Epoxy Polyamide Painting System 101
Painting System No. 13.01 – Epoxy Polyamide Painting System
1.1 This speciﬁcation outlines a three-coat epoxy polyamide painting system for the protection of steel surfaces subject to industrial exposure, marine environments, and areas subject to chemical exposure such
as acid and alkali.
1.2 This system, when properly applied and cured, is capable of giving excellent protection to steel surfaces in Environmental Zones 2A (frequently wet by fresh water), 2B (frequently wet by salt water), 3A
(chemical, acidic), 3B (chemical, neutral), and 3C (chemical, alkaline), but not in potable water tanks. Although the coating herein speciﬁed has exhibited good chemical protection, its resistance against speciﬁc
chemicals should, in the absence of applicable case histories, be appropriately tested.
2.1 This painting system consists of surface preparation by SSPC-SP 6, “Commercial Blast Cleaning, and application of an epoxy polyamide primer, intermediate, and topcoat speciﬁed in SSPC -Paint 22, “Epoxy
Polyamide Paints (Primer, Intermediate, and Topcoat).”
2.2 Each coating of this system (primer, intermediate, and topcoat) is a two-part product consisting of a base component and a curing agent component. The base component contains an epoxy resin together
with corrosion-resistant pigments, prime color pigments, mineral ﬁllers, gellant, leveling agent, and volatile solvents as appropriate to meet the performance requirements. The curing agent component contains a
liquid type polyamide resin and volatile solvents.
3. Referenced Standards
3.1 The latest issue, revision, or amendment of the referenced standards in effect on the date of invitation to bid shall govern, unless otherwise speciﬁed.
3.2 If there is a conﬂict between the requirements of any of the cited referenced standards and this speciﬁcation, the requirements of this speciﬁcation shall prevail.
3.3 SSPC STANDARDS AND JOINT STANDARDS:
PA 1 Shop, Field, and Maintenance Painting of Steel
PA 2 Measurement of Dry Coating Thickness With Magnetic Gages
PA Guide 4 Guide to Maintenance Repainting with Oil Base or Alkyd Painting Systems
Paint 22 Epoxy Polyamide Paints (Primer, Intermediate, and Topcoat)
SP 5/NACE No. 1 White Metal Blast Cleaning
SP 6/NACE No. 3 Commercial Blast Cleaning
SP 8 Pickling
SP 10/NACE No. 2 Near-White Blast Cleaning
3.4 AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) STANDARD:
B 117 Standard Practice for Operating Salt Spray (Fog) Apparatus D 714 Standard Test Method for Evaluating Degree of Blistering of Paints
D 1654 Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments
D 3925 Standard Practice for Sampling Liquid Paints and Related Pigmented Coatings
G 23 Practice for Operating Light-Exposure Apparatus(Carbon Arc Type) With and Without Water for Exposure of Non-Metallic Materials [Withdrawn 2000. Replaced with appropriate cycle of G 151 – G 155.]
3.5 FEDERAL STANDARDS AND SPECIFICATIONS:
MIL-DTL-24441 Paint, Epoxy Polyamide, General Speciﬁcation [Use 23236. Formerly MIL-P-24441]
4. Surface Preparation
4.1 SSPC-SP 6, “Commercial Blast Cleaning,” or SSPCSP 8, “Pickling.” If speciﬁed in the procurement documents, better degrees of blast cleaning shall be substituted (SSPC-SP 5, “White Metal Blast Cleaning,”
or SSPC-SP 10, “Near-White Blast Cleaning”).
5.1 PRIMER: SSPC-Paint 22, “Epoxy Polyamide Paints,” primer.
5.2 INTERMEDIATE (SECOND COAT): SSPC-Paint 22, “Epoxy Polyamide Paints,” intermediate.
5.3 FINISH COAT: SSPC-Paint 22, “Epoxy Polyamide Paints,” topcoat.
6. System Requirements
6.1 TEST PANELS: Test panels shall be carbon steel, minimum size of 10 x 20 x 0.3 cm (4 x 8 x 1/8 inch) unless otherwise speciﬁed. They shall be blast cleaned in accordance with SSPC-SP 10, “Near-White Blast
Cleaning.” The coating system shall be spray applied and air dried. Air drying and test conditions shall be 23 to 27°C (74 to 80°F) and 40 to 50 percent relative humidity. Final dry ﬁlm thickness shall be between
175 and 225 micrometers (7 and 9 mils).
6.2 ADHESION: Prepare four panels as in Section 6.1. Scribe an “X” as per ASTM D 1654, in the lower half of each panel down to the bare metal, and coat the back and edges of the panels with a fast-dry paint.
Then place the panels in a distilled water bath at 23 to 27°C (74 to 80°F) so that the “X” scribe is completely submerged. After ﬁve days in immersion, remove the panel, allow four hours recovery time, and test the adhesion by attempting to separate the coats with the knife. Any delamination shall constitute failure.
6.3 SALT SPRAY RESISTANCE: Prepare at least two test panels as in Section 6.1. Protect the backs and edges. Expose for 1000 hours to ﬁve percent salt spray in accordance with ASTM B 117. During the test,
the panels shall be inclined at an angle of 15 degrees off the vertical. At the end of the test period there shall be no blistering or underﬁlm corrosion.
