HOW TO SET SLOPES (FALLS/GRADES)
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Working Example (when you do NOT know the % grade to set) - Continued
If the laser is switched off , this value is lost.
Keep the detector clamped in place on the measuring staff & by moving between covers A & B,
keeping a continuous tone on the detector, the ground can be cut away at the base of the staff ,
following the grade set by the laser.
Obviously allowance must be made for the actual depth of the pipes’ exit & entry positions in each
manhole.
As an example,
if distance “D” is 10m (10,000mm) & “F” is 125mm, from the formula shown at
the bottom of the “Gradient Conversion Chart”:
(Distance in height / distance) x 100 = Percentage Grade.
i.e. 125/10,000 x 100 =
1.25%
From the chart on page 23, this is a 1:80 Grade (fall) used typically for a foul drain run.
