B09_Amd8_-_Spec_43_41_43_-_POLYETHYLENE_CHEMICAL_TANKS_0008.pdf

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POLYETHYLENE CHEMICAL TANKS

SECTION 43 41 43 - POLYETHYLENE CHEMICAL TANKS

PART 1 - GENERAL

1.1 SUMMARY

A. This Section includes upright, cylindrical, polyethylene tanks, molded in one- piece seamless construction by rotational molding, and associated fittings and accessories. The tanks are designed for above-ground, vertical installation and are capable of containing chemicals at atmospheric pressure.

B. Brine tanks (TK3103 and T1801) will be provided by OSHG vendor and should follow this specification where applicable.

C. SHC tanks (TK3104 and T1802) will be provided by OSHG vendor and shall follow this specification unless approved otherwise by Engineer.

D. Related Sections include but are not necessarily limited to:

1. Division 01 - General Requirements.

2. Section 01 33 00 - Submittals.

3. Section 10 14 00 - Identification Devices.

4. Section 40 05 00 - Pipe and Pipe Fittings - Basic Requirements.

5. Section 40 05 31 - Pipe - Plastic.

6. Section 40 72 00 - Level Instrumentation.

7. Section 46 61 27 - On-Site Sodium Hypochlorite Generation.

1.2 QUALITY ASSURANCE

A. Reference Standards:

1. American Society of Testing Materials (ASTM).

a. D638, Standard Test Method for Tensile Properties of Plastics.

b. D790, Standard Test Methods for Flexural Properties of Unreinforced and

Reinforced Plastics and Electrical Insulating Materials.

c. D1505, Standard Test Method for Density of Plastics by the Density-Gradient

Technique.

d. D1525, Standard Test Method for Vicat Softening Temperature of Plastics.

e. D1693, Standard Test Method for Environmental Stress-Cracking of Ethylene

Plastics.

f. D1998, Standard Specification for Polyethylene Upright Storage Tank.

2. National Sanitation Foundation (NSF):

a. 61, Drinking Water System Components.

1) Includes all tank appurtenances.

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B. Qualifications:

1. Manufacturer’s Experience:

a. Tanks shall be constructed by a firm that has at least ten years prior experience in construction of similar cross-linked polyethylene tanks in similar applications.

b. Tanks shall be manufactured by a firm with a nationally accepted quality standard

(e.g., ISO 991 or equal).

1.3 SUBMITTALS

A. Shop Drawings:

1. Product technical data including the following.

a. Tank manufacturer’s catalog data.

b. Complete shop drawings with dimensions and mounting details, including locations and dimensions of all fittings and penetrations.

c. Details of inlet/outlet fittings, vents, mountings for level elements, sight glass level gage, and manway, with bolt and gasket material.

d. Wall thickness calculations per ASTM D1998 using 600 psi design hoop stress at

100 DegF.

e. Weight of tanks.

f. Statement of fabrication is in accordance with test specifications.

g. Certificate of Compliance from the tank manufacturer stating:

1) All fittings, heat tracing, insulation, etc. have been installed by the tank manufacturer.

2) Hydrostatic tests have been performed by the manufacturer and all fittings were installed prior to the tests.

h. Complete anchor bolt, wind load, and seismic calculations stamped by a Profession

Engineer in CA.

i. Anchoring system details.

j. Tank expansion (at discharge nozzle) measured as dimensional difference between empty and full dimensions (radius).

k. Details on packaging.

l. Instructions for handling, storage, and installation of tanks.

m. Resin used and a complete manufacturer specification of the resin used.

n. Samples of a representative tank wall.

o. Statement that materials and resin used are suitable for intended service.

B. Operations and Maintenance Manuals:

a. The mechanics and administration of the submittal process.

b. The content of Operation and Maintenance Manuals.

C. Informational Submittals:

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1. List of five previous similar site installations in the past 36 months or provide a list of three or more customers using tanks for the same chemical application and similar weather conditions for at least ten years.

2. Supporting information of UL or NSF tank manufacturing capabilities.

1.4 PROJECT / SITE CONDITIONS

A. The tanks will be located inside a semi-heated building or outdoors.

1. Temperatures: Between 60 DEGF and 130 DEGF.

2. Relative humidity: Between 20 and 50%.

1.5 WARRANTY

A. The equipment furnished under this section shall be free of defects in materials and workmanship, including damages that may be incurred during shipping, for a period of five years from start-up.

B. The severity of the defect will determine the requirement of a site visit.

C. All travel expenses, accommodation, etc., for a service visit due to a defect deemed severe by the manufacturer shall be included in the warranty.

