- The speed of the water must be at maximum for a horizontal circulation of 2 meters per second. (For example in the basement in a crawl space in your technical room).
- The speed in your riser should be a maximum of 1.5 metres per second.
Calculation formula
We will not deal here with the problem of pressure drops in an installation, however it is important to think about the right balance between the number of appliances served and the diameter of their supply.
The maximum flow rate can be calculated by the following formula :
The maximum flow rate in m3 per second is equal to the area of your pipe diameter in m2 multiplied by the silent speed in meters per second.
D (m3/s) = (π d ² (in meters) / 4) x V (meter per second)
For example, for a copper pipe with an internal diameter of 10 mm the maximum flow rate for a speed of 1.5 metres per second is :
(3,14159*0,01*0,01/4) *1,5= 0,0001178 m3/s
In cubic metres per hour : 0.0001178*3600 = 0,4241m3/h
In litres per minute : 0,4241*1000/60= 7,0686 l/mn
We can thus make the following table for the copper tubes that we propose to you:
Inner diameter of the copper pipe in mm | Speed 1.50 Meters per second | Maximum flow rate in m3/s | Maximum flow rate in m3/h | Maximum flow rate in l/min | Maximum flow rate in l/s |
10 | 1.50 | 0,000118 | 0,4241 | 7,069 | 0,118 |
12 | 1.50 | 0,000170 | 0,6107 | 10,179 | 0,170 |
14 | 1.50 | 0,000231 | 0,8313 | 13,854 | 0,231 |
16 | 1.50 | 0,000302 | 1,0857 | 18,096 | 0,302 |
20 | 1.50 | 0,000471 | 1,6965 | 28,274 | 0,471 |
26 | 1.50 | 0,000796 | 2,8670 | 47,784 | 0,796 |
30 | 1.50 | 0,001060 | 3,8170 | 63,617 | 1,060 |
33 | 1.50 | 0,001283 | 4,6186 | 76,977 | 1,283 |
38 | 1.50 | 0,001701 | 6,1242 | 102,070 | 1,701 |
40 | 1.50 | 0,001885 | 6,7858 | 113,097 | 1,885 |
50 | 1.50 | 0,002945 | 10,6029 | 176,714 | 2,945 |
For example, for a copper pipe with an internal diameter of 10 mm the maximum flow rate for a speed of 2 meters per second is :
(3,14159*0,01*0,01/4) *2= 0,00015 m3/s
In cubic metres per hour : 0.00015708*3600 = 0,5655m3/h
In litres per minute : 0,56548*1000/60= 9,42477 l/mn
We can thus make the following table for the copper tubes that we propose to you:
Inner diameter of the copper pipe in mm | Speed 2.00 Meters per second | Maximum flow rate in m3/s | Maximum flow rate in m3/h | Maximum flow rate in l/min | Maximum flow rate in l/s |
10 | 2.00 | 0,00015708 | 0,5655 | 9,4248 | 0,157 |
12 | 2.00 | 0,00022619 | 0,8143 | 13,5717 | 0,226 |
14 | 2.00 | 0,00030788 | 1,1084 | 18,4725 | 0,308 |
16 | 2.00 | 0,00040212 | 1,4476 | 24,1274 | 0,402 |
20 | 2.00 | 0,00062832 | 2,2619 | 37,6991 | 0,628 |
26 | 2.00 | 0,00106186 | 3,8227 | 63,7114 | 1,062 |
30 | 2.00 | 0,00141372 | 5,0894 | 84,8229 | 1,414 |
33 | 2.00 | 0,00171060 | 6,1581 | 102,6357 | 1,711 |
38 | 2.00 | 0,00226823 | 8,1656 | 136,0937 | 2,268 |
40 | 2.00 | 0,00251327 | 9,0478 | 150,7963 | 2,513 |
50 | 2.00 | 0,00392699 | 14,1372 | 235,6193 | 3,927 |
We hope that thanks to this information, this popularization of simple formula that you will be able to better understand the basic principles of your installation of your sanitary network.
5 Comments
giuseppe 2023-06-08 Reply
Tabelle interessano in modo particolareBiopur habitat 2023-06-29 Reply
Grazie.babdelhalim 2022-05-30 Reply
pour avoir une bonne pression sur une hauteur de 15 m il faut un tuyau de diametre 40 a la source puis le reduire a la distribution...Christophe Adam 2021-09-29 Reply
Bonjour , il y a beaucoup d'avis mitigé mais j'ai décidé de passer commande pour une maison MAX POWER ,je viens juste de changer mon cumulus justement à cause du calcaire .J'espère que le resultat sera au rdv car cela fait plusieurs mois que je me tataisCordialement
Biopur habitat 2022-03-07 Reply
Bonne installation à vous.