All products covered by the Gas Appliances Regulation require the participation of a third party in the conformity assessment before being placed on the market. More specifically, this third party refers to the notified body.
The notified bodies are laboratories specialising in testing a type of product, and an EU member state has notified the Commission of it. Only these notified bodies are authorised to carry out conformity assessment tasks.
The list of notified bodies authorised to carry out conformity assessments under the Gas Appliances Regulation can be found in the NANDO database maintained by the Commission.