6.4 ACCELERATED WEATHERING: Prepare two 7.6 x 15 cm (3 x 6 inch) steel panels as in Section 6.1. Expose to accelerated weathering for 500 hours in accordance with ASTM G 23. At the end of the test period
the coating system shall show no cracking, checking, or ﬁlm failure other than chalking or loss of gloss.
6.5 CHEMICAL RESISTANCE: Prepare a test panel as in Section 6.1 except allow to cure for 14 days at room temperature prior to conducting spot test. Place a small piece of absorbent cotton or ﬁlter paper on
the test panel. Apply two to six drops of test solution and cover with a 2.5 cm (1 inch) watch glass. Allow to stand 24 hours. Wash panel with water and examine immediately, and after an eight-hour recovery.
Staining may occur with certain colored topcoats. Typical performance is as follows:
5% by weight, sodium hydroxide—no effect 5% by weight, sulfuric acid—stain 5% by weight, phosphoric acid—no effect 5% by weight, ammonium hydroxide—no effect 5% by weight, acetic acid—slight blister
(8F max, ASTM D 714)
5% by weight, hydrochloric acid—slight stain
7. Paint Application
7.1 PAINT APPLICATION: Follow the requirements of SSPC-PA 1, “Shop, Field, and Maintenance Painting of Steel.”
7.2 RECOATING: Each coat shall be air dried a minimum of four hours at 25°C (77°F) prior to recoating. Longer recoat times will be required at lower temperatures. Normal recoat time is within 72 hours. Longer
recoat times may require special surface preparation. These coatings shall not be applied at temperatures below 10°C (50°F).
7.3 MAINTENANCE PAINTING: The provisions of SSPCPA Guide 4, “Guide to Maintenance Repainting with Oil Base and Alkyd Painting Systems” should be followed.
7.4 NUMBER OF COATS: Minimum of three.
7.5 DRY FILM THICKNESS OF PAINT SYSTEM: Not less than the following as measured in accordance with SSPC-PA 2, “Measurements of Dry Coating Thickness with Magnetic Gages”—primer 64 micrometers (2.5
mils); intermediate coat 64 micrometers (2.5 mils); ﬁnish coat 50 micrometers (2.0 mils); for the three-coat paint system 175 micrometers (7.0 mils). The dry ﬁlm thickness of the three-coat system shall not
exceed 380 micrometers (15 mils).
8.1 All work and materials supplied under this speciﬁcation are subject to timely inspection by the purchaser or his authorized representative. The contractor shall correct such work or replace such material as is
found defective under this speciﬁcation (See Note 10.1.). In case of dispute, unless otherwise speciﬁed, the arbitration or settlement procedure established in the procurement documents shall be followed. If no
arbitration or settlement procedure is established, then a procedure mutually agreeable to purchaser, material supplier, and contractor shall be used.
8.2 Samples of paints under this painting system may be requested by the purchaser and shall be supplied upon request along with the manufacturer’s name and identiﬁcation for the materials. Samples may be
requested at the time the purchase order is placed, or may be taken from unopened containers at the job site.
8.3 Unless otherwise speciﬁed, the sampling shall be in accordance with ASTM D 3925.
9.1 While every precaution is taken to ensure that all information furnished in SSPC standards and speciﬁcations is as accurate, complete, and useful as possible, SSPC cannot assume responsibility nor incur any obligation resulting from the use of any materials, coatings, or methods speciﬁed herein, or of the speciﬁcation or standard itself.
9.2 This speciﬁcation does not attempt to address problems concerning safety associated with its use. The user of this speciﬁcation, as well as the user of all products or practices described herein, is responsible for instituting appropriate health and safety practices and for insuring compliance with all governmental regulations.
Notes are not a requirement of this speciﬁcation.
10.1 The procurement documents should establish the responsibility for samples, testing, and any required afﬁdavit certifying full compliance with the speciﬁcation.
10.2 The coatings listed in this speciﬁcation are compatible with one another.
10.3 This speciﬁcation applies to both new construction and maintenance painting.
10.4 Reference is made to MIL-P-24441, “Paint, Epoxy Polyamide, General Speciﬁcation for, designed for both fresh and salt water immersion service, where lead-free or higher ﬂash point epoxy paints are
required. MIL-P-24441 has been superseded by MIL-DTL-24441.
10.5 Alternate formulations to meet air pollution requirements and regulations shall pass the performance criteria of this speciﬁcation.
10.6 Other generic topcoats may be used for improved color and gloss retention.
10.7 Alternative two-coat system high-build can be used provided it meets the performance criteria in this speciﬁcation.
10.8 It is well recognized that epoxy polyamide systems are often applied over zinc-rich primers. This will result in superior long-term protection. However, the manufacturer’s instructions need to be followed for
the proper application technique. Such coating systems may also include an aliphatic urethane topcoat.
10.9 ALTERNATIVE FORMULATIONS: Salt fog exposure and other test requirements may be added as agreed upon in the contract.
Painting System No. 13.01 – Epoxy Polyamide Painting System