NOx Tier Compliance Check
Determine the applicable NOx Tier (I, II or III) under MARPOL Annex VI Regulation 13 from the engine's installation date and current operating area, compute the rated-speed-dependent limit, and compare against the EIAPP-certified NOx emission rate.
Engine inputs
Applicable Tier
Tier III
Engine installed on/after NECA effective date: Tier III applies inside any designated NECA.
Applicable NOx limit
3.40g/kWh
Compliance margin
0.40g/kWh
12% margin below limit.
Status
PASS
Certified NOx 3 g/kWh ≤ Tier III limit 3.40 g/kWh.
Formula, limits, and tier-applicability rules
Tier I, II, III limits as function of rated speed
| Tier | n < 130 rpm | 130 ≤ n < 2000 rpm | n ≥ 2000 rpm |
|---|---|---|---|
| Tier I | 17.0 g/kWh | 45 × n^(−0.2) g/kWh | 9.8 g/kWh |
| Tier II | 14.4 g/kWh | 44 × n^(−0.23) g/kWh | 7.7 g/kWh |
| Tier III | 3.4 g/kWh | 9 × n^(−0.20) g/kWh | 2.0 g/kWh |
Tier-applicability by installation date
- Engine installed before 1 January 2000: not subject to Annex VI NOx limits (subject to "major conversion" rule under Reg 13.2).
- Engine installed 1 January 2000 to 31 December 2010: Tier I globally.
- Engine installed 1 January 2011 to NECA effective date: Tier II globally.
- Engine installed on/after the NECA effective date: Tier II outside NECAs and Tier III inside NECAs. NECA effective dates: North America & US Caribbean 2016, Baltic & North Sea 2021.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| n | Engine rated rotational speed | rpm | EIAPP Certificate |
| NOx limit | Cycle-weighted average NOx limit | g/kWh | MARPOL Annex VI Reg 13 |
| Certified NOx | Engine's EIAPP-certified weighted-average NOx | g/kWh | EIAPP Certificate |
| Margin | Limit − Certified (positive = compliant) | g/kWh | result |