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Factory Production Control

When a manufacturer brings a product to the European market, the manufacturer must declare the relevant performance in the CE-mark and take responsibility for the conformity of that product with its declared performance. Manufacturers must ensure that production procedures are in place so that products maintain their declared performance. When deemed appropriate, manufacturers shall carry out sample testing of construction products brought to market to ensure the accuracy, reliability and stability of the declared performance of these.

VELUX checks 40 different critical parameters for roof window production to ensure compliance with declared values and supplements this with sample tests on the performance of the produced windows.

The parameter checks are part of a comprehensive factory production control system to ensure full control of the manufacturing process and to ensure VELUX products comply with their declared values.

In order to secure compliance with performance values, VELUX has a complete start-to-end system of checks done according to predefined parameters that are important to be in control of.

Compliance checks are firstly done on sub-suppliers and materials when they come into VELUX factories. This is followed by compliance checks on the predefined parameters during the manufacturing process. This ensures that the series production is in compliance with the declared performance of the window. Finally, windows are sampled frequently from production for internal control tests of their performance.

This means that already in the design phase and right through production to when finished products leave the warehouse, VELUX monitors processes and checks parameters required to ensure consistency, uniform and high-quality roof windows.

These measures and checks are an integral part of this all-encompassing factory production control system, which is unique to VELUX in the roof window industry. It ensures that VELUX roof windows are compliant with their product declarations. The windows and their components are checked based on 40 critical parameters and according to relevant European standards.

At VELUX, the bar for quality is high and our factory production control system is proof of this,” says Jörn Neubert, Senior Vice President Supply. “We have a team of 20 employees dedicated directly to the systems required for a professional factory production control system set-up. On top of this, already in the early design process we focus on risk evaluation and verification of essential parameters and processes and every employee involved directly in production is responsible for monitoring our roof windows as they move through the production line and they have a clear modus operandi for elevating any issues that could jeopardise the quality of our products. In this way we are in full control and we can proudly say that our factory production control system is second to none in the roof window industry.

Uw-value – a key measure of quality

One of the key components checked as part of the factory production control system is the Uw-value or thermal performance of roof windows. The critical parameters that can influence the Uw-value, and which are monitored during these checks, include the gas filling ratio, the glass coatings, the thickness of the insulating glass unit and the thermal characteristics of the sash and frame, to name a few. Each parameter has a certain tolerance level that must be met to achieve the declared Uw-value for the final product brought to market. Furthermore, the data on critical parameters, which are monitored and analysed by the VELUX Quality System, are filed and made available for external audits, as well as for market authorities. Parallel to the checks of critical parameters, roof windows are sampled frequently for internal control tests of their Uw-values. Around 80 roof windows are sampled frequently during a year for tests of the Uw-value in a hotbox in accordance with EN ISO 12567-2.

Independent testing

Supplementary to the VELUX Factory Production Control system, VELUX procures the global consultancy Navigant to independently purchase in various markets roof windows - made by VELUX and other roof window manufacturers - for testing by two different European notified test institutes, ift Rosenheim, Germany, and Centrum Stavebního Inženýrství a.s. (CSI), Czech Republic.

By monitoring critical parameters, adhering to a stringent factory production control system, sampling windows for internal tests, plus also arranging for independent bodies to test further and in accordance with European standards for testing Uw-values, VELUX ensures we deliver what we promise to our customers.

What is factory production control?

Factory Production Control is a system set up to ensure that products brought to market conform to the performance characteristics stated in the Declaration of Performance and the CE mark. In terms of thermal performance, it ensures compliance between the declared Uw-value in the CE-mark and the Uw-value of the product brought to market. Learn more about the VELUX Factory Production Control.

Our promise

  • The declared Uw-value is based on the reference size 1,23 x 1,48 m in accordance with EN 14351-1 and documented via an initial type test in accordance with EN ISO 10077-1/2.
  • The Factory Production Control system is set up to monitor critical parameters of the Uw-value and to control that these are within their tolerances required to meet the declared performance.
  • Data from our Factory Production Control are used to calculate that the statistical performance of our products is as declared, and in accordance with EN 14351-1
  • The Factory Production Control methodology and results are frequently verified by correlating with sample testing of roof windows, in accordance with EN ISO 12567-2 (in a size as close to the reference size as possible).
  • Thereby, VELUX can promise that windows brought to market live up to their declared performance values.