When dealing with excavation shoring in British Columbia, it's crucial to comply with the Occupational Health and Safety Regulation B.C. Reg. 296/97 [1]. Here's a breakdown of key requirements:

1. When Shoring is Required: Shoring is needed when an excavation is over 1.2 m (4 ft) deep, or when a worker approaches the side or bank closer than the depth of the excavation [2]. The sides of the excavation must be sloped, benched, or supported [2].

2. End Shoring: If the end of a trench is over 1.2 m (4 ft) deep and not adequately sloped, end shoring is required [2]. Walers for end shoring must bear against the walers along the sides of the trench or provide equivalent structural restraint [1]. If the end shoring waler length exceeds 1.8 m (6 ft), a professional engineer must design it [1].

3. Shoring Specifications: Shoring must extend from at least 30 cm (1 ft) above ground level to as close to the bottom of the trench as possible, but no more than 60 cm (2 ft) from the bottom [1]. Timber shoring materials must be lumber graded Number 2 or better from specific species groups like Douglas fir-larch or hemlock-fir [1].

4. Safe Procedures: Install shoring from the top down and remove it in reverse order [1]. Workers must not enter an excavation to remove shoring if ground conditions have deteriorated [1]. Shoring must be installed in firm contact with the excavation faces to prevent soil loss [1]. Voids between the shoring and excavation face must be backfilled or blocked [1].

5. Trench Support Structures: For trench support structures not designed by a professional engineer, Table 20-1 can be used, considering soil conditions (hard/solid, likely to crack/crumble, or soft/sandy/filled/loose) [3]. Cross braces and trench jacks must be horizontal and secured against dislodgment [3]. The number of cross braces depends on trench depth [3].

6. Additional Considerations:

   • Spoil piles: If the average depth of a spoil pile adjacent to a supported excavation exceeds 60 cm (2 ft), the shoring must account for the increased lateral soil pressure [4].
   • Underground utilities: Before excavating, accurately determine the location of all underground utility services [2].
   • Scaling: The sides of an excavation must be scaled and trimmed or otherwise stabilized [4].

Remember to always check for the most current legislative requirements in your jurisdiction related to protective systems [5].