DESIGN : DEAR PLUMBERS 15
Storm water design of a building and the premises ( erf ) of the building
By
D . S ( Vollie ) Brink Pr . Eng . MSAICE , MPMISA
The SABS Standards and regulations are relevant for the services and buildings up to the boundaries of the erf .
SANS10400-R addresses the building ( s ) and the relevant services on the property of the “ owner .” The “ owner ” is the “ legally responsible person ”. However , the owner in most cases appoints a “ competent person ” to do the design on behalf of the owner , who then becomes responsible for the design .
The objective of such a retention system is to control the flow of storm water from the property to be equal to what it was before the property was developed . It must be noted that the storm water design of streets was designed on a very low rainwater downfall which is why the discharge from the properties must be controlled and retained .
Vollie Brink is one of the industry ’ s longest-serving wet services engineers . He continues to serve on SABS committees and has been involved in the Green Building Council ’ s Green Star rating system . Brink continues to consult for various organisations while enjoying a wellearned retirement .
A very important part of the design is how to discharge the storm water from the building ( s ) and the property and how to discharge it via the adjacent properties besides and below the erf from where the storm water is coming .
The storm water coming from the property and the adjacent properties and below , can seriously affect the buildings and damage can end up in serious legal situations . Therefore , the design of a storm water drainage system is intended to manage the storm water from the buildings and the erf without consequences .
Certain properties require “ storm water retention systems ” to control the flow of storm water discharged from the property and the design of this requires a competent civil engineer and the design must be approved by the responsible local authority .
Apart from what is required in SANS10400-R , there are also legal requirements that are important to follow . The most important design requirement is that the storm water must not be concentrated and discharged to another property below or beside the property . The natural topography must be considered and not disturbed , and if it must be disturbed for some reason then the design of the stormwater system must be designed in consideration of this situation as well as the properties around the new development .
Channeling and piping in the new property and the surrounding properties must be designed in conjunction with all the property owners . Retaining walls , subsoil drains , storm water drains , and paving and channels etc . for storm water systems , must be designed by competent professionals to render appropriate and effective storm water management .
All photos by © Plumbing Africa | Rory Macnamara
The “ owner ” is the “ legally responsible person ”.
August 2022 Volume 28 I Number 6 www . plumbingafrica . co . za