FEATURE 23
Prevention of failure : In either a one pipe or two pipe system ensure that vent pipes are used to ensure that the pressure in the branch pipes never differs greatly from that in the open air .
Another standard comes from the Dept of Water and Sanitation ( DWS ) and is a compulsory standard and that is SANS 10252 Part 1 & 2 . Whilst SANS 10400 is the National Building Regulation ( NBR ) 10252 : – Water supply installation for buildings – Part 1 : Water supply installations for buildings and Part 2 : Drainage installations for buildings , this focusses on water and waste fully .
Alternatives to water borne sewer systems These cater for the areas where , for whatever reason , waterborne sanitation is not supplied . Nonetheless the sanitation facilities must provide a healthy environment for the people living in these areas . Some of these are :
• Pit Latrines – unacceptable by any standard and possibly government will be facing legal action that these have not been replaced by healthier modes of sanitation .
• Ventilated Improved Pit Latrines – the bottom of the pile but permissible due to the ventilation aspect .
• Low flush volume – used in conjunction with septic tanks and conservancy tanks
• Septic tank effluent drainage – carries clear effluent from septic tanks to French drains or communal drain via small diameter pipe ( 50mm )
• Septic tank with French drain – associated with low density , low frequency application remote from waterborne sanitation facilities .
• Conservancy tanks – sewage is pumped out of holding tanks and transported away for processing . b . c .
d .
Be impervious to liquid It must be not less than two ( 2 ) metres from the property boundary or another structure Such tanks should carry an Agrement SA Certificate or be rationally designed by a competent person or designed and constructed in accordance with standard drawings issued by a local authority . PA
" SANS 10400 : P is very specific about Conservancy tanks , Septic tanks and French drains ."
These are the main ones and there are others which are researched by the CSIR and the Water Research Commission which are developing innovative types of sewage removal concepts .
Agrement SA is certifying a number of these alternatives that meet ‘ fit for purpose ’ conditions .
Septic tanks and French drains treat sewage at location rather than connecting to the sewer system or remote treatment works . The tanks must serve the same purpose which is to condition raw sewage which has a clogging effect on soil and reduces the capacity of the absorption field ( French drain ) the tanks must function as both a sedimentation tanks and a digester . Maintenance is minimal but should be checked at least annually to de-sludge .
What is a conservancy tank ? As it is chemical-resistant , conservancy tanks are used to dispose of both black and grey water . It serves as temporary storage only , requiring the waste to be pumped out whenever the tank is full . This is done by licensed hauling companies who dispose of the waste accordingly .
SANS 10400 : P is very specific about Conservancy tanks , Septic tanks and French drains and the siting thereof . a . Access to the cleaning of the tanks
March 2022 Volume 28 I Number 1 www . plumbingafrica . co . za