20.—(1) Vibratory or drilled “pin” piling must be used as standard, with percussive piling only used if required to drive a pile to its design depth and where the relevant undertaker has established, following the carrying out of a desk top study informed by appropriate survey information, that vibratory or drilled “pin” piling would be ineffective.
(2) Where percussive piling is established to be necessary in accordance with sub-paragraph (1)—
(a)soft-start procedures must be used to ensure incremental increase in pile power over a set time period until full operational power is achieved;
(b)the soft-start duration must be a period of not less than 20 minutes; and
(c)should piling cease for a period greater than 10 minutes, then the soft start procedure must be repeated.