SS-01025
(New)

THE STANDARD SPECIFICATIONS, SERIES 2001, ARE AMENDED BY THE FOLLOWING MODIFICATIONS AND ADDITIONS. THESE ARE SUPPLEMENTAL SPECIFICATIONS AND THEY SHALL PREVAIL OVER THOSE PUBLISHED IN THE STANDARD SPECIFICATIONS.

01025.01 DESCRIPTION
For the galvanized steel designated for painting on the plans, the work shall consist of the following:

A.  Surface cleaning of the galvanized steel surface.

B.  Surface preparation for painting of the galvanized steel surface.

C.  Application of an intermediate coat of polyamide epoxy with a coating thickness of 3 mils to 4 mils (75 mm to 100 mm).

D.  Application of a topcoat of aliphatic polyurethane which matches the Federal Standard Color number listed in the contract documents.

All cleaning, preparation for painting, and painting shall be done in the same shop to ensure single source responsibility of the entire coating system.  In addition, sequence of operation shall be submitted to the Iowa Department of Transportation, Attn:  Structures Engineer, Office of Materials, 800 Lincoln Way, Ames, IA, 50010, describing the procedure used in preparing the galvanized surface, the brand names of the paint to be used, and certification that the paint that is used is compatible with galvanized surfaces.

01025.02  Materials
The two-coat epoxy/polyurethane paint system shall be one of the paint systems identified below:

Carboline Paint Co.
     Intermediate Coat: 893 Epoxy
     Top Coat: 133 HB Polyurethane

Ameron Protective Coating
     Intermediate Coat: 385 Epoxy
     Top Coat: 450 SA Polyurethane

Sherwin-Williams Company
     Intermediate Coat: Recoatable Epoxy Primer, B67 Epoxy
     Top Coat: Corothane II B65 W200 Series Polyurethane

International / Porter
     Intermediate Coat: Interseal 670
     Top Coat: 990 PHA010

Coating Dry Film Thickness (dft):
     Intermediate Coat: 2.6 mils to 4 mils (65 μm to 100 μm)
     Top Coat: 2 mils to 4 mils (50 μm to 100 μm)

All materials used in the coating system shall be compatible and from the same manufacturer.

All materials shall have been and continue to be stored in such a manner as to prevent freezing and/or overheating.  Manufacturer recommendations shall be followed as to maximum and minimum storage temperatures.

A.  Surface Preparation Of Galvanized Surfaces
The galvanized steel surfaces shall be prepared and primed as soon after galvanizing as possible but the surfaces shall be primed within 24 hours of the galvanizing operations.  There should be no visible signs of zinc oxide or zinc hydroxide, which first appear as a fine white powder.

B.  Surface smoothing
Zinc high spots shall be removed by cleaning with hand or power tools as describe in SSPC SP2 or SP3.  The zinc should be removed until it is level with the surrounding area, taking care that the base coating is not removed by the cleaning methods.  After cleaning, the surface shall be inspected for conformance to the required zinc thickness in accordance with ASTM A 123 utilizing a magnetic or eddy current type thickness instrument in accordance with ASTM E 376.  Any item falling below the required zinc thickness, before or after removal of any high spots, shall be repaired in accordance with practice ASTM A 780.

C.  Surface cleaning
Hot dip galvanized surfaces must be clean and free of oil and grease before they are painted.

Absolutely no water quenching or chromate conversion coating is allowed of the galvanized surface that is to be painted, as they will interfere with the adhesion of the paint coatings to the zinc surface.

Any of the following methods as deemed necessary by the paint manufacturer shall be used for surface cleaning of the galvanized surfaces:

1.  Aqueous Alkaline Cleaning
An alkaline solution, with a pH of 11 to 13 may be used to remove traces of oil, grease, or dirt.  Alkaline cleaner may not be used for removal of heavy build-up of zinc oxide or wet storage stain.  The solution can be applied through immersion in a tank filled with the solution, sprayed, or brushed with a soft bristle brush.  After cleaning, rinse thoroughly in hot water or water under pressure.  Heated drying to accelerate the complete removal of water from the surface should be used.

2.  Solvent Cleaning
Typical cleaning solvents, such as mineral spirits or high-flash naphtha, can be used to remove oil and grease.  The procedure to be used is as specified in SSPC SP1.  Proper rags or brushes should be used to wipe the galvanized parts.  These rags or brushes should be cleaned or recycled often since oil can accumulate on their surfaces and be transferred back to the galvanized part.  After cleaning, rinse thoroughly in hot water or water under pressure.  Allow to dry completely before proceeding.

