On completion of all sewerage and plumbing work, but before such work is connected to a conserving-tank, a septic tank or a public sewer, such work shall be inspected by one of the following tests shall, in the presence of such employee, be applied, and such work shall withstand such tests to the satisfaction of the local authority—

a) for all sewerage work—

i) the interior of every pipe or series of pipes between two points of access shall be inspected throughout its length by means of a mirror and a source of light; a full circle shall appear to the observer, and the pipe or series shall be seen to be unobstructed;

ii) a smooth ball having a diameter of between 12 and 25 millimetres less than the nominal diameter of the pipes shall, when inserted at the higher end of the pipe or series of pipes, roll down without assistance or interruption to the lower end;

iii) before any pipe or series of pipes is covered, all openings of the pipe or series of pipes to be tested having been plugged or sealed, air shall be pumped into the said pipe or series of pipes until a manomic pressure of 100 millimetres of water is indicated, after which without further pumping the said pressure shall remain greater than 75 millimetres for a period of at least 10 minutes;

iv) after all the trenches have been refilled to ground-level, the same test as set out in sub paragraph (iii) shall be applied, except that the stated pressure shall be maintained for 3 minutes;

b) for all plumbing work, before any pipe or series of pipes is covered, all openings of the pipes or series of pipes to be tested having been plugged or sealed, and all traps associated therewith filled with water, air shall be pumped into the pipe or series of pipes until a manomic pressure of 40 millimetres of water is indicated, after which, without further pumping, the said pressure shall remain greater than 25 millimetres for a period of at least 10 minutes.