Attachment01_StatementOfWork.pdf

Statement of Work - Inspect and Clean Eight (8) Potable Water Storage Tanks

Project Summary This project will encompass cleaning of the potable water storage tanks at Ozark National Scenic Riverways. This includes eight (8) tanks ranging in size and material.

The contractor will furnish all personnel, equipment, tools, materials, supervision, and other items necessary for the inspection, cleaning, and disinfection of the eight (8) potable water tanks. Water tank sizes, materials, and locations are noted below:

Tank General Location Tank Size (gallons) Material Coordinates

1 Akers Ferry 20,000 Fiberglass 37°22'37.19" N, 91°33'23.27" W

2 Pulltite 110,000 Steel 37°19'44.29" N, 91°28'29.48" W

3 Round Spring 10,000 Fiberglass 37°17’15.89” N, 91°24'29.96" W

4 Round Spring 50,000 Steel 37°16’38.78” N, 91°24’38.79” W

5 Alley Spring 75,000 Steel 37°09'02.10" N, 91°26'46.40" W

6 Two Rivers 10,000 Fiberglass 37°11"13.63" N, 91°16'31.75" W

7 Big Spring Campground 100,000 Steel 36°57'33.96" N, 90°59'30.04" W

8 Big Spring Cabins 86,000 Metal 36°56'41.68" N, 90°59'34.99" W

Inspection, cleaning, and disinfection will be done with water in the potable water tanks.

The contractor will have the option to do this with a drained tank or through diving in the tank.

Safety Requirements

1. A safety site plan is required. The selected contractor must submit a site specific safety plan. Onsite work shall not begin until the safety plan has been accepted by the government.

2. The Contractor shall comply with all health and safety regulations and requirements of OSHA (or State Health and Safety Regulatory Agency), SSPC- PA Guide 3, and the paint and abrasive manufacturers.

3. All rigging and fall protection equipment used shall meet or exceed OSHA/ANSI standards.

4. Provide adequate illumination (SSPC-Guide 12) for the task being performed.

5. Contractor shall be responsible for the permitted confined space and shall adhere to all OSHA requirements regarding confined space including providing all equipment and personnel necessary.

6. The Contractor shall maintain a clean work area and have fire extinguishers on-hand.

Background These tanks are to be cleaned, disinfected, and inspected in accordance with the following publications:

• Missouri Department of Natural Resources - Inspection of Water Storage Facilities - PUB2112 (effective date July 01, 2019) This document can be found at:

https://dnr.mo.gov/document-search/inspection-water-storage-facilities-pub2112/pub2112

• Missouri Department of Natural Resources - Technical Guidance for Inspection of Water Storage by Divers - PUB2043 (effective date June 01, 2015) This document can be found at:

https://dnr.mo.gov/document-search/technical-guidance-inspection-water-storage-divers-pub2043/pub2043

• American Water Works Association – AWWA C652-11 (effective date October 01, 2011)

Tank Cleaning Both the interior and exterior of the tanks will be cleaned.

The exterior of the water tanks shall be pressure washed to remove any mold, mildew, and/or grime from exposure to the elements. This includes, but is not limited to, the tank, ladder, and handrails.

Interior of the potable water tanks shall have any debris and sediment removed from interior of the tank.

During this task, the contractor shall isolate the facility in accordance with AWWA C652-

11. If divers are used to perform this task, then the contractor will also perform the work in accordance with Missouri Department of Natural Resources - Technical Guidance for Inspection of Water Storage by Divers - PUB2043.

Tank Disinfection and Inspection Guidelines and procedures for the inspection and disinfection of the tanks will follow the Missouri Department of Natural Resources - Inspection of Water Storage Facilities - PUB2112 and AWWA C652-11.

https://dnr.mo.gov/document-search/inspection-water-storage-facilities-pub2112/pub2112 https://dnr.mo.gov/document-search/inspection-water-storage-facilities-pub2112/pub2112 https://dnr.mo.gov/document-search/technical-guidance-inspection-water-storage-divers-pub2043/pub2043 https://dnr.mo.gov/document-search/technical-guidance-inspection-water-storage-divers-pub2043/pub2043

If the contractor choses to perform this task with divers, then they shall isolate the facility in accordance with Missouri Department of Natural Resources - Technical Guidance for Inspection of Water Storage by Divers - PUB2043.

PUB2112 outlines a series of questions that an inspector should address concerning the sanitary conditions of the tank, structural conditions of the tank, safety concerns with the tank, security issues, and the coating system conditions of the tank. The contractor will be required to perform all these areas of inspections. Specific areas of evaluation and inspection for the water storage tanks include but are not limited to the following:

Sanitary conditions Birds, bats, bees, wasps and unidentifiable animals entering and contaminating storage facilities have caused water borne disease outbreaks and boil water notices. Water in storage facilities has also been contaminated by bird droppings and other contamination washed into facilities by precipitation. Therefore, any sanitary defect found shall be immediately brought to the attention of the facility owner so it can be quickly corrected.

