Structural steel painting
Content
Primer coat – Epoxy zinc – Phosphate 125 micron Prime coat is used to promote adhesion of certain one-part silicone sealants and coatings to a variety of construction materials such as ply wood masonry and metal. In most cases, when one coat of manufacturer’s prime paint is specified, it must be assumed that some rusting will occur if the product is exposed to moisture. The extent of the rusting is dependent on the length of time that the deck is exposed to the elements. “A common mistake in steel roof deck specifications is how finishes are specified. The manufacturer’s standard finish is a primer coat of paint applied over clean, bare steel. This primer coat is less expensive than galvanized coating and will serve the purpose for most projects. The primer paint is intended to provide a base for a finish coat and is not weather resistant for a long time. If the insulation and roofing are going to be applied quickly, then the primer coat will be sufficient.”12 (The Construction Specifier, November 1991, reprinted with permission.) Selecting a Protective Coating The life of any protective coating depends largely upon the corrosion condition to which it is exposed. Therefore, it is essential to define the environment in which the steel deck is to function before selecting a protective coating. Steel deck serves multiple functions during and after construction and is subjected to two different environments, one on the top surface and one on the bottom. A list of the wide range in environmental exposures has been provided by the Steel Structural Painting Council (SSPS).17 (See Appendix B). The Canadian Sheet Steel Building Institute indicates in its June 1991 Newsletter that its product standards have consistently called for the following: “...a minimum zinc coating...on steel exposed to the interior environment of a building conditioned for human comfort.”23 The most important factors controlling the rate at which zinc corrodes in atmospheric exposures are the duration and frequency of moisture contact, the rate at which the surface dries, and the extent of industrial pollution in the atmosphere. The life of zinc coatings in rural districts is four to ten times that of the same coatings in industrial districts. There are a number of benefits in selecting multiple films. This allows a corrosion-resistant primer to be top-coated with a low-pigment color paint film. The top coat can be chosen to resist weathering or other corrosive environments without concern for its ability to adhere to the metal as long as it adheres to the prime coat. The requirements of the top coat interacting with its environment is different than the requirements of the prime coat interacting with the metal (Figure 5 below shows additional benefits).33 The primary concern was corrosion caused to carbon steel equipment due to wet insulation. None of the experts suggested that galvanized or Galvalume coatings would prevent corrosion in a wet
insulation environment. On the contrary, there was a strong suggestion that zinc coatings are a poor choice, and that non-zinc paint films are a better choice.
He makes the statement, “Finally, many coatings depend on some form of sacrificial inhibitor or are essentially only that (for example inorganic zinc rich coatings). Zinc rich coatings have given extremely poor performance in our plants under insulation.” He gives the following reasons for the poor performance: 1. “There is the possibility of reversal in the polarity of galvanic couples, with increasing temperature. 2. Salts carried in and deposited with the water interfere with or destroy the effectiveness of the inhibitors. 3. The sub insulation environment is not freely ventilated and may not have adequate oxygen or carbon dioxide for film forming reactions to occur.”
Fire Retardant Paints are especially formulated with silicone and polyvinyl chloride or other substance to reduce the flame spread of a combustible material. Heat Resistant Paints are specially formulated w/ silicone resins to withstand high temperatures Intumescent Coatings, when exposed to the heat of a fire, swell to form a thick insulating layer of inert foam that retards flame spread and combustion. Metal surfaces: All metal surfaces must be cleaned and dry Remove any rust, mill scale or loose paint by wire brushing, sandblasting/sandpapering. Bare spots on shop-coated steel must be wire- brushed and spot primed. Remove oil and grease with paint thinner or mineral spirits. No priming necessary when applying exterior latex to weathered galvanized metal. SURFACE PREPARATION (Exterior): The surface to be painted must be clean and free of wax, dirt or grease Cracks and holes must be repaired with patching plaster Patched areas must be spot primed Old glossy surfaces should be prepared by sanding SURFACE PREPARATION (Interior): Avoid painting in the hot sun. Try to paint those surfaces that have already been exposed to sunlight Apply a coat of paint primer Finish with two-coat of top coats
PAINT DEFECTS (Exterior): Dirt Pickup: Accumulation of dirt, dust particles and/or other debris on the paint film; may resemble mildew. PAINT DEFECTS (Exterior): Possible Causes:
Use of low quality paint, esp. lower grades of satin/semi-gloss Soil splashing onto siding. Air pollution, car exhaust and flying dust collecting on house body and horizontal trim.
