Steel is strong
What could possibly be said about steel and aluminum prefabrication that hasn’t been said before? What should be a straight forward supply chain management is actually a complex and very regulated, defined process supported by numerous codes, standards, and specifications.
And it changes all the time.
To stay current with industry requirements and changes, training and experience is everything.
Without a certain amount of accurate knowledge, it can be an expensive and not always pleasant experience. We’re not going to go into too many details, but we would like to use this opportunity to enrich our clients and partners with some basic information about the execution of the steel and aluminum prefabrication supply chain, and what is expected to be supplied from the clients.
The introduction of the European Standard EN-1090 in 2015 was a final attempt to regulate and define the criteria
for all supply of prefabricated steel and aluminum structures inside the European Union (EU). As defined by the execution class (EXC) a particular structure must be fabricated and supplied afterward. By stating the execution class on the drawings, the workshop knows exactly what to do, test, and document. Classifying the consequence class, service category, and production category are where the challenges lie. Together with the end-user and designer, the client has to justify and document his/her choice based upon the correct consequence class, service category,
and production category. Norway Steel Group has prepared a template, which is normally used by the client in a case like this. The template also provides guidance for determining the right steel material grades as per selected service temperature and the right corrosion class; choosing a 'too high' execution class will automatically lead to increased costs. A ‘too low’ execution class might result in even bigger costs. It is important to determine the right classes, as this is not something that can be left for the workshop to determine. It is the responsibility and ownership of the client.
EN-1090 clearly states what in-house knowledge, resources, and routines a manufacturer must possess and strictly
follow to be certified to fabricate and supply to the specific execution class (it is renewed every year). It also clearly states how to mark the structure before shipment, often referred to as a CE-marking.
For US supply we normally refer to the AWS D1.1 standard or other standards in this series. All of Norway Steel Group’s pre-qualified workshops in China and one workshop in Poland possess both EN and AWS certification. A difference between the US and EN standards that is of interest is the right to use the pre-qualified welding procedure (WPS) as per AWS D1.6 when supplying to the US as per AWS standards.
An important change that also deserves attention happened in 2019, when China re-defined its corresponding European steel grade S355 from Q345 to Q355, meaning that foreign designers no longer have to consider the lower yield strength.
This was a step in the right direction.
Surface treatment is another issue that could also lead to high-cost incidents if not taken seriously or not involving experienced personnel. At Norway Steel Group, we have FROSIO certified engineers, and we also have close cooperation with JOTUN. Worth mentioning is the demand for supported calculation and documentation for the eventual fire-protection of steel structures and the determination of the right painting system based on the defined corrosion class. Lately, more and more clients choose to have wet or powder painting on galvanized structures; this is an extremely challenging procedure. We’ve experienced our share of ‘lessons learned’ before we, together with JOTUN, and some selected workshops in Germany and Poland, were able to get this under control.