1. The roof and sidewalls of all structures must be watertight with no openings except properly constructed vents, manways, overflows, cathodic protection equipment, power cord entrances, risers, drains, pump mountings, control ports or piping for inflow and outflow. Also, no unprotected opening between the walls and roof is permissible.

2. Any openings in a roof must be curbed (four to six inches) or sleeved with proper additional shielding to prevent precipitation and surface or floor drainage water from getting into the structure. Duct tape is not an acceptable method of sealing an opening and caulking is considered a temporary repair to be used only until the permanent repair is made.

3. Roof access hatches must have watertight covers that overlap the framed opening and extend down around the frame at least two inches. The covers must be hinged on one side and have a locking device. All hatches should be checked to ensure proper operation and fit.

4. Water storage roofs must be well-drained and not hold water. Low spots or structures that allow ponding of water must be corrected.

5. All finished water storage facilities must be properly vented and overflows cannot be used as vents.

6. Vent construction must prevent the entrance of surface water and rainwater and exclude birds, animals and insects. Vents must be screened with No.18 mesh, noncorroding material.

7. Vents must be designed so they do not become bird roosts and bird droppings cannot enter the storage facility through the vent by washing, falling or being inhaled. The old style ball and finial type vents do not meet these requirements.

8. Vents must be sized adequately to prevent differential pressures between the inside and outside of the storage facility.

9. Vents must be constructed to prevent them from clogging with dust or frosting over or provided with vacuum valves or other failsafe devices.

10. Overflows on elevated tanks, standpipes and tall ground storage facilities must discharge at an elevation no higher than 12 to 24 inches above ground and discharge into or onto a drainage inlet structure or splash plate.

11. Overflows must be sized to carry more than the largest filling rate of the storage facility.

12. Overflows cannot be directly connected to sewers or buried drains.

13. Overflows must be screened or equipped with a flap valve to prevent the entrance of birds, animals and insects. Flap valves must be designed so they close completely, fit tightly and cannot high center and stick open.

14. Brackets connecting overflow piping to the structure must be checked to assure they are secure to both the structure and the overflow pipe and that they are not damaged by corrosion.

15. If water stands stagnant or silt collects in the bottom of a tank bowl, the tank must be modified to minimize this or provided with siphon drains or freeze proof direct drains. The water and deposits must be removed periodically to prevent microbial growths, to minimize corrosion and to prevent the deposits from going into the distribution system.

16. Check for evidence of contamination of the storage interior.

17. Hydrants, cleanouts or similar flushing devices must be provided on the piping of all water towers, standpipes and ground storage tanks. These devices must be located so they can drain the storage facility while it is isolated from the system. Flushing devices on separate lines directly connected to the storage facility are acceptable substitutes. Valves or plugs installed in wet risers or standpipes are intended to drain the last foot or two of water and sludge in a wet riser or standpipe and not to drain the entire tank. Drain valves should be freeze proof.

18. Taps or sampling stations suitable for collecting microbiological samples must be provided on the discharge piping of each storage facility. These must be located so that water directly from the storage facility can be sampled.

Structural conditions In the event that significant structural defects are identified, public water system officials should consult with a Missouri registered professional engineer to evaluate the inspection findings and recommendations. Some inspection firms will provide this service if it is specifically requested.

1. Are anchor bolts rusted enough to materially reduce their strength?

2. Are anchor bolts tight?

3. Are column shoes clean and painted?

4. What is the condition of the grout under the column shoes and riser plate?

5. Does dirt, grass or weeds accumulate on the column shoes or riser plate?

6. Is there any indication of settlement of column or riser foundations?

7. Do areas exist where water pools or erosion has occurred around the foundations?

8. Do the foundations extend far enough above ground level to protect the column shoes and riser plates from excessive moisture and corrosion?

9. What is the physical condition of the concrete foundations?

10. Are the wind rods in good condition and properly tightened?

11. Where the wind rod connecting pins are secured with cotter pins or welded washers, check each connecting pin and report any missing cotter pins or washers.

12. Where the wind rod connecting pins are secured with nuts and bolts, check to make sure that each nut is full threaded and the bolt thread is well battered.

13. Are the leg struts and their connections in good condition?

14. Is the riser straight and are the riser stay rods in good condition?

15. Check the entire structure for water leaks including all manways, risers and tower legs.

16. Check all welds and seams for cracks.

17. Check all bolts and rivets for corrosion and leaks.

18. Older style elevated tanks with spider rods and hubs should have these removed and replaced with a stiffener ring welded around the upper perimeter of the tank wall.

19. Check to see that all cables, conduits, antennae and similar devices are properly secured to the storage structures.

20. All roof trusses, rafters and their connections must be checked for ice damage, corrosion and soundness. This must include the welds connecting the roof to the rim angles and trusses.

21. Concrete facilities should include close examination and documentation of all cracking.

Safety and security conditions Many safety requirements are set by the Occupational Safety and Health Administration (OSHA) and its latest requirements should be followed. While most OSHA requirements do not apply to political subdivisions, they do apply to privately owned firms hired to inspect, maintain and repair publicly owned facilities and are used as standards of safety by many courts. Publicly owned facilities should meet OSHA requirements to avoid liability issues, and more importantly, to protect people working on the storage facilities.

