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The manholes featured in a previous post are being connected by underground pipework. Here we look at the building sequence of the foul drain that will run under the pedestrian walkway south of the building.
First the trench is dug to the correct depth, Here the builders are lining up the profile battens.
Next the pipe is laid on a layer of fine gravel, known as pea gravel, to give it a uniform support.
After checking the alignment, it is partially covered by pea gravel.
A pressure test is then applied to make sure the joints are sound and the pipe is not leaking. The trench is only filled in after the building inspector has done his own pressure test and approved the bedding.