Pipes/piping rehabilitation

Figure 10.11 Cured-in-place pipe rehabilitation. Reproduced with permission from Dow Chemical Company, Midland, MI, USA...

TABLE 4.32 Estimated Costs for Water Pipe Rehabilitation by Cement Mortar Lining... 

Oxner K B and AUsup T (1998) Advances in cured-in-place pipe rehabilitation for pressurized piping systems, http //www.insituform.com,... 

There are three basic issues in lead pipe rehabilitation (i) lead pipe lateral rehabilitation on the public portion of the water supply system that runs from the water main to the water meter or stop-cock (curb-stop) (ii) lead pipes on the private portion of the water supply line from the meter or stop-cock to the house and (iii) lead pipe-work within the house. Whilst the only 100% control method will be the removal or all lead pipes, there are substantially less expensive alternatives available consisting of chemical treatment and internal cathodic protection. Total lead pipe removal also has the problem of split ownership and responsibility, disturbance, and destruction of land-scaping (external) and decoration (internal). 

There are six basic technologies in use today for lead service pipe rehabilitation, namely (i) open-trench, replacement along an existing route, (ii) replacement along a new route, (iii) pipe pulling of a new pipe, (iv) slip lining, (v) pipe coating, and (vi) internal cathodic protection. 

The probabilistic analysis presented in this chapter is not restricted to a specific fabrication approach but rather presents results as a function of the fiber volume fraction and can be applied to a wide range of pipe rehabilitation methods. The time-dependent failure probability analysis is illustrated for specific fiber volume fractions and can be repeated for any fiber volume fraction depending on the manufacturing process of interest. Typical fiber volume fractions of 30% and 40% are selected conservatively for example probability analysis conducted in the chapter. Recent efforts to measure fiber volume fractions used in composite pipe applications report fiber volume fraction values ranging from 47.6% to 54% for filament-wound composite pipes (Abdalla et al., 2008), and Chin and Lee (2005) measured volume fractions of 47% for unidirectional laminates manufactured via resin transfer molding in a trenchless rehabilitation scheme. 

The instantaneous failure probabilities at time T = 0, of a fully deteriorated pipe rehabilitated with carbon-FRP (CFRP) and glass-FRP (GFRP) composites versus... 

Figure 5.4 Failure probability of carbon fiber-reinforced polymer (CFRP)-composite pipe rehabilitation versus time.

The effect of composite thickness in a pipe rehabilitation can significantly impact the failure probability of an as-built rehabilitation (for a constant COV) in fact, incremental increases in thickness result in significant reductions in failure probability. 

Studies on internal repair of steel pipe rehabilitations... 

Muenchmeyer, G.P., Gemora, I., 2007. Mainline Pipe Rehabilitation Using Cured-in-place Pipe (CIPP) Folded Pipe Technology (accessed 23.09.14.). muenchmeyerassoc.com/pdf/ cipp01.pdf. 

Oxner, K.B., AUsup, T., 1999. Advances in Cured-in-place Pipe Rehabilitation for Pressurized Piping Systems (accessed 16.09.14.). www.insituform.com/mm/flles/Adnvances incured. pdf. 

Use of a PET liner (Neofit by Wavin) that is inserted into the pipe to be rehabilitated to form a close-fit liner. 

Rehabilitation of internally corroded pipelines is somewhat more difficult to manage than external corrosion. Internally corroded pipes require cutting out and replacing the affected sections of the pipeline. Other methods of internal rehabilitation consist of pulled liners and epoxy flood coating. Cost estimates for these options can vary greatly and predominantly dependent on the extent of cleaning required to prepare the internal surface for coating. 

Alternatives other than rehabilitation and replacement such as abandonment of the pipe section with a bypass loop increasing the frequency of ILI enables greater accuracy in determining the point of failure for existing defects. Derating the pipe may extend the life of the pipe provided throughput requirements are met. For the replacement or repair option, it is generally necessary to have a loop system and allow for pressure restrictions or interruptible service to facilitate repairs. 

Pipe Diameter (cm) Cost for Rehabilitation in Relation to Pipe Replacement (%)... 

---