Conducting a Site Assessment‍

• Before starting any trenching or excavation, it’s essential to conduct a thorough site assessment. In interior settings, identify load-bearing walls, electrical conduits, and plumbing. This helps ensure that structural elements are not compromised and reduces the risk of hitting utilities. Working with the client to gather information about the building’s infrastructure and potential hazards is crucial.
• Site assessments should also consider confined space requirements. Even shallow trenches inside can be hazardous in confined spaces, where airflow may be restricted, and toxic gases can accumulate.

‍

Shoring and Shielding

• Although interior trenches might be relatively shallow, any trench over 5 feet requires protective systems, such as shoring, shielding, or benching, to prevent collapse. Even with smaller, shallow trenches, wall collapses can occur due to soil instability or external vibrations, particularly in older retail buildings with compromised foundations. Shore up the sides of any trench in areas with poor soil conditions or where nearby structures may affect stability.

• Incorporate trench shields or use prefabricated trench boxes when needed to reinforce trench walls. For shallow trenches in confined interior spaces, trench boxes designed for smaller dimensions work well and provide essential protection without occupying excess floor space.

‍

Access and Egress

• Plan for safe entry and exit points in each trench or excavation site. Ladders or ramps should be readily available and positioned every 25 feet in trenches deeper than 4 feet. For interior settings, ensure that access points do not block aisles, exits, or fire doors. Communicate the planned access points to team members and nearby occupants to prevent accidental entry and ensure clear pathways.

‍

Hazard Communication and Signage‍

• In an occupied space, hazard communication is vital. Post signs and barricades to prevent unauthorized personnel from entering the trench or coming into contact with equipment. Establish clear verbal communication with occupants or client representatives about areas where trenching will occur, the expected duration, and the associated hazards.
• Conduct a daily inspection before starting work to check for shifting or changes in trench walls and surroundings. Document findings and communicate any changes to all workers on-site to reinforce awareness.

‍

Managing Utility Lines

• Utility lines pose a particular risk in indoor trenching. Always contact utility companies and review blueprints for any potential lines running through work areas. Electrical or gas lines require special handling, including potentially isolating or rerouting to avoid unintended contact.

Monitoring for Air Quality and Ventilation

• In indoor trenching, confined space hazards like oxygen deficiency and toxic gas accumulation can present real risks. For larger trenches or longer projects, monitor air quality, and use ventilation systems as needed to maintain a safe environment. Workers should be trained on confined space protocols and provided with personal protective equipment (PPE) suited for indoor trenching.

‍

Key Takeaways

‍Interior trenching requires a careful balance of trench safety standards and consideration of the surrounding structures and occupants. Conducting a thorough site assessment, securing the trench, and implementing clear communication protocols ensure that the work is completed safely, even within an active retail space.