ST_PETERSBURG_TANK_SPECIFICATION.doc

City of St. Petersburg

Water Plant Sodium Hypochlorite Tank Installation A.

Overall Description of Work

The Contractor shall furnish and install four 5,250-gallon double-walled polyethylene sodium hypochlorite tanks, including all fittings, plumbing connections to and from the tank and all ancillary equipment including tank foundations, to integrate into the existing sodium hypochlorite system for the City of St. Petersburg Cosme Water Treatment Plant located at 16015 Race Track Road, Odessa, Florida 33556. The existing system consists of three 5,250-gallon double-walled tanks and a triplex chemical feed pump skid along with associated piping. The tanks will be used to store up to 15 Trade Percent sodium hypochlorite. As part of the work, the Contractor shall provide tank drawings, installation drawings, restraint calculations for 160 mph winds and material cut sheets for approval within two weeks of purchase order award. The drawings and calculations shall be signed and sealed by a Florida registered Professional Engineer. The tanks must be installed within five weeks of drawing/material approval by the City of St. Petersburg. All work must be done by a Florida licensed General Contractor.

Gregory Blocker shall be the Owner’s Project Manager. He is not able to answer any questions on the bid but please contact him for a site visit at (608) 461-8747 or e-mail gregory.blocker@stpete.org.

B.

Tank Supply 1.

Scope of Work

1.1 This specification covers the supply of a four upright, double wall, flat bottom linear polyethylene (or cross-link polyethylene) resin 5,250-gallon bulk storage tanks for storage of sodium hypochlorite. The double-walled assembly consists of one cylindrical inner primary tank and one blended form octagonal or round outer secondary tank. Each tank shall be molded in one-piece seamless construction by rotational molding. The tanks shall be designed for above-ground, vertical installation and capable of containing chemicals at atmospheric pressure. The assembly shall be designed to prevent rainwater from entering the containment tank. The design shall allow direct primary tank base retention for up to seismic zone 4 conditions per UBC code requirements. The containment tank shall be designed to hold a minimum of 115% of the normal fill capacity of the primary tank. Included in this specification are requirements for material properties, design, construction, dimensions, tolerances, workmanship, and appearance.

1.2 The tank(s) shall have the following nominal dimensions, size and characteristics:

Size:

5,250 Gallons (minimum) Height:

119” Diameter:

156” Color:

Natural Max Temperature: 110 Degrees F (Of Stored Chemical)

2.

Applicable Documents

2.1 ASTM (American Society for Testing and Materials) Standards:

D618 Conditioning Plastics and Electrical Insulating Materials for Testing

D638 Tensile Properties of Plastics

D790 Flexural Properties of Unreinforced and Reinforced Plastics and

Electrical Insulating Materials

D883 Definitions of Terms Relating to Plastics

D1505 Density of Plastics by the Density-Gradient Technique

D1525 Test Method for Vicat Softening Temperature of Plastics

D1693 Test Method for Environmental Stress-Cracking of Ethylene Plastics

D1998 Standard Specification for Polyethylene Upright Storage Tanks

D2765 Degree of Crosslinking in Crosslinked Ethylene Plastics as

Determined by Solvent Extraction

D2837 Method for Obtaining Hydrostatic Design Basis for Thermoplastic Pipe Materials

D3892 Practice for Packaging/Packing of Plastics

F412 Definitions of Terms Relating to Plastic Piping Systems

2.2 ARM (Association of Rotational Molders) Standards: Low Temperature Impact Resistance (Falling Dart Test Procedure)

2.3 ANSI Standards: B-16.5 Pipe Flanges and Flanged Fittings

2.4 OSHA Standards:

29 CFR 1910.106 - Occupational Safety and Health Administration, Flammable and Combustible Liquids

2.5

BUILDING CODES:

Uniform Building Code (UBC) 2006 Edition

International Building Code (IBC) 2009 Edition

Florida Building Code (FBC) 2010 Edition

2.6 NSF/ANSI Standard 61 – Drinking Water System Components

3. Chemical Compatibility

3.1 In addition to what is specified herein, chemical compatibility for any materials or components supplied hereunder shall also be according to the following references:

Pruett, Kenneth M., "Chemical Resistance Guide for Elastomers III", “Chemical Resistance Guide for Metals and Alloys” and “Chemical Resistance Guide for Plastics”, Compass Publications.