D. Travel expenses for procedures classified as routine maintenance are not included under this warranty.

PART 2 - PRODUCTS

2.1 MATERIALS

A. Materials used shall be virgin polyethylene resin as compounded and certified by the manufacturer.

B. The interior of the HDXLPE tank shall have an anti-oxidant LLDPE liner for sodium hypochlorite service or be constructed of HDLPE.

C. High Density Linear Polyethylene (HDLPE) tanks shall be made from high density linear polyethylene resin as manufactured by Exxon Mobile Chemical, Chevron Phillips, or resin of equal physical and chemical properties.

D. The plastic shall not contain any fillers.

E. All plastic shall contain a minimum of 0.25 PCT U.V. stabilizer and a maximum of 0.60 PCT.

F. Tanks shall be manufactured from materials certified to NSF/ANSI Standard 61 for chemical storage.

G. HDXLPE material shall meet or exceed the following test properties, based on molded parts.

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1. Density (ASTM D1505): 0.938 - 0.946 g/mL.

2. Tensile strength, ultimate, 2 inches minimum (ASTM D638): 2,830 psi.

3. Elongation at break, 2 inches minimum (ASTM D638): 700%.

4. ESCR, 100% Igepal, Cond. A, F50 (ASTM D1693): >1,000 hours.

5. ESCR, 10% Igepal, Cond. A, F50 (ASTM D1693): >1,000 hours.

6. Vicat softening point (ASTM D1525): 250 degrees F.

7. Flexural Modulus (ASTM D790): 86,780 psi.

8. Impact resistance at -40 degrees F (Phillips SSL-193): >120 feet/LB.

H. HDLPE material shall meet or exceed the following test properties, based on molded parts.

1. Density (ASTM D1505): 0.942 - 0.947 g/mL.

2. Tensile strength at Yield, 2 inches minimum (ASTM D638): 2,700 psi.

3. Elongation at break, percent, 2 inches minimum (ASTM D638): 350%.

4. ESCR, 100% Igepal, Cond. A, F50 (ASTM D1693): 400 - 1000 hours.

5. ESCR, 10% Igepal, Cond. A, F50 (ASTM D1693): 200 - 500 hours.

6. Vicat softening point (ASTM D1525): 235 degrees F.

7. Flexural Modulus (ASTM D790): 97,000-103,000 psi.

8. Impact resistance at -40 degrees F (Phillips SSL-193): >120 feet/LB.

I. Fitting, gasket, and bolt materials shall be compatible with intended chemical service of each individual tank.

2.2 TANK CONSTRUCTION

A. The polyethylene tanks shall be constructed by the rotational molding process.

B. The tank diameter shall be measured externally.

1. Tolerance on the outside diameter including out of roundness shall be plus or minus two percent.

2. Measurement shall be taken in a horizontal position.

3. The knuckle radius at bottom of wall shall be a minimum of 1 inch.

C. All edges cut out, such as entrance to manway, shall be trimmed to have smooth edges.

D. Tank wall thickness shall be per ASTM D1998.

2.3 DESIGN REQUIREMENTS

A. Hypochlorite tanks provided under this section shall have the following design characteristics.

1. Shell Style: Upright.

2. Top Style: Domed top.

3. Bottom Style: Flat bottom.

4. Exposure: Semi-heated space or Outdoors.

5. Color: Natural.

6. Straight Wall Capacity:

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a. Furnace Creek: 300 GAL.

b. Cow Creek: 115 GAL.

7. Diameter:

a. Furnace Creek: 3.5 FT.

b. Cow Creek: 2.5 FT.

8. Height, Overall:

a. Furnace Creek: 4.75 FT.

b. Cow Creek: 4 FT.

9. Chemical design specific gravity: 1.1 g/mL.

10. Maximum fluid temp: 90 degrees F.

11. Minimum fluid temp: 40 degrees F.

12. Minimum ambient air temp: 40 degrees F.

B. Potable Water tank provided under this section shall have the following design characteristics.

1. Shell Style: Upright.

2. Top Style: Domed top.

3. Bottom Style: Flat bottom.

4. Exposure: Semi-heated space.

5. Color: Natural.

6. Straight Wall Capacity: 755 GAL.

7. Diameter: 5.3 FT.

8. Height, Overall: 6 FT.

9. Chemical design specific gravity: 1.0 g/mL.

10. Maximum fluid temp: 95 degrees F.

11. Minimum fluid temp: 40 degrees F.

12. Minimum ambient air temp: 40 degrees F.

C.

