NBAFS Final Inspection Report Rev 1 8-31-2022-_Redacted.pdf

2 Bldg 107 and 135 Tank Cleaning and Insection Final Report

• Used the rung ladder that was installed into the concrete walls of the B Side of the Building 135 tank to access the interior for cleaning, repair and inspection.

• Set up a tripod and winch system that provided fall protection for workers climbing in or out of the tank. The winch system also acted as a backup for worker extraction in the event mechanical rescue was necessary.

• Entered the tank following Company submitted confined space protocols.

monitored the atmosphere in the tank on a continuous basis and documented readings on the half hour in the applicable section of the confined space permit.

Permits were issued daily and closed at the end of the work shift.

• Pumped residual water out of the tank. The pump was placed in the sump of the tank to maximize the amount of water removed.

• Cleaned the tank interior with hand tools and pressure washers to remove scale and organic buildup.

• Inspected the tank interior for cracks or other defects.

• Operations team concluded that there was no observable damage to the tank or superficial damage to the equipment housed within.

• Final rinse of the tank interior, removing all liquids and any solids generated during the cleaning and inspection operations prior to final inspection.

• Final inspection by facility personnel and authorization to move to the Building 107

Tank.

• Final inspection conducted; Side B returned to facility personnel control.

• Received facility personnel authorization to move to the Building 107 Tank.

NOTE: Items required to support the work inside either half of the Building 135 tank were lowered into the confined space utilizing ropes and winches to support the weight. The Confined Space Supervisor notified all workers in the confined space to stop work and move to a safe area inside the tank when supplies or equipment were lowered into the tank. Items being removed from the tank were hoisted once the item was secured to the rope and the crew moved to a safe location.

Building 107 – 60,000 Gallon Tank

Building 107 Tank

• Used existing facility pumps in conjunction with pumps supplied by to pump/drain water from the 60,000 gallon tank at Building 107. Water was discharged through the same Silt Sock, Silt Fence and lay flat hose set-up for the A Side of Building 135 Tank dewatering.

• Installed fall protection barriers around the access hatches.

• Used the rung ladder that was installed into the concrete walls of the A Side of

Building 107 tank to access it’s interior for cleaning, repair and inspection.

• Set up a tripod and winch system that provided fall protection for workers climbing in or out of the tank. The winch system also acted as a backup for worker extraction in the event mechanical rescue was necessary.

• Entered the tank following Company submitted confined space protocols.

monitored the atmosphere in the tank on a continuous basis and documented readings on the half hour in the applicable section of the confined space permit.

Permits were issued daily and closed at the end of the work shift.

3 Bldg 107 and 135 Tank Cleaning and Insection Final Report

• Pumped residual water out of the tank. The pump was placed in various locations throughout the base of the tank to maximize the amount of water removed.

• Cleaned the tank interior with hand tools and pressure washers to remove scale and organic buildup.

• Inspected the tank interior for cracks or other defects.

• All staging equipment and necessary tools were lowered into the tank utilizing ropes directly below the access hatch.

• Staging was assembled in two tiers; the crew verified load integrity and safety systems at each elevation prior to increases in height.

• Staging was moved to each work location and locked out prior to utilization by the crew

• Repaired cracks using an approved hydraulic cement (BASF MasterSeal 581).

• Interior overflow pipe was inspected for defects and a screen fitting was installed at the base of the pipe.

• Piping related to the tank’s sump pump was dismantled; entrants lowered the piping in stages to the tank base.

• Piping was then attached to lines attached to the supplied tripod and block.

• Entrant crew withdrew from area to the rear of the tank and the piping was hoisted out of the tank and packaged for transport and disposal.

• Both 4" holes created by removal were sealed with hydraulic cement.

• The pre-existing tank ladder was detached at each anchor point, removed from the tank and packaged with the sump piping.

• The crew made a second pass over each anchor point to ensure that each was plumb and level to the rest of the tank wall.

• Due to the height limitation of B107's ceilings, and with the approval of the BCE, we cut the ladder in half, and installed the new ladder that had the cut ends regalvanized and stainless steel bolts clasping the ends together.