4. Materials

4.1 The material used shall be virgin polyethylene resin as compounded and certified by the manufacturer. The tanks shall be made from cross-linked or XLPE resin (Type I) as manufactured by Schulink XL 350 or equivalent or linear polyethylene resin (Type II) and as manufactured by ExxonMobil Chemical Escorene 8460 conventional or resin of equal physical and chemical properties. No fillers shall be added to either resin.

4.2 All tanks used for outdoor installation shall contain a suitable ultraviolet stabilizer, minimum 0.3% 2-hydroxy-4-n-Octoxy-benzophenone or equivalent. The stabilizer shall be compounded into the polyethylene.

4.3 Pigments may be added at the purchaser's request but shall not exceed 0.25% (dry blended) of the total weight.

4.4 The resin suppliers recommended maximum material use temperature for cross linked resin is 150 degrees F, and for LDPE resins is 120 degrees F. Generally, the less exposure to elevated temperatures, the greater the tank life.

4.5 Mechanical Properties of Type I tank material:

4.6 Mechanical Properties of Type II tank material:

5. Design Requirements

5.1 The minimum required wall thickness of the cylindrical shell at any fluid level shall be determined by the following equation, however, shall not be less than 0.187 in. thick.

T = P x O.D./2 SD = 0.433 x S.G. x H x O.D./2 SD

T = wall thickness

SD

= hydrostatic design stress, PSI

P = pressure (.433 x S.G. x H), PSI

H = fluid head, ft.

S.G.

= specific gravity, g/cm^3

O.D.

= outside diameter, in.

5.1.1 The hydrostatic design stress shall be determined by multiplying the hydrostatic design basis, determined by ASTM D2837 using rotationally molded samples, with a service factor selected for the application. The hydrostatic design stress is 600 PSI at 73 degrees Fahrenheit for Type I and Type II materials. In accordance with the formula in 6.1, the tank shall have a stratiform (tapered wall thickness) wall.

5.1.2 The hydrostatic design stress shall be derated for service above 100 degrees Fahrenheit and for mechanical loading of the tank.

5.1.3 The standard design specific gravity shall be 1.9 (2.2 if sulfuric acid).

5.2 The minimum required wall thickness for the cylinder straight shell must be sufficient to support its own weight in an upright position without any external support. If applicable, secondary containment tanks shall be designed to meet this same containment thickness requirements. If a double-walled tank, the secondary containment shall be configured to allow shipment of the primary tank inside of the secondary tank. The shipment shall be done without the aid of additional spacer blocks, which can be lost during shipment causing tank damage.

5.3 The top head must be integrally molded with the cylinder shell. The minimum thickness of the top head shall be equal to the top of the straight wall. If a double-walled tank, the primary tank top shall be configured to prevent rainwater from entering the secondary containment tank. The top head of tanks shall be designed to provide a minimum of 1300 square inches of flat area for fitting locations. If a double-walled tank, the primary tank shall be keyed to the secondary tank preventing primary tank rotation. The secondary containment shall have 115% of the normal fill capacity of the primary tank.

5.4 Tanks shall have a minimum of 3 lifting lugs either integrally molded into the top head or SS316 attached lugs. The lifting lugs shall be designed to allow the erection of an empty tank (or if a double-walled tank the primary and secondary tank as a unit). The tank restraint attachments may be used in place of the lifting lugs depending upon how they are installed.

5.5 The tank shall be designed to provide a minimum of 4 tie-down lugs. The tie-down lugs shall be designed to allow tank retention in wind and seismic loading situations without tank damage. The primary/secondary tank unit shall be configured to allow direct primary tank base retention for seismic load conditions. The base retention unit shall be anchor bolted to an appropriate structure and not require additional spacer blocks. Refer to section 10.2 for tank tie-down accessories.

6. Dimensions and Tolerances

6.1 All dimensions will be taken with the tank in the vertical position, unfilled. Tank dimensions will represent the exterior measurements.

