Steel Joist Shop Primer/Metal Building Primer

Applying Steel Joist Shop Primer/Metal Building Primer

PAINT SPECIFICATION NO. 15 – Steel Joist Shop Primer/Metal Building Primer

1. Scope
1.1 This specification covers a one coat shop-applied primer for open web and long span steel joist and joist girders and for cold formed steel framing, and primary and secondary structural framing for metal buildings. This coating is intended to provide temporary protection to the steel joist during delivery, storage on site, and erection in an atmosphere comparable with SSPC Environmental Zone 1, normally dry. This coating is intended to be used as a holding primer that may or may not be removed before or after erection or assembly in the field.

1.2 The specification does not address the formulation of the coating but covers the physical and performance char­acteristics of the coating.

2. Description
2.1 COMPOSITION:
2.1.1 Wide latitude is given for the composition of the primer coating. The formulation will be agreed upon between the contracting parties, so that the coating is compatible with the owner’s facility and processes, while meeting or exceeding the performance requirements of this specification.
2.1.2 This specification will cover all generic classes of coatings.
2.2 VOLATILE ORGANIC COMPOUND (VOC) REQUIREMENTS:
2.2.1 The VOC content of a merchantable coating meet­ing the compositional and performance requirements of this specification can vary from less than 60 g/L to over 420 g/L.
2.2.2 The specifier should consult applicable government regulations to determine the maximum allowable VOC content and the proper VOC test method for their application. As a part of the purchase documents, the specifier should state the required VOC limit, test method, and governing regulations. (See Note 11.1.)

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. Standards marked with an asterisk (*) are referenced only in the Notes, which are not requirements of this specification.

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:

3.4 ASTM INTERNATIONAL STANDARDS:
A 36 Specification for Carbon Structural Steel
B 117 Practice for Operating Salt Spray (Fog) Apparatus
D 562 Test Method for Consistency of Paints Measuring Krebs Units (KU) Using a Stormer-type Viscometer
D 714 Test Method for Evaluating Degree of Blis­tering of Paints
D 1200 Test Method for Viscosity by Ford Viscosity Cup
D 1308 Test Method for Effect of Household Chemicals on Clear and Pigmented Organic Finishes
D 1475 Test Method for Density of Liquid Coatings, Inks, and Related Products
D 1654 Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments
D 2243 Test for Freeze-Thaw Resistance of Water-Borne Coatings
D 3359 Test Methods for Measuring Adhesion by Tape Test
D 3363 Test Method for Film Hardness by Pencil Test
D 3924 Specification for Standard Environment for Conditioning and Testing Paint, Varnish, Lacquer, and Related Materials
D 3925 Practice for Sampling Liquid Paints and Related Pigmented Coatings
*D 3960 Practice for Determining Volatile Organic Compound (VOC) Content of Paints and Related Coatings
D 4062 Test Method for Leveling of Paints by Draw-Down Method
D 4585 Practice for Testing Water Resistance of Coatings Using Controlled Condensation
D 5894 Practice for Cyclic Fog/UV Exposure of Painted Metal, (Alternating Exposures in a Fog/Dry Cabinet and UV/Condensation Cabinet)

3.5 BAY AREA AIR QUALITY MANAGEMENT DISTRICT (BAAQMD)
* METHOD 41 Determination of Volatile Organic Compounds in Solvent Based Coatings and Related Materials Containing Parachloro­benzotrifluoride

4. Standard Testing Conditions
4.1 When testing the paint and its application, the condi­tions under which it is applied and cured shall conform to ASTM D 3924.
4.2 The hot rolled steel test panels shall conform to ASTM A 36 or equivalent.  Prior to preparing the surface, the amount of rust and mill scale on the surface shall conform to Condi­tion A or Condition  B as described in SSPC-VIS 1. Panel size shall be 100 mm x 150 mm x 4.8 mm (4 in x 6 in x 3/16 in) or greater.
4.3 Surface preparation shall consist of SSPC-SP 1 and SSPC-SP 2.
4.4 The dry film thickness of the primer shall be as recom­mended by the manufacturer. If no recommendation is given, the dry film thickness shall be a minimum of 20 micrometers
(0.8 mils) unless indicated otherwise. Measure dry fi lm thick­ness in accordance with SSPC-PA 2.
4.5 All coated panels to be tested will be allowed to cure for a minimum of seven days under ambient laboratory condi­tions before physical testing is to begin.

