Trenching and Excavation Safety: Planning is Paramount

In an instant and without notice, an unsupported trench can give way and a worker can be buried alive. “Even though small amounts of dirt may not seem treacherous, a single cubic yard of dirt can weigh more than 3,000 pounds, which can fatally crush or suffocate workers,” NIOSH states. OSHA notes that excavation and trenching are among the most hazardous construction operations, with cave-ins being perhaps the most feared trenching hazard. Other hazards in this line of operation include: falls, hazardous atmospheres, and falling loads.

How can employers help keep workers safe? NIOSH recommends that employers do the following before beginning a trenching or excavation project:

·       Designate a trained “competent person” to check that all safety precautions are in place. In relation to trenching, OSHA defines a competent person as “an individual who is capable of identifying existing and predictable hazards or working conditions that are hazardous, unsanitary, or dangerous to workers, soil types and protective systems required, and who is authorized to take prompt corrective measures to eliminate these hazards and conditions.”

·       Call 8-1-1 to ensure no utility lines are in the job area and to mark any existing lines.

·       Locate safe places away from the trench to place spoil piles and heavy equipment paths.

·       Ask the competent person to determine what kinds of protective systems will be needed for the job and have the systems in place before workers are allowed in the trench or excavation.

·       Enforce the rule that workers who are younger than 18 are not allowed in the trench or excavation.

·       Assign workers to the job only if they have been trained about hazards and work practices in a language and at a literacy level they understand.

·       Have a written emergency action plan in place that details the steps to take in the event of a trench incident and do hands-on training of that emergency action plan.

·       Make sure all workers know to never enter an unprotected trench.

·       Teach workers to immediately exit a trench and call for the competent person if they find any evidence of problems with the protective system.

Trench Rescue Awareness for Emergency Services Personnel

A dispatch call for a trench emergency rescue is not common for EMS and fire departments. But when a call like this comes, is your department prepared to respond to a trench rescue incident? Are your providers trained in what to do? This article provides some awareness-level information for responding to a technical rescue in a trench.

While trench rescues may not be common, trenches in municipal public works are. Often at construction sites, trenches are dug for workers to install or repair underground utilities, including water pipes, sewer pipes, and electric lines. These types of trenches are often narrow and deep, descending anywhere from four to 20- plus feet. These excavations differ from other trenches that are wide and deep, often used for repairs of streets, gas lines, or water main repairs. At times workers operating in excavations will be using a protective trench box or shoring.

If an emergency occurs in a trench, it could be a cave-in or a non-cave-in situation. Cave-ins are generally due to changing weather conditions, machinery, or vibrations that cause the walls to collapse, or removed dirt from the spoil pile falling back into the trench. A non-cave-in situation may be a medical emergency in the trench, entrapment of a worker under a pipe or machinery, flooding, or equipment failure.

It is crucial that first-arriving emergency units establish command, contain the incident, and request the appropriate resources. To establish command, follow your written “incident command guidelines.”

·       Notify dispatch

·       Size up the situation and determine if it is a cave-in or non-cave-in

·       Determine the number and types of victims

·       Determine the nature of the emergency

·       Determine the hazards on the scene (utilities, weather, water, hazmat, machinery)

·       Determine the approximate depth of the trench

·       Determine if it is a rescue or recovery operation

·       Establish “hot, warm, and cold” zones (hot= only trained rescuers, warm= trained support staff, and cold = non-trained personnel are not allowed within a 10-foot radius around the trench)

·       Make sure no first responders endanger themselves by urging them not to play hero and enter the “hot” zone without the proper training and technical equipment

·       Establish a staging area for equipment and personnel coming to the scene

A trench rescue incident requires a technical rescue team. A minimum of 20-30 rescue technicians are needed for the operation. Since most municipalities don’t have the personnel or the training to perform a trench rescue, it is much more feasible to thoroughly and effectively plan out your trenching jobs and use the appropriate techniques to protect your workers prior to sending them into a trenching situation.

Specialized equipment will need to be brought in by rescue teams, such as airbags, struts, shoring, hand tools, buckets, ladders, ground pads or plywood to stabilize the area around the trench, ropes and rigging, generators, and lighting. For extended incidents consider additional resources such as food, water, and warming equipment for rescuers. Rescues are not generally done in a few minutes. Often they take hours and many times result in a recovery rather than a rescue.

Two feet of soil covering a victim can be the equivalent of 600-1000 pounds on their body. Clearly, crushing and airway compromises are strong possibilities. Once an EMS can assess a victim, the following should be treatment priorities:

·       Airway access and control

·       Oxygenation

·       Maintain body temperature

·       Intravenous access before removal of victim

·       Head, eye, and ear protection

·       Pain management

·       Fracture management and immobilization

It is highly recommended that all responders take a trench rescue awareness and operation course that meets NFPA standards. While trench rescues are rare, they are technical operations requiring a great deal of personnel, resources, and logistics. The best way to prevent a trench rescue situation is to follow strict safety procedures in setting up your municipal trenching and excavation situations before you put workers at risk in the trenches!