6.1.1 The tolerance for the outside diameter of the primary tank, including out of roundness, shall be per ASTM D1998.

6.1.2 The tolerance for fitting placements shall be +/- 0.5 in. in elevation and 2 degrees radial at ambient temperature.

7. Test Methods/Quality Assurance 7.1 The tanks of the same material furnished under this Section shall be supplied by a manufacturer who has been regularly engaged in the design and manufacturing of rotationally molded chemical storage tanks using cross-linked and high-density linear polyethylene tanks for over ten years.

7.2 The Tank shall be certified for to meet potable water standards by NSF-61.

7.3 Test specimens shall be taken from fitting location areas or piggy-back test molds.

7.4 Low Temperature Impact Test

7.4.1 Test specimens shall be conditioned at -40 degrees Fahrenheit for a minimum of 2 hours.

7.4.2 The test specimens shall be impacted in accordance with the standard testing methods as found in ASTM D1998. Test specimens < 1/2" thickness shall be tested at 100 ft.-lb. Test specimens > 1/2" thickness shall be tested at 200 ft.-lb.

7.5 Ultrasonic Tank Thickness Test

7.5.1 All tanks shall be measured for tank wall thickness at 6”, 1ft., 2ft. and 3ft. on the tank sidewall height at 0° and 180° around the tank circumference with 0° being the tank manway and going counterclockwise per ANSI standard drafting specifications. A copy of this test report shall be sent out to the Owner prior to shipment. All tanks shall meet design thickness requirements and tolerances.

7.6 Hydrostatic Water Test

7.6.1 The hydrostatic water test shall consist of filling the tank to brim full capacity for a minimum of four hours and conducting a visual inspection for leaks. A hydrostatic water test will be conducted by the manufacturer prior to shipping the tank.

7.7 The tank shall be visually inspected by the manufacturer prior to shipment to determine that it meets the Specification and to look for material defects and quality issues as are discussed in Section 8.

8. Workmanship

8.1 The finished tank wall shall be free, as commercially practicable, of visual defects such as foreign inclusions, air bubbles, pinholes, pimples, crazing, cracking and delaminations that will impair the serviceability of the vessel. Fine bubbles are acceptable to the degree in which they do not interfere with proper fusion of the resin melt.

9.2 All cut edges where openings are cut into the tanks shall be trimmed smooth.

9. Tank Fittings (Nozzles)

9.1 Fittings - Threaded Bulkhead

9.1.1 The tank(s) shall be supplied with a 4” bulkhead fitting on the top for a vent. The bulkhead fitting(s) shall be constructed of either Schedule 80 or Schedule 40PVC. Gaskets shall be a minimum of 1/4" thickness and constructed of 60-70 durometer Viton.

9.1.2 The tank(s) shall be supplied with a 3” bulkhead fitting on the top sidewall under the manway or otherwise located above the sidewall height for an overflow. The bulkhead fittings shall be constructed of Schedule 80 PVC. Gaskets shall be a minimum of 1/4" thickness and constructed of 60-70 durometer Viton.

9.1.3 The tank(s) shall be supplied with a 4” fitting on the top for a level sensor. The fitting shall be installed on a flat spot on the tank and be accessible from the ladder. The bulkhead fittings shall be constructed of Schedule 80 PVC. Gaskets shall be a minimum of 1/4" thickness and constructed of 60-70 durometer Viton.

