Introduction When applying coating system to structures such as bridges, tanks, and pipelines the main goal is to apply a continuous film to help prevent structural deterioration throughout the life of the structure. Unaddressed discontinuities can result in undercutting corrosion of the substrate, where the integrity of the structure could be prematurely compromised. This article […]
Holiday Detection and Dielectric Strength Issues Read More »
When a coating system fails prematurely, it is rarely because of the coating itself. Either the surface preparation was inadequate, the surface was contaminated, or the coating was mixed or applied incorrectly. As the old adage goes, a house is only as strong as the foundation it is built on. When it comes to coatings,
What is a “Dust-Free Surface?” ISO Method Versus Practical Evaluation Read More »
ANSI/ASHRAE/IES Energy Standard 90.1-2010 and the 2012 International Energy Conservation Code require that building envelopes be designed to limit uncontrolled air leakage into and out of buildings. Air leakage in buildings is controlled at the time of construction by installing air barrier systems. ASTM E1186-17, “Standard Practices for Air Leakage Site Detection in Building Envelopes
Localized Assessment of Air Leakage in Building Air Barriers Read More »
Introduction Adhesion is an important physical characteristic of applied coating films and systems, and testing is frequently used as an indicator to whether an adequate bond exists between the substrate and primer (first coat) and/or between coats in multiple coat applications. Adhesion testing may be a requirement of a coating specification, or may be used
Coating Adhesion Testing using Knife/Tape Methods Read More »
Background/Introduction The AASHTO/AWS D1.5M/D1.5 Bridge Welding Code: 2015 published by the American Welding Society (AWS) covers the welding requirements for The American Association of State and Highway Transportation Officials (AASHTO) welded highway bridges fabricated from carbon and low-alloy constructional steels. This code covers welding fabrication requirements applicable to welded highway bridges. The code is applicable
Changes to the 2015 Edition of the AASHTO/AWS D1.5 Bridge Welding Code Read More »
Introduction Surface profile is defined as a measurement of the maximum peak-to-valley depth generated by abrasive blast cleaning and impact-type power tools. These operations effectively increase the surface area and provide an “anchor” for the applied coating system. The surface profile depth must be compatible with the total coating system thickness; typically, the thicker the
Surface Profile Measurement Options on Rough/Pitted Steel Surfaces Read More »
This Month’s Case Was Selected From Several Investigations Related To Failures That Occur When Applying Coating To The Underside Of Metal Deck Panels (Fig. 1). This Case Focuses On An Adhesion Failure Of Coatings Applied To Previously Painted Deck Panels. A paint contracting company was hired to apply an epoxy ester dry-fall coating to portions
Introduction Coating specifications and contract documents often contain stipulations for the maximum length of time a prepared steel surface can remain uncoated. We’ll refer to this as the “prep-to-prime window.” This brief article highlights common requirements, discusses the purpose of the requirements, presents industry references, questions the variability in the time periods, and explores a
Window of Time – Surface Preparation to Priming Read More »
Introduction Coating thickness measurement is one of the most common quality assessments made during industrial coating applications. SSPC-PA 2, Procedure for Determining Conformance to Dry Coating Thickness Requirements is frequently referenced in coating specifications. As SSPC-PA 2 has evolved over the past four decades, a number of procedures and measurement frequencies are referenced in both
Using Scanning Probe Technology to Measure Coating Thickness Read More »
Chemical contaminants on a surface can include chlorides, ferrous ions, sulfates and nitrates, among other types of soluble salts. Chloride may come from deicing materials or marine/coastal environments, ferrous ions are a by-product of corrosion, sulfates can be airborne, particularly in industrial environments (e.g., coal-fired power plants) and nitrates may come from the soil (e.g.,
Surface Soluble Salt Measurement – Conductivity Verses Ion-specific Methods of Analysis Read More »
