912 COATING SYSTEMS FOR STRUCTURAL STEEL
- The Office of Materials Technology (OMT) will maintain a list of Approved Paint Manufacturers. Only manufacturers on this list will be acceptable. Unless otherwise specified, paint shall be tested in accordance with Federal Test Method Standard 141. Only one formulation per color will be permitted per project. Tests shall be performed at 75 F and 50 percent relative humidity unless otherwise specified. All paint shall be satisfactory for brushing, rolling, or spraying. All paints within a system shall be from the same manufacturer and shall be tinted at the point of manufacture to differentiate between coats, existing coats, and bare metal. Paint shall be shipped in the original containers and all containers shall bear the identification of the paint, consisting of the manufacturer’s name, the name or title of material, volume of contents, manufacturer’s paint identification number, the date of manufacture, color name and number, handling instructions, precautions, and the batch number.
- 912.01.01 Approved Paint Manufacturers. Admission onto the list of Approved Paint Manufacturers will be based upon the acceptance of the manufacturer’s submitted Quality Control Plan.
- 912.01.02 Quality Control Plan. The Quality Control Plan shall define the manufacturer’s process to ensure the quality of the products during and upon completion of the manufacturing process. As a minimum, the Quality Control Plan shall list the following information:
- (a) Name of quality control tests and test procedures used.
- (b) Detailed description of the test procedures if not a standard test.
- (c) Frequency of quality control tests.
- (d) Maintenance of quality control records and length of time that they will be maintained.
- 912.01.03 Acceptance. The paint manufacturer shall furnish certified test results for each lot and color of paint as specified in TC-1.03. Certified test results for each lot shall list the actual test results for the specified properties. The certification shall be approved by OMT prior to shipment, and a copy shall accompany each shipment.
- 912.01.04 Original Infrared Spectrogram. The manufacturer shall submit an original analysis of vehicle solids by infrared spectroscopy performed as specified in D 2621 as follows:
- (a) For zinc primer coatings, infrared spectrum (2.5 to 15 μm) of each vehicle component.
- (b) For two component coatings, infrared spectrum (2.5 to 15 μm) of each single component and each mixed component, when applicable, in appropriate mixing ratios.
- 912.01.05 CertificationA document which verifies that the material and work complies with the applicable specifications and includes the actual test results to confirm the statement. The contents of the certification shall be on the Contractor's/vendor's/manufacturer's letterhead or approved document and shall be duly signed by a company officer. Certifications for metal products, when required, shall include a statement that the material was melted and manufactured in the United States except as provided in Section 165 of the Surface Transportation Assistance Act of 1982, as amended by Section 1041(a) and 1048(a) of the Intermodal Surface Transportation Efficiency Act of 1991 with regard to the furnishing and coating of iron and steel products. A nationwide waiver for this provision has been granted for pig iron and processed, pelletized, and reduced iron ore. Verification Tolerances. The manufacturer’s facilities will be visited at random intervals, and samples will be taken. A comparison will be made between the manufacturer’s certified test results and the AdministrationShall mean any one of the Administrations within the Maryland Department of Transportation, as listed in GP 1.02.’s tests results on the same batch. The tolerances between these results shall meet the following:
TEST TOLERANCE TEST METHOD Total Solids by mass, % ±2 D 2369 Pigment Content by mass, % ±2 D 2698 or D 4451 Vehicle Solids by mass, % ±2 D 2369 Viscosity, KU ±10 D 562 Unit Weight, lb/gal ±0.5 D 1475
912.02 PRIMER COATS AND SEALERS.
- 912.02.01 Inorganic Zinc Rich. M 300, Type I or IA. Zinc dust shall meet D 520, Type II.
- 912.02.02 Aluminum Epoxy Mastic. Aluminum epoxy mastic primer shall have one component that is the condensation product of the reaction of epichlorohydrin with bisphenol A. Drying times shall be 8 hours maximum to touch, 24 hours minimum to 30 days maximum for recoat, and 48 hours maximum for hard. Minimum pot life shall be three hours. Solids by weight shall be 90 percent minimum and 80 to 90 percent by volume. Viscosity shall be 95 to 140 KU and flexibility shall pass a 180 degree bend around a 3/4 in. mandrel when tested per D 522. The material shall resist sagging when tested per D 4400 with no sagging at the manufacturer’s recommended wet film thickness. The material shall weigh 13.0 ± 0.5 lb/gal.