Solution:
Wash off all surface dirt before priming and painting. If unsure whether the problem is dirt/mildew, conduct a simple spot test. Clean off dirt with a scrub brush and detergent solution, followed by a thorough rinsing with a garden hose. While dirt pickup can't be eliminated entirely, top quality exterior latex paints typically offer superior dirt pickup resistance & washability. Also, higher gloss paints are more resistant to dirt pickup than flat paints, which are more porous and can more easily entrap dirt.
Barrier coat – Epoxy MIO 100 micron Finish – Polyurethane 75 micron
HAZARDS IDENTIFICATION
EFFECT OF OVER EXPOSURE • Inhalation : Vapour or mist can irritate the nose, throat and lungs and cause headache & nausea. • Skin Contact : Irritating to skin upon repeated or prolonged contact. • Eye Contact : Moderately irritating to eyes. FIRST-AID MEASURES • Inhalation : Move subject to fresh air. • Eye & Skin Contact : Flush eyes with a large amount of water for at least 15 minutes. Consult a physician, if irritation persists. • Ingestion : If swallowed, dilute by giving two glasses of water or drink. Consult a physician. Never give anything by mouth to an unconscious person. SECTION-5 FIRE FIGHTING MEASURES • Flash Point : > 40°C • Auto Ignition Point : Data not available • Lower Explosion Limit (%) : 1 % • Upper Explosion Limit(%) : 6 % • Unusual Fire & Explosion Hazards : Flamability rating 2 (moderate)
ƒ Nepa Harard Signals : Health - 1 Flammability - 2 Reactivity - 0 • Hazardous Decomposition : Oxides of Carbon & Nitrogen Products • Extinguishing Media : Carbon Dioxide, Dry Chemical Foam and/or water Fog Fire fighters must wear self-contained Breathing apparatus or air masks. Containers exposed to fire should be Kept cool with water spray. SECTION-6 ACCIDENTAL RELEASE MEASURES • Steps to be taken in case material is released or spilled
Keep spectators away. Floor may be slippery, use care to avoid falling. Dike and contain spill with inert material (e.g. sand, earth). Transfer liquid to containers for recovery or disposal and solid diking material to separate containers for disposal. Keep spills and cleaning run-offs out of municipal sewers and open bodies of water. SECTION-7 HANDLING AND STORAGE Store in cool, clean , ventilated, fire proof area. Keep away from heat, sparks, open flames & incompatible materials. Protect containers against physical Damage . Keep containers closed when not in use. Empty containers may contain product residue including flammable vapours. SECTION-8 EXPOSURE CONTROLS / PERSONAL PROTECTION • Ventilation Type : Sufficient ventilation in volume and pattern should be provided to keep air contaminant concentration below WES/TWA limits. • Respiratory Protection : Class AUS 1 half face respiratory with Type-A Organic vapour filter and class P-1 Particulate filter. • Protective Gloves : Gloves of Neoprene or Nitrile rubber. • Eye Protection : SECTION-9 PHYSICAL &CHEMICAL PROPERTIES (AS PER LAB REPORT). • Appearance : Smooth & uniform liquid • Odour : Mild odour • Flash Point : Above 22°C Solvent resistant safety eye wear.
insulation environment. On the contrary, there was a strong suggestion that zinc coatings are a poor choice, and that non-zinc paint films are a better choice.
He makes the statement, “Finally, many coatings depend on some form of sacrificial inhibitor or are essentially only that (for example inorganic zinc rich coatings). Zinc rich coatings have given extremely poor performance in our plants under insulation.” He gives the following reasons for the poor performance: 1. “There is the possibility of reversal in the polarity of galvanic couples, with increasing temperature. 2. Salts carried in and deposited with the water interfere with or destroy the effectiveness of the inhibitors. 3. The sub insulation environment is not freely ventilated and may not have adequate oxygen or carbon dioxide for film forming reactions to occur.”