D.  Surface preparation
Any of the following methods as per the written recommendation of the paint manufacturers may be used to prepare the galvanized surface for painting:

1.  Sweeping Blasting
Abrasive sweep or brush blasting which uses a rapid nozzle movement will roughen the galvanized surface profile.  The abrasive material shall provide a stripping action without removing excess zinc layers.  Particle size should be in the 8 mils to 20 mils (200 mm to 500 mm) range.  Materials that can be used are aluminum/magnesium silicate, soft mineral sands with a mohs hardness of 5 or less, corundum, limestone, and organic media such as corncobs or walnut shells.  The purpose of the sweep blasting is to deform not to remove the galvanized metal.  Any area falling below the required zinc thickness, before or after the sweep blasting should be repaired in accordance with ASTM A 780.  The procedure for this process can be found in SSPC SP7. Sweep blasting of zinc shall not be less than 130 square yards per hour (110 m²/h) using these types of abrasives.  Substrate should be maintained at a temperature greater than 5°F (3°C) above the dew point temperature.  Following abrasive blast cleaning, surfaces should be blown down with clean, compressed air.  The formation of zinc oxide on the blasted surface will begin very quickly so the paint coating should be applied immediately, within 60 minutes, after sweep blasting.

2.  Wash Primer Treatment
This process involves the use of a metal conditioner to neutralize surface oxides and hydroxides along with etching the surface.  One example of a wash primer is SSPC-Paint Specification No. 27.  The process is based on three primary components: a hydroxyl-containing resin; a pigment capable of reacting with resin and acid; and an acid capable of making the resin insoluble by reacting with the resin, the pigment, and the zinc surface.  The result is a film of approximately 0.3 mils to 0.5 mils (8 mm to 13 mm).  Failures can occur if the film exceeds 0.5 mils (13 mm).

The film is usually applied by spray, but may be applied by soft bristle brush, dip, or roller coater.  Using these latter coating methods, it may be difficult to control the film thickness.

For drying time prior to topcoating, follow the manufacturer’s instructions.

This wash primer treatment may be better suited to certain types of paint systems.  See SSPC-Paint Specification No. 27 for the best match of this treatment to a paint system.

3.  Acrylic Passivation/Pretreatment
The passivation/pretreatment process consists of applying an acidic acrylic solution to the newly galvanized surface and then allowing it to dry, forming a thin film coating.  When applied, the solution first reacts with the zinc surface forming a passivating conversion coating while simultaneously forming an acrylic coating suitable for painting on top of the passivation layer.  The underlying conversion coating provides strong adhesion to the galvanized surface while the thin film acrylic layer provides barrier protection that inhibits corrosion and provides a highly compatible surface for the application of organic paint films.  There are versions of these solutions that contain chrome and versions without chrome.

The application methods for these water-based treatments are dipping, flow coating, spraying, or other appropriate means.  Following application the coating is dried in an oven or in air.  In some instances the coating is applied to hot galvanized articles in which case separate drying is not necessary.  Rinsing is not required.  The coating is approximately 0.04 mils (1 mm) thick.

Painting is possible any time during a period of four months after application as long as the surface is free of visible zinc oxides or zinc hydroxides.  However, if harmful contaminants such as dust, dirt, oils, grease, or deposits are present, they must be removed with a mild alkaline degreasing solution, pH 11.5 maximum, followed by a thorough rinse with hot water (140°F (60°C) maximum temperature) or a pressure wash, and then, thoroughly dried.  This treatment applied in the galvanizing plan or later in the paint shop.  When applied in the paint shop, the surface must first be appropriately cleaned as described above to remove contaminants picked up after galvanizing.

E.  Final painting
All material must be applied under conditions within the following tolerances permanent records should be kept of the processing conditions during the complete finishing process:

1.  Air temperature 50°F (10°C) minimum and 90°F (32°C) maximum.
2.  Steel surface temperature 50°F (10°C) minimum and 100°F (37°C) maximum.
3.  Humidity 85% maximum.
4.  Steel temperature at least 5°F (3°C) above the dew point.

All surfaces must be dry and free from dust, dirt, oil, grease, or other contaminants.

Total thickness including epoxy intermediate coat and urethane topcoat shall be from 5 mils to 10.5 mils (130 mm to 260 mm) dry film thickness.

After the painted galvanized steel has been erected in the field, all areas where the shop paint has been damaged shall be touched up with the same materials as specified for shop application.  All paint materials for the shop and the field touch-ups shall be supplied by the same paint manufacturer.

