Excavation Review

As a site contractor we do a lot of excavation work and like any job the more you repeat a job the more you get comfortable with it. Well that comfort level is a bad thing! In the United States excavations have caused fatalities and very serious injuries to employees that have become to comfortable working in and around excavations. So what do we need to do to keep our selves safe?

Let’s review some excavation basics!

Before you even start to dig do you have a plan? How deep is this excavation going to be? Do we have room to slope the sides of the excavation? Do we have a trench box big enough for what we are doing? Are there going to be utilities in the way? Do we have to build a box and do we have the correct materials to build a box?   How are we going to get in and out of the excavation?
Now that we have a plan, can we start? - NO, hold a quick meeting and make sure everyone on the crew knows what we are going to do to complete the excavation in a safe manor.
Sloping - We will treat all soils that we excavate as Type C - loose granular material. If you are going to use sloping as a means of protection, make sure you have the space to do so. For Type C material a 2 to 1 ratio is required.
Trench Box - This system is the best when there is not enough space to slope and there are no utilities in the way. Remember this when the box is put into the excavation 18 inches is supposed to be above grade to prevent material going into the excavation. Also the foot of the trench box can not be more then 2 feet off the bottom of the excavation.
Sheeting - This system is best when there is not enough space to slope and there are utilities in the area of excavation. Before you start to dig make sure you have the correct materials on site for the sheeting pit to be built. Also plan out how we are going to support the utilities and ensure that we do not undermine them.
Access - Any time we have an excavation that is 4 feet or deeper a ladder needs to be in the trench.   The ladder needs to extend 3 feet above the top of excavation. Also the ladder needs to be at a 4 to 1 ratio (for every 4 feet up it needs to be kicked out 1 foot).

Remember Excavations are deadly; make sure there is adequate protection even if the job to be performed will take a few seconds. All it takes is a few seconds for that serious injury to occur.         (Thanks go to S. Dygd for this contribution.)