• The new supplied fabricated tank ladder was lowered into the tank, positioned and all hoisting lines were locked out to proved stability during the installation process.

• The crew worked base to entry hatch to install each anchor point at the corresponding mounting tab.

• Once all anchors were installed, inspection of the ladder was conducted to ensure snug connections and utilization would be most efficient.

• Rinsed the tank interior, removing liquids and any solids generated during operations prior to final inspection.

• Final inspection conducted; the Tank was returned to facility personnel control.

• Demobilization and site clean up was conducted to ensure that all areas were left in a manner equal to pre-operations conditions.

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Inspection Results

The following section presents the results of the inspection/cleaning activities conducted.

Building 135 Building 135 – General Condition and Exterior Inspection

The exterior of the Building 135 water tank and associated components (walls, overflow, roof, vents and hatches) was inspected as part of our scope of work (see pictures in Appendix).

Building Walls

All exposed wall surfaces appear to be in good condition with no obvious spall, cracks or other fatigue

Tank Roof - Exterior

The exterior of the roof of the tank appears solid and intact.

Tank Hatch Covers

Three aluminum hatches provide access to the interior of the water tank structure. One hatch provides access into each of the east and west cells of the 110,000 gallon tank while a third hatch provides access into the effluent chamber.

All three 96" by 48" inside diameter hatches were found in good working condition. The each of the three of the hatches were secured with padlocks.

Building 135 Pump House Interior

The interior of the Building 135 pump house was clean and well lit. The exterior of the piping inside the pump house showed minimal corrosion and appears to be well maintained (see pictures in Appendix). There is a disinfectant odor in the pump house consistent with water treatment facilities of similar scope and size.

Building 135 – Interior Inspection of Side A / West half of the 110,000 Gallon Tank

The interior of this water storage tank (and components) was inspected including sediment accumulation, condition of the floor, walls, sumps, pumps, process piping, vents and overflow piping. (see pictures in Appendix)

Sediment Accumulation

Sediment accumulation varied throughout the tank. However, there was approximately ¼ inch of a brownish red semi-solid coating on the floors and pumps/intakes in the tank. The sediment was not tested but resembled iron oxide precipitate.

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Walls

The majority of the exposed wall surfaces appear to be in good condition with no obvious spall, cracks or other fatigue. The walls were pressure washed to remove residual solids, but the majority of the staining remained. There were no new cracks or defects observed during the inspection. Sections of the tank that were previously addressed with hydraulic cement had shown continued deterioration. addressed each area with BASF MasterSeal 581 to close all cracking. Any spalling was also filled with BASF MasterSeal 581 to bring all walls to a solid uniform state. The walls were stained with reddish brown iron oxide.

Floor

The floor was pressure washed to remove accumulated solids. The floor was inspected after cleaning. The floor of the tank appeared sound and intact with no visible evidence of degradation, spalling or cracks. The floor was colored with iron oxide staining.

Piping pressure washed the exterior of pipes that were found inside the tank (extending through the roof of the tank). The exterior of the pipes were inspected once washed. Upon inspection found one overflow pipe strainer was threaded fitting had degraded and needed to be replaced. (see pictures in Appendix) furnished and installed a new strainer to bring the unit back up to full designed operation.

Access Ladder

The ladder leading from the hatch into the tank interior showed no physical degradation and appeared to be firmly embedded in the concrete wall.

Building 135 – Interior Inspection of Side B / East half of the 110,000 Gallon Tank

The interior of this water storage tank (and components) was inspected to include sediment accumulations and condition of the floor, walls, sumps, pumps, process piping and vents and overflow piping.

Sediment Accumulation

The thickness of sediment accumulation varied throughout the tank but was consistent with the East chamber at approximately ¼ inch. The sediment resembled iron oxide precipitate and stained the walls and floor of the tank.

Walls

All interior wall surfaces appear to be in good condition. Upon inspection the walls of the tank appeared sound and intact with no visible evidence of degradation, spalling or cracks.

The walls were pressure washed to remove residual solids, but the majority of the iron oxide staining remained.

