Back to Working with Inclination Data

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• The pipe ID is shown in the top-left of the inclination panel along with the date and time of the inspection that is currently in view.

• In this example, the test has been done from the upstream end and has been done forwards, so the total length of the pipe which is in the pipe header information can be seen on the lower right hand end of the x axis of the graph, so it goes from left to right, 0 m to 23 m. If this example had an inclination test done from the other end, then 23 would be on the left and zero would be on the right, because the measurement points are always measured from the end where the CCTV truck is located, regardless of the inclination test direction.

• The upstream manhole is plotted on the left side of the graph, always. This is independent of the inspection direction or the inclination test direction as has been described previously.

• The downstream manhole is plotted on the right side, always.

• The pipe diameter can be seen on the graph by the distance between the two sloping brown lines. These lines represent the ‘perfect’ line of the pipe at its invert (the bottom of the pipe) and at its crown (the top of the pipe), so by looking at the scale on the left side of the graph, we can see the difference between 2.2 and 1.9 is 0.3 m which is the diameter of the pipe in the section header.

• The inclination curve is always draw from the end where the CCTV truck is placed, so the blue curve is either drawn from left to right or right to left based on the inspection and inclination directions, but the starting altitude is taken from the section header data. In this example, the pipe depth at the upstream end is 2.2 m, so this is the starting point for all the following points as the test is carried out and the camera goes down the pipe.

• Notice the key above the upstream manhole ID on the graph. This describes the lines that you can see - the thick blue curve and the thin brown lines of the pipe.

• Notice the key above the downstream manhole ID on the graph which shows that the green arrow above the centre of the graph shows the CCTV inspection direction and the blue arrow shows the inclination test direction. These two directions are mutually exclusive from each other.

• In the bottom right corner we see the ‘Measured distance’. This is not the length of the pipe or the length of the inspection. It is the length of the inclination test which is not necessarily the same as the other length values and is also independent of the other lengths. So, in this example, the inclination test does not quite cover all of the pipe (21.75 ÷ 23 = 0.95 or 95 %) so only 95 % of the pipe was tested in the inclination test. There is no shame in this value, it is quite normal for these lengths to not quite align, but in perfect conditions, the values should be as close as possible.

• In the top left quadrant of the panel there are number of user options which can affect what is shown on the report (more on these later), the calculated delta height (fall) value, the calculated gradient value and a printing button which will print the currently displayed graph. Note - the inclination charts can also be printed from the printing control panel, with the same results, but the difference there is that all of the graphs from the project will be printed, not just the currently selected graph.

• In the top right quadrant there are some navigation buttons to view the next/previous inclination test in the project and a delete button which will delete the current test from the project, and then above these controls (not indicated on the image above), there are a lot of user controls that affect the ouput which we will go into more detail later.

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These are calculated from the received data points and are good values that describe a ‘happy’ drain that is flowing the right way.

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Settings Tab

Now we should look more close at the data option in the top-right quadrant of the panel. For this example, the basic data looks like this:

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Another advantage of activating the ‘Fit to Altitudes’ option is that if the CCTV inspection was abandoned half way along the pipe due to a problem and the inclination test was carried out, then the thick blue line will be fixed to the pipe and will only draw half way across the graph, so again, it will give an intuitive representation of the data that has been collected.

Calculation Method Tab

In the ‘Calculation Method’ tab, we have the option to change the way that the data is presented from the ‘WinCan’ method (is the default method) to the SV-P91 method (formerly known as VAV-P50):

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SV-P91 modelling display.

The SV-P91 system is a Swedish building (SV = Svensk Vaten or Swedish Water) standard specification for newly built sewers which describes acceptable limits for the ‘straightness’ of a pipe when its inclination is measured. There is no other standard like this in the world and it used by many countries in the absence of any alternative.

As mentioned, the specification is for newly built sewers, so it may not be considered appropriate to use it on old pipes that are maybe 100 years old, but the tolerance values can be adjusted by the engineer if they wish to use the same logic but soften (or harden) the bands for a ‘good’ pipe.

When this option is activated, there are 3 sets of tramlines activated on the graph, in pairs either side of the lower brown line (the ‘perfect’ invert line of the sewer). These are tolerance bands for good (Class A), medium (Class B) and bad (Class C) and are defined in millimetres. The values for these classes are defined in SV-P91 and are dependent on the measured inclination of the pipe from the GPS data and the pipe diameter, so good GPS data is essential for this type of output.

Checking the boxes in the ‘Out A', ‘Out B’ and ‘Out C’ boxes activates the thick coloured parts of the thick blue line where the curve crosses the tolerance line so that the engineer can see very quickly if the pipe inclination test is confirming that the installation is a Class A, B or C. These classes are very tight as defined in the standard.

By default, the classes are set to the SV-P91 values, but by clicking on the ‘Class’ button, we can modify the values to suit our own needs or maybe contractual definitions for other countries.

Print the Reports in WinCan VX

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