity of water consistent with proper performance and cleansing of fixtures and appurtenances.
Devices for heating and storing water should be designed, installed, and maintained to guard against rupture of the containing vessel because of overheating or overpressurization.
The wastewater system should be designed, constructed, and maintained to guard against fouling, deposit of solids, and clogging.
Provision should be made in every building for conveying storm water to a storm sewer if one is available.
Recommended tests should be made to discover any leaks or defects in the system. Pipes, joints, and connections in the plumbing system should be gastight and watertight for the pressure required by the tests.
Plumbing fixtures should be located in ventilated enclosures and should be readily accessible to users.
Plumbing fixtures should be made of smooth, nonabsorbent materials. They should not have concealed fouling surfaces. Plumbing fixtures, devices, and appliances should be protected to prevent contamination of food, water, sterile goods, and similar material by the backflow of wastewater. Indirect connections with the building wastewater system should be provided when necessary
Every fixture directly connected to the wastewater system should be equipped with a liquid-seal trap. This is a fitting so constructed that passage of air or gas through a pipe is prevented while flow of liquid through the pipe is permitted.
Foul air in the wastewater system should be exhausted to the outside, through vent pipes. These should be located and installed to minimize the possibility of clogging and to prevent sewer gases from entering the building.
If a wastewater system is subject to the backflow of sewage from a sewer, suitable provision should be made to prevent sewage from entering the building.
The structural safety of a building should not be impaired in any way as a result of the installation, alteration, renovation, or replacement of a plumbing system.
Pipes should be installed and supported to prevent stresses and strains that would cause malfunction of or damage to the system. Provision should be made for expansion and contraction of the pipes due to temperature changes and for structural settlements that might affect the pipes.
Where pipes pass through a construction that is required to have a fire-resistance rating, the space between the pipe and the opening or a pipe sleeve should not exceed 1â„2 in. The gap should be completely filled with code-approved, fire-stopping material and closed off with close-fitting metal escutcheons on both sides of the construction.
Pipes, especially those in exterior walls or underground outside the building, should be protected, with insulation or heat, to prevent freezing. Underground pipes should be placed below established frost lines to prevent damage from heaving and in high traffic areas should be encased in concrete or installed deep enough so as to not be damaged by heavy traffic. Pipes subject to external corrosion should be protected with coatings, wrappings, cathodic protection, or other means that will prevent corrosion. Dissimilar metals should not be connected to each other unless separated by a dielectric fitting. Otherwise, corrosion will result.
Each plumbing system component, such as domestic water, natural gas, and wastewater pipes and fixtures, should be tested in accordance with the plumbing code. All defects found during the test should be properly corrected and the system retested until the system passes the requirements of the test.
Enough water to meet the needs of occupants must be available for all buildings.
Further water needs for fire protection, heating, air conditioning, and possibly process use must also be met. This section provides specific data on all these water needs, except those for process use. Water needs for process use must be computed separately because the demand depends on the process served.