One drainage job needs a push camera.
The next needs a powered crawler.
And sometimes the difficult part is knowing which approach is right before the equipment has even been unloaded from the vehicle.
Push rod and crawler systems are both established ways of carrying out CCTV pipe inspection, but they are designed around different working conditions.
Choosing between them should therefore start with the job: pipe diameter, inspection distance, access, camera control and the information that needs to be captured.
What is a push camera system?
A push camera uses a flexible pushrod or cable to move the camera through the pipe manually.
The operator feeds the camera into the system from the access point while watching the inspection on a monitor.
Push systems are particularly useful because they can be compact, quick to deploy and relatively easy to move between inspection points.
For smaller diameter drainage work and straightforward runs, that simplicity can be a major advantage.
When does a push camera make sense?
A push camera is often a sensible choice where the job involves:
- smaller diameter pipework;
- shorter or medium inspection distances;
- limited access around the inspection point;
- frequent movement between jobs;
- rapid deployment; and
- work where a manually pushed camera can comfortably reach the area.
Different push systems offer different capabilities.
Some use compact axial camera heads for a clear forward view. Others provide pan-and-tilt camera control where the operator needs to examine connections, joints or defects in more detail.
The important point is that “push camera” covers a wide range of systems.
The right one depends on the pipe size, distance and level of inspection required.
Where can a push camera become limiting?
The main limitation is contained in the name: the camera has to be pushed.
As inspection distance increases, friction between the pushrod, camera and pipe can make progress more difficult.
Bends, changes in diameter, deposits and difficult pipe conditions can also affect how far the camera can be pushed effectively.
A system may have a long pushrod on the reel, but that does not automatically mean the full length will be achievable in every pipe.
Real-world push distance depends on the application.
This is where a powered crawler can become the better inspection tool.
What is a CCTV crawler system?
A crawler is a powered inspection unit that drives through the pipe rather than being manually pushed from the access point.
The operator controls the crawler remotely while viewing the camera image from the surface.
Crawler systems are generally used in larger pipes and sewers where longer inspection distances, powered movement and greater camera control are required.
Because the crawler provides its own traction, it is less dependent on an operator physically pushing the camera through the pipe.
When does a crawler make more sense?
Crawler inspection becomes particularly useful where the application involves:
- larger pipe diameters;
- long mainline sewer runs;
- inspection distances that would be difficult to achieve by pushrod;
- powered movement through the pipe;
- precise positioning around suspected defects;
- pan-and-tilt camera inspection; and
- professional mainline CCTV survey work.
The crawler gives the operator more control over how the inspection unit moves through the line.
That can make a substantial difference where the inspection involves longer runs or features that need to be examined carefully.
Pipe diameter is the first question
One of the quickest ways to narrow down the choice is to establish the diameter of the pipe.
Very small drainage lines may only accommodate a compact push camera.
As the pipe diameter increases, more camera and crawler options become available.
For example, Rausch push camera systems cover applications beginning in small-diameter pipework, while crawler systems are designed for larger mainline applications.
That means the pipe diameter can immediately rule some systems in or out.
Then consider inspection distance
The next major factor is how far the camera needs to travel.
For a relatively short run, deploying a crawler may add complexity that is not required.
A suitable push camera can often complete the work more quickly and with less equipment around the access point.
But as the required distance increases, a crawler can provide a more practical way of moving the inspection camera through the pipe.
This is particularly true in larger mainline sewers where long runs are part of normal survey work.
Do you need axial or pan-and-tilt viewing?
The camera view also matters.
An axial camera looks forward along the pipe.
For many drainage surveys, that is exactly what is required.
A pan-and-tilt camera gives the operator more control over the direction of view.
That can be useful when inspecting:
- laterals and connections;
- joints;
- cracks;
- areas of infiltration;
- surface damage; and
- other features where a straight-ahead view is not enough.
Pan-and-tilt capability is available in both certain push-camera systems and crawler configurations, so the choice is not simply “push equals axial” and “crawler equals pan-and-tilt”.
Again, the application should determine the configuration.
Access around the pipe matters
Inspection equipment has to work above ground as well as underground.
A compact push reel may be easy for one operator to carry through a building, down steps or between multiple access points.
A crawler system can involve a larger cable reel, control equipment and additional components.
That extra equipment is justified when the job requires the capability.
But for a straightforward small-diameter inspection, carrying more equipment than necessary can simply slow the job down.
The best system is therefore not automatically the most capable one.
It is the system that provides the required capability without adding unnecessary complexity.
What if your work regularly requires both?
This is where things become more interesting.
Some drainage contractors do not operate within one narrow range of pipe sizes or inspection types.
One job might involve push-camera work.
The next may require a crawler.
That creates a question about whether to carry completely separate systems or use a platform that can adapt between different inspection arrangements.
A system such as Omicron sits between the traditional categories
The Rausch Omicron is an example of a platform designed around that need for flexibility.
It can be configured for push inspection as well as powered crawler operation using compatible Rausch camera and crawler equipment.
That means a contractor can use one control platform across different types of inspection rather than treating push and crawler work as completely separate systems.
The original reason this kind of platform is useful is not simply because it has more functions.
It is useful where the contractor genuinely encounters different inspection requirements from one job to the next.
More flexibility is not automatically better
A combined platform is not necessarily the right choice for everybody.
If almost all of your work involves small-diameter domestic drainage, a dedicated compact push camera may be quicker, lighter and more economical.
Likewise, a contractor whose work is focused almost entirely on large mainline sewer inspection may be better served by a dedicated crawler setup or complete inspection vehicle.
Flexibility has value when the work requires flexibility.
It should not be purchased simply because more capability sounds better.
Ask what the crew actually encounters
Before specifying a system, it helps to look at the jobs completed over the last few months.
What pipe sizes appear most often?
How long are the runs?
How often does the existing equipment fail to reach the required area?
How often is a more controllable camera required?
How often are crews carrying equipment that never gets used?
Those questions can reveal more about the right inspection setup than simply comparing two specification sheets.
A simple way to choose between push and crawler
As a starting point:
- Choose a push camera where the work is mainly smaller diameter, relatively short-distance inspection and fast deployment matters.
- Choose a crawler where the work involves larger pipes, longer distances and powered mainline inspection.
- Consider a flexible combined platform where your workload regularly moves between push-camera and crawler applications.
There are exceptions to every rule because pipe condition, access and camera requirements vary.
But those three questions provide a useful starting point.
See the equipment on a real application
A specification can tell you the pipe diameter and cable length a system is designed around.
A demonstration shows you what it is actually like to move, set up and operate.
That is particularly useful when choosing between inspection approaches because the difference is not only technical.
It also affects the workflow for the crew using the equipment.
Rausch UK can demonstrate push camera systems, crawler systems and flexible inspection platforms on customer applications across the UK.
If you are unsure which approach fits your work, start with the pipe diameter, required inspection distance and the type of camera control you need.
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