STATEMENT OF PROBLEM:

On 1/10/23 Central Excavating was performing some exploratory excavations in preparation for tying into the 30" BWD line east of the plant. Prior to beginning their work, Superintendent Jim Baut instructed Central to use chains in order to rig the trench box they were using. The operator failed to use chains to rig the trench box while moving the box over th exposed 42" pipe, and while pinching the box with the excavator it slipped causing it to drop on top of the pipe and puncturing it causing final plant water to leak out. This cause the plant to shut down and required them to get water from BWL in order to meet demand.  

ROOT CAUSE:

Central failed to utilize chains to properly rig the trench box while moving it where underground pipe and utilities were present. 

COURSE OF ACTION:

Once the incident occurred, CCC made the plant aware of the damage. CCC superintendent then notified the PM. Once the PM arrived we quickly met on what steps to take and CCC directed Central to get their owner and a hydro vac truck on site ASAP. The operator was sent to get a drug test and was removed from the site for 5 days. CCC asked Central if they had someone available to check on a repair fitting. They indicated they thought one existed in South Carolina. After several hours of preparation and mitigating flow loss, CCC's director was able to locate a company that had a fitting that would possibly fit. Around 1 am, we were able to get the diameter of the pipe and relayed that information to the repair company. The company was on site around 4 am with the parts. Further excavation and prep had to take place prior to them doing the repair. They showed back up around 8 am on Wednesday and after a few hours the excavator was not going to have the hole ready in time for the plant to run for their 5 pm high demand time frame. It was determined that the repair would need to be done the following morning, and it was completed at approximately noon on Thursday, January 12th. The plant then energized the pipe to full flow and by 2 pm the plant lifted the conserve water restriction to the community. 

LESSON FOR FUTURE PROJECTS:

1. On critical excavations where underground pipe/utilities are known to exist, make sure subs review the PTP in full prior to beginning any work. If any deviation from the PTP, subs should stop work immediately and fill out the MOC section of the PTP. 
2. Trench boxes should never be resting on top of utilities/pipes. 
3. In critical excavations, or lifts over underground utilities, trench boxes should always be rigged properly with chains. NO EXCEPTIONS. 
4. Equipment buckets are not to be used to move trench boxes when working around utilities. 
5. Always have a contingency plan if something does go wrong, and discuss that with the subcontractor prior to beginning work. 
6. Everyone should have a job to do and know their role in an emergency situation.
7. CCC should be prepared to quickly mitigate an emergency situation in the event a subcontractor does not have the personnel available to do so. (i.e., make phone calls to other subs to get needed materials/services in place in a timely manner).