92.What is the Smoke Density and what is its regulation limits and operation limits?

Flue gas consists of large quantity of CO is smoke. When light can pass through the flue gas fully, the smoke density is 0%. When no light pass through the flue gas, smoke density is 100%.

Smoke emission of 20% in the chimney is allowed. However a good practice is to operate a boiler within 0 to 5% smoke density in the flue gas.

Operation of a boiler at more than 40% for more than 5 min in a day is an offense and subject to penalty by Government.