Agricultural Boilers & Heaters

Boilers or heaters used for agricultural purposes (e.g., greenhouses, tree seedling nurseries) that have a capacity greater than 0.15 MW (megawatts)  must be registered under the Code of Practice for Agricultural Environmental Management (AEM Code). Smaller boilers or heaters with 0.15 MW or less capacity, do not need to be registered but must meet a design standard, as required in the AEM Code. Boilers or heaters that are powered by electricity do not need to be registered. 

Emissions Limits 

This table summarizes the applicable opacity level and particulate matter limits set out in the AEM Code. 

Boiler and heater emission limits

Total Capacity


(Maximum Allowable)

Particulate Matter

(Maximum Allowable)

≤ 1 MW 20% Not applicable
> 1 MW and ≤ 3 MW 10% 50 mg/m3
> 3 MW 10% 35 mg/m3

Opacity Tests

Opacity is the degree to which an emission obstructs the view of an object in the background, expressed numerically from zero percent (transparent) to 100 percent (no transparency). In accordance with the AEM Code, all emissions from biomass-fuelled boilers and heaters must be visually tested for opacity during operation, at least 60 minutes after the boiler or heater is started and before shutdown procedures begin.

The Ringelmann test is normally used to visually assess the density of smoke (opacity). An example of a Ringelmann Smoke Chart (below) shows shades of grey that can be used to compare against the density of smoke coming from a stack. 

Ringelmann Smoke Chart






Particulate Matter Tests 

In accordance with the AEM Code, emissions from any biomass-fuelled boiler or heater that has an output greater than 1.0 MW or its capacity increased by more than 25 percent, must be tested for particular matter as indicated in the B.C. Field Sampling Manual – PART B: Air and Air Emissions Testing (PDF) or the B.C. Environmental Laboratory Manual.

How to Determine Boiler Output Capacity

Boiler capacity information may be found on the boiler nameplate (the metal tag attached to the boiler) or requested from the boiler manufacturer. Only register boilers that are, or will be, in operating condition and are required for the heating season. Capacity values need to be reported in megawatts (MW) for registration. If the boiler capacity is not in MW, please use the following formulas for conversion to MW.

  • ________  GJ/hr X 0.2778  =  ________MW
  • ________  MMBTU/hr X 0.2931  =  ________MW
  • ________  Boiler BHP X 0.009803  =  ________MW

The boiler nameplate indicates an energy input of 400 BHP:

  • 400 BHP X 0.009803 = 3.9212 MW 

Disclaimer: The information on this page is guidance only. Please refer to the Code of Practice for Agricultural Environmental Management for specific regulatory requirements.