Marine SCR – Tier III Certification

To comply with IMO Tier III emissions limits, marine diesel engine systems fitted with SCR must fulfil the surveying and certification requirements laid out in MARPOL Annex VI Resolution MEPC.198(62) and the NOx Technical Code 2008. Thus, the SCR is not certified as a stand-alone technology but as part of the engine system. Seagoing ships are required to obtain an Engine International Air Pollution Prevention (EIAPP) Certificate and there are two ways to accomplish this:

  1. The engine fitted with SCR is tested on bench, certified and sent to shipyard (Scheme A)
  2. The engine and SCR are tested separately due to restrictions in size (Scheme B)


Scheme A


Scheme B

(Scaled Test + Onboard)

No need of testing on boardLonger time for preparing documentationShorter timeframe

(1 day in laboratory, 1 week for model calculation, several days on board for verification and finalisation of the documentation)

Engine documentation must be delivered to the applicant or the engine maker can provide it to the certification society directly.
Engine family can be certifiedHigher cost of testbench (mounting/dismounting the engine)Engine family can be certified
SCR measured with pre-settled parameter, no real conditionsLower CAPEX (lab-test and class society inspection)
No possibility to change the parameters on board and while running in a NOx ECA.Exact measurement of engine in real operating conditions
Identical engines: only onboard verification test is required at a later stage
Optimisation of urea injection leading to lower OPEX