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