A very common problem in London is the blocked drains. The main enemies of the drains are cooking grease, soap scum, food deposits and hair. Drains need regular maintenance to keep them working. The autumn leaves also block the drain. Sometimes it’s very difficult to determine the condition of the drain. At that time the special equipments are used to determine the condition of the drain. Drain cleaning is the most important part of housekeeping routine services of any building. This work is done by the professional drain surveyor which takes a complete survey with the help of special equipments and CCTV before the drain cleaning.
The flow conditions within multi-storey building drainage networks may be characterized as unsteady free surface flows and as such may be analyzed and simulated by the use of the method of characteristics to solve numerically the governing equations of continuity and momentum. However the application of such simulations must take into account the possibility of defective system installation and must be able to predict the wave attenuation following appliance discharge and the consequent effects upon solid transport due to system defects caused by faulty installation or the development of obstructions to the flow.
The complete drain survey represents both the summary of a detailed survey of defects in the building drainage networks and the development of appropriate boundary conditions that allow the method of characteristics based computer simulation to accurately predict the effect of defects on system performance. We provide a complete drain survey, CCTV survey in the presence of professional drain surveyor and clean the blocked drains.

http://www.londoncitydrains.co.uk/