USACE / NAVFAC / AFCESA / NASA UFGS-33 16 15 (April 2008)
----------------------------
Preparing Activity: USACE Superseding
UFGS-13 16 15 (October 2007)
UNIFIED FACILITIES GUIDE SPECIFICATIONS
References are in agreement with UMRL dated January 2009
SECTION 33 16 15
WATER STORAGE STEEL TANKS
04/08
NOTE: This guide specification covers the requirements for steel standpipes,
ground storage tanks (reservoirs), and elevated water tanks 380 to 1890 kL (100,000
to 500,000 gallon) capacity.
Edit this guide specification for project specific requirements by adding, deleting,
or revising text. For bracketed items, choose applicable items(s) or insert
appropriate information.
Remove information and requirements not required in respective project, whether
or not brackets are present.
Comments and suggestions on this guide specification are welcome and should
be directed to the technical proponent of the specification. A listing of technical
proponents, including their organization designation and telephone number, is
on the Internet.
Recommended changes to a UFGS should be submitted as a Criteria Change Request
(CCR).
PART 1 GENERAL
NOTE: This Section covers welded and bolted steel water storage tanks and includes
the design, fabrication, and erection of a complete system to augment an existing
or future water distribution system and the inspection and repair of existing
water storage tanks. This specification must be edited to specify the required
type of tank.
The following information will be shown on the project drawings:
1. Detail plans to show tank location, elevation, valve vault if required,
and connection to system.
2. Accessories as depth indicator, telemetering automatic controls, protection
against freezing, or other special project requirements.
3. Requirements of Federal Aviation Agency to determine if tank constitutes
a hazard to aerial navigation. If so, show pattern for orange and white painting.
Detail obstruction lights or beacon and intermediate lights as required. Refer
to Federal Aviation Agency Aviation Circular AC 70/7460-1G, "Obstruction Marking
and Lighting".
4. Requirements for cathodic protection system, including details of anodes,
anode layout, wiring connections, and rectifier (as applicable).
1.1 REFERENCES
NOTE: This paragraph is used to list the publications cited in the text of
the guide specification. The publications are referred to in the text by basic
designation only and listed in this paragraph by organization, designation,
date, and title.
Use the Reference Wizard's Check Reference feature when you add a RID outside
of the Section's Reference Article to automatically place the reference in the
Reference Article. Also use the Reference Wizard's Check Reference feature
to update the issue dates.
References not used in the text will automatically be deleted from this section
of the project specification when you choose to reconcile references in the
publish print process.
The publications listed below form a part of this specification to the extent referenced. The publications are
referred to within the text by the basic designation only.
[AMERICAN SOCIETY OF CIVIL ENGINEERS (ASCE)ASCE 7(2005; Supp 1) Minimum Design Loads for Buildings and Other Structures][AMERICAN WATER WORKS ASSOCIATION (AWWA)AWWA B300(2004) HypochloritesAWWA B301(2004) Liquid ChlorineAWWA C104/A21.4(2003) Cement-Mortar Lining for Ductile-Iron Pipe and Fittings for WaterAWWA C105/A21.5(2005) Polyethylene Encasement for Ductile-Iron Pipe SystemsAWWA C110/A21.10(2008) Ductile-Iron and Gray-Iron Fittings for WaterAWWA C111/A21.11(2000) Rubber-Gasket Joints for Ductile-Iron Pressure Pipe and FittingsAWWA C115/A21.15(2005) Flanged Ductile-Iron Pipe With Ductile-Iron or Gray-Iron Threaded FlangesAWWA C150/A21.50(2002; Errata 2003) Thickness Design of Ductile-Iron PipeAWWA C151/A21.51(2002; Errata 2002) Ductile-Iron Pipe, Centrifugally Cast, for WaterAWWA C500(2002; R 2003) Metal-Seated Gate Valves for Water Supply ServiceAWWA C504(2006) Standard for Rubber-Seated Butterfly ValvesAWWA C508(2001) Swing-Check Valves for Waterworks Service, 2 In. (50 mm) Through 24 In. (600 mm) NPSAWWA C600(2005) Installation of Ductile-Iron Water Mains and Their AppurtenancesAWWA C652(2002) Disinfection of Water-Storage FacilitiesAWWA D100(2007) Welded Steel Tanks for Water StorageAWWA D103(1997) Factory-Coated Bolted Steel Tanks for Water Storage][ASME INTERNATIONAL (ASME)ASME B16.3(2006) Malleable Iron Threaded Fittings, Classes 150 and 300ASME B40.100(2005) Pressure Gauges and Gauge Attachments][ASTM INTERNATIONAL (ASTM)ASTM A 197/A 197M(2000; R 2006) Standard Specification for Cupola Malleable IronASTM A 48/A 48M(2003; R 2008) Standard