Safety on Site: Excavating and Trenching
There are several hot button topics in our industry, especially when safety practices are involved. Excavations and open trenching are prime examples, leaving regulators concerned due to the sheer risk involve. In fact, according to National Institute for Safety and Health (NIOSH) estimates, there have been nearly 400 deaths since 2003 in open excavations alone.
While the telecommunications industry uses machinery to install most of its underground plant, there are occasions when construction hands and contractors are involved in excavations. This is usually done to repair cut lines or gain access to places that machinery cannot reach. These open excavations do not tend to be very deep, and do not carry a significant risk of entrapment or engulfment. But keep in mind that the deeper the excavation, the heavier the potential weight of the soil – an important point to consider if the excavation were to collapse and bury an employee, even partially.
Let’s look at a generic breakdown of different soil types. If we average topsoil weighing roughly 78 pounds per cubic foot with wet sand weighing 115 pound per cubic foot, we will get a rough estimate of 97 pounds per cubic foot. Considering a cubic yard of soil, which is 27 cubic feet, we can calculate that an employee who suffers a cubic yard-collapse would feel 2,600 pounds of weight on them – roughly the weight of a car! This much weight can break limbs, restrict breathing, and even crush equipment.
Even if an employee is covered in soil only to the waist or just slightly above, drawing a deep breath would be extremely difficult, and in some cases, impossible. As a person inhales, their stomach flattens as their chest fills – and the soil surrounding them begins to fill in the void. Each breath becomes harder to take, and the consequences can, in the worst cases, be fatal.
There are other hazards associated with an open excavation as well, like equipment parked dangerously close to the excavation’s edge. This places excessive weight on the side walls, causing potential collapse. There is even the risk of that same equipment falling into the excavation on top of the employee(s) if it is parked too closely to the open edge. Consider falling objects too, like tools and fire extinguishers, that can injure an employee below. Hazardous or potentially flammable atmospheres pose a threat as well!
There are even obscure and random hazards to consider, such as animal and insect bite exposure. No matter how unlikely, OSHA expects you to consider all hazards and attempt to account for their risk management.
