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TECHNICAL
Is pipe lining getting clogged up ?
By
Rory Macnamara
Pipe lining is no quick fix or band aid to leaking pipes . It is a science requiring the knowledge of specialists . Should a plumber be doing such specialist work ?
The straightforward answer is yes , only if he or she has acquired the additional knowledge to reline pipes . In other words , much like a doctor ( GP ) who wishes to do heart surgery . The GP has the knowledge to perform the function of a GP but not heart surgery . So , with the plumber who has the basic plumbing knowledge acquired over three or four years they need to upskill themselves in this field of pipe lining and much like the GP wanting to specialise and become a heart surgeon – more learning , more study , more practical work .
Human life expectancy in South Africa is 64 years , and 77 in Europe , whereas the life expectancy of a building under South African building codes is between 50-100 years – and with the correct maintenance it can even be extended to 150 years . So , as the average lifespan of pipes in South Africa is not even lasting 20 years – in some cases we have 40-year-old pipes however the buildings and the occupants are outliving the pipes . So , when pipe rehabilitation takes place , a 6- or
24-month warranty simply does not meet the life expectancy of the rest of the building .
Now our non- revenue water ( NRW ) wastage averages between 46 and 54 %, depending on who one speaks to . That is wastage we can ill afford in a semi-arid country like South Africa . Yet the figure continues to keep within this range , and we are relining pipes . What is the matter then ?
We leave that for the pipe liners ’ themselves to answer !
What is encouraging is that the Southern African Society for Trenchless Technology ( SASTT ) and Institute of Plumbing SA ( IOPSA ) have set up a technical committee ( TC ) to move toward a standard which should fall under the National Water Act making it compulsory . One cannot see the DWS declining an amendment to include such a standard .
SASTT have done excellent work in formulating its own technical standard SASTT-TS-TT4 : 2021 which is what the joint TC will consider in conjunction with the SABS .
In the meantime , we have a look at the requirements of accepted standards like BS EN ISO 11296-4:2018 + A1:2021 , Plastics piping systems for renovation of underground non-pressure drainage and sewerage networks Part 4 : Lining with Cured in Place Pipes ( CIPP ) because of the link SABS has with ISO . This is part of a family of standards around the topic .
The SASTT Technical document refers to the American Society for Testing and Materials ( ASTM ) which is detailed and referred to in the main by their members . SASTT is mostly involved in Gravity pipe underground rehab . Both standards , however , are current and provide a basis for portions of this article as what the end user should appreciate when specifying relining or pipe rehabilitation .
The business of pipe lining is not a ‘ one size fits all ’ practice and when such work is conducted the application must be clear especially when one is in the realm of potable / drinking water .
Nu flow
Left : How is should not look . Right : How is should look and showing different grits .
For plumbers the lining work for potable networks is in the smaller diameter range of pipe ( 15 to 50 mm ) and the standards relating to this are :
www . plumbingafrica . co . za @ plumbingonline @ plumbingonline @ PlumbingAfricaOnline March 2022 Volume 28 I Number 1