Specification for Gray Iron CastingsASTM A 53/A 53M(2007) Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless][MANUFACTURERS STANDARDIZATION SOCIETY OF THE VALVE AND FITTINGS INDUSTRY (MSS)MSS SP-80(2008) Bronze Gate, Globe, Angle and Check Valves][NSF INTERNATIONAL (NSF)NSF 61(2008) Drinking Water System Components - Health Effects][THE SOCIETY FOR PROTECTIVE COATINGS (SSPC)SSPC PS 4.04(1982; E 2004) Four-Coat White or Colored Vinyl Painting System (For Fresh Water, Chemical, and Corrosive Atmospheres)SSPC PS Guide 17.00(1982; E 2004) Guide for Selecting Urethane Painting SystemsSSPC Paint 104(1982; E 2004) Paint Specification No. 104 White or Tinted Alkyd PaintSSPC Paint 21(1982; E 2004) Paint Specification No. 21 White or Colored Silicone Alkyd Paint (Type I, High Gloss and Type II, Medium Gloss)SSPC Paint 25(1997; E 2004) Paint Specification No. 25Zinc Oxide, Alkyd, Linseed Oil Primer for Use Over Hand Cleaned Steel Type I and Type II][U.S. DEPARTMENT OF DEFENSE (DOD)MIL-DTL-24441(Rev C; Supp 1; INT Amd 1) Paint, Epoxy-PolyamideMIL-PRF-23236(Rev C) Coating Systems for Ship Structures][U.S. FEDERAL AVIATION ADMINISTRATION (FAA)FAA AC 150/5345-43(Rev F) Obstruction Lighting Equipment]1.2 SYSTEM DESCRIPTION
1.2.1 Design and Construction Standards
NOTE: When required by the corrosive nature of stored water, lack of proper
maintenance facilities, or by climatic conditions, this paragraph will be modified
to provide for a corrosion allowance.
Determine basic wind speed for use with ANSI procedure from ANSI,UFC 3 310-01
LOAD ASSUMPTIONS FOR BUILDINGS or UFC 3-320-05A STRUCTURAL DESIGN CRITERIA FOR
STRUCTURES OTHER THAN BUILDINGS. The choice between the ANSI and AWWA procedures
allows the supplier to provide a tank using the AWWA approach up to the point
at which the ANSI procedure will provide the greater pressure. (This usually
occurs with a basic wind speed around 145 km per hour (90 miles per hour), depending
on the height of the tank.)
Use 1200 Pa (25 psf) snow load for most heavy snow climates; delete snow load
where maximum snow is insignificant. In some cases, local climate and topography
will dictate that a value greater than 1200 Pa (25 psf) be used for snow loading.
This may be determined from UFC 3 310-01.
Provide seismic requirements for tank related equipment supports, if a Government
designer is the Engineer of Record, and show on the drawings. Delete the inappropriate
bracketed phrase. Pertinent portions of UFC 3-310-04 and Sections 13 48 00
and 13 48 00.00 10, properly edited, must be enclosed in the contract documents.
NAVFAC P-355, "Seismic Design for Buildings," does not allow the use of pedestal
type elevated tanks in areas of moderate and high seismic activity, so use only
elevated tanks with cross-braced columns instead. Bolted tanks are available
only as standpipes and ground reservoirs.
The design, fabrication, and erection of the [elevated tank] [standpipe] [reservoir] shall be in accordance with
the applicable requirements of AWWA D100 or AWWA D103 except as modified herein. Earthquake design shall be
[in accordance with UFC 3-310-04 SEISMIC DESIGN FOR BUILDINGS and Sections 13 48 00 SEISMIC PROTECTION FOR MISCELLANEOUS
EQUIPMENT and 13 48 00.00 10 SEISMIC PROTECTION FOR MECHANICAL EQUIPMENT] [as indicated]. No additional thickness
for corrosion allowance will be required. Design metal temperature shall be [_____] degrees C degrees F. The
elevated tank shall be designed for a basic wind speed of [_____] km/hourmph in accordance with ASCE 7 or designed
in accordance with AWWA D100 wind load design, whichever provides the greater pressure. [The elevated tank shall
be designed for a snow load of 1200 Pa 25 psf [_____]]. The [standpipe] [reservoir] shall be designed for a
peak wind speed of [_____] and snow load of [_____].
1.2.2 Welding
Qualification of welding procedures, welders, and welding operators shall be in accordance with Section 8.2 of
AWWA D100.
1.2.3 Design Requirements
NOTE: The blank spaces will be filled in for capacity and governing elevations;
minimum diameters of tank and riser pipe. The following table should be used
in selecting minimum requirements:
Size of riser
(Tank capacity, Diameter, (warm and
kL minimum temperate zones)
------------- --------- ----------------
380 8.50 m 910 mm
570 9.75 m 1220 mm
760 10.95 m 1220 mm
950 11.6 m 1220 mm
1135 12.2 m 1520 mm
1515 13.7 m 1520 mm
1890 15.25 m 1830 mm
(
Size of riser
(Tank capacity, Diameter, (warm and
gallons minimum temperate zones)
------------- --------- ----------------
100,000 28 ft. 0 in. 3 ft. 0 in.
150,000 32 ft. 0 in. 4 ft. 0 in.
200,000 36 ft. 0 in. 4 ft. 0 in.
250,000 38 ft. 0 in. 4 ft. 0 in.