1. Older elevated water tanks that do not have leg ladders but require maintenance workers to climb a tower leg are serious safety hazards.

These must have properly constructed safe ladders installed.

2. Check ladder brackets to ensure enough are provided, they are not damaged by corrosion and they are secure to both the structure and the ladders.

3. Check all ladder rungs to ensure they are secure and not damaged by corrosion.

4. Check to see that all ladders (interior and exterior) are constructed to OSHA requirements and adequate room exists between the storage structure and the ladder rungs (seven inches minimum). Replace any flimsy or improperly constructed ladders.

5. Make sure safety devices that incorporate safety harnesses, friction brakes and sliding attachments are provided on all ladders and that they are properly secured and operate safely.

6. Cables, power conduits, antenna brackets or similar devices should not be attached to any ladder or be installed behind a ladder because they will obstruct the ladder and prevent the safe use of the ladder and its safety devices.

7. Ladders or sections of ladders having pitches greater than 90 percent are prohibited and must be replaced with properly constructed ladders or sections.

8. All conduits, cables and wires to devices on the storage structure must be installed using properly designed brackets that safely secure them to the storage structure while allowing the storage facility to be sandblasted and painted.

9. Check catwalk railings and posts to make sure they are securely attached.

All catwalks must have railings that meet OSHA construction regulations.

The intent of OSHA regulations is to have railings that do more than prevent people from falling. They must also prevent equipment, work material and other objects from falling. Therefore, the spacing between railings must meet standards and toe plates must be provided.

10. Check the condition of all landings and catwalks to make sure they are clean, they drain properly and are not damaged by corrosion.

11. Large diameter wet risers in the bottom of elevated tanks are fall hazards so guardrails must be installed to protect people from falling into the riser.

Grates over the riser tops do not meet OSHA standards, are easily damaged and displaced by ice and are dangerous to repair. If the wet riser pipe is extended into the tank for this purpose, it must meet the same criteria as a guard rail system (extend a minimum of 42-inches, have a top rail that can be gripped, etc.).

12. All water storage structures must have at least two access ways such that when ventilation equipment blocks one, the other is free from obstruction.

Elevated water tanks must have at least two access ways in the tank portion of the structure. The manway in the riser does not satisfy this requirement. The number of manways required depends on the size of the facility.

13. Check to see that all manways are large enough (24-inches in diameter minimum).

14. Shell manway covers should have two handles and be equipped with either a hinge or davit to facilitate the handling of the cover plate.

15. Check all painter’s rings and brackets to assure they are sound, securely attached and not excessively corroded.

16. Inspect all Federal Aviation Administration warning lights to see that they are working properly.

Security Issues On elevated water tanks, standpipes and tall ground storage facilities, exterior ladders must terminate at least eight feet above ground and have their bottom sections covered with locking ladder guards.

1. Access to water storage structures must be restricted to only authorized people. Check to see that signs announcing authorized personnel only are posted. Check to see that security fences are sound and that their gates and locks work properly.

2. Check to see that all doors and access hatches are locked.

3. All gates, doors, hatches and manways should be locked with only one lock. Daisy chains of locks are a security threat.

Coating system conditions The following things should be done when inspecting the coating systems on a storage facility and explained in the facility inspection report. All coating system testing should be conducted in accordance with current applicable ASTM testing methods.

1. Determine the type and general condition of the interior and exterior paint systems.

2. Determine lead and chromium levels on any interior or exterior coating to determine if it is high in lead or chromium.

3. If rusting is continuous, approximate the percent of rusted area and determine the character of the areas (loose paint, blotchy, general corrosion, no paint).

4. Determine the extent, nature and depth of pitting.

5. Determine total system film thickness and conduct adhesion tests.

6. Check the paint for chalking, blistering and other defects. If paint is delaminating determine where the delamination is occurring (between coats of paint or from tank surfaces).

7. Determine surface profiles.

8. Concrete structures should be inspected for signs of concrete deterioration (spalding, cracking, leaking, etc.).

9. Glass coated structures should be inspected for cracking, bolt corrosion and other signs of coating deterioration.

Deliverables The contractor will be responsible for providing a completion report containing the following for this project:

• Before and after cleaning photos of the interior and exterior of each tank.

• Documentation on cleaning and disinfection procedures for each tank.

• Documentation on sediment depths within each tank before cleaning.

• Addressing the inspection questions for each tank that are outlined in Missouri

Department of Natural Resources - Inspection of Water Storage Facilities -

PUB2112.

Period of Performance The anticipated period of performance is September 15, 2024 to December 15, 2024.

Existing Condition Pictures of Tanks (June 2024)

Tank 1 – Akers

Tank 2 - Pulltite

Tank 3 – Round Spring

Tank 4 – Round Spring

Tank 5 – Alley Spring

Tank 6 – Two Rivers Water Tower

Tank 7 - Big Spring Campground

Tank 8 – Big Spring Cabins