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pipefall being laid on a drainage pipe in a ditch

Measuring Pipe Gradients on Site Without a Laser Level

All above ground and below ground horizontal drainage pipes need to be laid to an adequate gradient – this is usually somewhere from 1 in 40 to 1 in 100.

Why is this necessary? Simply put, the gradient or fall is needed to allow the pipes to drain. A perfectly level drainage pipe, or one with a gradient of less than 1 in 100, could cause the flow to slow down and solid waste to become stranded, causing a blockage. A 1:40 to 1:100 gradient will normally give adequate flow velocities.

So how is a fall calculated?

Fall calculations are made when planning a building project in order to provide adequate flow rates and ensure solids don’t cause blockages in the drainage system. In a nutshell, the “fall” of a pipe means the vertical amount the pipe drops from point A to point B over a certain distance. This means a gradient can be defined as fall divided by distance.


For example, a 1 in 40 pipe fall means that for every 40 units of length, the pipe drops by 1 unit. So in a 40 metre run of pipe, the pipe would drop vertically by 1 metre. And the gradient would be 1/40, or 0.025.


What’s the easiest way to measure the fall?

Often, on site contractors tend to use laser levels to prove to the site inspector that the pipe they’ve laid is within the correct parameters made during planning. Laser levels are expensive though, and for a DIYer or jobbing builder needing a quick check this kind of specialist equipment is out of the question.

There are also various DIY solutions with spirit levels like this one, but there is also another way which will save you time and effort on site.

Metex PipeFall is an innovative and unique manual pipe gradient measuring tool with pre-set falls of 1:40, 1:60, 1:80 and 1:100. It allows the installer to quickly and accurately lay drainage pipes to a required fall, or do a quick check to prove the gradient to the site inspector – without having to invest in a laser level or spend extra time and effort putting together a DIY solution.   

 It’s simple to use, as all you need to do is lay the tool over the pipe, turn it around to show the desired gradient on the top, and then adjust the pipe until the spirit level bubble shows when the fall has been achieved – see how in the video below! 

Redesigning Pipefall 

Pipefall’s old design was about 1.6m long with a sliding spirit level, but was slightly cumbersome and not ideal for shorter lengths of pipe, so the tool has been redesigned for convenience. The new version is less than 1m long, which allows it to be handled, stored and transported conveniently and makes it easier to use with shorter pipes. 

It is made from the same tough materials as the previous version: An anodised Aluminium section with an engineering plastic body which houses the spirit level. The engineering plastic used to house the spirit level is tough and impact resistant – in fact it’s the same material used to manufacture LEGO blocks! We all know how tough these are and how painful they are to tread on… 

The new version of Pipefall has no moving parts, so there no longer a concern about grit and site debris getting caught in them.  This means that the tool no longer needs to be set to a particular gradient, it simply needs to be placed onto the work area in the correct orientation.  As these orientations are moulded into the body, this could not be easier. 

PipeFall is available from Plastics Express, Drainstore, Mad4Tools and other stockists – for more information on PipeFall stockists, click HERE!