300,000 40 ft. 0 in. 5 ft. 0 in.
400,000 45 ft. 0 in. 5 ft. 0 in.
500,000 50 ft. 0 in. 6 ft. 0 in.
)
In cold climates, where the water turnover in the tank is sufficient to make
tank heating unnecessary, the following rule will be used to govern the size
of the riser, provided the rule would make the riser larger than required by
the preceding table for warm and temperate zones. Where the location shows
the following temperatures on the isothermal maps contained in NFPA 22, Water
Tanks for Private Fire Protection, the riser size indicated will be used.
Minus 12.2 degrees to minus 28.9 degrees C. 1220 mm
(Plus 10 degrees to minus 20 degrees F. 4 ft. 0 in. riser)
Minus 29 degrees to minus 34 degrees C... 1520 mm
(Minus 20 degrees to minus 30 degrees F. 5 ft. 0 in. riser)
Minus 34.4 degrees C..................... 1830 mm
(Minus 30 degrees F. and below......... 6 ft. 0 in. riser)
In northern areas, water tanks that serve fire systems primarily and those where
the daily consumption is small will be provided with heating facilities in accordance
with NFPA 22. The size of the heating system may be reduced by an amount commensurate
with the W (Btuh) input from makeup water during periods of minimum consumption;
however, the heating facility will be capable of maintaining the coldest water
in the tank at a minimum temperature of 6 degrees C (42 degrees F). Frostproof
casings will not be provided in lieu of heat for large riser tanks.
The capacity of the tank will be based on calculations according to UFC 3-230-09A
WATER SUPPLY, WATER STORAGE and UFC 3-230-04A WATER DISTRIBUTION. Generally
a balcony around the bottom of the tank will not be provided. The elevation
at the top of the foundation will be not less than 200 mm (8 inches) above the
finished grade.
The elevated tank shall have a storage capacity of [_____] L gallons. The high-water level of tank shall be
at elevation [_____] with the top of column foundations at elevation [_____]. The range between high and low
water levels shall be approximately [_____] m feet. The existing grade at the tank site is approximately elevation
[_____]. The top of straight side sheets, where a cone-shaped roof is furnished, shall not be less than 150
mm 6 inches above the top of the overflow weir. The tank diameter shall be not less than [_____] mm feet and
the riser diameter not less than [_____] mm feet. The tank shall [be of the style shown] [have an ellipsoidal
bottom, with vertical side sheets and a cone shaped top, or shall be of an elliptical or oval design as approved.
In the latter design, the lower section of the roof may be used for water storage]. The tower supporting the
tank shall be constructed of structural shapes of the open type, or of tubular sections, to permit inspection
and painting. The tower shall be thoroughly braced with horizontal struts and diagonal ties. The tower columns
may be vertical or inclined as the design may require. Main column splices shall be as few as possible and shall
be located as near as practicable to the intersection of the centerline of the struts. Splice plates shall be
welded so as to hold the members in line and transmit any tension or shearing stresses to which the members may
be subjected. The connections of the tank, with the columns shall be made to distribute the load properly over
the column sections and over the shell of the tank. Around the bottom of the tank a balcony meeting the requirements
of Section 4.7.2 of AWWA D100 and conforming to all federal or local laws or regulations shall be provided.
Balcony floor plates shall be at least 6 mm 1/4 inch thick and shall be suitably punched or drilled for drainage.
1.2.4 Sizing and Design
Sizing and design of elevated tank shall be in accordance with Section 4 of AWWA D100. Submit a certificate
signed by a registered professional engineer providing: (1) description of the entire tank and foundation structural
design loading conditions, (2) description of structural design methods and codes used in establishing allowable
stresses and safety factors, (3) statement that the structural design has been checked by experienced engineers
specializing in hydraulic structures to ensure that design calculations for member sizes, dimensions, and fabrication
processes are as prescribed by ACI and AWWA standards, and (4) certification that the completed work was inspected
in accordance with AWWA D100 or AWWA D103 as applicable.
1.2.5 [Standpipe] [Reservoir]
The [standpipe] [reservoir] shall have a storage capacity of [_____] L gallons. The high-water level of [standpipe]
[reservoir] shall be at elevation [_____] with the top of foundation approximately at elevation [_____]. The
range between high and low water levels will be approximately [_____] mm feet. Existing grade at proposed location
is approximately elevation [_____]. The [standpipe] [reservoir] shall have such standard shell height and such
diameter as will meet the requirements for the selected standard capacity and for the high-water level specified
above. The [standpipe] [reservoir] may have [supported cone roof,] [supported toriconical roof,] [self-supporting
umbrella roof,] [self-supporting dome roof, or] [ellipsoidal roof,] [aluminum self-supporting dome roof,] as
approved. The [standpipe] [reservoir] shall be of welded or bolted construction.
1.2.6 Sizing of Standpipe and Reservoir
Section 6 of AWWA D100 or Section 4 of AWWA D103.