- 912.02.03 Organic Zinc Rich. SSPCSociety for Protective Coatings-Paint 20, Type II.
- 912.02.04 Zinc Rich Moisture Cured Urethane. One-component having a minimum zinc pigment content in the dry film of 80 percent. Minimum solids shall be of 80 percent by weight and 62 percent by volume. The viscosity shall be 95 to 105 KU, and shall be capable of being applied at 50 percent greater film build than required without runs or sags per D 4400. The interval for application of the next coat shall be 8 hours minimum and 30 days maximum. The coating shall also meet the Moisture Cured Urethanes Additional Performance Criteria Table except that the maximum loss for Abrasion Resistance shall be 82.0 mg, and Salt Spray after 1000 hours shall be 1/32 in. maximum.
- 912.02.05 Micaceous Iron Oxide and Aluminum Filled Moisture Cured Urethane. A minimum solids of 75 percent by weight and 60 percent by volume.
- The viscosity shall be 95 to 100 KU. The coating shall also meet the Moisture Cured Urethanes Additional Performance Criteria Table.
- 912.02.06 Penetrating Sealer. A viscosity of 75 to 101 KU and be able to penetrate and seal existing coatings and substrate. It shall be suitable for application over marginally prepared steel and most generic types of aged coatings. The sealer shall conform to one of the following:
- (a) Epoxy penetrating sealer shall be cross-linked amido-amine epoxy primer/sealer having two components mixed in accordance with the manufacturer’s recommendations. It shall be a minimum 95 percent solids by weight.
- (b) Moisture cured urethane micaceous iron oxide filled penetrating primer/sealer shall be one component having a minimum 75 percent solids by weight. It shall also meet the Moisture Cured Urethanes Additional Performance Criteria Table.
912.03 INTERMEDIATE COATS.
- 912.03.01 Acrylic. A single component 100 percent acrylic and have minimum solids of 48 percent by weight and 36 percent by volume. Maximum dry time to touch and recoat shall be 2 and 8 hours, respectively.
- 912.03.02 Epoxy Polyamide. Epoxy polyamide intermediate coat shall have one component that is the condensation product of the reaction of epichlorohydrin with bisphenol A. The epoxy polyamide shall have a 3.0 minimum fineness of grind (Hegman Units), and minimum solids of 75 percent by weight and 62 percent by volume. Maximum dry time to touch and recoat shall be 6 and 15 hours, respectively.
- 912.03.03 Micaceous Iron Oxide Moisture Cured Urethane. Micaceous Iron Oxide Moisture Cured Urethane shall be one-component having minimum solids of 80 percent by weight and 60 percent by volume. The viscosity shall be 90 to 100 KU. The interval for application of the next coat shall be 8 hours minimum and 30 days maximum. The coating shall meet the Moisture Cured Urethanes Additional Performance Criteria Table. The micaceous iron oxide content shall be at least 3.0 lb/gal.
912.04 FINISH COATS.
- The color number will be specified in the Contract DocumentsThe written agreement executed between an Administration and the successful bidder, covering the performance of the work and furnishing of labor, equipment and materials, by which the Contractor is bound to perform the work and furnish the labor, equipment and materials, and by which the Administration is obligated to compensate him therefore at the mutually established and accepted rate or price. The Contract Documents shall include the Invitation for Bids, Notice to Contractors, Instructions to Bidders, Proposal, Contract Forms and Bonds, General Provisions, Specifications, Supplemental Specifications, all Special Provisions, all Technical Provisions, all Plans and Notices to Proceed, also any written Change Orders and Supplemental Agreements that are required to complete the construction of the work in an acceptable manner, including authorized extension thereof and shall conform to Federal Standard 595. All finish coats shall resist sagging when tested per D 4400 with no sagging at the manufacturer’s recommended wet film thickness.
- 912.04.01 Acrylic. Refer to 912.03.01.
- 912.04.02 Aliphatic Urethane. Finish coat shall have minimum solids of 70 percent by weight and 47 percent by volume. Drying time to touch and hard shall be the minimum recommended by the paint manufacturer.
- 912.04.03 Moisture Cured Aliphatic Urethane. Finish coat shall be one-component having a maximum free monomer content of 0.7 percent. Minimum solids shall be 75 percent by weight and 60 percent by volume, and the viscosity shall be 70 to 80 KU. The interval for application of the next coat shall be 8 hours minimum and 30 days maximum. The coating shall meet the Moisture Cured Urethanes Additional Performance Criteria Table.
