VKG Quality Requirements & Opinions: an update

The manual describes the complete process from construction to production, assembly and maintenance

VKG Keurmerk ensures a high quality standard as a trade association and quality mark. It stimulates sustainable innovation, reuse and recycling in the plastic window frame industry and offers the certainty of independent inspection and warranty (including the VKG Guarantee Fund). An important role is reserved for the VKG Quality Requirements & Advice Manual, in which all technical quality requirements from construction to production, assembly and maintenance are clearly bundled.

"The VKG Quality Requirements & Advice Handbook was created more than 20 years ago and is a dynamic document that is continuously updated based on trends, advice and experience in the market," says Edwin van Houten, VKG branch manager. "The handbook describes the complete process from construction to production, assembly and maintenance. For example, functional (construction) requirements such as air permeability, water tightness, thermal insulation, soundproofing, wind load and dimensions & tolerances are covered in detail. If manufacturers of plastic window frames wish to become VKG Keurmerk members, they must first comply with the Assessment Guideline (BRL) 0703 (KOMO attest with product certificate). In addition, they must comply with the quality requirements and advice in our handbook, which includes the guidelines of the Building Decree, various NEN standards and a number of European standards. This makes the VKG Quality Requirements & Advice Handbook a solid document and the basis for quality assurance in the plastic window frame sector."

Certainty of quality

Architects and clients working with a VKG Keurmerk member can rely on a high-quality and innovative end product that meets the high standards of VKG Keurmerk, Van Houten emphasizes. "The production process of our manufacturer members is checked periodically and in accordance with BRL 0703 by certification institute and notified body SKG-IKOB. Here, for example, temperature settings, welded joints, mechanical connections and recording through corresponding documentation are examined. For the inspection of, for example, assembly, cleaning and maintenance and environmental aspects, we ourselves employ a Technical Inspector who randomly visits projects in the field, tests them and discusses possible improvements with the members. Naturally, the VKG Quality Requirements & Recommendations are leading here."

Handbook update

As mentioned, the VKG Quality Requirements & Advice Manual is a dynamic document. "Within the branch organization, a technical committee has been formed with experienced technicians from our constituency, which regularly discusses current affairs, new (adapted) regulations, innovations, experiences and progressive insights," Van Houten said. "Based on this, products are regularly tested and - if necessary - technical quality requirements are adjusted, supplemented or clarified."

Flatness of profile encounters and seams

An update of the VKG Quality Requirements & Advice Manual has recently been published, in which, among other things, chapter 4.10.2 (Partially welded joints) has been adjusted. "For example, there has been discussion in the market about the flatness of profile joints (measured in the plane of the façade, at mitre joints and T-joints), which has been adjusted from 0.3 to a maximum of 0.6 after investigation. In fact, the machine manufacturers could not handle the old requirement as a continuous process. The seams between the mechanically connected profile encounters and between the profiles (at partial welded corner joints) were, however, set to a maximum of 0.3 mm
remain standing."

Fall-through barriers

The fixings were also scrutinized. Especially with regard to fall-through protections, Van Houten explains. "Here it was decided that the attachment of fall-through protections to the plastic façade elements must take place according to the supplier's instructions, whereby water infiltration must never occur or take place."

Ventilation grilles in rotating parts

As for the steel in the plastic window frames, additional requirements have been added for surface treatment. "Moreover, a very important adjustment relates to ventilation grilles (directly on glass) in hinged parts, in which, based on research at SKG-IKOB, a number of conditions and determination methods have been added. The performance requirement has also been tightened. Hereby it is concluded that the integration of ventilation grilles in rotating parts and directly on glass is not allowed, provided that under KOMO certification the additional stated requirements are met."

Steel frames and structural frames

The spacing of the mounting screws was adjusted from 700 to 600 mm on the advice of the system houses. "A very important adjustment also concerns the durability of the standing frames or adjustment frames, which must be treated in the correct layer thickness and all around," said Van Houten. "In addition, we have expanded and optimized the guidelines for the increasingly used plastic standing frames. For example, with regard to the circumferential clearance (± 4 mm), of which clear drawings can be found in the VKG Quality Requirements & Advice Manual."

The most up-to-date version of the VKG Quality Requirements & Advice Manual is now online. However, this does not mean that the technical committee can sit back, Van Houten stresses "At the moment we are investigating, for example, the wind and water tightness (and corresponding guidelines) of alternative low step sills and the preconditions for reuse and recycling." To be continued, no doubt.