1.2.7 Coatings Certification
Coating materials for interior applications and all other materials which will be in normal contact with potable
water shall conform to NSF 61. Certification by an independent third-party organization that all interior coatings
and materials, that come in contact with potable water, comply with NSF 61 shall be provided.
1.3 SUBMITTALS
NOTE: Review submittal description (SD) definitions in Section 01 33 00 SUBMITTAL
PROCEDURES and edit the following list to reflect only the submittals required
for the project. Submittals should be kept to the minimum required for adequate
quality control.
A “G” following a submittal item indicates that the submittal requires Government
approval. Some submittals are already marked with a “G”. Only delete an existing
“G” if the submittal item is not complex and can be reviewed through the Contractor’s
Quality Control system. Only add a “G” if the submittal is sufficiently important
or complex in context of the project.
For submittals requiring Government approval on Army projects, a code of up
to three characters within the submittal tags may be used following the "G"
designation to indicate the approving authority. Codes for Army projects using
the Resident Management System (RMS) are: "AE" for Architect-Engineer; "DO"
for District Office (Engineering Division or other organization in the District
Office); "AO" for Area Office; "RO" for Resident Office; and "PO" for Project
Office. Codes following the "G" typically are not used for Navy, Air Force,
and NASA projects.
Choose the first bracketed item for Navy, Air Force and NASA projects, or choose
the second bracketed item for Army projects.
Government approval is required for submittals with a "G" designation; submittals not having a "G" designation
are for [Contractor Quality Control approval.][information only. When used, a designation following the "G"
designation identifies the office that will review the submittal for the Government.] The following shall be
submitted in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:
SD-02 Shop Drawings
Tank Installation[; G][; G, [_____]]
Detail and erection drawings, before proceeding with any fabrication. Complete drawings with
details of steel, pipe, and concrete work, and of the assembling of items required for the total
installation. Use standard welding symbols as recommended by the American Welding Society.
Details of welded joints referenced on the drawings shall be included.
SD-03 Product Data
System Description
Foundations
Design Analyses and Calculations.
SD-06 Test Reports
Tank Installation
Testing of Valves and Piping
Each coating manufacturer's technical data, application instructions, Material Safety Data
Sheets (MSDS), and certificate for compliance for VOC content.
Copies of the following test results:
a. Manufacturer's mill test reports for plate material.
b. Mill and shop inspections by a commercial inspection agency.
c. After acceptance of the structure, the radiographic film and test segments.
d. At the conclusion of the work, a written report prepared by the Contractor covering the
hydrostatic test and certifying that the work was inspected in accordance with Section 11.2.1
of AWWA D100.
SD-07 Certificates
System Description
Foundations
Certification by an independent third-party organization that all interior coating and materials
that come in contact with the potable water comply with NSF 61.
A certificate signed by a registered professional engineer, providing the following information:
a. Description of the structural design loading conditions used for the design of entire
tank including the foundation.
b. Description of the structural design method and codes used in establishing the allowable
stresses and safety factors applied in the design.
c. A statement verifying that the structural design has been checked by experienced engineers
specializing in hydraulic structures.
d. A statement verifying that the detail drawings have been checked by experienced engineers
specializing in hydraulic structures to determine that they agree with the design calculations
in member sizes, dimensions, and fabricating process as prescribed by applicable ACI and AWWA
standards.
1.4 DELIVERY, STORAGE, AND HANDLING
Deliver paint in unopened containers with unbroken seals and labels showing designated name, specification number,
color, directions for use, manufacturer, and date of manufacture, legible and intact at time of use. Handle
and store water storage tank systems, components, and parts to prevent distortions and other damage that could
affect their structural, mechanical, or electrical integrity. Replace damaged items that cannot be restored
to original condition. Store items subject to deterioration by exposure to elements, in a well-drained location,
protected from weather, and accessible for inspection and handling.
PART 2 PRODUCTS
2.1 MATERIALS
Provide materials conforming to the following requirements:
2.1.1 Steel
Section 2 of AWWA D100 or Section 2 of AWWA D103.
2.1.2 Shop Fabrication
Section 9 of AWWA D100 or Section 7 of AWWA D103.
2.1.3 Ductile-Iron Pipe
Pipe for fluid conductors, except for overflow pipe, shall be ductile-iron pipe and shall be either of the following:
2.1.3.1 Bell-and-Plain End Pipe
NOTE: See AWWA C150/A21.50 or C151 for thickness design of ductile iron pipe.
Piping materials, other than ductile iron, conforming to Section 33 11 00 WATER
DISTRIBUTION may be used when warranted.
AWWA C150/A21.50 and AWWA C151/A21.51, for not less than 1035 kPa 150 psi working pressure, unless otherwise
shown or specified. Joints shall be push-on or mechanical-joint conforming to AWWA C111/A21.11. Pipe shall
be cement mortar lined in accordance with AWWA C104/A21.4. Linings shall be standard thickness.
2.1.3.2 Flanged Pipe
Flanged pipes shall conform to the applicable portions of AWWA C110/A21.10, AWWA C115/A21.15 and AWWA C151/A21.51
, for not less than 1035 kPa 150 psi working pressure, unless otherwise shown or specified. Pipe shall have
flanged ends in accordance with AWWA C115/A21.15. Pipe shall be cement mortar lined in accordance with AWWA C104/A21.4
. Linings shall be standard thickness.