912.05 PAINT SYSTEMS.
- As specified in the Paint Systems Table.
PAINT SYSTEMS TABLE PAINT COAT SECTION DRY FILM THICKNESS,
mils, min - max
USAGE SYSTEM A Inorganic Zinc I 912.02.01 3.0 - 5.0 Shop Primer Acrylic II 912.03.01 2.0 - 4.0 First Field Coat Acrylic III 912.04.01 2.0 - 4.0 Finish Coat SYSTEM B Inorganic Zinc I 912.02.01 3.0 - 5.0 Shop Primer Epoxy Polyamide II 912.03.02 5.0 - 8.0 First Field
Aliphatic Urethane III 912.04.02 2.0 - 3.0 Finish Coat SYSTEM C Organic Zinc I 912.02.03 3.0 - 5.0 Primer/First
Epoxy Polyamide II 912.03.02 5.0 - 8.0 Second Cover-All Coat Aliphatic Urethane III 912.04.02 2.0 - 3.0 Finish Coat SYSTEM D Organic Zinc I 912.02.03 3.0 - 5.0 Primer/First
Acrylic II 912.03.01 2.0 - 4.0 Second Cover-All Coat Acrylic III 912.04.01 2.0 - 4.0 Finish Coat SYSTEM E Aluminum Epoxy Mastic I 912.02.02 5.0 - 8.0 Primer/First
Epoxy Polyamide II 912.03.02 5.0 - 8.0 Second Cover-All Coat Aliphatic Urethane III 912.04.02 2.0 - 3.0 Finish Coat SYSTEM F Micaceous Iron Oxide,
Aluminum Filled Moisture Cured Urethane
I 912.02.05 2.0 - 3.0 Primer/First
Micaceous Iron Oxide Moisture Cured Urethane II 912.03.03 3.0 - 5.0 Second Cover-All Coat Moisture Cured Aliphatic Urethane III 912.04.03 1.5 - 2.0 Finish Coat SYSTEM G Zinc Rich Moisture Cured Urethane I 912.02.04 2.0 - 3.0 Primer/First
Micaceous Iron Oxide Moisture Cured Urethane II 912.03.03 3.0 - 5.0 Second Cover-All Coat Moisture Cured Aliphatic Urethane III 912.04.03 1.5 - 2.0 Finish Coat SYSTEM H Penetrating Sealer I 912.02.06 1.0 - 2.0 Sealer Aluminum Filled Epoxy Mastic II 912.02.02 3.0 - 5.0 Spot Coat Aliphatic Urethane III 912.04.02 3.0 - 5.0 Finish Coat MOISTURE CURED URETHANES ADDITIONAL PERFORMANCE CRITERIA TABLE TEST PROPERTY TEST METHOD TEST CRITERIA COAT I and II ENTIRE SYSTEM Cyclic Salt Fog/UV Exposure of Painted Metal D 5894 Final Ratings:
Rusting: 6 min
Blistering: 10 min
Rust Creep: 6 max
Cracking: Degree and Type
Flaking: Degree and Type
1000 hr 3000 hr Salt Spray B 117 1/32 in Scribe, 1/16 in. max undercut 1000 hr 3000 hr Abrasion Resistance D 4060 Taber Abraser, CS-17 Wheel, 1000 g load, 1000 cycles, max loss 100 mg 56 mg Adhesion D 3359 Cross-Cut Tape Test No peeling or removal No peeling or removal Flexibility D 522 Conical Mandrel Bend Test, min elongation 10 % 40 % Pencil Hardness D 3363 min F F Accelerated Weathering G 53 QUV using UV - B Lamp, time after no more than 10 % loss of gloss — 400 hr Impact Resistance D 2794 min — 40 in.·lb Chemical Resistance, Solutions Fed. Spec. T-C-550 4.4.6 5 % Sodium Hydroxide
5 % Hydrochloric Acid
5% Sulfuric Acid
5 % Acetic Acid
— Unaffected - Slight discoloration permitted Reversed Impact D 2794 Rapid Deformation — No cracking or delamination
SPECIAL PROVISION INSERTS
The following Special Provision Inserts update Section 912 after the official publication of the Standard SpecificationA written description of functional characteristics, or the nature of a construction item to be procured. It may include a. Updated documents may be found within the Standard and Supplemental Specifications for Construction and Materials on the MDOTMaryland Department of Transportation SHA web page.
- SPI-Section 912-Coating Systems for Structural Steel. Dated 5/11/2018.