How to check with a calculation
Wherestep 3 Calculation and checksabove the tiles and (the number of issues is next to them)the window Water and drainage · calculation per SP 30 opensOn the left are the input data, on the right the totals as tiles, issues, flows by floor, head, stacks, pipes and the specification.
Steps
- Set the number of residents. If the rooms are marked out, it is counted automatically: living rooms plus one. Set the level of the invert at the tie-in to the drain stack. It is measured on site from the floor of the storey, without the podium.
- If the pressure at the service entry is known (from the management company or from a pressure gauge), enter it in MPa. Without it the head is calculated but not compared.
- Look through the issues. Click on an issue closes the window and shows the place on the plan.
- Fit diameters writes the calculated diameters into the pipes.
- In the pipe window you can see its flow and velocity, and for drainage also the slope and the invert levels.
What is checked
- The network is connected: a pipe leads to every outlet, the ends are connected, the network reaches the stack or the entry, no foreign system is connected. Between floors the network runs along pipe drops and stacks: in a building the source is the entry and the outlet, in an apartment the stacks.
| Water supply | flow per SP 30, velocity not above 1.5 m/s. The required head at the entry (cl. 8.27) for the governing fixture: lift, pipe losses along the length and local ones (+30 %), losses in the meter and a free head of 20 m at the fixture (cl. 8.21). If the pressure at the entry is not enough: an issue at the governing fixture; above 0.45 MPa without a regulator: an issue at the entry (cl. 8.22). |
|---|---|
| Service entry | a meter at the entry (cl. 12.13) at a height of 50–150 cm (cl. 12.5), a valve and a filter before it, a check valve after it, a valve before the regulator. Losses in the meter not more than 5 m. Hot water from its own water heater needs no meter. |
| Drainage | the diameter is not less than the fixture outlet, behind a toilet not less than 110; the slope is not less than 0.03 for pipes 40–50 and 0.02 for 110; whether the fall is enough up to the tie-in to the stack; cleanouts. |
- Drain stacks (the table Drain stacks): not thinner than the branch (cl. 19.2) and able to carry the wastewater flow (Annex K, 87.5° branch, the strictest of PVC, PP and cast iron). The table is shown by the Vent column: above the roof the stack is ventilated (K.1–K.3), with an air admittance valve per K.8 (cl. 19.8; valve 1650 mm² for stack 50, 3170 mm² for 110), without a vent it is unventilated (K.5–K.7, cl. 19.6), above 9 m an issue. In an apartment the stack is considered ventilated.
- Stack ventilation of the building: the top above the roof (Shaft top → Above the roof, 0.2 m, cl. 18.18) or an air admittance valve at the mouth (cl. 18.22); at least one stack led out above the roof per outlet (cl. 18.25, note 4). Not checked in an apartment.
- Apartment fire hose valve: in an apartment building a separate valve of at least Ø15 with a hose and a spray nozzle on cold water is required (SP 30, cl. 8.29; SP 54, cl. 6.2.4.3). Tile: → Apartment fire hose valve.
- Pumps: the head of a booster pump is added to the pressure at the entry; if it is not set, an issue tells how much is needed: Hp = Hgeom + ΣH + Hпр − Hгар (cl. 13.11, formula 19). Hot water circulation in the building runs with a pump (cl. 13.1). A pump in a living room, behind its wall, above or below it gives an issue (cl. 13.6; SanPiN 2.1.3684-21, cl. 137).
What is not calculated: a standby pump (cl. 13.15 refers to SP 31, which has no categories for residential buildings), the length of the fire hose (the norms do not set it), a towel warmer bypass as a separate pipe (cl. 9.9 only allows it), pipe laying heights for water supply (SP 30 has none).
What Not enough fall: raise the outlet by {v} cm or move the fixture closer to the stack means. The fixture trap is lower than the pipe invert must be to reach the stack with a slope. Raise the fixture onto a podium or place it closer to the stack. The podium is set in Plan: room properties → Floor level, for example . The tie-in to the stack stays at its own level.
Calculation assumptions
- Pipe losses by the Darcy–Weisbach formula at 10 °C. Pipe roughness is taken as a reference number, SP 30 has none.
- Meter resistance per SP 30, Table 12.1; the unit cannot be read in the text of the standard, m/(L/s)² is assumed, as in SNiP 2.04.01-85, Table 4. Check: a meter DN 15 at 3 m³/h loses about 0.1 MPa, as in the data sheets.
- The stack capacity is taken from the strictest of the tables K.1–K.3: the editor does not know the stack material.
- The head of hot water from its own water heater is counted from the cold water source: the cold path to the water heater plus the hot path from it. Losses in the water heater itself are not counted: they are in its data sheet.