An Ohio municipal utility was performing assessments on their sanitary collection system to establish realistic goals, budgets and schedules for their CMOM (Capacity, Management, Operation and Maintenance) program. To do so, they needed to know the actual physical condition of one of their 96-inch concrete sewer mains, so they wouldn鈥檛 come upon any surprises when it was time to perform scheduled work.
Bulldog Diving was chosen to execute the project, as its diversely trained crews are vastly experienced and certified in all facets of confined space entry, semi-watered environments containing potentially hazardous gases, and all manner of inspection, repair, maintenance and retrieval work.
Problem
The job was a difficult one. It involved a visual inspection that required safely accessing and lowering a technician into the sewer main, through a manhole entryway that ranged up to 14 feet high. Once inside, divers had to drill core samples from the eight-foot diameter line. Job specifications required a 6-inch core sample, which proved a challenge due to the structural rebar in the sewer line.
The work took long enough that it required enclosed operating helmets (positive air masks) with fresh air supply for the technicians, because of potential presence of deadly H2S gas inside the pipe.
Solution
The 4-man crew knew that the coring drill would require stabilization to create clean cores, as the slightest movement of the core drill would break the samples. This presented a serious challenge, as Bulldog was not permitted to drill additional holes in the sewer line to anchor the core drill, but Bulldog鈥檚 dive teams are known for their persistence and ingenuity. Ultimately, a mobile stabilizer arm was fabricated in-house that would secure the coring drill.
The divers were able to safely retrieve the coring samples, but realized they鈥檇 need two-way communications with topside staff, who were running the operation. This was difficult with the air helmets on, but they managed to use handheld radios in varying degrees of success; enough to allow them, using the stabilizer, to successfully complete the job.
Result
The Bulldog crew was able to complete the job on schedule, allowing the utility to accurately assess the condition of their sewer main in a timely manner. Using this empirical data, they were able to develop a realistic maintenance and repair schedule and budget for current and future use.
This was one of the jobs that inspired company president and veteran diver, Bram Williams, to develop a lightweight, positive air flow helmet with built-in, two-way comms that would allow its crews to work comfortably and safely in topside environments that may involve the presence of hazardous or toxic gases.
The results was Bulldog鈥檚 patent-pending Ultra Lite MK3 topside positive air helmet. This innovative headgear takes the place of heavy, cumbersome, traditional diving helmets to provide full head protection, comfort, and mobility in confined spaces where toxic fumes may be present. Designed as a positive pressure air helmet with continuous air supply, the MK3 offers unparalleled safety features, making it an indispensable tool in such settings such as the large sewer main in Ohio.