(1)
The total length of distribution pipe shall
(a)
not be less than 30 m when constructed as a shallow buried trench, or
(b)
not be less than 40 m for any other absorption trench.
(2)
Except as provided in Sentences (1), (3), and (4) every leaching bed constructed by means of absorption trenches shall have a total length of distribution pipe not less than the value determined by the formula, L = QT/200 where, L = total length of distribution pipe in metres, Q = the total daily design sanitary sewage flow in litres, and T = the design percolation time.
(3)
Except as provided in Sentence (1), where a leaching bed receives effluent from a Level II, Level III or Level IV treatment unit as described in Table 8.6.2.2., the leaching bed may have a total length of distribution pipe not less than the value determined by the formula, L = QT/300 where, L = total length of distribution pipe in metres, Q = the total daily design sanitary sewage flow in litres, and T = the design percolation time.
(4)
Except as provided in Sentence (1), where the leaching bed is constructed as a shallow buried trench, the total length of the distribution pipe shall not be less than the value determined by Table 8.7.3.1.
Table 8.7.3.1. Length of Distribution Pipe in Shallow Buried Trench
Forming Part of Sentence 8.7.3.1.(4)