2.1.4 Specials and Fittings (except for overflow pipe)
2.1.4.1 Ductile-Iron with Bell-and-Plain End
AWWA C110/A21.10 and AWWA C151/A21.51 for not less than 1035 kPa 150 psi working pressure, unless otherwise shown
or specified. Specials and fittings shall be cement mortar lined in accordance with AWWA C104/A21.4. Linings
shall be standard thickness.
2.1.4.2 Ductile-Iron with Flanged Ends
AWWA C110/A21.10 and AWWA C151/A21.51 for not less than 1035 kPa 150 psi working pressure unless otherwise shown
or specified. Fittings shall have flanged ends in accordance with AWWA C110/A21.10. Specials and fittings shall
be cement mortar lined in accordance with AWWA C104/A21.4. Linings shall be standard thickness.
2.1.4.3 Fittings for Screw-Joint Pipe
Malleable-iron, galvanized, 1035 kPa 150 psi, ASTM A 197/A 197M, threaded ends, ASME B16.3.
2.1.4.4 Joints Inside Valve Chamber
All joints inside the valve chamber shall be flanged.
2.1.5 Valves
2.1.5.1 Gate Valves
Gate valves shall be opened by turning counterclockwise. Valves 80 mm 3 inches and larger shall be iron body,
brass mounted, conforming to AWWA C500. Valves smaller than 80 mm 3 inches shall be all bronze and shall conform
to MSS SP-80, Type 1, class 150. Valves 80 mm 3 inches or larger located in valve chambers shall be equipped
with hand-operating wheels and shall be flanged.
2.1.5.2 Butterfly Valves
Butterfly valves shall be opened by turning counterclockwise. Valves shall conform to AWWA C504. Body and disc
shall be cast iron, conforming to ASTM A 48/A 48M. Shaft shall be 18-8 stainless steel. Resilient seat shall
be bonded to the valve body. Butterfly valves shall be stainless steel to rubber seated, tight closing type.
2.1.5.3 Check Valves
NOTE: Check valves as specified in AWWA C508 do not include cushioning devices
such as springs or weighted arms.
Check valves shall be of the horizontal swing-check type, suitable for the purpose and the operating conditions.
The body shall be iron and shall have a removable gate assembly and a cover removable for inspection. The gate,
gate seat, shaft, gate studs, and nuts shall be bronze or other suitable alloy. Valves shall conform to AWWA C508
.
2.1.5.4 Altitude Valve
NOTE: Altitude valves should be used only where required in a system with differential
pressures and should be installed in a valve vault with appropriate shut-off
valves and check valve. The size of the altitude valve will be inserted. In
general, for a pipe connection larger than 200 mm (8 inches) in diameter, the
altitude valve may be one or two sizes smaller.
The supply to the [elevated tank] [standpipe] [reservoir] shall be controlled by a [_____] mm inch altitude valve,
automatic in operation and accurately set to prevent overflow of the [elevated tank] [standpipe] [reservoir].
The valve shall have flanged ends and a heavy cast iron body, shall be bronze fitted with renewable cups and
seats, and shall be designed without metal-to-metal seats. The valve shall be cushioned when opening and closing
to prevent water hammer or shock. Valves shall be provided with a travel indicator.
2.1.6 Pressure Gauge
Pressure gauge of the direct-reading type, equipped with a shutoff cock, shall be provided, in the valve chamber,
on the tank side and on the discharge side of the check or altitude valve. Gauges shall have 150 mm 6 inch dials,
shall be stem mounted, and shall conform to ASME B40.100. Accuracy of gauges shall be Grade A or better. Gauges
shall be calibrated in kPa and psi psi in not more than10 kPa and psi 2 psi increments from 0 to 350 kPa and
0 to 50 psi 0 to 50 psi in excess of the normal operating pressure at the tank.
2.2 ASSEMBLIES
2.2.1 Tank Accessories
Section 7 of AWWA D100 or Section 5 of AWWA D103 and as specified. Additional requirements for accessories are
as follows:
2.2.1.1 Manholes and Pipe Connections
Section 7 of AWWA D100 and Section 5 of AWWA D103 represent the minimum requirements. Number, type, location,
and size of manholes and pipe connections shall be as shown on the drawings. Inlet pipe connections to extend
[_____] mm inches above tank bottom and shall be provided with deflectors as shown on the drawings. Outlet pipe
connections to extend [_____] mm inches above tank bottom and shall be provided with vortex breakers as shown
on the drawings.
2.2.1.2 Overflow
The overflow for the tank shall consist of an overflow weir and [stub overflow] [outside drop pipe, adequately
supported and] capable of discharging at a rate of [_____] L/second gpm with [_____] mm inches of head [, without
the water level exceeding [_____]]. [The top of the weir shall be [_____] mm inches below [_____].] [The weir
shall be located as indicated.] The [stub overflow shall be steel, ASTM A 53/A 53M or equal, and shall be fitted
with a screen] [overflow pipe shall be steel, ASTM A 53/A 53M or equal, and shall terminate 300 to 600 mm 1 to
2 feet above grade and shall be fitted with a flapper valve or screen to prevent ingress of animals and insects].
