Galvanized steel potable water supply and distribution pipes are commonly found with nominal pipe sizes from 3?8 inch (9.5 mm) to 2 inches (51 mm).
It remains in common use for repair of existing "galv" systems and to satisfy building code non-combustibility requirements typically found in hotels, apartment buildings and other commercial applications.
It is also extremely durable and resistant to mechanical abuse.Black lacquered steel pipe is the most widely used pipe material for fire sprinklers and natural gas. Źródło: https://en.wikipedia.org/wiki/Plumbing
Water systems of ancient times relied on gravity for the supply of water, using pipes or channels usually made of clay, lead, bamboo, wood, or stone.Hollowed wooden logs wrapped in steel banding were used for plumbing pipes, particularly water mains. Logs were used for water distribution in England close to 500 years ago. US cities began using hollowed logs in the late 1700s through the 1800s.8 Today, most plumbing supply pipe is made out of steel, copper, and plastic; most waste (also known as "soil")11 out of steel, copper, plastic, and cast iron.11 The straight sections of plumbing systems are called "pipes" or "tubes". A pipe is typically formed via casting or welding, whereas a tube is made through extrusion.
Pipe normally has thicker walls and may be threaded or welded, while tubing is thinner-walled and requires special joining techniques such as brazing, compression fitting, crimping, or for plastics, solvent welding.These joining techniques are discussed in more detail in the piping and plumbing fittings article.Źródło: https://en.wikipedia.org/wiki/Plumbing#Materials
The difference between pipes and tubes is simply in the way it is sized.PVC pipe for plumbing applications and galvanized steel pipe for instance, are measured in IPS (iron pipe size).
Copper tube, CPVC, PeX and other tubing is measured nominally, which is basically an average diameter.These sizing schemes allow for universal adaptation of transitional fittings.
For instance, 1/2" PeX tubing is the same size as 1/2" copper tubing.
PeX and CPVC tubing also comes in rigid "joints" or flexible rolls.The temper of the copper, that is whether it is a rigid "joint" or flexible roll, does not affect the sizing.7 The thicknesses of the water pipe and tube walls can vary. Pipe wall thickness is denoted by various schedules or for large bore polyethylene pipe in the UK by the Standard Dimension Ratio (SDR), defined as the ratio of the pipe diameter to its wall thickness.
Pipe wall thickness increases with schedule, and is available in schedules 20, 40, 80, and higher in special cases.
The schedule is largely determined by the operating pressure of the system, with higher pressures commanding greater thickness.
Copper tubing is available in four wall thicknesses: type DWV (thinnest wall; only allowed as drain pipe per UPC), type 'M' (thin; typically only allowed as drain pipe by IPC code), type 'L' (thicker, standard duty for water lines and water service), and type 'K' (thickest, typically used underground between the main and the meter).Because piping and tubing are commodities, having a greater wall thickness implies higher initial cost.
Thicker walled pipe generally implies greater durability and higher pressure tolerances.Źródło: https://en.wikipedia.org/wiki/Water_pipe#Difference_between_pipes_and_tubes.