5. Physical Properties
5.1 TEST INFORMATION: The paint manufacturer shall measure and record batch testing information that will allow certification that a batch meets the necessary standards established by the manufacturer for the primer as tested per Section 5.
5.2 CONDITION IN CONTAINER: Each component as received shall show no evidence of livering, skinning, or hard settling of the pigment. The inside of the container shall not be corroded. Multi-component material shall be easily dispersed in the liquid portion by hand stirring to form a smooth, homo­geneous primer.
5.3 COLOR: There is no color requirement; however, color will be agreed upon between the contracting parties or be the color of the sample submitted under Section 9.2.
5.4 VISCOSITY: The viscosity of the stirred primer shall be determined in accordance with ASTM D 562.  Variance of viscosity measured in KU shall be within 12 percent of the viscosity of the previously qualified coating and the value published by the manufacturer (e.g., technical data sheet or container label). For viscosities lower than 55 KU, a number 4 Ford Cup shall be used in accordance with ASTM D 1200.  Variations shall be within five seconds of the previously qualified coating. The contracting parties may agree to different variances.
5.5 DENSITY: Density of the mixed primer shall be determined in accordance with ASTM D 1475.  Variance shall be within ± 48 g/L (0.4 lb/gal) of the sample submitted under Section 9.2.
5.6 FREEZE-THAW RESISTANCE (WATER-BORNE COATINGS ONLY): The liquid (water base) coating shall be tested in accordance with ASTM D 2243.  At the end of three cycles there shall be no gelling or excessive thickening, co­agulation, lumps, or coarse particles. The maximum increase or decrease in viscosity shall not exceed 10 Krebs units.

6. Performance Testing Requirements
6.1 RUST AND BLISTER RESISTANCE:
6.1.1 Test Panel Preparation: Apply one coat of the steel joist shop primer to the front of nine steel panels in accordance with the standard testing conditions specified in Section 4. Coat and seal all edges and the back side of each panel with a coating or masking that will provide the necessary protection to these surfaces. Scribe a 5 cm (2 inch) vertical line through the lower middle portion of the primed panels so as to expose the underlying metal before testing. The conditions of making the scribe are described in ASTM D 1654.
6.1.2 Salt Spray: Three replicate panels shall be exposed in a salt spray conducted in accordance with ASTM B 117. The duration of the test shall be 96 hours. The rust rating of each replicate panel shall be 8 or higher according to SSPC-VIS 2 (see Note 11.2). The blister rating of each panel shall be no worse than No. 4 “Few,” No. 6 “Medium,” or No. 8 “Medium Dense” using ASTM D 714 (see Note 11.3). The maximum undercutting or rusting measured from the center of the scribe of each replicate panel shall not exceed 3.2 mm (1/8 inch) at any point along the scribe (see Note. 11.4).
6.1.3 Cyclic Salt Fog/UV Exposure: Three replicate panels shall be exposed in a cyclic corrosion test conducted in accordance with ASTM D 5894. The duration of the test shall be 336 hours that represent one week of UV/condensation followed by one week of cyclic salt fog. The rust rating of each replicate panel shall be 8 or higher according to SSPC-VIS 2. (see Note 11.2). The blister rating of each panel shall be no worse than No. 4 “Few,” No. 6 “Medium,” or No. 8 “Medium Dense” using ASTM D 714 (see Note 11.3). The maximum undercutting or rusting measured from the center of the scribe of each replicate panel shall not exceed 3.2 mm (1/8 inch) at any point along the scribe.
6.1.4 Condensation: Three replicate panels shall be exposed in a condensing cabinet according to ASTM D 4585, continuous condensation at 38°C (100°F) for a duration of 96 hours. The rust rating of each replicate panel shall be 8 or higher according to SSPC-VIS 2. (see Note 11.2). The blister rating of each panel shall be no worse than No. 6 “Few” or No. 8 “Medium” using ASTM D 714. (see Note 11.3). The maximum undercutting or rusting measured from the center of the scribe of each replicate panel shall not exceed 3.2 mm (1/8 inch) at any point along the scribe.
6.2 ADHESION: Apply one coat of the steel joist shop primer to the front of a steel panel in accordance with the standard testing conditions specified in Sections 4.1 through 4.4. After seven days, apply a second coat under similar conditions. Allow the second coat to cure for a minimum of seven days under ambient laboratory conditions before physical testing is to begin. Evaluate adhesion to the base metal as well as between coats using ASTM D 3359, Method B “Cross-Cut Tape Test,” spacing the cuts 1 mm apart. A minimum rating of 4B is required (see Note 11.5).
6.3 WATER SENSITIVITY: Apply one coat of the steel joist shop primer by the drawdown method (ASTM D 4062) to a 100 mm x 200 mm (4 x 8 in) cold-rolled steel panel in accordance with Sections 4.1 and 4.4. Allow to dry at 21 to 25°C (70 to 77°F) and 50% ± 5% relative humidity. After 24 hours drying time, subject the coating to a water spot test for four hours in accordance with ASTM D 1308, using the open spot test and 2 to 3 ml of potable water. No blistering shall occur. The film may soften, but film integrity shall return after a 24 hour recovery period. Film integrity is defi ned as losing no more than one pencil hardness unit (ASTM D 3363) compared to the unexposed film.
6.4 FLASH RUST RESISTANCE TEST (WATERBORNE COATINGS ONLY): Coat a hot rolled steel panel blast cleaned to SSPC-SP 6 or better in accordance with Sections 4.1, 4.2, and 4.4. Allow to dry for 24 hours. The coatings shall show no signs of flash rusting or bleeding.

