Reduce NRMM & Genset Emissions with HJS Retrofits

We offer the first and only Energy Saving Trust (EST) certified retrofit exhaust systems for all power bands, helping you achieve Stage 5 compliance and reduce emissions on existing equipment.

The Greater London Authority Low Emission Zone for Non Road Mobile Machinery

The Low Emission Zone in London applies to all Non Road Mobile Machinery (NRMM) with a net power rating of between 37kw and 560kw operating within central London. The minimum emission standards for NRMM within London are detailed below:

Central Activity Zone or Canary Wharf
Greater London
From Sept 2020
Stage IV or best available retrofit technology
Stage IIIB or best available retrofit technology

With an estimated 10,000 active construction sites in London at any one time NRMM has been identified as one of the largest contributors to poor air quality in London.

Plant hire companies machine operators and construction organisations have the following compliance options:

HJS SCR/SCRT Emission Reduction Technology

The HJS SCRT system combines a diesel particulate filter to reduce particulate matter with an SCR catalyst to reduce Nitrogen Oxide.  The system uses an ammonia-based fluid called AdBlue which is finely atomised and injected directly into the exhaust system at calculated intervals during operation.  In the hot exhaust gas stream, the AdBlue evaporates and hydrolyses to ammonia which is mixed with the dirty gases which then pass over a catalyst. The ammonia reacts with the nitrogen oxide within the exhaust gas breaking the Nitrous Oxides down to form Nitrogen and water.

For the reduction of particulate matter, a highly efficient oxidation catalyst is located upstream of a diesel particulate filter which reduces particulate emissions by as much as 99%.

If required, an electric heater can be installed in the exhaust tract upstream of the AdBlue injection position which helps with low exhaust gas temperatures e.g. after a cold start or during operation with low load and low engine speeds in order to maintain adequate exhaust gas temperatures for high efficiency of the SCR/SCRT system.

The HJS SCR/SCRT system does not require constant maintenance during normal operation, apart from the need to refill the AdBlue which is indicated via the HJS service display. 

For the majority of operators the retrofitting of existing machinery will be the quickest, most effective and most reliable way of ensuring that they comply with the conditions set within the LEZ.