The Association of Manufacturers and suppliers of Power Systems and ancillary equipment

Is it correct that compliance with level IIIA emissions is not a requirement on LTP rated Stand-by sets?

For clarity the following additional point is to be considered.

  • If a PRP rated set is used as a Stand-by it is presumed that the set would need to be IIIA emissions compliant as the set is not defined as a stand-by rating.

The real question therefore becomes:- Is the requirement for emissions compliance based on the application (therefore any set, LTP or PRP rated, to be used as a stand-by does not have to be emissions compliant), or is it based on the declared set rating of LTP or PRP (in accordance with ISO8528) regardless of application?

What really matters is whether the application is considered to be “stationary” or “mobile”.

In the EU, anything that is installed in one place, with a view to it staying there for its life, would be considered “stationary”. There are currently no European requirements on these sets whether LTP or PRP rated. There may, however be local requirements.

If the set is intended to be moved around during its life then it is considered to be “mobile” and should meet stage IIIA emission levels, again regardless of LTP or PRP rating.

Compliance to IIIA is required for 19-36 kW and 75-560 kW sets with engines built after the 1st January 2011, and for 37-74 kW sets from the 1st January 2012.

There is no current regulation for sets rated below 19 kW or above 560 kW.


Directive 97/68/EC (emission of gaseous and particulate pollutants from internal combustion engines to be installed in non-road mobile machinery) was adopted in 1997. This has been amended several times, the last amendment Directive being 2012/46/EU.

The Directive was implemented into UK law by the "Non-Road Mobile Machinery (Emission of Gaseous and Particulate Pollutants) Regulations 1999" (Statutory Instrument No. 1999/1053) as amended. The Regulations apply to new engines to be installed in non-road mobile machinery, intended and suited to move, or to be moved on the ground, either on or off the road.

There are forthcoming “Stage V” emissions requirements coming into force for engines powering mobile equipment, including generators, and also the Medium Combustion Power Directive will apply to engines greater than about 400 kW in stationary applications from approximately 2019 onwards.

Important Note

Absence of case law means that much of this advice is based on current understanding, a number of draft documents and is subject to revision at any time. Any decisions should be verified with an expert on European Law on a case-by-case basis.

FAQ 1004

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