Should the ventilated part of the sewer riser always be led to the roof?
In some cases, it is allowed not to do this. In paragraph 4.13. SP 40-107-2003, as well as the Standard “SanteIIIIproekt” specify the regulations for the use of reverse air sewer valves HL900N and HL900NECO, namely: “If it is not possible to install an exhaust part and a non-vented sewer riser, it is allowed to use a reverse air valve for sewage (a vacuum valve for sewage ) (Appendix B) ... ”.
What is a sewer check valve used for?
Non-return air valves (vacuum valves) can be used: to increase the throughput of unventilated sewer risers (SP 40-107-2003 and Standard SantekhnIIIIproekt); to prevent the breakdown of hydraulic locks in devices connected to horizontal pipelines (MGSN 4.19-2005); for supplying air to the backup gutters (MGSN 4.19-2005).
Is it possible to install non-return air valves for sewage on all risers in a building?
The exhaust part of the sewer riser performs two functions: the first is the satisfaction of the ejection ability of water, i.e. ability to carry air during the maximum drainage hours, and the second - ventilation of external sewage networks during the minimum drainage hours. Therefore, when installing risers equipped with non-return air sewer valves, it is necessary to take into account the need for ventilation of the external sewer network serving the building under construction. The number of ventilated sewer risers is determined by the formula: n = kW / Q. Where n is the number of exhaust parts of risers Ø100 mm; k = 80-100 - daily rate of air exchange in the sewer network; W - capacity of the calculated section of the sewer network, m³; Q = 320 m³ / day - estimated consumption of polluted air leaving the exhaust part of a single sewer riser Ø100 mm. All other risers in the building may be unventilated or equipped with HL non-return air valves (vacuum valves). (p. 17.21 Standard "SantekhNIIproekt")