Fire Retardant Paints are especially formulated with silicone and polyvinyl chloride or other substance to reduce the flame spread of a combustible material. Heat Resistant Paints are specially formulated w/ silicone resins to withstand high temperatures Intumescent Coatings, when exposed to the heat of a fire, swell to form a thick insulating layer of inert foam that retards flame spread and combustion. Metal surfaces: All metal surfaces must be cleaned and dry Remove any rust, mill scale or loose paint by wire brushing, sandblasting/sandpapering. Bare spots on shop-coated steel must be wire- brushed and spot primed. Remove oil and grease with paint thinner or mineral spirits. No priming necessary when applying exterior latex to weathered galvanized metal. SURFACE PREPARATION (Exterior): The surface to be painted must be clean and free of wax, dirt or grease Cracks and holes must be repaired with patching plaster Patched areas must be spot primed Old glossy surfaces should be prepared by sanding SURFACE PREPARATION (Interior): Avoid painting in the hot sun. Try to paint those surfaces that have already been exposed to sunlight Apply a coat of paint primer Finish with two-coat of top coats
PAINT DEFECTS (Exterior): Dirt Pickup: Accumulation of dirt, dust particles and/or other debris on the paint film; may resemble mildew. PAINT DEFECTS (Exterior): Possible Causes:
Use of low quality paint, esp. lower grades of satin/semi-gloss Soil splashing onto siding. Air pollution, car exhaust and flying dust collecting on house body and horizontal trim.
Solution:
Wash off all surface dirt before priming and painting. If unsure whether the problem is dirt/mildew, conduct a simple spot test. Clean off dirt with a scrub brush and detergent solution, followed by a thorough rinsing with a garden hose. While dirt pickup can't be eliminated entirely, top quality exterior latex paints typically offer superior dirt pickup resistance & washability. Also, higher gloss paints are more resistant to dirt pickup than flat paints, which are more porous and can more easily entrap dirt.
Barrier coat – Epoxy MIO 100 micron Finish – Polyurethane 75 micron
HAZARDS IDENTIFICATION
EFFECT OF OVER EXPOSURE • Inhalation : Vapour or mist can irritate the nose, throat and lungs and cause headache & nausea. • Skin Contact : Irritating to skin upon repeated or prolonged contact. • Eye Contact : Moderately irritating to eyes. FIRST-AID MEASURES • Inhalation : Move subject to fresh air. • Eye & Skin Contact : Flush eyes with a large amount of water for at least 15 minutes. Consult a physician, if irritation persists. • Ingestion : If swallowed, dilute by giving two glasses of water or drink. Consult a physician. Never give anything by mouth to an unconscious person. SECTION-5 FIRE FIGHTING MEASURES • Flash Point : > 40°C • Auto Ignition Point : Data not available • Lower Explosion Limit (%) : 1 % • Upper Explosion Limit(%) : 6 % • Unusual Fire & Explosion Hazards : Flamability rating 2 (moderate)
ƒ Nepa Harard Signals : Health - 1 Flammability - 2 Reactivity - 0 • Hazardous Decomposition : Oxides of Carbon & Nitrogen Products • Extinguishing Media : Carbon Dioxide, Dry Chemical Foam and/or water Fog Fire fighters must wear self-contained Breathing apparatus or air masks. Containers exposed to fire should be Kept cool with water spray. SECTION-6 ACCIDENTAL RELEASE MEASURES • Steps to be taken in case material is released or spilled
Keep spectators away. Floor may be slippery, use care to avoid falling. Dike and contain spill with inert material (e.g. sand, earth). Transfer liquid to containers for recovery or disposal and solid diking material to separate containers for disposal. Keep spills and cleaning run-offs out of municipal sewers and open bodies of water. SECTION-7 HANDLING AND STORAGE Store in cool, clean , ventilated, fire proof area. Keep away from heat, sparks, open flames & incompatible materials. Protect containers against physical Damage . Keep containers closed when not in use. Empty containers may contain product residue including flammable vapours. SECTION-8 EXPOSURE CONTROLS / PERSONAL PROTECTION • Ventilation Type : Sufficient ventilation in volume and pattern should be provided to keep air contaminant concentration below WES/TWA limits. • Respiratory Protection : Class AUS 1 half face respiratory with Type-A Organic vapour filter and class P-1 Particulate filter. • Protective Gloves : Gloves of Neoprene or Nitrile rubber. • Eye Protection : SECTION-9 PHYSICAL &CHEMICAL PROPERTIES (AS PER LAB REPORT). • Appearance : Smooth & uniform liquid • Odour : Mild odour • Flash Point : Above 22°C Solvent resistant safety eye wear.