The paint manufacturer's product data sheets shall be submitted to the Engineer prior to the start of work and the requirements as outlined in the data sheets shall be followed.  The intermediate coat of epoxy shall be applied in two applications.

The coating shall be packaged in separate containers bearing a label clearly showing the name of the manufacturer, brand name of the product, lot number, and date of manufacture.

The topcoat shall match Federal Standard Color number listed in the contract documents.  Samples of the topcoat color shall be submitted to Iowa Department of Transportation, Office of Materials, 800  Lincoln Way, Ames, IA  50010.

Special handling will be required to prevent any damage to the paint system during lifting, shipping, and installation.

Any defect or damage to the paint system after completing construction shall be properly prepared and repainted as per the manufacturer’s specifications.  All steel surfaces to be repainted shall be free of contaminants including dirt or concrete.  All paint used for repairs shall be from the same manufacturer of the paint used for the shop painting.  Adjacent surfaces not to receive paint shall be adequately protected by masking or other means of protection.

F.  Shop Conditions
The surfaces to be painted after surface preparation must remain free of moisture and other contaminants.  The Contractor shall control the operations to insure that dust, dirt, or moisture does not come in contact with surfaces prepared or painted that day.  In addition to the manufacturer's written instructions for surface preparation and painting, the following conditions shall apply (when in conflict, the most restrictive conditions shall govern):

The minimum steel and air temperatures shall be 40°F (4°C).  Painting shall not be applied to steel that is at a temperature that will cause blistering, porosity, or be otherwise detrimental to the life of the painted surfaces.  Painting shall not be applied when the steel surface temperature is less than 5°F (3°C) above the dew point.  Painting shall not be applied to wet, damp, or frosted surfaces. Paint shall not be applied when the relative humidity is above 85%.

Work accomplished under unfavorable weather conditions will be considered unacceptable and complete recleaning and painting of these areas will be required at no additional cost to the Contracting Authority.

G.  Equipment.
All cleaning and painting equipment shall include gauges capable of accurately measuring fluid and air pressures and shall have valves capable of regulating the flow of air, water, or paint as recommended by the equipment manufacturer.  The equipment shall be maintained in proper working order.

Spray painting and surface preparation equipment shall utilize filters, traps, or separators recommended by the manufacturer of the equipment and shall be kept clean.  The methods and intervals for cleaning the filters, traps, and separators shall be as recommended by the manufacturer of the equipment.  In addition, paint pots shall be equipped with air operated continuous mixing devices.

Pressure type abrasive air blasting equipment shall be capable of providing the minimum required pressure and volume, free of oil, water, and other contaminants.

Prior to beginning all painting operations, air equipment shall pass the requirements of ASTM D 4285.  This test will be repeated as determined by the Engineer.

H.  Quality Control.
The Contractor shall conduct a quality control program that ensures that the work accomplished complies with these specifications.  The quality control program shall consist of:

1.  Qualified personnel to manage the program and conduct quality control tests.
2.  Proper quality measuring instruments.
3.  Quality Control Plan.
4.  Condition and quality recording procedures.

The personnel managing the quality control program shall have experience and knowledge of industrial coatings and the measurements needed to assure quality work.  The personnel performing the quality control tests shall be trained in the use of the quality control instruments.  These personnel shall not perform surface preparation and painting.  Painters shall perform wet film thickness measurements.

The Contractor shall supply all necessary equipment to perform quality control testing of shop conditions, equipment, surface preparation, and profile and paint film thickness.  The Contractor’s personnel in accordance with the equipment manufacturer’s recommendations shall calibrate these instruments.

The Contractor shall implement a Quality Control Plan approved by the Engineer including a schedule of required measurements and tests as outlined herein, procedures for correcting unacceptable work, and procedures for improving surface preparation and painting quality as a result of quality control findings.  The Contractor shall supply and use forms approved by the Engineer to record the results of quality control tests.  These reports shall be available at the work site for review by the Engineer.

The purpose of the quality control program is to assist the Contractor in the proper performance of the work.  Quality control tests performed by the Contractor will not be used as the sole basis for acceptance of the work.

01025.05  BASIS OF PAYMENT
The cost of cleaning, surface preparation, and painting of galvanized structural steel shall be included in the contract price for the items that have galvanized steel designated for painting as listed in the contract documents.  This incidental cost shall include all labor, materials, and equipment to complete the cleaning, surface preparation, and painting in accordance with these Supplemental Specifications.  It shall also include any costs to repaint or repair the paint system after erection.