Sometimes it may be necessary to double check the dimensions of drop in liner against the dimensions of the tank or containment area to be lined itself. With the liner unfolded nearby it is possible to measure the dimensions of the liner just as we would on our shop floor as part of the final quality inspection.
On the bottom of the tank liner are a series of creases running from corner to corner. These crease marks correspond to the width and length of the liner. There will also be similar crease marks running from the bottom corner to the corresponding top corner. This represents the depth of the tank liner. Finally there will be a crease mark along the top perimeter that represents the top rim of the tank. Most tank liners are designed to wrap back under the top rim and there will be a crease for that bend as well. It is on this section that you would see the holes for use with the Wittclips™.
Measuring the tank liner is simply a matter of laying the liner as flat as possible along the crease mark to be measured and then measuring. Starting at the corner of the crease walk the tape measure hand over hand to the other corner. There may be some slight discrepancy between this measurement and the actual dimension of the liner because of any folds or bumps in the liner and the radius of the corners but it should provide a close enough measurement of the liner to ensure accuracy against the tank or pit itself.