9.1.4 All fitting locations shall be specified on the Contractor’s shop drawings submitted to the Owner for approval.

9.2 Bottom Sidewall Fitting(s)

9.2.1 For a double-wall tank(s), the bottom fitting shall be designed to tie the inner and outer tanks together to prevent leakage from the inner to outer tank and from the outer tank to the environment. The approved designs are as follows: (1) Assmann flanged fitting constructed of titanium (for sodium hypochlorite); (2) Snyder Unified Fitting Outlet (UFOTM) fitting which shall provide a flexible containment seal between the inner primary tank and the outer secondary containment tank. This fitting outlet when used in combination with fittings as per sections 10.2 and 10.3 provides access for connecting piping to the inner primary tank while maintaining containment integrity between the inner primary tank and the outer secondary containment tank. The fitting outlet shall consist of a 2” Schedule 80 CPVC flange connecting the tank to a 1 ea. flexible polyethylene containment boot, 1 ea. appropriate fitting gasket (see below), 1 ea. UFO gasket (see below), 1 ea. solid 304 stainless steel UFO flange, 1 ea. split 304 stainless steel UFO flange, and 12 ea. 3/8 in. 304 stainless steel bolt assemblies; or (3) Poly Processing Boot assembly consisting of a molded in 2” Boss gasketed (see below) fitting with four bolts through the inner tank tied to a flange on the outside of the inner tank inside a rubber boot tied to the outer tank with a SS316 gasketed (see below) flange. All Gaskets for the above assemblies shall be a minimum of 1/4" thickness and constructed of 60-70 durometer Viton. All flange bolts in contact with the inner tank shall be encapsulated titanium (for sodium hypochlorite).

9.2.2 The tank manufacturer shall supply an appropriate flexible connection for the bottom sidewall fitting and the fitting shall be submitted for Owner’s approval with the shop drawings. This fitting shall be designed to allow 4 percent design movement. Movement shall be considered to occur both outward in tank radius and downward in fitting elevation from the neutral tank placement.

9.2.3 The Contractor shall install the piping to the chemical feed equipment from the tank(s). Such piping shall be Schedule 80 CPVC and shall incorporate an isolation valve on either side of the flexible connection and a “T” to a drain valve. Additional suction line piping may be specified later.

9.3 Fittings - Siphon Tube Fittings

9.3.1 Siphon tubes shall be added to the fittings specified in section 9.2. A siphon tube will allow these fittings, when used as drainage fittings, to provide better tank drainage.

10. Tank Attachments

10.1 Tank Attachments – Ultrasonic Level Indicator

10.1.1 Install a 4” Schedule 80 PVC bulkhead fitting on a flat spot on the tank for Owner to install an ultrasonic level sensor at a future date.

10.2 Tank Attachments - Manway

10.2.1 Manways shall be (24 inches with a minimum opening diameter of 22 inches, vented and threaded (safe surge or pop-up manways are acceptable and may be specified for non-fuming chemicals or preferred for chemicals offloaded with air). All manways shall be constructed of polyethylene material.

10.3 Tank Attachments – External Fill Pipes

10.3.1 An external 2” Schedule 80 CPVC bulkhead fitting shall be supplied to attach 2” fill pipe. A 2” Schedule 80 Schedule 80 CPVC fill line shall be attached to the bulkhead fitting with a 2” isolation ball valve and male chemlock fitting on the end. The line shall be installed in such a manner to allow for at least a one inch (1/2” for tanks under 1,000 gallons) of vertical expansion/contraction of the tank between filling and emptying operations.

10.4 Tank Attachments - Vents

10.4.1 A 4” Schedule 40 or Schedule 80 PVC shall be supplied with the tank with a vinyl bug screen on the end. Vents must comply with OSHA 1910.106 (F) (iii) (2) (IV) (9) normal venting for atmospheric tanks or other accepted standard and shall be as large as the filling or withdrawal connection, whichever is larger but in no case less than 2 inches nominal inside diameter.

10.5 Tank Attachments - Overflow

10.5.1 A 3” Schedule 80 PVC bulkhead fitting shall be installed under the manway with a connecting 3” Schedule 80 PVC line for an overflow fitting.

11.1 Tank Accessories – Tie Down Systems

11.1.1 The tank manufacturer shall supply a tie-down system using SS316 cables and either SS316, galvanized or HDLPE feet and attachments rated for 160 mph winds.

11.1 Ladders

11.2.1 Not Applicable

11.3 Heat Tracing and Insulation

11.3.1 Not Applicable

11.4 Leak Detectors

11.4.1 Not Applicable

12. Marking, Packing and Packaging

12.1 The tanks shall be marked to identify the product, date (month and year) of manufacture, capacity, and serial number. The tank shall be shipped with a 3 of 9, HRI bar code label containing tank description, manufacturing order number, part number, serial number, manufacturer, and date.