2.2.1.3 Vent
Vent shall be welded to the cover plate of the center manhole on the roof. Vent will be tank manufacturer's
standard type mushroom vent with aluminum bird screen. The free area of the vent shall be sized 50 percent in
excess of the [_____] L/second gpm pump-in rate and [_____] L/second gpm pump-out rate. Screening for vent shall
conform to Section 5.7.2 of AWWA D100 or Section 5.7.2 of AWWA D103which ensures fail-safe operation in the event
that screen frosts over and the bottom of the screen shall be sufficiently elevated for snow consideration in
the area.
2.2.1.4 Ladders and Safety Devices
Ladders and safety devices shall be provided in accordance with Sections 7.4 and 7.5 of AWWA D100 or Sections
5.4 and 5.5 of AWWA D103. Location of ladders shall be as shown on the drawings. Sections 7.4 and 7.5 of AWWA D100
and Secions 5.4 and 5.5 of AWWA D103 represent the minimum requirement. In addition, safety cage, rest platforms,
roof ladder handrails, and other safety devices shall be provided as required by federal or local laws or regulations.
2.2.1.5 Scaffold Cable Support
Provision shall be made for the attachment of a scaffold cable support at the top of the roof on welded tanks.
2.2.1.6 Balconies
Provide a balcony a minimum of 600 mm 2 feet wide with a standard guard railing. Provide a structural steel
railing with a top rail 1050 mm 42 inches above balcony platform with an intermediate rail halfway between.
Guard rail shall be capable of withstanding a force of 888 N 200 pounds applied in any direction. Install a
steel toe board with minimum height of 100 mm 4 inches. Bottom of toe board shall be a maximum 6 mm 1/4 inch
from platform top. Extend guard rail and toe board entire length of balcony except where access openings are
required. For balcony floors use diamond plates a minimum of 6 mm 1/4 inch thick, punched or drilled for drainage.
[Equip access openings in guard rail with a gate which closes automatically.] Hatches through balcony floor
shall be counterbalanced or otherwise arranged to open from below.
2.2.1.7 Coating for Welded Tanks
Provide exterior coating systems conforming to Section 09 97 13.27, "Exterior Coating of Steel Structures," and
interior coating systems conforming to Section 09 97 13.16, "Interior Coating of Welded Steel Water Tanks."
2.2.1.8 Coating for Bolted Tanks
NOTE: Bolted tanks are factory coated, interior and exterior. No field painting
is needed other than repair to damaged areas. Where cathodic protection will
be installed, electrical continuity must be established across the bolted joints
to ensure proper cathodic protection system operation.
As supplied by the manufacturer.
2.2.2 Valve Chamber
Valve chamber shall be sufficiently large to house all control valves and fittings. Pipes, valves, and fittings
shall be supported on concrete blocks where necessary. The valve chamber shall be constructed to provide not
less than [_____] mm feet of cover over the pipes. The valves and fittings shall extend from the [standpipe]
[reservoir] [riser pipe] connection to a point one length of pipe outside the valve chamber walls on the main
or feed line to the [elevated tank] [standpipe] [reservoir]; the drain line will be carried to an outlet as indicated
on the drawings. The access manhole shall be not less than 760 mm 30 inches in diameter.
2.2.3 Anchors for [Standpipe] [Reservoirs]
The following requirements shall be met:
a. An adequate number of anchors designed to prevent overturning of the [standpipe] [reservoir] when
empty shall be installed. If anchor bolts are used, the nominal diameter shall not be less than 25 mm
one inch, plus a corrosion allowance of at least 6 mm 1/4 inch on the diameter. If anchor straps are
used, they shall be pre-tensioned before welding to the tank shell.
b. The anchor bolts shall be a right angle bend, hook, or plate washer, while anchor straps shall have
only a plate welded to the bottom. The anchors shall be inserted into the foundation to resist the computed
uplift.
c. Attachment of anchors to the shell shall not add significant localized stresses to the shell. The
method of attachment shall consider the effects of deflection and rotation of the tank shell. Anchors
shall not be attached to the tank bottom. Attachment of the anchor bolts to the shell shall be through
stiffened chair-type assemblies or anchor rings of adequate size and height.
2.3 CONCRETE WORK
Concrete work shall conform to Section [03 31 00.00 10 CAST-IN-PLACE STRUCTURAL CONCRETE][03 30 00 CAST-IN-PLACE
CONCRETE].
2.4 CHLORINE
AWWA B300 for hypochlorites or AWWA B301 for liquid chlorine, mixed with water to give the solutions required
in AWWA C652.
