Krah Pipes under difficult conditions - Field report from Egypt
Introduction
Since our existence in Egypt we have realized many projects, with kilometres of pipes in several sizes, as well as fittings and manholes. All pipes, fittings and manholes are according to the newest version of DIN16961. Basically, all pipes have an inspection friendly bright (yellow) smooth inside surface and they are jointed with our special integrated electro-fusion jointing system. Overall, the number of failures due to unexpected loads or wrong handling at site is fairly low, but they exist. One of the major question is always: “How to repair the pipe, the fitting or the manhole?”, and from time to time we must also show our repairing skills to the project owner. One of the biggest issues in Egypt is the existence of very soft, cohesive soil, so all pipes and system components are based on extensive structural analysis, to be on the safe side, because a proper backfilling is not easy at all.
A typical view of our loose soil
In the day to day business inadequate transport procedures, wrong handling and/or storage can cause pipes damages. External mechanical force may also damage pipes which are already installed. Another origin of leakage can be a bad or wrong jointing of the pipes, for example the power generator stopped during the electro-fusion joining and the worker didn´t check, even the welding report will show a failure (not enough energy in the joint) or manual welding was carried out in dirty conditions.
Depending on the project, the product, the failure and the environment we have different solutions to fix the problem. All products are produced out of 100% virgin PE100 material – and they passed the requested quality control program, according to DIN16961 and our additional internal guidelines. All manholes are pre-fabricated at the plant and installed on site, by using the electrofusion system. From time to time, special connections are done on site.
The way of repair must consider the origin of the damage, the type of product, the jointing-procedure and the on-site-conditions. That’s why we provide several repair-procedures and always choose the best solution accordingly. In this report four different solutions (cases) will be explained, to show the range of possibilities. An important issue is that each solution is a long-term solution (minimum 50 years) and the pipe properties like stiffness and internal pressure rating shall be kept.