Latest Publications

Description Category Date Author
Changes to specifying inorganic zinc silicates to AS/NZS 2312

Australian/ New Zealand Standard AS/NZS 2312 Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings provides guidelines for selection and specification of coating systems for co...

CTG1009.pdf
Coatings 29/04/2016 Kevin Cowie
Paint Coating Selection and Specification: Changes to AS/NZS 2312

Australian/ New Zealand Standard AS/NZS 2312 Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings provides guidelines for selection and specification of coating systems for corrosion pr...

CTG1008.pdf
Coatings 23/02/2016 Kevin Cowie
Galvanic/Dissimilar Metal Corrosion

Galvanic corrosion is the additional corrosion that occurs when dissimilar metals are in contact in the presence of an electrolyte. The corrosion of a metal, the anode, results from the positive current flowing from the anode to the less re...

CTG1007.pdf
Coatings 20/09/2010 Kevin Cowie
Steel Corrosion Rates in Water and Soil

Guidance on typical corrosion steel rates in water and soil for design use is provided in the recently published NZS3404.1 Steel Structures Standard - Materials, Fabrication, and Construction (SNZ,2009). The design rates given are those to ...

CTG1006.pdf
Coatings 20/10/2009 Kevin Cowie
Primers for Steel: Their Purpose and Performance

This article addresses some problems that can occur when primers are incorrectly specified, and examines some misconceptions on their expected performance. Costly remedial rework can be incurred if a shop primer is damaged or exposed to ext...

CTG1005.pdf
Coatings 12/02/2009 Michael Williams
Durability of Attachments to Glass-Fibre Reinforced Concrete Panels

Glass-fibre reinforce concrete (GRC) panels are a versatile and lightweight façade system. Various surface colours and textures are available, making GRC adaptable to numerous architectural applications. They can be designed wi...

CTG1004.pdf
Coatings 07/11/2008 Kevin Cowie
Preventable Coating Defects

This article identifies some preventable coating problems noticed on 7 year old coated steel structural elements. The steelwork is located a couple of kilometres from the sea within an Atmospheric Corrosivity Category (ACC) at the high end ...

CTG1003.pdf
Coatings 01/05/2008 Raed El Sarraf
How to Specify a Corrosion Protection Coating System

This article provides a summary of the steps to specify a coatings system for a desired time to first maintenance. An example is given including maintenance recommendations.

CTG1002.pdf
Coatings 28/11/2007 Raed El Sarraf
An Overview of the New Zealand Steelwork Corrosion Coatings Guide

This article provides an overview of the New Zealand Steelwork Corrosion Coatings Guide, HERA R4-133, (Clifton and El Sarraf, 2005) as well as the topics covered in the Guide.

CTG1001.pdf
Coatings 28/11/2007 Raed El Sarraf
Email me when new posts are made to this blog

Changes to specifying inorganic zinc silicates to AS/NZS 2312

Written by Kevin Cowie on April 29th, 2016.      0 comments

Australian/ New Zealand Standard AS/NZS 2312 Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings provides guidelines for selection and specification of coating systems for corrosion protection of structural steelwork. The designer can choose from a selection of systems based on exposed service life to first maintenance for various environments. AS/NZS 2312 has recently undergone a major update. A short summary of the major changes to AS/NZS 2312 and use of the standard is provided in Steel Advisor GTG1008.  In addition changes have been made to the designation system for Inorganic Zinc Silicates which will be highlighted in this article.

Topics: Coating Coatings
 

Paint Coating Selection and Specification: Changes to AS/NZS 2312

Written by Kevin Cowie on February 23rd, 2016.      0 comments

Australian/ New Zealand Standard AS/NZS 2312 Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings provides guidelines for selection and specification of coating systems for corrosion protection of structural steelwork. The designer can choose from a selection of systems based on exposed service life to first maintenance for various environments.  AS/NZS 2312 has recently undergone a major update. Galvanizing and metal spraying have now become separate standards.  A short summary of the major changes to AS/NZS 2312 and use of the standard is provided.