PART 3 EXECUTION
3.1 FOUNDATIONS
Foundations for the [standpipe] [reservoir] [tank columns and riser] and for the valve chamber shall be constructed
of concrete, reinforced where necessary, and designed in accordance with Section 12 of AWWA D100 or Sections
11 and 8.5 of AWWA D103 for earth with a bearing value of [_____] MPa psf, at elevation [_____], and constructed
in conformance with the applicable requirements of Section [03 31 00.00 10 CAST-IN-PLACE STRUCTURAL CONCRETE][
03 30 00 CAST-IN-PLACE CONCRETE], except as shown or specified herein. An AWWA D100 Type 1 or an AWWA D103 Type
1 or Type 2 foundation shall be provided for the [standpipe] [reservoir]. Factor of safety on overturning of
[elevated tanks] [standpipe] [reservoir] under design wind load shall be 1.33 minimum. When a footing is required,
an inverted truncated pyramid of earth with 2 on 1 side slopes above top of footing may be used in determining
overturning stability.
3.2 EXCAVATING, FILLING, AND GRADING
Excavating, filling, and grading shall conform to the applicable requirements of Section 31 00 00 EARTHWORK.
3.3 CATHODIC PROTECTION
NOTE: Evaluate need for cathodic protection on an individual project basis.
Cathodic protection shall be provided, conforming to Section 26 42 15.00 10 CATHODIC PROTECTION SYSTEM (STEEL
WATER TANKS).
3.4 OBSTRUCTION LIGHTING
NOTE: Obstruction lighting will be included in the contract specifications
only when required and will be detailed on the drawings, in accordance with
UFC 3-260-05A or AFM 88-14 and AFR 88-16. The Contracting Officer will determine
the type of control to be used, based on local requirements. Automatic control
of the obstruction lights will be by either a time switch with an astronomic
dial or a light sensitive device. Where it is known that the obstruction lights
will be operated from the control tower, an automatic control will not be provided.
Obstruction lighting shall be provided and installed as shown, and shall conform to Section 26 20 00 INTERIOR
DISTRIBUTION SYSTEM or FAA AC 150/5345-43.
3.5 BEACON
NOTE: The beacon and beacon platform should be included in the specifications
only when required by AFM 88-14 and AFR 88-16, or by the Base Commander.
Beacon shall be provided and installed as shown, and shall conform to Section 26 20 00 INTERIOR DISTRIBUTION
SYSTEM.
3.6 TANK INSTALLATION
Tank installation shall be in accordance with the following requirements:
3.6.1 Welding
Section 8 of AWWA D100 or Section 6 of AWWA D103.
3.6.2 Erection
Section 10 of AWWA D100 or Section 8 of AWWA D103.
3.6.3 Inspections and Testing
Tank inspection and testing shall be in accordance with Section 11 of AWWA D100 or Section 9 of AWWA D103. Mill
and shop inspections [are not required] [are required and shall be performed by an approved commercial inspection
agency]. Perform the radiographic inspections of the welded tank shell, the hydrostatic test and the vacuum
box leak test of the tank bottom. Final hydrostatic and leak tests shall be performed before painting of welded
tanks.
3.7 PIPING INSTALLATION (EXCEPT FOR OVERFLOW PIPING)
3.7.1 General Guidelines
Where details of fabrication or installation are not shown on the drawings, installation shall conform to Section
1 and 3 of AWWA C600.
3.7.2 Testing of Valves and Piping
After the [elevated tank] [standpipe] [reservoir] has been erected and the valves and piping installed, and before
field painting is begun, the valves and piping shall be hydrostatically tested in accordance with Section 4 of
AWWA C600. Replace with sound material any defective material disclosed by the pressure test; the test shall
be repeated until the test results are satisfactory.
3.7.3 Polyethylene Encasement of Underground Ductile-Iron Piping
NOTE: Appendix A of AWWA C105/A21.5 will be utilized in determining whether
polyethylene encasement should be used.
Polyethylene encasement of underground ductile-iron piping shall be provided in addition to asphaltic coating
in accordance with AWWA C105/A21.5.
3.7.4 Plugging Ends
Pipe ends left for future connections shall be capped or plugged as directed.
3.8 PAINTING AND COATING OF TANK
NOTE: Some state and local health agencies have listings of acceptable paint
materials to be used for the interior of potable water tanks and to be used
on the exterior of structures. As an example, the State of California will
not allow vinyl paints to be applied due to air emission restrictions. The
designer must contact the appropriate state and local authorities to determine
if the paint systems are acceptable. If these systems are not acceptable, the
designer must determine the best acceptable system and revise this specification
accordingly. However, any deviation from this specification and AWWA Standards
must be submitted with justification to CEMP-ET for approval.
Each coating manufacturer's technical data, application instructions, Material Safety Data Sheets (MSDS), and
certificate for compliance for VOC content shall be submitted to the Contracting Officer. Application, curing
time, mixing and thinning of the coating materials shall be in strict accordance with the manufacturers instructions.
The use of thinners shall not alter the required minimum dry thickness or adversely affect the VOC content.
