To qualify for the NTR Control, the certification system for treated wood which entitles products to carry the NTR mark, companies must implement a functioning internal quality control system. The purpose of these internal quality controls is to be able to control treatment processes in such a way that they will produce the required product quality.
In addition to the special requirements and demands of the Nordic Wood Preservation council regulations, there are other conditions the internal quality controls have to meet, such as those required for certification according to ISO 9002 and the SFS 1998:901 directive on companies’ own internal controls.
The most important points that need to be covered by internal quality controls are:
- Inspection of the wood before treatment
- Inspection of the treatment solution before treatment
- Selection of the appropriate treatment process as well as documentation of the entire course of the process
- Checking the results (penetration and retention of the treatment solution) after the treatment process
- Labelling of the treated wood
- Checking correct fixation and the storage of treated wood
- Treatment protocols
These requirements is described NWPC documents and in the publication Factory Production Control.
To enable the internal quality controls to be carried out in the best possible way, it is imperative that the operating staff and the supervisors are properly trained and that they show their interest and commitment to production and quality issues and that they are authorised to remedy any shortcomings or defects should they arise.