As per the city of Cape Town’s recent post, the cost of relaying 650m of mains water piping in Kraaifontein cost a staggering ZAR2,600,000.00!
To put this staggering amount into perspective and working at the average salary of all South Africans (R17169.74 from 2004 to 2025 – Trade Economics), this equates to “Joe Average’s” monthly salary for 12.75 years! – or just 51m for each full year’s employment!
Can we afford to ignore it?
But can we afford to just ignore the task of keeping our country’s infrastructure up to date? Sadly, by not attending to the constant maintenance required to ensure that our country’s vital infrastructure is conserved in a high degree of working order, can ultimately result in a best-case scenario of an overall increased cost of repair, and as a worse case scenario, a complete breakdown – such as suffered by Eskom after years of neglect!
Unfortunately, the various municipalities’ reply seems to stick on one or two points, either insufficient budget or secondly, more important issues to spend the available funds on such as new RDP housing, so what can be done to free up resources without adversely increasing the rates payable?
The obvious choice would be to have the municipalities change their priorities, financial weighting and concentrate on being more efficient – as well as cutting out any fraud, the rampant nepotism and extraordinary and flagrant bonuses which are becoming so common place within our government’s structures.
What causes underground pipes to fail
When looking at the problems which could result in damage to an in the ground piping system, most of the factors could be either related to natural causes, – such as the root systems of trees and plants, seismic anomalies such as earth tremors, natural compaction over time, extreme weather, or temperature fluctuations can shift soil and affect pipe alignment -, physical composition of the piping material used – fibre cement (containing asbestos) and cast iron were the go to materials for piping networks 50 years ago -, or could go back to the workmanship and technologies available when the system was laid,
What can be done about it
Certain of these problems could be alleviated by instruction and regulation, such as educating users of what to, and what not to flush into the sewerage systems, such as insoluble and solid materials (building debris, grease, feminine sanitary items, plastics etc. which can cause blockages) but certain naturally resulting problems such as the intrusion of root systems, physical pipe degradation through corrosion or material deterioration, or natural settlement, as well as previous workmanship errors – such as offset pipe joints and bellying (also known as a sag or dip, occurs when a section of the sewer line loses its proper gravitational slope causing water to pool in the low spot mostly caused by inadequate bedding, insufficient initial soil compaction, or pipe leaks/joint failure washing away supporting soil)
The modern alternative: relining instead of replacing
So we must also be sure to utilize as much of our new modern technologies as possible, such as relining pipes instead of doing a physical replacement – In South Africa, relaying an average sewer line can cost anything between R4000 to R8000 per running meter when taking into consideration such points as project complexity, pipe bore, location, excavation, new pipe, backfill, and site restoration as well as seasonal considerations, (pumping of water from excavations during the rainy season) preliminary camera inspection to confirm the physical inlaid pipe’s condition and employing benefits of scale where if increasing the scale of the refurbishment could lead to a Rand per meter saving.
For pipe relining – dependant on the condition of the pipe to be serviced – costs can be up to 80% cheaper than replacing pipes, making it a more cost-effective option.
One of the most financially beneficial factors are the time and labour saving of not having to expose the whole length of the repair, and the rehabilitation of the affected ground on completion of the project. So, in many cases this system of pipe rehabilitation seems like a no-brainer, but what are the various steps involved?
The six stages of pipe relining
- to clear the pipe of any obstructions by either flexible rod, (also known as sewer snakes or sewer augers) root cutter, sewer brush, hydraulic jet or vacuum
- to inspect the condition of the interior of the pipe, usually via CCTV systems
- by inserting the lining medium, usually either Epoxy resins, Vinyl Ester, Polyester resins, Felt liners, Fibreglass liners, HDPE or PVC, dependant on structural needs, chemical and corrosion resistance and hydraulic performance as well as installation feasibility method
- inflating the liner so that it seals onto the interior surface of the original pipe to create a strong and stable bond
- deflate the inflation mechanism and remove from the pipe leaving the lining in place and cured to the original pipe’s inner surface
- final inspection of the refurbished pipe’s interior to ensure that there are no fault cracks, holes or material failures.
Unfortunately, in cases of severe bellying, the affected areas would need to be straightened prior to lining as well as the portions of pipe experiencing negative gravitational laying would be required to be made true prior to lining.
