In early eighties and speaking generally, the sole internal pipeline inspection was either carried out by the sewer inspection companies, who be inspecting mainly dry sewer pipe sections over short distances; typically not exceeding 150m and who stop if your pipe became surcharged so much that you would become submerged as well as the oil industry support companies who does run ‘intelligent pigs’ the oil pipes to assess weld integrity, pipe wall thickness and overuse injury in order to assess pipeline longevity and safe operating pressure.
Currently water companies have been largely oblivious towards the internal condition with their pipelines, adits, aqueducts and tunnels were beginning to have concerns concerning the integrity of these assets, most of which ended up constructed in the Victorian times or more recently noisy . fifties coupled with never been inspected and were unsuccessfully searching for companies and/or equipment that could accomplish such surveys.
In some instances we were holding in a position to de-water the pipelines and when just right diameter, they might send a confined space team into conduct a visual survey; such surveys were obviously fraught with potential dangers, not least which included the possibility of collapse, flooding as well as the accumulation of toxic gasses.
De-watering included its very own pair of potential risks to the structural integrity of the concrete, tunnelled and brick constructed pipelines; in most cases, small leaks developed by displaced joints, erosion and localised damage etc. enabled the leaking water to locate a path with the ground and over a number of years, earth could be passed from around the pipe, often producing large water filled voids forming round the outside of the pipeline.
The newly de-watered pipeline which will get partially dependent on the pinnacle water within the pipeline (attempting to push the walls out), to take care of its structural integrity, could suddenly encounter several a lot of water not in the pipeline (attempting to push the walls in), creating localised areas of external underhand, which will often result in pipe failure and localised collapse, causing subsidence of the ground across the pipeline manifesting as holes on your lawn that might appear ‘over-night’.
About on this occasion there was clearly an ever-increasing demand from your Water Companies for you divers up water filled pipes armed with CCTV cameras, to survey for as far his or her nerve or umbilical length would permit.
In a very short time period the HSE Diving Executive, showed a keen fascination with the safety part of sticking divers up pipes and very quickly an excursion range of around 30m as being a maximum was considered safe, providing that the essential safety precautions were set up.
More details about in line inspection view this webpage.