SECTION 22 12 23 - POTABLE WATER STORAGE TANKS

PART 1 GENERAL

1.1 RELATED DOCUMENTS

A Drawings and general provisions of the Contract, including General and Supplementary
Conditions and Division 01 Specification Sections, apply to this Section.

1.2 SUMMARY

A Section Includes:

1. Plastic, non-pressure, potable-water storage tanks.

1.3 DEFINITIONS

A HDPE: High-density polyethylene plastic. b. LDPE: Low-density polyethylene plastic.

1.4 PERFORMANCE REQUIREMENTS

1.5 SUBMITTALS

A Product Data: For each type of product indicated.

1. Include construction details, material descriptions, dimensions of individual

components and profiles, and finishes for water storage tanks.
2. Include rated capacities, operating characteristics, and furnished specialties and
accessories.

1.6 INFORMATIONAL SUBMITTALS

A Product Certificates: For each type of potable-water storage tank, from manufacturer.

B Source quality-control reports.

C Purging and disinfecting reports.

1.7 QUALITY ASSURANCE

A Comply with NSF 14, "Plastics Piping Components and Related Materials," for plastic
potable-water storage tanks and components. Include appropriate NSF marking.

B Comply with NSF 61, "Drinking Water System Components - Health Effects," for
potable- water storage tanks. Include appropriate NSF marking.

Page 144 of 366

1.8 COORDINATION

A Coordinate sizes and locations of concrete bases with actual equipment provided.

B All outdoor water pumps, control panel and water tank shall be provided with shade.

C All By-pass connection shall be provided as per RSB regulations.

D All irrigation/outdoor water connection shall be provided with gravity pressure as per
RSB requirements.

PART 2 PRODUCTS

2.1 GENERAL

A Water tank shall be obtained from single source and single manufacturer, having the
ability and capability of designing, manufacturing, assembling, Testing and
commissioning certifications from relevant international and local authorities.

B All water tanks sizing shall be carried out as per ADUPC and RSB requirement and shall
be submitted by Contractor for Engineer’s review and approval prior to any material
selection and procurement.

C ADQCC and WRAS certification shall be provided for all water tanks.

2.2 PLASTIC, NON-PRESSURE, POTABLE-WATER STORAGE TANKS

A PE Potable-Water Storage Tanks:

1. The proposed water storage tanks shall be designed, manufactured by a reputed

firm which has not less than 10 years of experience in supplying similar systems
in UAE and have their local regional office represented by specialized and
qualified engineers.
2. Piping Supports and Hangers shall comply to the Section 22 05 29.
3. Use only new material, free of defects, rust and scale, and meeting the latest
revision of BS and/or ASTM specifications as listed in this section of
specifications.

a. Description: PE, vertical, flat-bottom, non-pressure-rated water tank;

complying with NSF 61 barrier materials for potable-water tanks.
b. Construction: ASTM D 1998, molded PE.
c. Tappings: Factory-fabricated bulkhead fittings attached to tank.

DN 50 and Smaller: With female thread.

DN 65 and Larger: Flanged.

4. Vertical Tank Support: Separate factory-fabricated steel stand capable of

supporting entire bottom of tank.

B Manhole: Watertight, for tank more than 600mm in diameter.

C Cover for Open Tank: Plastic, same as or similar to tank material and with shape that
encloses top of tank.

Page 145 of 366

 D The tank shall have 4 layers for outdoor installed tanks includes UV stabilizer outer
layer white, sun shield sun layer black second layer, thermal insulator centre layer and
potable enhancer inner layer white.

E The tank shall be one-piece moulded body has no joints and shall be maintenance free
and corrosion resistant.

F The tank shall be manufactured using food grade polyethylene granules.

G Specialties and Accessories: Include tapping’s in the tank and the following:

1. Vacuum relief valve.

2. Free air vent with insect screen.
3. Thermometer.
4. Gage glass, brass fittings, compression stops, and gage-glass guard.
5. Warranty: 5 Years.

