Harmonisation and standardisation in the internationalisation of adhesive bonding standards

What are the current developments in the internationalisation of adhesive bonding standards? Frank Stein, head of the independent certification body TBBCert, was on hand as a speaker at the 20th Bremer Klebtage on 22 and 23 June 2022. With his presentation »Adhesive bonding standards are becoming international«, he gave a brief update on the current status of the internationalisation of adhesive bonding standards and also shed light on special areas such as defence technology and shipbuilding as well as, of course, the upcoming transformation of the DIN 6701 series of standards (Adhesive bonding of railway vehicles and parts) to EN 17460.

In 2016, TBBCert, as an independent certification body of Fraunhofer IFAM, took over the activities of the recognised body affiliated with IFAM in Bremen, which had been carrying out the adhesive bonding certification of companies in rail industry according to DIN 6701 since December 2006. In the meantime, the certification activities are no longer limited to the rail vehicle sector, but have been extended to other areas in trade and industry (DIN 2304-1) as well as bonding in defence industry (TL A-0023). The TBBCert team looks after more than 600 customers worldwide and, together with 11 other external auditors - including many colleagues from Fraunhofer IFAM - carries out more than 400 certifications per year.

Frank Stein is both manager and auditor. He visits companies in various countries and audits bonding technology processes. During the corona pandemic, TBBCert also introduced remote audits as part of the audit processes. Due to the positive experiences, some of the processes from the remote audits that proved to be very efficient were also carried over into the »post-COVID« period. These include, for example, the implementation of so-called pre-audits, as well as the control of deviations and suggestions for improvement. This approach makes it possible to make the entire audit process even more effective, which brings various advantages for the client, for the respective auditor as well as for the certification body itself.  For example, after an initial remote audit, the company to be certified has the opportunity to introduce a few changes and updates before the actual certification audit takes place on site. Furthermore, travel times, workload and costs are reduced through more efficient planning.

The current status: internationalisation of adhesive bonding standards

In his presentation at the Bremer Klebtage, Mr. Stein focused on the internationalisation of standards in bonding. For example, the DIN 6701 series of standards is currently being transferred to EN 17460. The English edition of EN 17460 has been published in the meantime. The German version is expected within the next two months. (Anmerkung Frank: wurde mittlerweile ebenfalls veröffentlicht) After a transition period of approximately three years, the DIN 6701 series of standards will be merged into EN 17460. One challenge in this process of internationalising standards is to reconcile the broad interests of the individual stakeholders in a meaningful way and with an efficient result. »It is a matter of finding a golden compromise,« says Frank Stein. »This is particularly important as over 60% of our clients are now international.«

In order to cope with future challenges and to give the adhesive bonding standards a comparable structure, an attempt is being made and has been made to structure the adhesive bonding standards on the basis of three so-called strategic core elements:

1. classification

2. personnel qualification

3. verification and implementation

What is new:

DIN 6701 - EN 17460

As already mentioned, the transformation of the DIN 6701 series of standards to EN 17460 is probably the most important update in the field of adhesive bonding technology standardisation in 2022. In order to ensure and accompany the further development and implementation of EN 17460 in the future, a European working group (ECARV European Committee Adhesive Bonding of Rail Vehicles) was founded in Berlin on 15 June 2022 in cooperation with the ECWRV (European Committee for Welding of Rail Vehicles), which has been established for many years. The main tasks and objectives of ECARV are:

- Approval and control of certification bodies and auditors

- Harmonisation of the certification activities of the certification bodies

- Adoption of resolutions on the implementation and interpretation of EN 17460

- Publication and maintenance of the A-Z collection

ISO 21368

The publication of the revised ISO 21368 (Adhesives - Guidelines for the fabrication of adhesively bonded structures and reporting procedures suitable for the risk evaluation of such structures) may be mentioned as another adhesive technology highlight of the year 2022. It should be particularly emphasised that the revision has succeeded in fully implementing the structuring already mentioned in the introduction to this article with regard to the »strategic core elements«.

TL A-0023 Bonding in Defence Industry / DIN 2304-Part 2 Bonding in Shipbuilding

Finally, a short update on bonding in Defence Industry and shipbuilding:

Currently, work is being done on the extension of DIN 2304-1 with regard to the requirements of shipbuilding. Among other things, the requirements for the approval of ships, fire protection requirements and shipbuilding-specific working methods for production and repair are to be taken into account. The results of the working group established for this purpose are to be published in DIN 2304-2.

The draft for the revision of TL A-0023 (Technical delivery condition - Bonding and related processes - Quality requirements for manufacturing and maintenance companies for military products) has already been completed and is currently being finalised and agreed with the responsible authorities.

In this revision, special emphasis was also placed on harmonising the requirements in comparison to the other bonding regulations. This applies in particular to the qualification of personnel (e.g. qualification of the bonding supervisors depending on the areas of validity of the operating licences). Furthermore, practical findings from the auditing activities of the past years, which have so far been included in the »A-Z-Guideline TL A-0023«, have been partially incorporated into the draft.

In the field of standardisation work, adhesive bonding technology is already very professional and up-to-date, as Frank Stein emphasises: »Standardisation in adhesive bonding technology has risen to a very progressive and exemplary level in recent years. The harmonisation and standardisation in the revision and creation of new standards has been actively promoted by Prof. Dr. Groß, Head of Continuing Education and Technology Transfer at Fraunhofer IFAM, and his team. We are therefore very optimistic about the future.« As a key technology of the 21st century, adhesive bonding technology can be applied in many industries and crafts and it is impossible to imagine life without it.

In order to keep quality high, to avoid mistakes and to use the full potential of this technology, certain rules are needed - in other words, standards and regulations. This will continue to be the case in the future - because as we all know, bonding still cannot be tested 100% non-destructively. And even if it should one day be possible to reliably test bonded joints 100% non-destructively: A defect avoided from the outset is always better than a »non-destructively tested detected« defect.