Plumbing code - Wikipedia:
Plumbing code is a code that provides regulations for the design, installation and inspection of building plumbing and sanitary systems. In the U.S., jurisdictions enact their own codes, some of which are based upon model plumbing codes.1 The most widely adopted plumbing code in the United States is the International Plumbing Code published by the International Code Council (ICC). This code is also used as the basis for the plumbing code of some other countries. Another model plumbing code published in the United States is the Uniform Plumbing Code published by IAPMO.
Different types of valves
Valves vary widely in form and application. Sizes typically range from 0.1 mm to 60 cm. Special valves can have a diameter exceeding 5 meters.
Valve costs range from simple inexpensive disposable valves to specialized valves which cost thousands of US dollars per inch of the diameter of the valve.
Disposable valves may be found in common household items including mini-pump dispensers and aerosol cans.
A common use of the term valve refers to the poppet valves found in the vast majority of modern internal combustion engines such as those in most fossil fuel powered vehicles which are used to control the intake of the fuel-air mixture and allow exhaust gas venting.
List of plumbing subsystems
The major categories of plumbing systems or subsystems are:
potable cold and hot tap water supply
plumbing drainage venting
sewage systems and septic systems with or without hot water heat recycling and graywater recovery and treatment systems
Rainwater, surface, and subsurface water drainage
fuel gas piping
hydronics, i.e. heating and cooling systems utilizing water to transport thermal energy, as in district heating systems, like for example the New York City steam system.