Technical Specification - BET Water Tank Cleaning.pdf

Potable Water Storage Tank Cleaning and Inspection Bethel, Alaska 17 April 2012 Specification - Page 1 of 6

TECHNICAL SPECIFICATION

TANK CLEANING AND INSPECTION

1.0 GENERAL

1.1 SCOPE OF WORK

1.1.1 The Work includes the comprehensive cleaning and inspection of the potable water storage tank described in these Specifications and shown in the Reference Drawings. A report detailing the findings of the inspection and all work performed shall be completed as part of these services as described in section 4.1 of these specifications.

1.2 BACKGROUND

1.2.1 The FAA owned tank is located in Bethel, Alaska and is to be cleaned and inspected as part of these services. The tank was constructed in 1996 and has not been cleaned or inspected. It is a bolted steel tank with exterior insulated panels, as shown in the Reference Drawings. The tank has a nominal capacity of 88,000 gallons, is 21’-6” in diameter, and is 32’” high. 120Vac electrical power is available at the tank. Bethel is a remote town in South West Alaska.

Bethel can only be reached by aircraft or ocean vessel and cannot be reached by road from Anchorage, Alaska.

1.3 INSPECTION CERTIFICATION AND PROCEDURE

1.3.1 Applicable Standards

A. American Water Works Association (AWWA)

a. D103-53 – Inspecting and Repairing Steel Water Tanks, Standpipes, Reservoirs, and Elevated Tanks for Water Storage.

b. C652-02 – Disinfection of Water-Storage Facilities

B. Occupational Safety and Health Administration (OSHA)

a. 29 CFR 1910.146 – Permit Required Confined Spaces.

C. American Society for Testing and Materials (ASTM)

a. D3359 – Standard Test Methods for Measuring Adhesion by Tape Test.

1.3.2 Field Inspector shall have a minimum 5 years of experience inspecting water storage tanks.

1.3.3 Inspection of the tanks shall be conducted in accordance with AWWA D103-

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53.

1.3.4 Cleaning and inspection of the tank may not interfere with domestic or fire water supply from the water storage tanks.

1.3.5 All equipment entering the water storage tanks during any portion of the services shall be disinfected per AWWA C652-02.

1.3.6 The water storage tank is a permit-required confined space. Any personnel entering the water storage tank during these services shall comply with the Owner’s confined space entry procedure per OSHA 29 CFR 1910.146. The Contractor shall submit a scope of work in accordance with OSHA 29 CFR

1910.146 for procedures to be utilized during confined space entry for approval prior to performing services.

1.3.7 No personnel shall be permitted to enter the water storage tank that gives evidence of illness or abnormal temperature, has been under a physician’s care, or has needed a physician’s care within a 7 day period of entering or working in the tank.

1.3.8 Contractor must submit a Safety Risk Management plan to the Government for approval prior to commencement of work.

1.3.9 Contractor shall notify the Contracting Officer a minimum of seven (7) calendar days prior to start of work activities at the project site in Bethel.

2.0 SERVICES

2.1 GENERAL

2.1.1 Services shall include the comprehensive inspection of the interior and exterior of the water storage tanks as well as cleaning of the interior. Acceptable methods include cleaning and inspection by Remote Operated Vehicle (ROV) or human inspectors. Removal of external insulation panel is not required.

2.1.2. Immediately following completion of on-site services by the Contractor, a water sample shall be taken from the water storage tank for bacteriological analysis by the Government.

2.2 INSPECTION

2.2.1 General

A. Inspection shall be performed in accordance with AWWA D103-53.

B. Equipment used for inspection shall be dedicated to potable water use only and shall contain no material that will contaminate potable water. Food grade lubricants must be used where applicable.

