NUCA/OSHA Trench Safety Stand Down June 14-21, 2024
Pic: Slide Rail used within the adjacent area of a tank. Why Slide Rail? Why Not A Trench Shield?
Part 4 of 5
Greetings! For the fourth day of the stand down---a comment or two on the concept of "adjacent" as used in the standard.
We have been considering basic concepts, myths and today what may actually be just a misunderstanding.
I chose this as a topic, since generally, when I ask an excavation safety CP class for what the meaning is of "adjacent"---the answer is usually "next to" or "across from" and sometimes "parallel".
As we noted yesterday---"next to" is within the meaning of the answer I will give from the standard---but it is not enough and leaves the field leadership without proper guidance.
As an instructor or safety consultant---we can do better.
That most of your people may not know what "adjacent" means is easily verified by just asking.
Generally, where possible, OSHA seeks to provide guidance that can be measured. Some call this Trench Safety By The Numbers. For example---is there an 18" rule, 2' rule (several), 3' rule, 4' rule (2), 5' rule, 6' rule, 20' rule, 25' rule and so forth?
Accordingly, in Appendix C a measurement for "adjacent" is given. It is a 1:1 relationship to the depth of the excavation/trench. Accordingly, if my pump station is 20 feet deep, everything within 20' of the edge is considered "adjacent" to the cut.
Why is this important?
If there is a building, retention wall (soil), or other structures within the "adjacent" area---the competent person has special considerations he must consider. Time does not permit elaboration, but this issue is one of those where OSHA is saying: Competent Person you are good---but you are not that good.
A careful reading of the standard suggests that there are certain conditions which will require underpinning, usually involves an engineer, and if the CP thinks that is not necessary---he will have an engineer to agree---in writing.
Another issue of when "adjacent" is operative is when you have mobile equipment moving parallel or required to come to the edge of the excavation/trench. Operator safety is also under his purview.
Most tabulated data references "adjacent". Some cowardly manufacturers leave the CP and employee safety up in the air in this regard. The issue is surcharge loads being applied to the protective system, be it shoring or shielding.
The word was once used for surface encumbrances...but replaced with "located so as to be a hazard to employees".
True, you will find the word "adjacent" used similarly in the 1972 Edition of Subpart P.
But it is only in Appendix C of the current standard that a definition is provided. 1926.650-652 Appendix C (d)(2)(ii)(A)
Adjacent is measurable. It is not left to one's imagination or vague sense of "next to".
Words matter! Failure to be attentive to this concept could prove disastrous.