How to read engine plates

What is an engine plate?

All engines manufactured in compliance with the EU engine emissions Directive 97/68/EC must be marked with certain information. These markings are commonly located on a so-called ˜emissions label™ or ˜emissions plate™, similar to the one in the picture below. They may be marked by any durable method such as printed, stamped, engraved, etc, and should include the name of the engine manufacturer and type approval number. 

Machinery owners and operators should familiarise themselves with the location of engine plates on their plant as this will make it easer and quicker when checking in to site or being inspected.

Why would you read engine plates?

The engine plate is marked with a code detailing the EU Engine Emission Stage, which tells us how much pollution an engine generates. The NRMM LEZ sets the minimum stage allowable, and should be recorded as part of an entry to the NRMM LEZ register.

Why would you not read engine plates?

Engine plates can be difficult to locate.  The reader should take care NOT to put any part of the body in a dangerous situation whilst seeking the necessary information. Please take extra care to turn-off and isolate equipment, and to ensure that it has properly cooled. Any parking brake or safety interlocks should be applied and operating keys removed.  You may want to consult health and safety advice.

How do you find an engine plate?

The markings should be locatable with the engine installed in the machine with any necessary access covers to the engine bay open. Where the engine plate is not visible on the engine there should be a duplicate plate in an alternative visible location, such as in the drivers cab, or inside the engine hood, so it may be helpful to check here first

How do you read an engine plate?

There is one key digit in the type approval number that provides explicit evidence of the emission level to which the engine was manufactured. This is the method by which surveillance authorities check the engine. There is a second digit that can be used as an indication as to whether the engine is typed approved for variable speed or constant speed operation. This second digit is of importance because constant speed engine regulation in the EU is currently limited to stage IIIA (stage IIIB and IV constant speed engines do not exist).
Note also that stage IV does not exist for any NRMM engines < 56 kW. In this case emission regulation in the EU is limited to stage IIIB.

engine plate


engine number


In this example the letters LA mean it is a variable speed stage IIIB 130 560 kW engine. This complies with 01 Sept 2015 GLA NRMM requirements for all zones, and complies with 01 Sept 2020 GLA NRMM requirement for all zones EXCEPT Central Activity Zone and Canary Wharf.

You can then use the first letter to find the EU Emissions Stage of the engine as follows:

Engine Category Letter EU Emissions Stage
A-C EU Stage I
D-G EU Stage II
Q-R EU Stage IV
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