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2.2.2 Comprehensive Inspection and Evaluation

A. The inspection shall include, but is not limited to, the following items for the water storage tank:

a. Condition of concrete or steel on the interior including;

approximate percent of cracking, corrosion, type of failure and locations of concentrated spalling.

b. Corrosion conditions of any exposed reinforcing materials.

c. Safety appurtenances such as ladders, anti-climb devices, anti-fall devices, painter’s rails and balconies are inspected, and their condition noted.

d. Sanitary conditions of tank hatches, vents and other penetrations.

e. Measurement of bottom sediment depths in at least (4) four locations.

f. Collection of a sample of the bottom sediment for analysis by the Government.

g. Condition of paint on the interior and exposed exterior including;

approximate percent of rusting, type of paint failure and locations of concentrated paint failure.

h. Metal loss due to corrosion such as pitting, layered corrosion or physical damage, especially joints, seams, rivets and roof members.

i. Cathodic protection systems (if applicable) inspected to assess the number of anode strings, presence or absence of reference cells and operation of a rectifier.

j. Foundation pads or ring walls inspected for cracking and other deterioration. Floor plate flange and grouting inspected also.

k. Test Adhesion of exterior coatings as per ASTM D3359.

l. Measure Dry Film Thickness of exposed Exterior Coating.

m. Condition of foundation and anchors.

n. Condition of insulation package.

o. All fasteners, such as cotter pins, anchor bolts, and turn-buckles, inspected for corrosion or signs of failure.

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p. Adhesion measured on the exposed exterior paint systems to determine possibility of top coating and estimated lifespan.

q. Inspect sanitary and security items such as lights, bug screens, hatches and padlocks.

B. Underwater inspection using an ROV:

The ROV used for inspection shall be dedicated to potable water use only, contain no liquids that will contaminate potable water, and shall utilize only food grade lubricants.

The ROV used for inspection must have the following capabilities:

a. Must be capable of abrading underwater surfaces for the purposes of corrosion evaluation.

b. Must be capable of measuring sediment depth.

c. Must have an integral camera with the ability to provide extreme close up inspection as well as long distance inspection for above water surfaces.

d. Must be capable of measuring metal thickness on floor and walls.

C. Underwater inspection using a diver:

The water storage tank is a permit-required confined spaces. The confined space entry requirements in section 1.3.6 of these specifications apply to any personnel entering the tanks.

Any diver used for water storage tank inspection shall have a current cold water diving certification and must have a minimum of 5 years of experience inspecting steel water storage tanks as a diver.

The diver and all diving equipment entering the tank shall be thoroughly disinfected per AWWA C652-02 immediately prior to entering the tank.

2.3 CLEANING

2.3.1 The water storage tanks shall be cleaned, if required as determined by the Government during inspection, to remove all accumulated sediment from the floor of the tank.

2.3.2 Wastewater from the tank cleaning may be discharged to a nearby sanitary sewer by permit at a rate not to exceed 20 gpm.

3.0 SUBMITTALS

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3.1 GENERAL

3.1.1 The following items shall be submitted for Government approval within 15 calendar days of receipt of Notice to Award by Contractor:

A. A safety risk management plan.

B. A scope of work for confined space entry in accordance with OSHA 29 CFR 1910.146, if applicable. Scope of work shall include detailed description of Contractor’s methods for entry into the confined spaces to comply with OSHA 29 CFR 1910.146.

4.0 DELIVERABLES

4.1 REPORT

A. Upon completion of cleaning and inspection, a report shall be provided to the Government that details the findings of the inspection, including the condition of all items inspected and cleaned as well as any safety or sanitary deficiencies noted. The report shall contain relevant photographs of any deficiencies noted during the inspection. Provide a complete video and audio DVD of the cleaning and inspection operation. The DVDs shall be compatible with Windows Media Player. Detailed recommendations for any sanitary, safety, or rehabilitation requirements shall be provided with estimated costs. The Contractor shall recommend time frames for repairs and/or replacements. (For example: Repaint the tank interior within five years.) The report shall be prepared by a registered Professional Engineer.

Five (5) hard copies of the report shall be supplied to the Government as well as all documentation and photographs from the cleaning and inspection. Five (5) electronic copies of the report and all photos shall be provided to the Government.

B. The report shall contain, at minimum, evaluation of the following for each water storage tank:

a. Presence and extent of any corrosion encountered.

b. Coating deficiencies.

c. Structural deficiencies.

d. Condition of anodes (if applicable).

6.0 REFERENCE DRAWINGS

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ALD-BET-801.012 Housing, Site Plan (Center) C1.2

ALD-BET-801.066 Housing, Sewer and Water Details 6 C6.6

Google Earth Image FAA Housing Bethel, AK

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