2.3 SOURCE QUALITY CONTROL

A Test and inspect potable-water storage tanks according to the following tests and
inspections and prepare test reports:

1. Pressure Testing for ASME-Code, Potable-Water Storage Tanks: Hydrostatically

test to ensure structural integrity and freedom from leaks. Fill tanks with water,
vent air, pressurize to 1-1/2 times tank pressure rating, disconnect test
equipment, hold pressure for 30 minutes with no drop-in pressure, and check
for leaks.
2. Pressure Testing for Non-ASME-Code, Pressure, Potable-Water Storage Tanks:
Hydrostatically test to ensure structural integrity and freedom from leaks at
pressure of 345 kPa above system operating pressure, but not less than 1035
kPa Fill tanks with water, vent air, pressurize tanks, disconnect test equipment,
hold pressure for two hours with no drop- in pressure, and check for leaks.
3. Testing for Non-pressure, Potable-Water Storage Tanks: Fill tanks to water
operating level to ensure structural integrity and freedom from leaks. Hold
water level for two hours with no drop- in water level.

B Repair or replace tanks that fail test with new tanks and repeat until test is satisfactory.

PART 3 EXECUTION

3.1 INSTALLATION

A Install water storage tanks on concrete bases, level and plumb, firmly anchored.
Arrange so devices needing servicing are accessible.

B Install thermometers and pressure gages on water storage tanks and piping if
indicated. Thermometers and pressure gages are specified in Division 22 Section
"Meters and Gages for Plumbing Piping."

C Install the following devices on tanks where indicated:

1. Pressure relief valves.

2. Temperature and pressure relief valves.
Page 146 of 366
 3. Vacuum relief valves.
4. Tank vents on non-pressure tanks.
5. Connections to accessories.

D After installing tanks with factory finish, inspect finishes and repair damages to
finishes.

3.2 CONNECTIONS

A Piping installation requirements are specified in Division 22 Sections. Drawings

indicate general arrangement of piping, fittings, and specialties.

B Install piping adjacent to potable-water storage tanks to allow service and

maintenance. c. Connect water piping to water storage tanks with unions or flanges
and with shutoff valves. Connect tank drains with shutoff valves and discharge over
closest floor drains.

1. Water Piping Connections: Make connections to dissimilar metals with dielectric

fittings. Dielectric fittings are specified in Division 22 Section "Domestic Water
Piping."

3.3 IDENTIFICATION

A Identify system components. Comply with requirements for identification specified in

Division 22 Section "Identification for Plumbing Piping and Equipment."

3.4 FIELD QUALITY CONTROL

A Perform the following final checks before filling:

1. Verify that air pre-charge in pre-charged tanks is correct.

2. Test operation of tank accessories and devices.
3. Verify that pressure relief valves have correct setting.

a. Manually operate pressure relief valves.

b. Adjust pressure settings.

4. Verify that vacuum relief valves are correct size.

a. Manually operate vacuum relief valves.

b. Adjust vacuum settings.

B Filling Procedures: Follow manufacturer's written procedures. Fill tanks with water to
operating level.

3.5 CLEANING

A Clean and disinfect potable-water storage tanks.

B Use purging and disinfecting procedure prescribed by authorities having jurisdiction

or, if method is not prescribed, use procedure described in AWWA C652 or as
described below:

Page 147 of 366

 1. Purge water storage tanks with potable water.
2. Disinfect tanks by one of the following methods:

a. Fill tanks with water-chlorine solution containing at least 50 mg/L of

chlorine. Isolate tanks and allow to stand for 24 hours.
b. Fill tanks with water-chlorine solution containing at least 200 mg/L of
chlorine. Isolate tanks and allow to stand for three hours.

3. Flush tanks, after required standing time, with clean, potable water until
chlorine is not present in water coming from tank.
4. Submit water samples in sterile bottles to authorities having jurisdiction. Repeat
procedure if biological examination made by authorities having jurisdiction
shows evidence of contamination.

C Prepare written reports for purging and disinfecting activities.

Page 148 of 366