7. Application
7.1 Coatings can be formulated for dip, flow coat, vacuum coat, airless, air atomized, brushed, or rolled application.

8. Labeling
8.1 Labeling shall conform to ANSI Z129.1.
8.2 Technical data shall be provided for at least all data elements characterized as “essential” in SSPC-Guide 13.

9. Inspection
9.1 All materials (coatings) supplied under this specifi­cation are subject to timely inspection by the purchaser or his authorized representative. The purchaser shall have the right to reject any materials supplied which are found to be defective under this specification (see Note 11.6). In case of dispute, unless otherwise specified, the arbitration or settle­ment procedure established in the procurement documents shall be followed. If no arbitration procedure is established, then a procedure mutually acceptable to the purchaser and material supplier shall be used.
9.2 Samples of paints 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.
9.3 Unless otherwise specified, the sampling shall be in accordance with ASTM D 3925.

10. Disclaimer
10.1 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 specifi ed herein, or of the specification or standard itself.
10.2 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 ensuring compliance with all governmental regulations.

11. Notes
Notes are not requirements of this specification.
11.1 ASTM D 3960 is a commonly used method to de­termine VOC, but this method may not be acceptable to all jurisdictions. The method of determining VOC content described in ASTM D 3960 does not address analysis of VOC exempt solvents such as PCBTF (parachlorobenzotriflouride).  Methods published by government agencies include Bay Area Air Quality Management District (BAAQMD) Method 41 and California Air Resources Board (CARB) Method 310.
11.2 A rust grade rating of 8 or better implies that no more than 0.1% of the surface area shall be rusted.
11.3 According to ASTM D 714, ratings that would be considered better than No. 4 “Few,” No. 6 “Medium,” and No. 8 “Medium Dense” would include No. 6 “Few,” No. 8 “Medium,” No. 8 “Few,” and No. 10 (no blisters).  Interpolated ratings not pictured in ASTM D 714 that would be considered better than No. 4 “Few,” No. 6 “Medium,” and No. 8 “Medium Dense” would include No. 5 “Few,” No. 7 “Medium,” No. 7 “Few,” No. 9 “Medium Dense,” No. 9 “Medium,” and No. 9 “Few.” In general, a higher number (smaller size) blister is considered better that a lower number blister of the same frequency.  Similarly, for a given size, fewer blisters are better.
11.4 The salt fog test, ASTM B 117, has been widely discredited as a method for evaluating paints. There have been many comparative paint studies using widely different formulations which showed no correlation and even negative correlation between salt fog results and atmospheric exposure results. There is a significant risk that a good coating can be rejected based on salt fog performance. Cyclic salt fog/UV exposure, ASTM D 5894, has been shown to have much better correlation with atmospheric exposures.
11.5 The adhesion test described in Section 6.2 is to prevent coating manufacturers from adding wax or other ad­ditives that would severely limit the adhesion of a subsequent coating layer.
11.6 The procurement documents should establish the responsibility for samples, testing, documentation of perfor­mance tests and results and any required affidavit certifying full compliance with the specification.

PAINT SPECIFICATION NO. 15 – Steel Joist Shop Primer/Metal Building Primer