12.2 The proper caution or warning signs as prescribed by OSHA standard 29 CFR 1910.106 shall be customer determined and supplied.

12.3 All packing, packaging, and marking provisions of ASTM Practice D3892 shall apply to this standard.

12.4 Customer specified labeling is available.

12.5 The tank shall be “shrink-wrapped” or otherwise protected to prevent or minimize the impact in transit of road material and other road hazards from defacing the tank.

12.6 All fittings shall be installed, removed and shipped separately.

C. Services

1. Pre-Installation

1.1 The Contractor shall provide signed and sealed drawings by a Florida registered professional engineer depicting the equipment layout for the upgraded sodium hypochlorite system for Owner’s approval within two (2) weeks after award. The submittal documents shall include equipment cut sheets and calculations showing that the proposed restraint system meets the minimum 160 mph wind threshold.

1.2 There is an existing tank foundation for two of the new tanks. The Contractor shall pour a 16’ x 24’ x 8” concrete pad on the north side of the existing tank foundation abutting it for the other two new tanks. The new concrete pad shall be the same height as the existing tank foundation. The new pad shall have #5 rebar on 12” centers in the bottom 3” and shall be 4,000 psi concrete.

2.

Contractor Installation

2.1 The Contractor shall install the new tank(s) in accordance with the manufacturer’s instructions.

2.2

The Contractor shall install the new tank(s) in the specified area and install all required attachments and plumbing connections. Once the tank is properly installed, the tank shall be water tested for a minimum of 24 hours.

2.3 Because of standardization of chemical systems, the Contractor shall use only Asahi Type 21 Schedule 80 CPVC true union vented ball valves for all chemical systems – NO EXCEPTIONS!

2.4 If the tank level is not visible through the tank, Contractor shall provide a provision to install sight-glasses for each tank on the feed piping. If Contractor deems that a sight-glass is not practical to install, it may instead provide a reverse float level gage as manufactured by Snyder Industries, Poly Processing or Assmann tanks.

2.5

The Contractor shall install (and replace as necessary) all fill line piping and feed line piping to the chemical feed pump skids as part of the work with Schedule 80 CPVC.

D.

Warranty

1. Tank Warranty

1.1

Contractor shall provide a three (3) year full warranty from the date of final testing after installation including parts and labor to replace the tank or any of its components as necessary. This warranty shall be in addition to, and not in lieu of, any warranty provided by the tank manufacturer.

1.2 The tank manufacturer shall provide a three (3) year warranty from the date of final testing after installation (such date shall not exceed thirty (30) days after arrival to the site or the warranty is deemed to have started) including parts and agrees to replace a failed tank or any defective parts during this period (to include the cost of shipping to the site).

E. Bid Submittals – Turned in With Bid

1. References - Submit five (5) references including name and phone numbers where similar tank installations were supplied and installed by Bidder and are being used for sodium hypochlorite.

2. Contractor’s License – Submit a copy of a current General Contractor with the bid.

3. Dimensions – Submit dimensions and tank manufacturer:

Diameter

Height

Manufacturer

4. Preliminary Tank Drawing – Submit Preliminary Drawing of Tank showing all fittings.

5. Pricing - Submit pricing for each item per the following:

Tanks with Fittings (FOB Destination)

Installation Price

Total Price

F. Contractor Submittals – Turned in After Contract Award

1. NSF-61 – Submit a copy of Tank Manufacturer’s NSF-61 Certification

2. Final Tank Drawing – Submit Final Drawing of Tank showing all fittings to include materials of construction and/or cut sheets of fittings as appropriate.

3. Tank Accessories – Submit cut sheets and shop drawings for any tank accessories provided hereunder including ladders, ultrasonic level sensors, heat tracing and mastic insulation and leak detectors.

4. Installation Shop Drawings – Submit installation drawings showing tank installation and location of all tank fittings, accessories and plumbing. Drawing shall be signed and sealed by a Professional Engineer registered in the State of Florida.

5. Warranty Statement – Submit a copy of manufacturer’s warranty statement along with Contractor’s warranty statement.