B08_Attachment_1_SOW.pdf

GREAT SAND DUNES

NATIONAL PARK & PRESERVE

CLEAN & INSPECT TWO WATER TANKS

MOSCA, COLORADO

GRSA

PMIS 306640

SCOPE OF WORK

NATIONAL PARK SERVICE

REGIONAL OFFICE SERVING INTERIOR REGIONS 6, 7 & 8

SOUTHERN ARIZONA OFFICE

Overview

This project will clean and inspect two potable water storage tanks within Great Sand Dunes

National Park & Preserve (GRSA), 11500 State Highway 150, Mosca CO 81146.

The first tank is a 50,000-gallon welded steel tank, and the second is a 74,000-gallon glass fused to steel tank, both located at the visitor center (VC) area. A comprehensive tank inspection shall be performed, and detailed report shall be provided to the National Park Service. As-built drawings are included which indicate tank dimensions and locations. All work to comply with Colorado Department of Public Health and

Environment, AWWA, and OSHA standards.

Image 1 Below: Location of Project Site (Orange Box) in relation to GRSA Visitor Center.

Image 2 Below: Location of both tanks at Project Site.

Scope of Services

1. Perform interior in-service inspection using ROV Inspection Robot, divers, or a combination of the two methods. Perform exterior inspection by trained personnel abiding by OSHA regulation. ROV equipment/divers to be disinfected before entering water tank interior.

2. Check for deficiencies and meet tank inspection requirements of OSHA, EPA, AWWA and NFPA.

Review all structural, sanitary, safety, security and coating conditions. Photograph and examine exterior, ladders, shell, roof, vent, manways, internal plumbing, inlet and outlet pipes, welds, joints, seams, foundation, anchors, safety systems, hatch, interior coatings, interior walls and floors, sediment depth and external overflow. Photo document all deficiencies to tank and appurtenances.

3. Perform the following tests during the inspection:

a. Mil thickness test (coating thickness) – Exterior only

b. Cross hatch test (paint adhesion) – Exterior only

c. Ultra-sonic test of tank shell– Exterior only

4. Perform interior in-service cleanout of sediment from the tank floors using ROV equipment, divers, or a combination of the two methods. The contractor will clean the accumulated sediment at the bottom of the tanks using underwater vacuuming equipment. Removal of up to 3 inches of accumulated sediment shall be included in this work. The removed sediment will be properly disposed of by the contractor outside of the park.

5. Submit a detailed written report of findings with photographs, electronic video file of inspection (on

USB), corrective recommendations and cost estimates. The report shall be signed by registered personnel. Two (2) paper copies and an electronic copy (PDF) of the report shall be submitted to this office within one calendar week after completing all inspection services. The water tank inspection report shall contain any deficiencies discovered and recommendations to remedy.

Qualifications

1. Offerors shall have a minimum of five years’ experience installing and providing cleaning services of glass-fused-to-steel bolted liquid storage tanks. Experience with “Aqua Store” manufactured tanks is preferred.

2. Inspectors shall have a minimum of five years of experience inspecting glass-fused-to-steel bolted liquid storage tanks.

Verification of Existing Conditions and Utility Location

Prior to preparing bid, contractor is responsible for verifying existing conditions. Alert CO of any conflicts with scope of work, via submission of a Request For information (RFI).

Submittals

1. Submit manufacturer’s information for all products used. Note: electronic submittals are acceptable. Sign and scan transmittal form for electronic submittals.

2. A site safety plan shall be submitted for review and acceptance by Contracting Officer (CO) and project NPS personnel. Submit prior to mobilization to site.

3. A Service Schedule shall be provided to the CO and onsite contract representative (COR) for acceptance of work timelines, and to organize logistical needs.

4. Inspection Report with finding and recommendations.

5. Certificates of insurance covering Workman’s Compensation, Occupational Disease, Employer’s Liability, and General Liability.

Safety Requirements

1. Site safety plans shall be subject to review by CO, and designated NPS personnel. The contractor shall not begin any onsite work until plan is received, reviewed and approved by CO.