2.4 FITTINGS

A. All sidewall fittings shall keep the storage solution from contacting the tank wall cross section.

B. Fittings terminate in socket or flanged connections.

1. Flanges: 150 pound ANSI/ASME B16.5.

C. Tanks provided under this section shall be provided with the following fittings. See the

Drawings for more detail on the height and orientation of each fitting.

1. Hypochlorite Tanks

a. Outlet Port: 2 inches IMF, UMO, or BFBF on side.

b. Fill Port: 2 inches SATBF on top.

c. Vent Line Port: 3 inches SATBF on top.

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d. Overflow Port: 2 inches BFBF on side.

e. Level Sensor Port: 2 inches SATBF on top.

f. Second Outlet Port: 2 inches BFBF on side.

2. Potable Water Tank:

a. Outlet Port: 2 inches IMF, UMO, or BFBF on side.

b. Fill Port: 2 inches SATBF on top.

c. Vent Line Port: 3 inches SATBF on top.

d. Overflow Port: 2 inches BFBF on side.

e. Level Sensor Port: 2 inches SATBF on top.

D. Bolted Flange Bulkhead Fittings (BFBF):

1. Constructed with one 150 pound flange installed inside the tank and one flange ring installed outside the tank.

2. Flange shall be socket or threaded according to specific connection requirements.

3. There shall be a minimum of four 1/2 inches diameter all thread bolts with bolt heads encapsulated in polyethylene preventing fluid contact with the metal material.

4. Polyethylene encapsulation shall fully cover the bolt head and a minimum of 1/4 inches of the threads closest to the bolt head.

5. Encapsulated heads shall have a gasket to provide a sealing surface against the flange.

6. Bolt holes shall straddle the principal centerline of the tank.

E. Bolted Flanged Fitting (BFF):

1. Flange shall be 150 pound socket or threaded according to specific connection requirements.

2. There shall be a minimum of four 1/2 inches diameter all thread bolts with bolt heads encapsulated in polyethylene preventing fluid contact with the metal material.

3. Polyethylene encapsulation shall fully cover the bolt head and a minimum of 1/4 inches of the threads closest to the bolt head.

4. Encapsulated heads shall have a gasket to provide a sealing surface against the flange.

5. Bolt holes shall straddle the principal centerline of the tank.

F. Integrally Molded Flange (IMF):

1. Located at the bottom of the sidewall and allows the tank to be fully drained.

2. Integrally molded into the tank during the rotational molding process.

3. Seamless, flanged, and manufactured from the same material as the tank.

4. Inserts are not acceptable.

5. A companion flange assembly with a split backing ring, bolts, and gasket shall be provided.

G. Self-Aligning Bolted Flange Fittings (SABFF):

1. Consists of a precision machined threaded swivel ball sealed inside a Bolted Flanged

Fitting (BFF).

2. No self-aligning bolted flange fittings permitted on sidewall.

H. Self-Aligning Threaded Bulkhead Fittings (SATBF):

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1. Consists of a precision machined threaded swivel ball sealed inside a Threaded Bulkhead

Fitting (TBF).

2. No self-aligning threaded bulkhead fittings permitted on sidewall.

I. Threaded Bulkhead Fittings (TBF):

1. Consists of double compression nuts threaded over a Schedule 80 long shank tube which penetrates the tank wall.

2. An integrally molded backing flange shall be provided at one end of the tube.

3. A closed cell, polyethylene gasket shall be installed on the tube between the backing flange and the inner wall of the tank.

4. High-torque design and shall provide a minimum of 85 PCT thread contact.

5. Provide an NPT pipe coupling on the exterior of the tank otherwise indicated.

6. No threaded bulkhead fittings permitted on wetted sidewall.

J. Unitized Molded Outlet (UMO):

1. A molded-in encapsulated Hastelloy for hypochlorite and stainless steel for potable water insert located at the bottom of the sidewall that allows the tank to be fully drained.

2. The insert shall be sealed off from the liquid contents of the tank by two O-rings installed on a specially machined schedule 80 PVC male pipe adapter.

2.5 TANK APPURTENANCES

A. Expansion Joints:

1. Provide an expansion joint for each tank nozzle.

2. Service: Chemical Systems.

a. Material:

1) Bellows: PTFE-62.

2) Flanges: PVC or CPVC.

3) Limit Belts and Nuts: Carbon steel epoxy coated.

4) Reinforcing Rings: Stainless Steel.

b. Pressure rating at 70 degrees F: 70 psiG.

c. Minimum axial movement: 3/8 inches.

