Nox Technical File

The NOx Technical File is the approved document carried on board for each marine diesel engine that defines the engine as NOx-certified and sets out how its emissions are verified in service. It records the engine’s NOx-critical components, settings, and operating values against which a surveyor runs the Parameter Check method. The requirement comes from MARPOL Annex VI Regulation 13 read with the NOx Technical Code 2008, and applies to installed marine diesel engines over 130 kW other than emergency-only units. The file supports the Engine International Air Pollution Prevention (EIAPP) Certificate; a missing file or off-spec settings are a port state control finding.