Drain Camera Inspection Systems

Probably the greatest advancement in the world of drainage in modern times has been having the ability to inspect the systems from the inside using drain camera inspection equipment, there are the obvious benefits such as being able to pinpoint and identify a particular defect on a system and being able to find these problems before they cause the system to fail and block.

As a contractor we can now find the defect, submit a drain report along with recommendations and just as importantly know who is paying for the repair before a shovel hits the ground, if the investigations are done correctly it should also be easier for the home owner to obtain like for like quotes but alas there are still far too many sub-standard drainage surveys and vague drain survey reports knocking around out there.

We first used drain cameras on problematic systems in order to find out why the system was blocking but they are now used for many other reasons as follows

• To chart and map larger systems and give a condition report, from this planned repair and maintenance schemes can be implemented.
• Surveys are often required on new build projects such as housing estates, schools and retail parks prior to the final hand over to the client
• Many shared systems beneath new housing estates have to be surveyed before the local authority or their allotted sewerage undertaker (water company) will adopt the system as a rateable system
• Cameras have been used effectively in property subsidence claims often saving unnecessary excavation works as a defective drain has been identified from within the system
• Many mortgage lenders now insist on a drain camera inspection survey of a property to basically assess any future subsidence risk or major drainage repair claims that may be just around the corner.

I have also used CCTV Inspection equipment to survey wells, chimneys, flues, mine shafts and the ventilation system on a coroners table, remote inspection cameras are also used in the oil and gas industries and basically any scenario where a pipe, conduit or duct are found.

Another happy by-product of the advancement in drain inspection technology has been the growth in No-Dig repair techniques which has been greatly beneficial to the public, their insurers and drainage contractors themselves.

Push Rod Drain Cameras

The original push rod cameras were black and white and you would attach the drain camera and its cable to a set of drain rods and push it into the system, we spent more time digging these things out than surveying as they were prone to becoming lodged. They would only negotiate slight bends or changes of direction as you went into the system but 9 times out of ten they would not pass through the same bend as you tried to retrieve the camera.

Nowadays the camera cable itself is sturdy enough to push the camera into the drain, most affective in 100mm and 150mm pipe work they can also be used in 225mm drains and sewers up to a certain distance.

There are now many push rod products on the market each with its own merits, some can be easily pushed on a straight run for 50 or 60 mtrs but they may struggle to negotiate more than one bend, others can pass through multiple bends and changes of direction but you will struggle to push them more than 30mtrs.

There are also smaller units for pipe work down to 50mm in diameter and they usually have about 20mtrs of cable, they have their place and are handy to have in the van but i wouldn't use them on larger diameter pipe work on a regular basis.

Most inspection systems now have a self leveling camera head so there is no need to stand on your head when you a trying to figure out if the junction is coming from the left or right hand side, and there are several push rod cameras that have pan and rotate heads for looking into joints and junctions.

Surveying Branch lines

These push rod systems are very flexible and as a result if you are surveying in an upstream direction on a 100mm or 150mm line you can easily divert the drain camera into a lateral connection or branch lines with a little effort, if you are on site for a Home Buyers Survey or Subsidence Investigations then this is the very least the client requires.

Main Line Crawler Systems

These systems propel themselves into the pipe on either wheels of tracks, they can access lines from 100mm upwards though on most domestic systems bends and general changes of direction are prohibitive for these cameras..

They are more commonly used on larger drain and sewer systems and again the picture is in colour, the camera heads can pan and rotate to inspect joints and lateral connections and there are now crawler systems that carry a satellite camera on their back which it can send into branch lines and lateral connections

Drain Camera Inspection Reports

A good domestic CCTV Drain Survey Report should be informative but easy to read and a site plan helps the home owner or client get some idea of what you are trying to say. A basic survey should contain the following

• Digital Recording - See Example To The Right
  A DVD or video file of the survey.               
  - Still Images if required to highlight settlement to gullies, fractured channel pipes   etc
• Data Sheets
  These should show the following;
  - Start and end point of survey.
  - Pipe size, material and length
  - Pipe depth
  - Direction of survey, upstream or downstream
  - System type, foul, storm or combined
  - Shared, privately owned or local authority
  - All connections and changes of direction on system
  - List of defects found including distance from start point of survey.
• Site Plan
  A drawing of the site or marked site plan, see example to the right
  - Showing numbered manholes, rodding points, gullies and soil vent pipes.
  - System layout including indication of direction of flow
  - Hard standings, lawns and flower beds.
  - Changes in landscape such as raised patios or steep inclines
  - Indication of system in respect to boundary lines, footpaths and roads
• Written Report\
  An overview of the completed survey and findings
  - Why the survey was carried out, home buyer survey, problematic system etc
  - Summary of what was found
  - Recommendations for repair if required

There are other items that could be included such as the weather if you are surveying a storm or combined system during prolonged rainfall and the water levels are high, if the system has been cleaned or not. Manhole reports are usually for bigger projects but if defects are noted this should be highlighted on the data sheets and in the recommendation section of the report.

I have been asked to assess many different reports over the years and they can range from page after page of data from which you would struggle to gather any useful information unless in the industry, through to a hand written note on the back of a fag packet including tea stain and mucky thumb print.

A well written report can cut straight to the defects and any recommendations required and the data sheets are there to back up the findings, a simple site plan can help the layman understand what is wrong, where it is and what you propose to do about it.

There are several software programs on the market that make collating the above information easy, neat and the reports professional looking, these can be edited on site or back in the office through a desk top computer.

Home Buyers Drain Inspection Surveys

A pre-purchase survey or Home Information Pack survey should contain all the above, you need to know the condition of the below ground pipe work, the manholes on the system and even the gully pots around the property, a good contractor should be lifting gully grids and looking for fractured and dropped gullies and general signs of water loss. Simply pushing a camera up and downstream from a manhole will not tell you the condition of a system.