Importance of Safety in Trench Excavation

Trenching and excavation activities are carried out millions of times around the world. Excavation is one of the riskiest jobs in the construction industry, becoming even more dangerous when trench excavation is involved.

Some of the major construction contractors involved in trenching and excavation include:

• General contractors
• Highway and street construction contractors
• Bridge and tunnel contractors
• Water, sewer, and pipeline contractors
• Communication and power line contractors
• Concrete workers and well drilling contractors

The use of a simple shovel is adequate for digging small trenches, but for deep and narrow trenches such as sanitary sewer installation or similar projects, cautionary measures must be taken. There are numerous risks associated with trench excavation, and most disasters occur in trenches 5-15 feet deep. Common mishaps include cave-ins, buried services damage, materials or equipment falling into trenches, struck-by accidents, asphyxiation, deep falls and drowning. In trenches, accidents happen unexpectedly, often with little or no warning.

Thousands of construction workers lose their lives each year while working on trench excavation, particularly when digging to lay pipe, place manholes, conduit runs or footings. This raises the question: how can we save the lives of workers involved in trench excavation and what is the most effective course of action?

Several steps should be taken to ensure safety during trench excavation. The importance of safety increases with the depth and narrowness of the trenches, and many workers die while trying to rescue their co-workers. Here are some important steps and safety guidelines for trench excavation:

• Employee Training: Workers should be trained in techniques to protect themselves, enabling them to quickly find a safe way out of the trench.
• Competent Supervision: The construction contractor supervising the trenching work should be registered and competent, able to identify possible risks, and have the authority to stop work immediately if an accident occurs. They should follow the trench excavation rules imposed by the Occupational Safety and Health Administration (OSHA).
• Pre-Shift and Post-Shift Inspections: Important steps should be carried out before and after each shift to observe any factors that might increase risks. For example, rain, vibration from nearby heavy equipment and passing trains. Also checking for movements of the trench walls which may cause cracking, scaling or bulging.
• Equipment Maintenance: Trenching equipment should be kept in good working condition. The supervisor must contact utility companies to block electricity, gas and water supplies. Many accidents occur due to electrical shocks or from a gas escape that can reduce oxygen or cause fires.
• Soil Inspection: Soil in close proximity to the trench should be inspected to ensure it is stable. Avoid excavating in wet trenches, as most cave-ins happen in clay. Use sloping, benching, shoring, or a trench box to prevent injuries or deaths. Avoid stacking construction materials or heavy equipment near the edges of the trench, as they may fall in and block the trench or cause injury. The walls of the trench should be safely sloped and secured by bracing.

The life of every worker should be equally important to employers, who have a duty of care to reduce risk and increase safety for individual workers at trench excavation sites.

Want more information on Trench Excavation? Speak to Groundforce Training

To find out more about the full range of excavation safety courses offered, call 0800 023 2663 or email groundforcetraining@vpplc.com.