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Floor

The floor was pressure washed to remove accumulated solids. The floor was inspected after cleaning. The floor of the tank appeared sound and intact with no visible evidence of degradation, spalling or cracks. The floor was colored reddish brown with iron oxide staining.

Piping personnel used a pressure washer to clean the exterior of pipes that extended through the roof of the tank. The exterior of the pipes were inspected once washed; did not observe any significant or catastrophic pitting or corrosion

Access Ladder

The ladder leading from the hatch into the tank interior showed no physical degradation and appeared to be firmly seated in the concrete wall.

Building 107 Building 107 – General Condition - Pump House Exterior and Interior

The exterior and interior of the pump house of Building 107 water tank and associated components (walls, overflow, roof, vents and hatches) was inspected as part of our scope of work (see pictures in Appendix).

Walls

The majority of the exposed wall surfaces appear to be in good condition with no obvious spall, cracks or other fatigue. observed some superficial cracking in various locations on the exterior of Building 107. At this time there is no cause for concern, however these should be monitored for continued growth over time.

Roof

The exterior roof of the tank (floor of the pump house) appeared solid and intact. No repairs were required.

Hatch

There is one hatch that leads to the interior of the tank. The hatch sits on a raised concrete platform and has a metal lip that fits into the S hatch cover. All components worked well and required no service.

7 Bldg 107 and 135 Tank Cleaning and Insection Final Report Building 107 - 60,000 Gallon Tank Interior Inspection

The interior of this water storage tank (and components) was inspected to include sediment accumulations and condition of the floor, walls, sumps, pumps, process piping and vents/overflow piping. (see pictures in Appendix).

Sediment Accumulation

Sediment accumulation varied throughout the tank. However, there was less than ¼ inch of a brownish red semi-solid coating on the floors and pumps/intakes in the tank. The sediment was not tested but resembled iron oxide precipitate.

Walls

The majority of the exposed wall surfaces appear to be in good condition with no obvious spall, cracks or other fatigue. The walls were pressure washed to remove residual solids, but the majority of the staining remained. There were no new cracks or defects observed during the inspection. Sections of the tank that were previously addressed with hydraulic cement had shown continued deterioration. addressed each area with BASF MasterSeal 581 to close all cracking. Any spalling was also filled with BASF MasterSeal 581 to bring all walls to a solid uniform state. The walls were stained with reddish brown iron oxide.

Floor

The floor was pressure washed to remove accumulated solids. The floor was inspected after cleaning. The floor of the tank appeared sound and intact with no visible evidence of degradation, spalling or cracks. The floor was colored with iron oxide staining.

Overflow/Vent

There is a 4 inch overflow that leads from the tank to an unknown location outside the building.

The pipe was corroded but was cleaned with a pressure washer. A screen fitting was installed at the base of the pipe to ensure continued functionality and full designed operational capacity.

Piping personnel used a pressure washer to clean the exterior of pipes that extended through the roof of the tank. The exterior of the pipes were inspected once washed. The inspection revealed no significant or catastrophic pitting or corrosion.

Access Ladder

Several of the middle rungs of the ladder leading from the hatch into the tank interior showed significant degradation. The ladder rungs were ground off at their respective anchor points.

The crew made a second pass through the vertical ladder run to remove any protrusions from the tank wall. Due to the height limitation of B107's ceilings, and with the approval of the BCE, we cut the ladder in half, and installed the new ladder that had the cut ends regalvanized and stainless steel bolts clasping the ends together. Multiple lines were attached to the supplied fabricated tank ladder. The ladder was lowered into the tank onto a temporary riser to set the ladder for installation. The entrant team worked base to entry hatch to secure each anchor point at the corresponding mounting tab. The temporary riser was removed and the lines were disconnected from the newly installed ladder. conducted a post installation inspection of the ladder to ensure maximal functionality and utilization had been achieved.

