Chapters
Transcript
Intro
Shoring protects you only when it's the right system, set up right. Support must go in as you dig. In Type 4 soil, where it can be done, the support must go in before the soil is dug out. In every soil type, it must support the walls continuously.
Setting Up & Moving the Box
Install, use and maintain the box the way its design says. Keep the gap to the walls to the minimum needed to move it forward. Normally, it must reach at least 0.3 m above the top of the trench. Where traffic passes and the trench is covered when no one is working, it need only reach the top. Below upper walls sloped for the soil, it must reach at least 0.5 m above the vertical lower walls. Best practice when the box moves: never ride it or stand between it and the soil or pipe. Keep hands clear of pinch points while slack is taken up, and lift only by its lifting points. Make it a habit that nobody stays in the trench or box while it moves.
Staying Protected
No one may enter a trench that doesn't meet the excavation rules. So don't step past the ends of the box into a part of the trench that isn't protected, even to measure, join pipe or grab a tool. A box protects the people inside it, and gives little or no support to the walls around it. A good habit: keep the shoring to the bottom unless its design allows otherwise; if soil comes from behind or under it, get out.
Looking After the Shoring
And it's wise never to remove or move a strut because it's in the way. Have your supervisor put in approved replacement support first. A good habit: check hydraulic shoring for leaks, bent bases, cracked nipples and bent welds, and again after any hit. If a strut is bent, leaking, loose or losing pressure, get out and report it.
Putting It In & Taking It Out
Best practice: shoring goes in top down, and comes out bottom up. Get everyone out before any piece that holds a wall is pulled. Support stays in until just before backfilling, and a competent person must supervise its removal.
Recap
To recap. Install and use the trench box the way its design says. Support goes in as you dig. It comes out at backfill, under a competent person. Never step out of the box into a part of the trench that isn't protected. And make it a habit to climb out before the box moves.
Sources
- Ontario Regulation 213/91, Construction Projects
- IHSA Construction Health and Safety Manual and IHSA trenching guidance
- Dashpot recommended practice (said as such in the video)
This video is for work in Ontario, Canada. It covers Ontario requirements and good practice, and the narration says which is which. Rules differ in other provinces and in the US. General information only, not legal advice. Always follow the regulations, your employer's procedures and the instructions of a competent person on your site. Narration is AI-generated (the Dashpot narrator voice); every script is checked against the sources listed above before it is voiced.
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