Safety Courses Using LocalGovU Online

OMAG offers online safety courses through LocalGovU. This is a free online training service provided to our member cities and towns. All you have to do is go to our website at www.omag.org and click on the “I want to…” tab at the top right of the page, then click on “train online” and select LocalGovU. Follow the instructions on how to access training and registration. If you have questions or issues, contact the LocalGovU staff with the phone number provided on the page. They will be able to walk you through the process.

Employees can go through the training programs individually or a supervisor/manager can hold a departmental training by connecting a computer with internet access to a TV or projector and hold a class at a location convenient to their staff and facilities. Just remember to have your staff sign a training roster and keep it in your training files. The best part of training this way is your employees will get safety training relating to their specific jobs. There are dozens of topics to choose from, and a course list is provided on the LocalGovU link.

OMAG’s partnership with LocalGovU is just another Value-Added-Service we provide to your municipality to assist you in your Risk Management program.

SEWER NEWS: Understanding CMOM (Capacity, Management, Operations and Management)

CMOM programs are a best practice for sewer line collection system owners and operators. Both comprehensive and holistic, a CMOM provides an information- based plan to effectively run a sewer collection system and help lower the risk of National Pollutant Discharge Elimination System (NPDES) permit violations and discharge violations. The EPA notes in their Asset Management for Sewer Collection Systems fact sheet: “Lacking adequate focus on operations and maintenance, many collection system utilities have slipped into a reactive mode, with most of their operational resources allocated to emergency response and rehabilitation or replacement of failed systems.” Instead, a proactive and even predictive approach is encouraged by following the CMOM program.  

In 2005, the EPA published a guide to evaluating and structuring a Capacity, Management, Operation, and Maintenance program. The CMOM approach is not enforced by regulatory authorities, nor is it legally binding, but can be mandated as a response to consent decrees. CMOM program documentation and subsequent audits may also be required when submitting applications for an NPDES permit. The goal of the CMOM process is to assure that discharge from treatment facilities is free from pollutants. Therefore, preventing sanitary sewer overflows, which are illegal under the Clean Water Act, is a priority. 

In a CMOM program, emphasizing all four segments equally will reap the most benefits, but the backbone of the program is the management portion. Utility optimization through CMOM programming aims to be adaptable, changeable, and frequently updated, moving away from the traditional long-interval master plans. Therefore, it is difficult to implement a CMOM program without reviewing the internal components of managing a collection system – things like organizational structure and staffing, training and budgeting. An effective management system helps ensure the operations and maintenance portions of the program can fully be addressed. 

Collection system operation also supports review, standardization, and transcription of activities and procedures within a department. Proper documentation allows for increased accessibility and accountability with a collection system’s organization. Operators and administrators thus identify and reflect best practices and ensure processes are kept consistent. This information, time and again, proves valuable in the event of an emergency. 

The EPA notes some of these responsibilities may include “monitoring discharges into the collections system for individual users; monitoring to determine the effects of sanitary sewer overflows on receiving waters; and recording any sampling that is done, according to the Guide for Evaluating CMOM Programs at Sanitary Sewer Collections Systems. Other operational activities include safety procedures and emergency preparedness and response programs. The EPA guide also lists modeling and mapping under the operations umbrella. New technologies, like tracking with flow rate monitors, are making it easier to create and structure managerial and operational tasks and even automate some maintenance activities. 

Operation and maintenance are often grouped together because their activities are so interrelated. The goal is to keep maintenance planned, as opposed to unplanned. Efficient assets have a longer useful life and reduce the likelihood of failure, decreasing emergency response costs. Like other aspects of a CMOM program, establishing written protocols helps standardize procedures and provides data that can be analyzed for patterns and trends. 

Ensuring pipelines are prepared to carry the necessary capacity is a complex task. The capacity of a collection systems relies on a number of variables, including the population being served, total system size, and location of house lateral lines. A routine evaluation of capacity can be coordinated in conjunction with the other operations and maintenance activities to round out a CMOM program. Determining capacity requires both testing and inspecting, which largely focus on finding sources of inflow and infiltration (I&I). I&I is a significant contributor to SSOs and CSOs during wet-weather events. Inspections are moving away from confined-space entry methods for the safety of inspection personnel, instead opting for qualitative testing and methods that utilize CCTV inspection technology and collect comprehensive data. Rehabilitation programs are also essential to CMOM and the goals of avoiding emergency situations and staying preventive and predictive. 

Implementing a CMOM program is not an easy task. It is both comprehensive and complex but worth the investment of time and resources because the benefits can be felt in both the short and the long term. In the pursuit of increasing efficiency, a CMOM program helps collection system owners and operators identify where the system and the organization as a whole are thriving and what areas need improvement. 

Thankfully, the bulk of the work in putting together a CMOM program is to codify and fine-tune existing processes within a collection system. The EPA and other government sources have released numerous resources to assist owners and operators in putting a CMOM program into action.