Choosing the size of hot and cold sanitary pipes should be done according to the amount of hot and cold water consumption in the building. In the following, how to choose the size of hot and cold sanitary pipe is described in detail:
1 Determining water consumption: First, hot and cold water consumption in the building must be determined. For this purpose, the number and type of water consuming devices such as sanitary faucets, bathtubs, showers, kitchens, etc. should be specified.
2 Calculation of water speed: After determining the water consumption, the speed of water flow in the pipes should be calculated. The speed of water flow should be such that it does not cause sedimentation and wear of pipes. If the speed is too high, it may cause some problems such as a decrease in water pressure and instability in the piping system.
3 Calculation of the diameter of the pipe: after calculating the speed of the water flow, the diameter of the pipe must be calculated. The diameter of the pipe should be such that the speed of water flow in it is minimized. For example, for a piping system with a flow rate of 50 liters per minute, the pipe diameter should be at least 3/4 inch.
4 Considering the distance between the valves: considering the distance between the valves, the diameter of the pipe should also be such that it works best to maintain the water pressure.
5 Compliance with standards: In choosing the size of sanitary hot and cold pipes, attention should be paid to the standards related to the plumbing system. In many countries, there are standards for choosing the size of sanitary hot and cold pipes that should be taken into account. For example, in the Iranian standard, for cold pipes, diameters of 1/2, 3/4, 1, 1.5 and 2 inches are used, and for hot pipes, diameters of 1/2, 3/4, 1, 1.25, 1.5 and 2 inches are used.
6 Number of faucets: It is very important to consider the number of faucets in choosing the size of sanitary hot and cold pipes. If the number of faucets is large, a pipe with a larger diameter should be used to maintain the water pressure and the optimal performance of the piping system.
In general, to choose the right size of hot and cold sanitary pipe, you should pay attention to the important points mentioned above. Also, in order to comply with the standards related to the piping system, architects and civil engineers should be consulted.