Independent verification of NTR compliance
Independent quality control is a core element of the NTR Quality System. It ensures that NTR-certified products are produced in accordance with approved NTR classes and that requirements are applied consistently across producers, countries and markets.
Quality control under the NTR system is based on third-party audits carried out by approved and independent control bodies.
Separation of roles
The NTR system is designed with a clear separation of responsibilities:
- NWPC owns and governs the NTR Quality System and the NTR mark
- Technical Expert Group evaluates and approves wood preservatives and technologies
- Approved control bodies carry out independent audits and inspections
- Producers are responsible for compliance with approved NTR classes
This separation safeguards impartiality, credibility and trust in the system.
Approved control bodies
Quality control is performed by control bodies that are approved by NWPC and operate in accordance with recognised principles for product certification.
Control bodies:
- are independent from producers
- operate under defined competence and impartiality requirements
- accredited according to EN ISO/IEC 17065
- apply NTR requirements consistently
- report audit results within the NTR system
Only control bodies approved by NWPC may carry out audits for NTR certification.
Scope of quality control
The scope of quality control is defined by the NTR classes that a producer has applied for and been approved to use.
Quality control covers:
- production processes and factory production control
- compliance with applicable NTR documents
- correct application of approved NTR classes
- laboratory tests of penetration and retention
- product marking and traceability
Only products included in the approved scope of control may be marketed as NTR-certified.
Initial and ongoing audits
Quality control under the NTR system includes:
- an initial audit before certification and licensing
- regular follow-up audits during the licence period
- additional inspections when required
This ensures that compliance is not a one-time assessment but a continuous obligation.
Non-compliance and sanctions
If deviations from NTR requirements are identified, the control body applies defined procedures to address non-compliance. Measures may include:
- corrective actions
- increased monitoring
- suspension of the certificate and the right to use the NTR mark
- withdrawal of the licence to use the NTR mark
The licence to use the NTR mark kan be revoked due to other non conformance such as failure to pay fees or misuse of the mark or the system.
These mechanisms protect the integrity of the NTR system and ensure equal treatment of all producers.
Why third-party control matters
Independent quality control:
- strengthens market trust in NTR-certified products
- protects producers against unfair competition
- provides confidence to customers and authorities
- supports long-term credibility of durable wood
Third-party control is essential for the value of the NTR mark.
Next step
Learn how fees and licences are structured within the NTR system.
