RAL Quality Assurance as a holistic approach

Consistency as an essential add-on in RAL quality assurance

Just as the whole is more than the sum of its parts, the quality assurance of all components of a value chain could be called the royal road. The very idea of bringing a large number of manufacturers into the quality assurance process, building on each other, gives an idea of the extent and effort that underlies this holistic understanding of quality.
The quality association launched this principle of consistency back in 2013, when the decision was made to take the step from profile to system and to integrate all components. The new RAL-GZ 716 was thus intended to become quality assurance in the sense of a holistic understanding of quality.
RAL-GZ 716 was therefore developed as a modular system, from the raw material to the end product. All components used in plastic windows, such as window profiles, the PVC-U formulation, sealing compounds, decorative foils, reinforcements and connectors are quality assured and are thus subject to quality assurance as a value chain. This means that we do not limit ourselves to testing the end product, but focus on the consistent quality of the entire manufacturing process.

Four quality associations cooperate for a common product

In the same way, this concept is continued by quality-assured fittings and insulating glass and is included in the quality assurance of a finished RAL plastic window. The quality assurance of the window production including installation is subject to the Gütegemeinschaft Fenster, Fassaden und Haustüren (Frankfurt).
On the industry side, the (vinyl) system provider assumes conceptual responsibility for all the above-mentioned areas, because in the system description he also defines the hardware / fittings to be used as well as specifications for window construction and installation.

Only quality-assured components may be used in a quality-assured system.

Why this strict requirement? Quality-assured plastic window profile systems must prove their suitability on the end product window or door. For this purpose, the final tests are carried out on sample windows. Before this, the components used have passed their requirements in order to be allowed to be used as "approved components" in the quality-assured window system in the first place. For all components, the "triple" of proof of suitability, manufacturers production control and regular external monitoring is specified. This ensures the continuous quality of the "modular system" that is handed over to the window manufacturer.
And what if a replacement is required? If a window manufacturer wants to replace a quality-controlled system component, he can use the components approved by the system supplier. If he chooses a component outside the system description, the replacement rules of RAL-GZ 716 must be observed. It should also be noted that the replacement of components can lead to the cascaded type test reports in accordance with EN 14351-1 (keyword "cascaded ITT") becoming invalid, thus invalidating the use for CE marking.
Such a thoroughly organized system reaches its limits when time is an issue, because for example approval procedures for U-PVC-formulation components are time-consuming due to the artificial weathering required. The quality association has solved this problem of supply chains by creating a so-called positive list, in which tests already carried out can be transferred. Thus, time is gained without circumventing the principle of holism.
 

Advantages and added value of the RAL quality assurance plastic window systems convince

The RAL quality assurance and thus the quality marks have been an integral part of an independent quality assessment of products since the 1950s and, due to their neutrality and objectivity, are a decision-making aid for the consumer. In addition to the certified quality of their products, manufacturers of quality-assured products benefit in particular from the impetus for continuous improvement of their production and management processes.

• The quality mark stands for the monitoring of the entire system along the value chain. All products and processes within the area of responsibility of the plastic system provider are subject to coordinated quality monitoring, resulting in a plastic window system from a single source. A system provider cannot hand over anything better to the window construction industry.
• Core of the RAL-GZ 716 is since decades not only the continuous serviceability, but since recently the plastic window is tested also regarding interior climate and environmental impact. Regular VOC tests and monitoring of energy and water consumption as well as waste generation are therefore prerequisites for obtaining the RAL quality mark.
• Quality assurance and, in particular, external monitoring serve as a "continuous improvement tool". The neutral and expert "view from the outside" may seem inconvenient, but it makes a lasting contribution to maintaining quality.
• Experts from the Quality Association continue to develop the state of the art in numerous expert and working groups and make this available to the window construction industry. The system is transparent and promotes the active participation of all partners involved in the vinyl window system.
• The common platform enables all manufacturers in the industry to access and participate in interdisciplinary problem solving.

Since November 2022, the new quality mark has been registered as a EU certification mark. This serves as an identification and proof of the quality characteristics and properties defined in the quality and test specifications. Thus, our quality mark stands for the guarantee of characteristics and not for the origin of the products, as was the case with the former collective mark.
The EU certification mark certifies characteristics to "ensure the special quality of manufacture, the special quality of technical properties and the durable suitability for use". These are:

• a complete and up-to-date system description with specified contents,
• Minimum requirements (values or classes) for various performance characteristics, to be demonstrated under defined test procedures on the test specimen (window and/or door) identified as the most system-critical design in each case, namely: operating forces, resistance to repeated opening and closing, air permeability, resistance to wind load, watertightness, behavior between two different climates, resistance to loads in the sash plane, resistance to static torsion.
• Minimum requirement for the characteristic load-bearing capacity of a T-connector in the direction of wind suction.
• As far as applicable: suitability of the adhesive system for direct glazing under different loads and defined aging influences by demonstrating its strength, adhesion behavior, creep behavior and compatibility with contact materials.
• Summary documentation of the tests performed
• Quality auditing of the system components profile - including any coloring surface -, gasket, reinforcement, connector, cover shell and the adhesive systems used (in each case, if present in the system)
   

Quality characteristics of plastic window profiles (including surfaces and coatings)

• Minimum requirements met by the materials used with regard to rheological and mechanical properties and their processability
• Mechanical strength of the profiles
• Surface quality, visual properties as well as resistance and durability
   

Quality characteristics of sealing materials and gaskets for window profiles

• Elasticity properties after oven storage, artificial weathering, ozone exposure and color fastness
• Suitability of the gasket built into sample windows
   

Quality characteristics of connectors

• Consistent quality, load-bearing capacity, pull-out strength and long-term serviceability
• Minimum requirements for construction, suitability, compatibility and durability
   

Quality characteristics of reinforcements

• Consistent quality, stability and endurance serviceability
• Minimum requirements for resistance, corrosion protection and wall thickness

Window manufacturers, project planners and consumers are thus provided with a modern, transparent and standardized mark of quality on which they can rely.

The RAL Quality Association has also published an article on this in bauelemente bau issue 8-2023 (German version).