P O B 0119 • 100 TOSCA DRIVE • STOUGHTON MA 02072 0119 • TELEPHONE 781 341 1777 • FAX 781 341 6246

8 Bldg 107 and 135 Tank Cleaning and Insection Final Report

Sump Piping

The piping for a previously decommissioned sump pump was removed from the tank and both 4" holes created by removal were sealed with hydraulic cement. utilized staging to put entrants at working height that would maximize safety or all involved. Both ends of the piping were tied off and slung to hold the free fall weight of the 4” piping. Each end was cut flush to eliminate protrusions through the corresponding wall. Once free of the wall, the piping was systematically lowered from the three working heights to the tank floor. Underneath the hatch a series of lines were lowered and attached to the piping for extraction. The entrant workers cleared the vicinity; exterior crew members removed the piping to pump house grade. Entrant workers returned to the piping work area and utilized BASF MasterSeal 581 to bring both walls to a uniform surface analogous to the surrounding wall.

This report, the conclusions, recommendations and comments prepared by are based upon examination of exterior components only. Should latent defects or conditions which vary significantly from those described in the report be discovered at a later date, these should be brought to the attention of a qualified individual at that time.

The comments and recommendations presented in this report should be viewed as information to be used by the Owner in determining the proper course of action and not to replace a complete set of specifications.

Repairs, if made, should be completed in accordance with AWWA Standards

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APPENDIX

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Building 135 – Side A / West Tank Interior Photographs

Pre Cleaning Environment

Overflow Pipe (Degraded Strainer) Damaged Overflow Pipe Strainer Rear Side Wall

Right / East Side Wall Right / East Side Wall Left / North West

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Midline Piping / Side Wall Ceiling / upper wall – Entry hatch Rear Half of Tank Ceiling

Right / East Left / West Right / North East

Ceiling / Upper Wall Corner Midline Ceiling / Upper Wall Front Ceiling / Upper Wall

Left / North West Left / West Left/ South West

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Front Ceiling / Upper Wall Front Ceiling / Upper Wall Front Corner / Side Wall

Left / South West Right / South East Right / South East

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Post Cleaning Environment

Rear Piping / Side Wall Rear Side Wall / Corner Mid Line Piping / Side Wall

Right / East North Center / East Right / East

Rear Piping / Side Wall Midline Piping / Side Wall Mid Line Piping / Side Wall

Right / East Left / West Left / West

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Midline Ceiling / Side Wall Midline Side Wall Front Corner / Side Wall

Left / West Left / West Left / South West

Front Corner / Side Wall Front Side Wall Under Hatch Front Side Wall Under Hatch

Left / South West Left / South West Center / South

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Front Side Wall / Tank Ladder Front Side Wall / Tank Ladder Midline Piping / Side Wall

Right / South East Right / South East Right / East

Repaired Overflow Pipe Strainer Rear Side Wall Right / East Left / North West

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Building 135 – Side B / East Tank Interior Photographs

Front Side Wall Front Side Wall / Tank Ladder Rear Side Wall

Left / South West Left / South West Right / North East

Rear Side Wall Mid Line Side Wall

Right / North East Right / East

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Front Side Wall Front Side Wall / Tank Ladder Side Wall

Left / South West Left / South West Right / East

Rear Corner / Side Wall Rear Corner / Side Wall Front Corner / Side Wall Right / North East Left / North West Left / South West

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Rear Corner / Side Wall Front Corner / Side Wall Rear Corner / Side Wall Right / North East Left / South West Left / North West

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Building 107 – Tank Interior Photographs

Rear Ceiling / Pump Piping Mid Line Ceiling Pre installed Tank Ladder Right / North East Right Center / East Right Front / South East

Mid Line Side Wall Rear Side Wall / Pump Piping Side Wall / Over Flow Pipe Left / West Right / North East Left / South West

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Pump Piping / Midline Side Wall Pump Piping / Midline Side Wall

Left / West Left / West

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Rear Ceiling / Pump Piping Rear Ceiling / Pump Piping Side Wall / Over Flow Pipe Right / North East Right / North East Left / South West

Over Flow Pipe screen Front Corner / Side Wall Newly Installed Tank Ladder Left / South West Right / South East Right / South East

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Newly Installed Tank Ladder Newly Installed Tank Ladder Sealed Sump Discharge Point Right / South East Right / South East Right / North East