814Painting Metal Structures

814.01 Description. This work consists of furnishing all materials and painting of metal

structures. It shall include, unless otherwise provided in the contract, the preparation of metal surfaces, application, protection and drying of the paint coatings, supplying of all tackle, scaffolding and other essentials necessary to complete the work in reasonably close conformity with the specifications and as indicated on the plans. The Coating System will consist of one shop coat of inorganic zinc, one field intermediate coat of acrylic latex and one field top coat of acrylic latex. The shop coat, field intermediate coat and top coat shall each have a dry film thickness of not less than 3 mils or more than 5 mils. Touch-up paint for field repair of damaged areas in the inorganic zinc shop coat shall consist of epoxy mastic applied to a uniform dry film thickness of not less than 4 mils nor more than 6 mils.

814.02 Materials.

814.02.1 Shop Coat. Paint for the shop or prime coat shall be an inorganic zinc primer

and meet the requirements of Subsection 710.03.

814.02.2 Acrylic Latex Intermediate Coat. Paint for the acrylic latex intermediate field

coat shall meet the requirements of Subsection 710.03.

814.02.3 Acrylic Latex Top Coat. Paint for the acrylic latex top field coat shall meet the

requirements of Subsection 710.03.

814.02.4 Epoxy Mastic Touch-Up Paint . Field touch-up paint for repair of damaged

inorganic zinc shop coat shall meet the requirements of Subsection 710.03.

814.03 Construction Requirements.

814.03.1 Mixing of Paint. All paint shall be mixed in accordance with the manufacturer's

printed instructions.

814.03.2 Weather Conditions. Solvent base paint shall not be applied when the

surrounding air temperature is below 40°F. Waterborne paint shall not be applied when the surrounding air temperature is below 50 °F. Paint shall not be applied when the surrounding air temperature is expected to drop to 32°F prior to drying of the paint. Paint shall not be applied when the metal is hot enough to cause blistering or produce a porous film. Paint shall not be applied when the steel surface is less than 5°F above the dew point nor shall it be applied in rain, snow, wind, fog, mist or when, in the opinion of the Engineer, conditions are otherwise unsatisfactory for the work.

814.03.3 Application.

814.03.3 1--Shop Coat. The coating shall be capable of being applied in accordance with

specification requirements and shall be app lied in accordance with the manufacturer's printed instructions. After initial mixing, the paint shall be strained through a metal 30-60 mesh screen. Stirring paddles on the mechanical mixing equipment shall reach to within one inch of the bottom of the paint container. Airless spray equipment for application of inorganic zinc silicate paint shall provide pressure of not less than 2200 psi at the nozzle. The fluid hose between the pot and nozzle shall not be less than 3/8-inch inside diameter. Pressure may vary depending on tip size and pump. Conventional spray equipment for application of inorganic zinc silicate paint shall provide pressure of not less than 10 psi at the pot and 30 psi at the nozzle.

814.03.3 2--Acrylic Latex Intermediate and Top Coats. All applications of the acrylic

latex intermediate and top coats shall be in accordance with the manufacturer's printed instructions. The primer coat and the intermediate coat sh all have dried a minimum of eight hours under normal conditions prior to application of the intermediate and top coats, respectively. All surfaces shall be free of any soluble residue and surfaces on which the primer coat has been applied shall be free of excessive amounts of loose zinc before a subsequent coat is applied. Dust and dirt that may have accumulated on the surface shall be removed from the dried film with a soft brush or rag before application of a subsequent coat. When applied by brushing or spraying, the coating shall deposit a uniform dry film thickness without running or sagging.

814.03.4 Removal of Paint. If any painting is unsatisfactory, it shall be removed and the

metal thoroughly cleaned and repainted.

814.03.5 Thinning Paint. Paint shall be thinned only in strict accordance with the

manufacturer's recommendations.

814.03.6 Painting Galvanized Surfaces. Prior to application of the acrylic latex field

coats, galvanized surfaces shall be primed with Epoxy Mastic Touch-Up Paint as specified in Subsection 814.02.

814.03.7 Cleaning of Surfaces. Surfaces to be painted sh all be thoroughly cleaned,

removing rust, loose mill scale, dirt, oil or grease and other foreign substances. All exposed and accessible surfaces of the me tal shall be cleaned by sandblasting in accordance with the requirements of Steel Structures Painting Council SSPC-SP-10, Near White Blast Cleaning. The surface, regardless of starting condition, shall in the opinion of the Engineer or the Engineer’s designated representative be at least equal to the appearance of Pictorial Swedish Standard Sa 2 1/2 of SIS 05 59 00, SSPC-VIS 1. All rust blooms shall be removed by re-blas ting before coating. The surface shall be constantly and diligently examined ahead of the coating operations for an y traces of rust, oil, grease or blemishes not permitted by the blast cleaning specifications.

814.03.8 Shop Painting. Unless otherwise specified, the shop coat shall be applied

immediately after the steel work has been accepted by the inspector. Shop contact surfaces shall not be painted. Field contact surfaces except for machine finished pins and holes shall receive a shop coat with a minimum dry film thickness of 1½ mils. All other surfaces that will be inaccessible after assembly or erection shall be given all required coats. Surfaces that will be embedded or in contact with concrete shall not require painting unless otherwise noted on the plans. They may be painted in whole or in part due to overspray provided the paint thickness does not exceed the requirements specified for adjacent areas. Structural steel that is to be field welded shall not be shop painted within two inches of the field welds. All surfaces of iron and steel castings except for machine finished pins and holes, shall be given two shop coats of paint. Erection marks for field identification of me mbers and weight marks shall be painted on areas previously painted with the shop coat. Material shall not be loaded for shipment until it is thoroughly dry and no sooner than 24 hours after the paint has been applied.

814.03.9 Field Painting. When the erection work is complete, including all bolting and

straightening of bent metal, all rust, scale, dirt, grease and other foreign material shall be removed. As soon as the Engineer has approved all field welding and bolting, the surfaces from which the shop coat of paint has worn off or otherwise become defective shall be cleaned and re- primed with the specified touch-up paint prior to application of the intermediate coat. Spans with concrete decks shall not be painted until after the deck is placed. All concrete spills and stains shall be washed from the structural steel prior to the mortar taking a set. Surfaces to be bolted in contact and surfaces that will be in contact with concrete shall not have a field coat applied. When the paint applied for retouching the shop coat has thoroughly dried and the field cleaning has been satisfactorily completed, the intermediate coat shall be applied. After the intermediate coat has thorough dried, the top coat shall be applied. In no case shall a subsequent coat be applied until the pr evious coat has dried throughout the full thickness of the paint film. To secure a maximum coating on edges of pl ates or shapes, bolt heads and other parts subjected to special wear and attack, the edges shall be stripped with a longitudinal motion and bolt heads with a rotary motion of the brush followed immediately by the general painting of the whole surface, including recoating of the edges and bolt heads. If, in the opinion of the Engineer, traffic produces an objectionable amount of dust, the Contractor shall, at no additional cost to the State, allay the dust for the necessary distance on each side of the bridge and take any other precautions necessary to prevent dust and dirt from coming in contact with freshly painted surfaces or surfaces prepared for painting. The Contractor shall protect pedestrian, vehicular and other traffic upon or underneath the bridge and also all portions of the bridge superstructure and substructure against damage