TC Spec. DBB-002

BOLTED SMOOTHWALL TANK SPECIFICATIONS
(for dry bulk solids storage)
 

GENERAL

The Engineer's selection of factory-coated bolted steel tank construction for this facility has been predicated upon the design criteria and construction methods specified. Deviations from the specified design and construction details will not be permitted. 

DRAWINGS AND SPECIFICATIONS

After receipt of order, the Vendor is required to furnish, for the approval of the Engineer, complete specification and construction drawings for all work shown on the bid drawings. When approved, one set of such prints will be returned to the Vendor marked Approved, and these drawings will govern the work detailed. The approval by the Engineer of the Contractor's drawings shall be an approval relating only to their general conformity with the bid drawings and specifications.  

The Owner’s drawings and specifications showing general dimensions and construction details shall govern construction. After approval by the Engineer of detailed drawings prepared by the Vendor, there shall be no deviation from the drawings and specifications except upon written order or approval from the Engineer.

QUALIFICATION OF BIDDER

The Bidder shall be a specialist in the design and fabrication of factory-coated, bolted steel tanks.  Bidder shall also submit, upon request, a list of five comparable tanks now in service in the United States for references.

I.  General Information

• Buyer's name: ____________________________________________________

• Jobsite location: City __________, State __________ Zip Code __________

• Product to be stored in tank: _________________________

• Loose density of product: __________ pounds per cubic foot

• Maximum compacted product density: __________ pounds per cubic foot

• Angle of repose: __________ degrees

• Required working capacity each tank: __________ cubic feet

• Suggested tank geometry: Diameter __________ Eave height __________

• Configuration – (Skirt support design) (Tank elevated on structural steel)

• Hopper slope (35, 40, 45, 50, 55, 60, 65, 70, other specify)_____________

• Clearance from foundation to hopper discharge __________ feet

• (Mass Flow) (Funnel Flow) (Fluidized) design loads ______________________

• System operating pressure and vacuum:_______/_______ ounces/square inch

• Dust collector and/or equipment load __________ pounds

• Roof live load: __________ PSF

• Earthquake:  Seismic Zone per IBC 2000 - requires zip code ________

• Wind: __________ mph per ASCE 7-98

II.  Scope of Supply

1. Furnish all material necessary for the tanks and appurtenances specified.

2. Tanks will be designed to be self-supporting on customer-supplied foundation or structure.

3. Receiving, unloading, and erection of tanks will be by (Owner)(Vendor).

4. Bolted tank installation services at the jobsite will be optional at customer request.

III.  Design Criteria 

Vendor to quote on the nearest standard size bolted tanks of manufacturer.

1. Standard wind design is 90 MPH wind velocity using ASCE 7-98 as a reference.

2. Seismic design (if applicable) is to be based on the 2000 edition of the International Building Code. When designing a tank in a seismic zone, the load producing the higher stresses comparing wind and seismic will control the dynamic portion of design.

3. Combined live and dead roof load shall be uniformly distributed with all nozzle, manhole, and filter locations designed for a minimum of 200 lbs. each. Live and dead loads to be a combined minimum of 25 psf. Roof to have 1:12 slope for water drainage. Roof is typically not designed as a working platform.

4. Tank wall design is to be based on the critical buckling formula from the book Structural Analysis of Shells by Baker, Kovalevsky & Rish, page 230. The walls above the hopper are to be designed using Janssen's formula for cylindrical bins.

5. Tank shall be designed for (center fill) (off-center fill) (center discharge) (off-center discharge) of product.

6. Tank design pressure shall be 4.5 oz. per square inch positive and .5 oz. per square inch negative (positive pressure decreases as tank diameter increases)(Design tank for atmospheric pressure.)

7. Tank design to be based on a level full capacity using the maximum compacted density of product.

8. Owner solicits recommendations that may improve the price, delivery, or performance of tanks. As an alternate, Vendor is invited to quote changes in physical dimensions, modifications to the design, fabrication, or stock of Vendor's standard equipment that would reduce the initial cost of the equipment as specified without changing the design premise.

Alternate quotations shall be listed as such in the proposal specifying the alternate and the price and delivery for the alternate.

IV.  Material Specifications

A.      Shell Structure

The materials, design, and fabrication of the bolted steel shell shall conform to the manufacturer's standard specifications including the following:

1.  Materials – Carbon Steel

a.       Hot Rolled Sheet and Plate - ASTM A1011 Grade 40 or equal with a minimum yield strength of 40,000 psi.

b.      Structural Shapes - Carbon steel structural shapes shall conform to ASTM A36 or ASTM A992.

