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4 Ways to Prevent Trenching Accidents

28 Feb 2019, Posted by F.A. in Concrete Facts

Construction work is fraught with dangers. Accidents such as falling loads, gas leaks, and machinery malfunctions can take place at any time. However, when it comes to construction, excavation and trenching pose the greatest risks.

Trenching accidents, such as cave-ins, can occur unexpectedly, but there are a number of factors that can be indicative of such a tragedy. These include soil conditions or failure of setting up appropriate protective systems.

In order to prevent any excavation and trenching mishaps, you should keep the following steps in mind.

Analyze Ground Conditions

Soil analysis is by far one of the most important factors when it comes to avoiding cave-ins during trenching or excavating. There are numerous different types of soil, but OSHA is concerned with four of the most susceptible types – Stable Rock, Type A, Type B, and Type C.

When beginning excavation, you must first determine whether the soil can stay in position without horizontal support or not.

OSHA requires that a responsible person must identify and classify the soil that is to be excavated, to ensure worker safety. The results of this test will classify the soil type. Here’s what you need to know once you see the test results:

  • Stable rock. This is the most stable type of ground since it is solid rock. When trenching in stable rock, no protective systems are necessary unless excavation goes below 20 feet.
  • Type A. This type of soil is cohesive and can remain stable even without horizontal support. Examples include clay, silty clay, sandy clay, and clay loam. If the soil is fissured, has been previously disturbed, or has water seeping through it, the soil cannot be classified as type A.
  • Type B. This soil is less cohesive, but can remain somewhat stable without horizontal support. Examples include angular gravel, silt, and silt loam. If the soil has been fissured, or is near a source of vibration, it is automatically classified as type B soil – even if it is Type A.
  • Type C. This soil is the least stable type and includes granular soils such as gravel and sand. Soil that has water seeping through, is automatically classified as type C, even if it is Type A in nature.

Inspect the Site & Equipment

Just like soil inspection, OSHA requires a person to examine the site and excavation equipment before beginning work to determine all possible hazards. These dangers must be rectified and only then should the work begin.

All staff members should also be properly trained—not only on how to excavate, but also on what to do in case a mishap takes place.

Use the Right Equipment & Protective Systems

For any excavation beyond the 20 feet mark, a protective system becomes compulsory. There are four types of protective systems; namely:

1. Engineered Design

An Engineered design system is usually seen around a building construction site where concrete needs to be poured in a deep trench for the foundations. The design may also be used on complex construction projects, such as around waterways or rivers.

2. Timber or Steel Shoring

Timber shoring is the only system suitable for use in large metropolitan areas. This is because most utility lines run below the city’s streets. OSHA’s excavation standards dictate that the excavator is responsible for supporting and protecting exposed utilities, in which case the timber shoring method is the best choice.

Unfortunately, timber shoring has a steep learning curve, which can greatly increase the likelihood of cave-ins due to malpractice or discrepancies in the process. This is the perfect time in the process to hire professional shoring contractors like Forming America.

3. Shield Systems

Shield systems are the most common protective systems used in trenching. The system is simple and requires nothing more than shields such as trench boxes holding the trench in place.

4. Sloping & Benching

Sloping and benching are the safest of the four protective systems, mainly because they greatly reduce the potential for a trench collapse and the formation of a hazardous atmosphere. This protective system makes it possible to easily interchange workers or introduce materials and equipment due to its sloped terrain.

This becomes a manager’s or supervisor’s greatest asset, and its functionality remains, even in the off chance that evacuation becomes necessary.

Each system boasts its own strengths and weaknesses, and depending on the environment of where the work needs to be done, one system may fit better than the other. While purchasing all the equipment for these processes may be extremely costly, a cost-effective way of shoring your project is to rent shoring equipment.

Continuously Inspect the Work

Last but not least, the work itself needs to be inspected, not only when it starts but throughout the whole process. You should assign a team of inspectors that inspect the trench after every shift, and have the authority to the take steps necessary to remove and remedy any hazard that might lead to a cave in. There is no sure-fire way to prevent trenching accidents; no matter how many steps you take, there is always a certain degree of danger associated with trenching and excavating. However, there are many protective measures that can be taken to ensure the safety of your workforce. According to OSHA standards, you will need to hire a competent and professional person that can safely help you shore your excavation or trenching process. Contact us today to learn about our shoring systems to help you prevent accidents on your job site.