§ 33.318. Excavations with hydrostatic pressure.

 (a)  For excavations not more than 8 feet in depth, timber shall be used as follows:

   (1)  Uprights. Two by 6 inch tongued and grooved close sheeting.

   (2)  Stringers. Six by 8 inch spaced vertically 4 feet apart center line to center line.

   (3)  Cross braces. Six by 8 inch spaced horizontally 6 feet apart center line to center line.

 (b)  For excavations more than eight feet in depth, timber shall be used as follows:

   (1)  Uprights. Three by 6 inch tongued and grooved close sheeting.

   (2)  Stringers. Eight by 10 inch spaced vertically 4 feet apart center line to center line.

   (3)  Cross braces. Six by 8 inch spaced horizontally or 6 by 10 inch spaced horizontally 6 feet apart center line to center line.

 (c)  The greater dimension of the stringers shall be placed at right angles to the sheeting.

 (d)  If desired, steel sheet piling and bracing may be substituted for wood.

   This section cited in 34 Pa. Code §  33.319 (relating to tables).