3.8.1 Exterior Surfaces (Welded Tanks)
NOTE: For rural areas, mild to fairly heavy industrial atmospheres, and mild
marine atmospheres, use the first bracketed paragraph. For moderately severe
to the most severe atmospheres, such as seacoasts and in corrosive industrial
areas, use the second bracketed paragraph. The vinyl system is fast drying
and best in congested areas where there is danger of property damage due to
overspray but should be used only in white or light gray colors because it fades
and chalks easily. The epoxy polyurethane system retains its color and gloss
well and is highly abrasion resistant and graffiti is easily removed. If the
tank is or will be an obstruction to air navigation, use the checkerboard pattern.
[A prime coat, minimum of 0.051 mm 2.0 mil thick followed by two coats of alkyd enamel, each a minimum of 0.038
mm 1.5 mil thick shall be applied. The prime coat shall be rust inhibitive red iron oxide, zinc oxide, oil and
alkyd primer without lead or chromate pigments, in accordance with SSPC Paint 25. The finish coats shall be
[white alkyd enamel in accordance with Type I of SSPC Paint 104] [[_____] gloss alkyd enamel in accordance with
SSPC Paint 21] [alternating panels (checkerboard) of white alkyd enamel in accordance with Type I of SSPC Paint 104
and international orange gloss alkyd enamel in accordance with SSPC Paint 21 color 12197].]
[[A gray vinyl prime coat a minimum of 0.038 mm 1.5 mil thick followed by two coats of [white] [light gray] vinyl
paint, each a minimum of 0.038 mm 1.5 mil thick shall be applied. The primer and paint shall be VR-3 in accordance
with SSPC PS 4.04] [A two-component catalyzed epoxy prime and intermediate coat, each a minimum of 0.076 mm 3.0
mil thick, followed by a two-component catalyzed aliphatic polyurethane finish coat, a minimum of 0.038 mm 1.5
mil thick, conforming to Type V of SSPC PS Guide 17.00 shall be applied. The prime coat shall be a green primer,
Formula 150 in accordance with MIL-DTL-24441. The intermediate coat shall be white Formula 152 in accordance
with MIL-DTL-24441 and may be tinted with pigment color. The finish coat shall be [white] [_____] [alternating
panels (checkerboard) of international orange and white]].]
3.8.2 Interior Surfaces (Welded Tanks)
NOTE: Where surface and ambient temperatures of 10 degrees C (50 degrees F)
and higher will be maintained during curing, the epoxy system shall be specified.
When this is not the case and heating is not practical but ambient temperatures
will be greater than 1 degree C (34 degrees F), specify the vinyl system.
[A prime coat at least 0.076 mm 3.0 mil thick and a [white] [_____] final coat at least 0.127 mm 5.0 mil thick
shall be applied. Each coat shall be a two-component catalyzed epoxy in accordance with MIL-PRF-23236. The
primer shall contrast with the color of the finish coat.] [Four coats, each at least 0.038 mm 1.5 mil thick,
of VR-3 vinyl resin paint in accordance with SSPC PS 4.04 shall be applied. The second, third, and fourth coats
shall be of contrasting colors.]
3.8.3 Bolted Tanks
NOTE: If the tank constitutes an obstruction to air navigation, the paint system
applied to the outside of the tank will be an international orange and white
checkerboard pattern. Galvanized coatings shall be disallowed when the stored
water is corrosive.
The tanks shall have a coating applied to both the interior and exterior surfaces in accordance with Section
10 of AWWA D103. Color shall be [as indicated on the drawings] [as approved] [_____].
3.9 DISINFECTION
The [elevated tank] [standpipe] [reservoir] and connecting lines thereto shall be disinfected with chlorine before
being placed in operation.
3.9.1 Tank
NOTE: In areas subject to regulations which are more stringent than requirements
contained in AWWA C652, the local requirement will apply and will be specified.
AWWA C652 covers three methods for disinfection. Typically, only one method
will be used for a given storage facility disinfection, but combinations of
the methods may be used. The three methods are:
1. Chlorination of the full storage facility such that the end of the appropriate
retention period the water will have a free chlorine residual of not less than
10 mg/L.
2. Spraying or painting of all storage facility water contact surfaces with
a solution of 200 mg/L available chlorine.
3. Chlorination of full storage facility with water having a free chlorine
residual of 2 mg/L after 24 hr.
This paragraph is mandatory for all PACNAVFACENGCOM projects. All other agencies
may use it after checking applicability.
The [elevated tank] [standpipe] [reservoir] shall be disinfected in accordance with [AWWA C652] [_____]. After
the chlorination procedure is completed and before the storage facility is placed in service, the Contracting
Officer will collect samples of water in properly sterilized containers for bacteriological testing from the
full facility in accordance with Section 7 of AWWA C652. The tank will not be accepted until satisfactory bacteriological
results have been obtained.[ After coating system has been inspected, approved, and cured, rinse tank with potable
water. Disinfect tank and connecting lines in accordance with AWWA C652, [Method 1] [Method 2] [or] [Method
3].]
3.9.2 Piping
The valves and piping shall be disinfected in accordance with Section 33 11 00 WATER DISTRIBUTION.
3.10 INSPECTION AND REPAIR
Prior to tank repair job, perform a detailed inspection of the structure and submit report by a certified inspector.