Surface World June 2019 Surface World June 2019 | Page 42

QUALICOAT UK & IRELAND Trust in chrome free technology There has recently been speculation that chrome free technology used in the pretreatment of architectural aluminium is not as robust as that of its chrome based alternative. QUALICOAT, the largest membership driven standard, specifi ed across the globe, disagrees. First we need to look back at why chrome- free systems were developed, when we know that chrome based pretreatment systems work so well. Key to any architectural powder coating finish is the quality of its pretreatment, whilst the thickness of powder finish is important, without a quality pretreatment in place, the substrate will not be protected from corrosion, and the powder paint will not adhere well to the substrate. Recently it became apparent that the use of chrome based chemicals can lead to an increase in some cancers. On this basis, and the fact that chrome based systems would eventually be banned by the EU, chrome free systems were developed. Early chrome-free pretreatment systems, introduced some 20 years ago, offered very little margin of error during processing. Today, chrome-free systems have advanced to the level where its experienced use is comparable to its chrome based cousin. This is a fact borne out by QUALICOAT’s own sample testing from its global membership over the last few years. So is chrome-technology suitable for external architectural powder coating? Definitely. Virtually all of QUALICOAT members in continental Europe offer chrome- free systems, whist in the U.K. more than half of QUALICOAT members have made the switch from chrome to a chrome-free pretreatment. There is no distinction made between indoor and outdoor architectural powder coating. 40 APRIL 2019 Guidance Note - No.5 Alternative conversion coating processes under EN12206-1 (2004) May 2019 Scope The International recognised quality label QUALICOAT is continually working towards higher industry standards, including but not limited to, the performance of the alternative conversion coating used prior to organic coatings for external use. The major concerns raised by applicators responding to tender enquiries are: • • Due to concerns over the environment and REACH implications in the use of chromium trioxide containing coatings and their acidic mixtures many QUALICOAT licensed applicators have changed to alternative conversion coating processes that are completely free of chromium trioxide. • Purpose These recommendations are intended to assist architects, contractors, owners and building managers who are involved with the specification of powder coated architectural aluminium. QUALICOAT demands that all alternative conversion coating processes are thoroughly tested to the latest revision of the specification adopting methods that follow international standards listed in Appendix A9 of this specification. Fully approved alternative conversion processes have been proven in quality and cost competitiveness and regularly checked through inspections undertaken in line with the general licensee. Statistical analysis, provided by QUALICOAT own working group, confirms that there is no significant difference in corrosion performance between the alternatives and chromium containing processes. An issue for many QUALICOAT applicators using these alternative conversion coating processes is the impact of potential loss of business under a restricted tender process following the rise of inclusion of EN12206-1 (2004) in the tender documentation. Tender documentation often does not recognise the important contribution of QUALICOAT in safe-guarding quality of external painted aluminium surfaces. National standard EN12206-1 (2004) is often specified in tender documentation based on the perception that it is a higher performance level than QUALICOAT and that fully approved alternative conversion processes endorsed by QUALICOAT do not meet the requirements of Annex B Outdoor Weathering. Tender process is increasingly influenced by stakeholder(s) directing continued use chromium trioxide or pre-anodising (PREOX, Flash Anodising) as the only acceptable and allowed pre-treatment for external painted aluminium surfaces. In an increasingly competitive market the interests of all our members is of primary importance and we remain committed to update all stakeholders within the supply chain in the use alternative conversion coating processes and we would like to summarise the following in response to the concerns raised. QUALICOAT specification (15th Edition, 2017) and EN12206- 1 (2004) allows for the following chemical conversion coating processes: • • • Chromate Conversion Coating Alternative Conversion Coating Anodic pre-treatment, electrolytic conversion (PREOX, Flash Anodising) A comparison of the test method and performance is summarised in Table 1 overleaf. To read online visit http://www.qualicoatuki.org/assets/05_chrome_free.pdf Today’s chrome-free systems, that are QUALICOAT approved, and that are applied by Applicators who are QUALICOAT approved, are robust and worthy of specification in any location. QUALICOAT have released a technical guidance note explaining all, which is available from the QUALICOAT U.K. & Ireland website at http://www.qualicoatuki.org/ assets/05_chrome_free.pdf Copies of the current fi fteenth edition of the QUALICOAT Standard, complete with amendments and updates, is freely available through the UK Association website, www.qualicoatuki.org together with an up-to-date list of Powder Suppliers, Pretreatment Suppliers and Applicators. Printed literature and telephone support is available from QUALICOAT UK & Ireland Head Offi ce in Birmingham on 0121 601 6746 or email [email protected]. The Association can also be followed on Twitter at @Qualicoat. twitter: @surfaceworldmag