Gradient pipe laying etc Please help

[dee2912]

Hi can any1 tell me where i could get a book or anything to help me study and understand gradient falls i am training to be a pipelayer an im having trouble understand gradient levels etc i have googled for books but im jus getting lost thanks in advance

[buildersmate]

Are you referring to the principles involved or are you seeking specific gradient information for a particular drainage situation?
If the former, than the book would be a candidate for the shortest in the world - it is really simple. A 1 in 80 gradient means that for every 80cm of horizontal travel, the pipe dips 1cm. So you measure the total level of the run in metres, divide it by 80 (or whatever fall you want) then it gives you a vertical distance. Take a level from one point to the other, then drop the end by the vertical distance calculated.

[dee2912]

hi buildersmate i am a trainee an will be working with a directional drill drilling an sticking to a gradient fall so when we pull back the product pipe the fall will be wat we set out to acheive so pretty much jus how the gradient chart works for instance is my fall was 1 in 173 on a gradient chart says 1 in 73 = 1.370% what is this 1.370

[quizman55]

Your 1.37% is arrived at by taking the gradient and multiplying by 100. 1/73 x 100 = 100/73 which = 1.37%

A gradient of 1 in 4 say would be a gradient of 25%

1/4 x 100 = 100/4 = 25% etc

[dee2912]

Hi quizman so am i rite in saying 1 in 73 = 1.37 so if i put in a pipe at 1 in 73 my pipe is falling at an angle of 1.37% is that rite??? also when it is 1 in 234 say is it still mutiplyed by 100 too

[sddsddean]

Its not an angle of 1.37%, its a gradient of 1.37%. If you use the formula quizman has given (about multiplying by 100), you can see that a flat/level line has a gradient 0% (ie [1/infinity] x 100 =0) and a vertical line has a gradient of infinity%( [1/0] x 100 = infinity). Now although you may use a level line, you would never use a vertical line. An angle of 45 degrees (ie 1 up for every 1 along) would have a gradient of 1 in 1 which is 100%. The whole point of this is that although it is easier to visualise gradients as 1 in whatever, most machines (such as pipe lasers, directional boring rigs etc) don't recognise them, so you have to enter the percentage gradient for the machine to work, so thats why you need to know how to switch between the two. Hope this makes sense!!

[quizman55]

Gradient of 1 in 234 gives a percentage of 100/234 = 0.427% approx. so to get the percentage equivalent figure of any gradient simply divide 100 by the number that is on the bottom line of the fraction (234 in this case). Hope this explains it better.