Sewer Camera – An explanation of the different types of camera hardware
The inspection of sewer and stormwater networks is commonly completed using a camera that records video footage from the inside of underground pipes also called the sewer camera. The photos and videos collected during a pipe inspection can be used to assign a condition grade to pipes through the identification of structural and service defects. Councils, municipalities, and water authorities use these condition grades to prioritise pipe maintenance (e.g., clearing roots and debris) and repair (e.g., patches and lining).
Access to pipes is usually obtained through maintenance holes or pits which can be located within roads, kerbs, public space, and private property.
A variety of different camera equipment is available to record video footage for defect analysis and scoring. Common sewer camera types include:
Crawler cameras are robust remotely controlled inspection robots that traverse through a pipe on wheels. They typically have a strong light source to illuminate the inside of the pipe and are connected via a cable to a vehicle on the surface that supplies power and transmits the video back to a vehicle computer for recording. The robot is controlled by an operator on the surface who directs the crawler’s progress through live vision fed back to their computer monitor. They can adjust for speed and direction, and often have the ability to pan, tilt and zoom the camera lens; leading to the term PTZ camera (they are also called tractor cameras in some regions). Crawler cameras are the most common type used for pipe network inspections throughout the world.
Fixed Zoom Cameras
Fixed zoom, or pole cameras, do not need to travel along the pipe to collect video footage. They consist of a fixed high-definition camera head attached to a pole that is lowered from the surface to the base of the pipe at surface entry locations. Using a combination of strong zoom, focus adjustment, and lighting; a video is recorded as the camera zooms in and the field of vision extends through the pipe from chainage zero to the end of pipe or bend. With a combination of optical (20-40x) and digital zoom (10-15x) they provide a fast and robust way to collect a condition overview of a network.
Push Rod Cameras
House connection branches or sewer laterals present unique challenges when collecting condition footage or diagnosing a problem. Their small diameter and frequent bends mean the larger camera hardware is unable to enter and travel through these smaller lines (typically < 150mm diameter). Push rod cameras are designed for tough and tight conditions. Appearing as a coiled cable on a real with a slim camera head, they can be inserted and controlled manually with imagery fed back to a control unit. The use of skids is sometimes employed to keep the camera head and vision steady and centred.
For large pipes that cover long distances, an inspection raft may be the only choice to collect imagery from within a pipe. These are often used for outfall tunnels where they can be sent downstream and caught with a hook or net at location that could be many kilometres further down the pipe. They are usually designed to stay upright and balanced.
With rapid advancement in UAV technology, the industry has seen an increase in the use of drones for pipe inspection over the last few years. Drones have some distinct advantages in certain situations, including; large pipes with high flow where a crawler may not be able to enter and raft would traverse along the pipe too quickly, and longer pipe inspections where equipment weight or cable length is prohibitive. It will be interesting to see how this technology develops and if it becomes a more mainstream option for pipe networks.
Manhole / Maintenance Hole Cameras
There are now a variety of dedicated cameras available for collecting photos, videos, and 3D scans of the vertical shaft that leads down to the benching and pipe channel. In the past this has been completed by visual surface or confined space entry inspection, using a regular camera, or with a crawler as it is lowered down to complete the main pipe inspection. Newer camera technology has been specifically designed to collect more detailed information with much higher resolution than ever before.
Jetter Nozzle Cameras
Jetters can be used by operators to clear sediment, obstructions, fats, oils, grease, and roots from pipes. Some hydro jetters on the market include a nozzle camera that can be used to help guide the camera through the pipe, locate specific issues and even steer into lateral pipes. The camera is also able to collect video footage following its cleaning run through the pipe to collect information on the effectiveness of the clean and provide an indication of the condition of the cleaned pipe.
VAPAR.Solutions is designed to process and score video footage from a wide variety of camera systems, providing a single cloud-hosted location for all your inspection videos, images, reports and decisions.