Topics: Coating Coatings
 

Galvanic/Dissimilar Metal Corrosion

Written by Kevin Cowie on September 20th, 2010.      0 comments

Galvanic corrosion is the additional corrosion that occurs when dissimilar metals are in contact in the presence of an electrolyte. The corrosion of a metal, the anode, results from the positive current flowing from the anode to the less reactive (more noble) metal, the cathode, through the electrolyte. Contact between dissimilar metals occurs frequently but is often not a problem. This article identifies what causes galvanic corrosion and how to avoid it. This article summarises material from the Australian Stainless Steel Development Association and the use of this material is gratefully acknowledged.
Topics: Coating Coatings
 

Steel Corrosion Rates in Water and Soil

Written by Kevin Cowie on October 20th, 2009.      0 comments

Guidance on typical corrosion steel rates in water and soil for design use is provided in the recently published NZS3404.1 Steel Structures Standard - Materials, Fabrication, and Construction (SNZ,2009). The design rates given are those to be used for long-term exposure, i.e. where the designer is calculating a required sacrificial thickness of steel in order to meet the specified design life. This article covers the background to the corrosion rates provided in NZS 3404.1.
Topics: Coating Coatings
 

Primers for Steel: Their Purpose and Performance

Written by Michael Williams on February 12th, 2009.      0 comments

This article addresses some problems that can occur when primers are incorrectly specified, and examines some misconceptions on their expected performance. Costly remedial rework can be incurred if a shop primer is damaged or exposed to exterior weather conditions for longer periods of time, or that are more severe than were expected, prior to being closed in or subsequent finishing coats being applied on site. These thoughts and observations are based on the author’s experience in the coatings industry. A common cause for arbitration on disputes over coating failures is where a short term, single pack primer has been specified and applied over St 2 (Hand Tool Clean) or more frequently St 3 (Power Tool Clean) prepared steel and left exposed for long periods during construction. Premature breakdown of the coating often initiates from undercut mill scale, transit damage, strop, chain and handling damage if it is left exposed to the weather without repair.
Topics: Coating Coatings
 

Durability of Attachments to Glass-Fibre Reinforced Concrete Panels

Written by Kevin Cowie on November 7th, 2008.      0 comments

Glass-fibre reinforce concrete (GRC) panels are a versatile and lightweight façade system. Various surface colours and textures are available, making GRC adaptable to numerous architectural applications. They can be designed with a face mix to achieve an appearance very similar to that of precast concrete panels. GRC and other lightweight systems are beneficial because they are easy to erect and generally do not require heavy steel structural support in the primary building structure and also result in reduced foundation requirements. For these reasons GRC and other lightweight systems often result in more economical steel frames.
Topics: Coating Coatings
 

Preventable Coating Defects

Written by Raed El Sarraf on May 1st, 2008.      0 comments

This article identifies some preventable coating problems noticed on 7 year old coated steel structural elements. The steelwork is located a couple of kilometres from the sea within an Atmospheric Corrosivity Category (ACC) at the high end of D. The ACC was determined from Table 4.1 of AS/NZS 2312 (SNZ, 2004) and Section 4 of NZCCG (Clifton and El Sarraf, 2005).
Topics: Coating Coatings
 

How to Specify a Corrosion Protection Coating System

Written by Raed El Sarraf on November 28th, 2007.      0 comments

This article provides a summary of the steps to specify a coatings system for a desired time to first maintenance. An example is given including maintenance recommendations.
Topics: Coating Coatings
 

An Overview of the New Zealand Steelwork Corrosion Coatings Guide

Written by Raed El Sarraf on November 28th, 2007.      0 comments

This article provides an overview of the New Zealand Steelwork Corrosion Coatings Guide, HERA R4-133, (Clifton and El Sarraf, 2005) as well as the topics covered in the Guide.
Topics: Coating Coatings
 
   
ABOUT SCNZ