2. The Contractor shall comply with all health and safety regulations and requirements of OSHA, NPS, State of Colorado, 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.

Sealants for Touch up work

The lap joint sealant shall be a one component, moisture cured, polyurethane compound. The sealant shall be suitable for contact with potable water and shall be certified to meet ANSI/NSF Additives Standard 61 for indirect additives.

The sealant shall be used to seal lap joints and bolt connections and edge fillets for sheet notches and starter sheets. The sealant shall cure to a rubber-like consistency, have excellent adhesion to the glass coating, low shrinkage, and be suitable for interior and exterior use.

• Sealant curing rate at 73°F and 50% RH.

• Tack-free time: 6 to 8 hours.

• Final cure time: 10 to 12 days.

• Neoprene gaskets and tape type sealer shall not be used.

The industrial membrane shall be applied on top of the new interior sealer. The membrane shall be a two-component product and completely cover the sealer and tank bolts. The new interior sealer shall be allowed to cure a minimum of 24 hours prior to the application of the industrial membrane. Industrial membrane shall be NSF 61 certified for potable water contact up to 180°F. Cure time: 24 hours

Disinfection of Water Storage Facility

The work of this section consists of the disinfection of all portions of the water storage tanks that may have become contaminated during cleaning activities. Disinfection execution will be in accordance with

AWWA 652-19, Disinfection of Water Storage Facilities. Disinfection shall not take place until tank sealant

(if applied) is fully cured. Divers and associated in-tank equipment shall be fully disinfected in compliance with AWWA standard C652-19. All gear and equipment entering the potable water tank shall be cleaned and disinfected and the dressed diver shall be sanitized with a 200 parts per million (ppm) concentration, NSF-60 approved sodium hypochlorite (“bleach”) solution immediately prior to entering the water tank.

For safety purposes, the inspector/diver shall utilize a helmet, dry suit, and shall always be in direct voice communication with outside personnel during diving operations. The contractor shall have high-resolution color video at all times during the inspection to allow for constant viewing and recording of the diver work and observations. All system entries will be conducted in accordance with applicable OSHA regulations pertaining to diving and confined spaces (29 CFR Part 1910 Subpart T).

Forms of Chlorine

1. Liquid Chlorine as specified in AWWA C652-19

2. Sodium hypochlorite as specified in AWWA C652-19

Execution

Acceptable Methods of Chlorination Shall be:

1. Chlorination method 1 as specified in AWWA C652-19

2. Chlorination method 2 as specified in AWWA C652-19

3. Chlorination method 3 as specified in AWWA C652-19

Application Methods shall be consistent with AWWA C652-19, Acceptable methods shall be Chemical feed pump, spraying, brushing, or painting of all water contact surfaces.

The tanks will be drained one at a time, manways opened, all sediment and debris removed, pressure washed on the interior, then closed, refilled, and brought back into service. Tank sediment shall be collected and removed from the interior. Debris and material can be removed through the manway entrances, slurry water from power washing can be discharged through the tank drain outlet. Any slurry or debris in which may cause clogging of tank drain shall be removed prior to using tank drainage system.

Due to the Time needed between disinfection testing, and refilling of storage tanks, this project may require two mobilizations to the job site.

Disposal of chlorinated water

Dispose of chlorinated water by neutralizing chlorine with a chemical listed on table C.1 of AWWA C651 and flushing onto ground surface at locations approved by park facility manger.

Bacteriological Examination

After the tank has been thoroughly flushed and disinfected, take samples from representative point in storage facility, according to AWWA C652. Submit samples to a state certified lab for bacteriological examination. If unsatisfactory, repeat the disinfection procedure until satisfactory results are obtained.

Coordination and Contacts

Owen Waltrip (Rusty) Gabriel Martinez (Gabe)

Maintenance Supervisor GRSA Project Supervisor/COR

Owen_waltrip@nps.gov Gabriel_martinez@nps.gov

719-378-6373 719-250-2364