B. Manways and Access Caps:

1. Closed top tanks over 500 GAL shall have a manway opening with a minimum inner diameter of 17 inches.

2. Closed top tanks less than 500 GAL shall have an access cap with a minimum inner diameter of 7 inches.

3. Manways and access caps shall be constructed of polyethylene material integrally molded with the tank.

4. Manways and access caps shall be sealable.

C. Pipe Supports:

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1. Provide pipe supports for the drop pipes attached to the tank.

2. Spacing of pipe supports shall be as recommended by the fabricator, but shall not be greater than 5 feet on-center.

3. Pipe supports shall allow removal of supported pipes.

4. The pipe support shall be a bolted fitting at the tank sidewall and shall include a bolt with a polyethylene encapsulated head installed on the interior of the tank wall. The polyethylene encapsulation shall fully cover the bolt head and a minimum of 1/4 inches of the threads closest to the bolt head. Pipe supports with exposed metal are not acceptable for use inside tanks.

D. Hazard and Safety Signs:

1. Caution Signs:

a. Each tank shall be provided with a minimum of one Chemical Caution Sign.

b. Tag type: Type D – Self-Adhesive Tape Tags and Signs.

c. Size: 5 IN x 7 IN.

d. Legend: Conforming to OSHA 1910.145(d)(4), Specifications for Caution Signs.

e. Schedule for T1802 and T3104:

1) Quantity: 1.

2) Location: Place in a visible location on each tank.

3) Text/Symbol: WEAR EYE PROTECTION, RUBBER GLOVES, AND

APRONS WHEN HANDLING CHEMICALS.

E. Tank Vents:

1. All closed top tanks shall be supplied with a U-vent that vents the tank outside of the building.

2. All vents shall be protected with a 24 mesh stainless steel screen at the terminal end of the vent.

2.6 OPTIONAL APPURTENANCES

A. Tanks provided under this section shall be provided with the following appurtenances. See the

Drawings for more detail on the height and orientation of appurtenances.

B. Tank Appurtenance Schedule:

1. T3102:

a. Drop Pipe, External on:

1) Overflow line.

C. Drop Pipe, External:

1. Provide a pipe drop leg outside the tank.

2. The drop leg shall be supported externally by pipe supports at 5 feet maximum intervals.

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3. The drop pipe supports shall be bolted fittings at the tank sidewall and shall include a bolt with a polyethylene encapsulated head installed on the interior of the tank wall. The polyethylene encapsulation shall fully cover the bolt head and a minimum of 1/4 inches of the threads closest to the bolt head. Pipe supports with exposed metal are not acceptable for use inside tanks.

D. Drop Pipe, Internal:

1. Provide a pipe drop leg inside the tank. The pipe drop leg shall extend down into the tank interior within 1 foot of the bottom of the tank.

2. The drop leg shall be supported internally by pipe supports at 5 feet maximum intervals.

3. The drop pipe supports shall be bolted fittings at the tank sidewall and shall include a bolt with a polyethylene encapsulated head installed on the interior of the tank wall. The polyethylene encapsulation shall fully cover the bolt head and a minimum of 1/4 inches of the threads closest to the bolt head. Pipe supports with exposed metal are not acceptable for use inside tanks.

E. Level Gauges:

1. Ultrasonic:

a. Ultrasonic level sensors be installed within tanks in accordance with Section 40 72

00.

F. Salt Well:

1. A perforated salt well will be placed vertically in the brine tank to allow liquid to pass through but exclude un-dissolved salt.

2. The primary fill line to the brine tank will be installed to flow into the salt well to promote a washing flow through the well and reduce plugging due to salt buildup.

3. The salt used as a softener shall be NFS-60 certified.

4. Tank Lids:

a. All open top tanks shall be furnished with a lid.

PART 3 - EXECUTION:

3.1 DELIVERY AND INSPECTION

A. Inspect tanks for gouges, pinholes, and other obvious defects, immediately following delivery of the tanks to the project site.

B. Defects in the tanks will be cause for rejection of the tanks.

3.2 INSTALLATION

A. Tanks shall be installed as shown and in accordance with the manufacturer’s written instructions.

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B. Each tank shall rest on a level, even base of concrete so that the entire bottom of the tank is supported.

3.3 FIELD TESTING

A. Tanks shall be field tested by filling the entire tank with water and monitoring the tanks and fitting connections for at least 24 hours.

B. Any leaks shall be corrected by the manufacturer’s representative prior to acceptance.

C. Following successful field tank testing, the tanks shall be completely emptied and dried.

3.4 FIELD REPAIR

A. If, after filling with chemical, a leak is detected, the Contractor shall be responsible for all expenses associated with removing the tank contents, repairing the tank, and replacing the tank contents.

END OF SECTION 43 41 43