February 2014 - Digging Your Own Grave
Digging Your Own Grave
Submitted by: Stephen Rodgers
How many times have you driven, or walked by an open trench, and how many of those had protection systems installed? I read a minimum of two or three articles per week on fatalities caused by trench collapses, and the same holds true for falling into unguarded trenches. If you are working in an unprotected trench when it collapses there is a high probability you will be hurt, or killed. The sad part is that following state and federal standards will both protect you, but many times these are disregarded. For example, NRS 455.010 in essence states that if you dig in the ground you must guard it with some kind of barrier, and OSHA standard 29 CFR 1926.650 Subpart P covers excavations and protection standards.
Our article today will focus on trench cave-ins, and what we can do to protect ourselves. First, we need to understand what is considered an excavation; by definition, excavation means “any man-made cut, cavity, trench, or depression in an earth surface, formed by earth removal.” Did you notice the word any in the definition? We shouldn’t be worried about a cave-in in a six inch ditch, but CFR 1926.652 states that any excavation 5 feet, or deeper will have some kind of protective system, unless it is cut entirely in stable rock. Here in Nevada we have very few places that can claim ”stable rock” so that means we need to use protective systems. These systems include sloping and/or benching, and support/shield systems. Generally speaking, very few projects can use benching and sloping due to the large areas that these methods require. Support and shield systems, specifically shield systems such as trench boxes, are the most commonly used. These systems will protect you against collapses when properly installed, but what about other engulfment issues such as water or hazardous atmospheres? You should never enter a trench that has water in it, water can make walls collapse. Another issue is how do you know if the atmosphere is hazardous? Well, just by atmospheric testing. Also, there are other things to consider when you enter into a trench because depending on what you are doing in the trench this space could become a confined space in some cases, and other safety standard will apply. That brings me back to my title; if you miss any of the above steps you may just be digging your own grave.
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