Boiler (Small) 

Steam generation capacity (tph)


Emission limit

Less than 2

Particulate matter


2 to less than 10

- do -


10 to less than 15

- do -


15 and above

- do -


*To meet the respective standards, cyclone / multicyclone is recommended as control equipment with the boiler.

**To meet the standard, bag filter / ESP is recommended as control equipment with the boiler.

Note :


12% of CO2 correction shall be the reference value for particulate matter emission standards for all categories of boilers.


These limits shall supercede the earlier limits notified under Schedule I at Sr.No.(34) of EPA, 1986 (GSR 742E, dated 30 August, 1990).


Stack Height for Small Boilers

For the small boilers using coal or liquid fuels, the required stack height with the boiler shall be calculated by using the formula

H = 14 Q 0.3

Where H = Total stack height I meters form ground level.

= SO2 emission rate in kg/hr

In no case, the stack height shall be less than 11 metre.

Where providing tall stacks are not feasible using above formula, the limit of 400 mg/Nm3 for SO2 emission shall be met by providing necessary control equipment with a minimum stack height of 11 metre.

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