Accueil
Détail de l'auteur
Auteur Chrissy Stewart |
Documents disponibles écrits par cet auteur
Ajouter le résultat dans votre panier Affiner la recherche
Applying coatings outside of the recommended thickness range / Chrissy Stewart in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 31, N° 2 (02/2014)
[article]
Titre : Applying coatings outside of the recommended thickness range Type de document : texte imprimé Auteurs : Chrissy Stewart, Auteur ; Richard A. Burgess, Auteur Année de publication : 2014 Article en page(s) : p. 15-23 Langues : Américain (ame) Catégories : Analyse des défaillances (fiabilité)
Cahier des charges
Epaisseur -- Défauts
Revêtements -- Défauts:Peinture -- DéfautsIndex. décimale : 667.9 Revêtements et enduits Résumé : The manufacturer's Product Data Sheet (PDS) should always be consulted when recommending a coating or coating system for a specification or when coatings will be applied. The PDS typically contains information regarding appropriate uses and environments, performance characteristics, and application information, including mixing, application methods and equipment, and the recommended thickness range for the mate-rial. The information provided by the manufacturer should be followed closely to maximize performance of the coating material.
Coating materials are selected for application with a target application thickness in mind. The manufacturer's recommended range and the thickness indicated in the project specification should be in agreement. If a discrepancy exists, the specifier and the coating manufacturer should be contacted. When applied at the appropriate thickness, the physical and protective properties of the coating material are optimized. Often, a problem with coating performance can occur if not enough attention is given to the thickness at which the materials are to be applied.
This article will investigate the possible failure mechanisms that can occur if a coating is applied at insufficient or excessive thickness.Note de contenu : - INSUFFICIENT COATING THICKNESS
- CONSEQUENCES OF INSUFFICIENT COATING THICKNESS : Visibility of substrate - Pinpoint - Cracked, brittle coating
- CONSEQUENCES OF EXCESSIVE COATING THICKNESS : Sagging and running - Cracking and delamination - Wrinling - Increased dry time
- METHODS OF COATING THICKNESS MEASUREMENT : Took gage - Nondestructive coating thickness gage - Microscope equipped with scalePermalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21658
in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 31, N° 2 (02/2014) . - p. 15-23[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 16091 - Périodique Bibliothèque principale Documentaires Disponible Contradictory information in a project specification / Chrissy Stewart in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 33, N° 9 (09/2016)
[article]
Titre : Contradictory information in a project specification : coating failure on the interior of a wastewater digester Type de document : texte imprimé Auteurs : Chrissy Stewart, Auteur Année de publication : 2016 Article en page(s) : p. 20-25 Langues : Américain (ame) Catégories : Analyse des défaillances (fiabilité)
Eaux usées -- Stations de traitements
Expertises
Revêtements -- Défauts:Peinture -- Défauts
Revêtements protecteurs -- DétériorationIndex. décimale : 667.9 Revêtements et enduits Résumé : The wastewater industry poses some of the most significant corrosion protection challenges for industrial protective coatings. In this case study, coating failure in the form of peeling and delamination (on concrete) and blistering (on steel) was observed on the interior of a digester at a wastewater treatment facility after only five years of service. Removal of sludge from the digester revealed disbonded pieces of coating, which alerted the facility owner to the failure. Due to the relatively short period of coating performance and the importance of a properly protected substrate, an investigation into the cause of the premature coating failure was undertaken.
The digester consisted of a concrete shell with a steel skirt plate situated at the top of the shell. A steel dome was attached to the skirt plate. The specification indicated that the operating temperature of the digester ranges from 95-to-131 F, and that a single coat was to be applied at a dry film thickness (DFT) of 125 mils on the concrete and 60 mils on the steel substrates. The specification listed several polyurethane coating materials that were deemed suitable for this environment. The coating selected for installation was one of the materials listed in the specification. The manufacturer’s product data sheet (PDS) listed a maximum service temperature of 120 F for immersion service and 180 F for dry conditions.
Because the contents in the digester were composed of sludge from a wastewater treatment plant, the environment would be considered immersion. The sludge included a mixture of organic and inorganic solids, grit, grease, scum and industrial solvents. Reportedly, small quantities of hydrogen sulfide, hydrogen and nitrogen gases were likely to be present as well. The design engineer for the digester reported that the contents were uniformly mixed to maintain consistent pH and temperature throughout the digester. Since the time that the selected coating material had been applied, the pH readings were reasonably close to 8 and the temperature ranged from 122-to-126 F.Note de contenu : - Site investigation
- Laboratory investigation
- Summary of the site investigation and forensic evidence
- FIGURES : 1. Cross section of sample removed below operating level - 2. Cross-section of sample removed above operating levelEn ligne : http://www.paintsquare.com/archive/?fuseaction=view&articleid=5923 Format de la ressource électronique : Web Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=28391
in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 33, N° 9 (09/2016) . - p. 20-25[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 18361 - Périodique Bibliothèque principale Documentaires Disponible The missing piece / Chrissy Stewart in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 34, N° 12 (12/2017)
[article]
Titre : The missing piece : Collaborations between field investigators and laboratory chemists Type de document : texte imprimé Auteurs : Chrissy Stewart, Auteur Année de publication : 2018 Article en page(s) : p. 19-24 Langues : Américain (ame) Catégories : Analyse des défaillances (fiabilité)
Cloquage (défauts)
Délaminage
Expertises
Revêtements -- Défauts:Peinture -- DéfautsIndex. décimale : 667.9 Revêtements et enduits Résumé : Coating failure analysis draws many parallels to these shows. In fact, you can almost envision it: a camera pans over a work site, dramatic music plays as a water tank is being drained. The manway slowly swings open to reveal massive and extensive blistering of the newly applied interior coating system. The owner frantically calls to report the dire situation he has just discovered. Cut to opening credits.
The most dramatic moment of the show is usually when some small detail that had been previously overlooked is discovered. The breakthrough can come from the investigator, the laboratory, even someone with minimal involvement in the case — a taxi driver, or a neighbor with a different perspective of what all the information means.
This can often be said for coating failure investigations as well. The key to solving these cases is to combine all of the knowledge gained during the investigation and let the data tell the story.
The type of information that can be obtained from the field investigation is much different than the data produced by the lab. The field investigation gives the investigator the opportunity to make observations on and around the structure, observe for coating failure patterns, test adhesion to the substrate, inspect the surface profile, sift through paint cans, interview individuals on-site — simply, the field investigator takes a more hands-on approach. The laboratory investigation gives the added benefit of examining coating samples from the field using sophisticated analytical techniques to gain information that would not be readily obtained without the proper instrumentation.
Two different scenarios will be described, one a laboratory investigation without the benefit of direct field knowledge and one that combines both field and lab investigations.Note de contenu :
- SCENARIO #1 : Coating delamination in scrubber tower : Laboratory investigation
- FAILURE SCENARIO #2 : BLISTERING ON BRIDGE RAILINGS : Field and laboratory investigations
- FIGURES : 1. Glossy top surface of red primer - 2. Cross-section of gray topcoat separated from red primer - 3. Uneven appearance of red primer - 4. Blistered area prior to scraping - Fig. 5 : Blistered area after scraping to reveal a red layer beneath the gray - 6. Cross-section of blister capEn ligne : http://www.paintsquare.com/archive/?fuseaction=view&articleid=6215 Format de la ressource électronique : Web Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30359
in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 34, N° 12 (12/2017) . - p. 19-24[article]Réservation
Réserver ce document
Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité 19542 - Périodique Bibliothèque principale Documentaires Disponible