2.  Materials – Stainless Steel & Aluminum

a.       Aluminum - 5052-H32, 6061-T6 typical grades

b.      Stainless steel - 304, 316, 316L, 317 typical grades

c.       Other grades of carbon steel, stainless steel and aluminum are available.

3.  Bolts

a.       Bolts shall be 1/2 inch diameter and shall meet or exceed API Specification 12B. Standard bolt coating is mechanically galvanized per ASTM B695, Class 50.

b.      Anchor bolts conform to ASTM A36 or A307.

c.       Other bolts shall meet or exceed ASTM A307 or ASTM325.

4.  Gaskets

 a.   Bolted connections shall incorporate white EPDM gasket material.

B.  Coatings

●     All carbon steel plates, members, and miscellaneous parts (except bolts) shall be factory coated in accordance with the provisions of Section B of these specifications.

C.  Appurtenances/Accessories

Standard Accessories

-      3’ x 6’8” walk-in door in skirt with louver

-         20” center roof dome with cover plate

-         Foundation loads

-         Foundation anchor bolts and clips

-         Hardware and gasket for assembly of tank

            Optional Accessories

-         Product Material testing

-         Double door access in skirt – 6’ wide x 6’8” ht.

-         12’ wide x 14’ height truck drive-through openings in skirt

-         Hillside flange in deck for mounting filter (size and weight required)

-         Hopper manway (manway with bolt-on cover)(hinged style)(quick access)

-         Specify - Stub and flanged nozzles required in deck, sidewall, and hopper

-         Specify – Level indicator nozzles/couplings/openings required

-         Complete fill pipe assembly (aluminum)(stainless)(carbon steel) specify schedule required

-         Wear-back elbows on fill pipe assembly

-         TC target box located in tank center dome

-         Deck manway access (20” snaplock)(20” combination manway ventilator)(20” combination manway PRV)(24” combination manway PRV)

-         Specify - Special hopper outlet size or configuration required

-         Deck perimeter guardrail with toeboard (OSHA)

-         Outside ladder with safety enclosure and rest platform(s) (OSHA)

-         Spiral stairway access to top of tank (OSHA)

-         Maintenance platforms (specify size & location)

-         Crossovers for access between tanks (OSHA)

V.  Shipping

●     All tanks, structures, and miscellaneous parts shall be packaged for shipment in such a fashion as to minimize abrasion or scratching of finished coating system.

●     Shipment will be by truck or ocean container if export.

VI.  End of Specification (Section B – Coating specification attached)

TC – Coating Spec. DBB-002 – Section B  

I.  Surface Preparation

●         Tank parts are thoroughly power-washed and rinsed to remove grease, oil and foreign matter

●         Cleaned parts are oven-dried

●         Parts are steel grit blasted to a near-white finish (SSPC-SP10) with a nominal 2 mil surface profile

II.  Interior Coatings

A.  Thermal Bond EP – dry bulk materials & food grade applications

●         One coat of FDA accepted modified epoxy powder to 3 mils DFT.

B.     Polyamide Epoxy – dry bulk materials & protective primer applications

●         One coat corrosion-inhibitive polyamide epoxy primer spray-applied at 2.0 mils

C.     No internal coating required

III.  Exterior Coatings

A. Thermal Bond EP – dry bulk materials & protective primer applications

●    One coat of modified epoxy powder to 3 mils DFT as a primer

B.  Polyamide epoxy - dry bulk materials & protective primer applications

●   One coat of corrosion-inhibitive polyamide epoxy primer, spray applied at 2.0 mils nominal DFT

C.  Thermal Bond EP with Polyurethane topcoat - prime + topcoat

●   One coat of modified epoxy powder at 3 mils DFT

●   One coat acrylic polyurethan, spry applied to 1.5 mils DFT.
(Standard light colors include: white, blue, green, gray, & tan) 
Note: Total coating system application - 4.5 mils DFT

D.  MaxCoat DRY Protection System - extreme external protection

●   Thermal Bond EP at 5 mils DFT

●     One coat of acrylic polyurethane, spray applied to 2 mils DFT.
(Standard light colors include: white, blue, green, gray, & tan) 
Note: Total coating system application - 7 mils DFT

E.  No external coating system required

F.  Special field applied coating system - to be specified

G.  Curing & Shipping

●         Baking oven to be used after each coat

●         All coated parts shall be inspected prior to shipment

●         Touch-up paint with instructions shall be included for application by erection crew