CPCB (Central Pollution Control Board) guidelines for stack monitoring testing includes frequency of testing, parameters, time of the year & depending of industry type number of stations.
Stack monitoring is a procedure for sampling of gas stream from an emission point. It measures emissions of industrial waste or pollutants entering the atmosphere.
Since the advent of industrial revolution, the air pollution levels have touched the sky! With the current scenario regarding to air pollution, it has become a necessary evil to curb the pollution at its source or find alternatives to reduce air pollution.
Using stack has definitely aided to reduce air pollution. A stack is a vertical pipe structure through which flue gases (combustion product gases) are exhausted out in the atmosphere, it can also be known as a chimney.
But, has the installation of stack really aided in control of air pollution or is it just a myth?
Such questions can only be answered with the help of analytical results, i.e; Stack monitoring. Stack monitoring will provide results which puts light on the pollutants beings released in the atmosphere and their levels.
To conduct Stack monitoring in India CPCB (Central Pollution Control Board) have put forth guidelines and permissible limits. Let’s have a look into CPCB Guidelines for Stack Monitoring.
The industrial units are required to monitor ambient Air Quality and stack emissions as the pollutants released in the atmosphere will have a detrimental effect on the human health and environment.
Stack sampling is conducted by diverting a part of the gas stream through a sampling train which includes the following basic components;
The sampling train consists of a nozzle placed in gas stream, a sampling probe through which the sample is drawn at different traverses, particulate and gas collection devices, a flow measuring device and a prime mover such as a vacuum pump.
A stack monitoring equipment or kit should have following components:
The Central Pollution Control Board (CPCB) mandates stack height adherence with the following specifications:
Additionally, CPCB requires gases to undergo either recycling or oxidation in an after-combustor before venting. Stack emission monitoring is crucial for scrutinizing pollutants released into the air through stack emissions.
To use this calculator, simply enter the required values into the respective fields:
The calculated stack height ensures compliance with CPCB guidelines for pollutant dispersion, minimizing ground-level concentrations. A taller stack promotes better dispersion and reduces environmental impact, safeguarding air quality and public health. Use the results to plan stack dimensions or verify adherence to environmental standards.
The General Stack testing procedure would be as follows;
On obtaining the results they will be compared with the permissible limits prescribed by CPCB. The guideline given by CPCB is like a Bible which helps us conduct stack monitoring efficiently. If in any scenario, the stack emission exceeds the permissible limit set by CPCB, stack monitoring will be an indication for adoption of new pollution control strategies. This will eventually help us curb air pollution.
As per CPCB, frequency for stack emissions monitoring depends upon various factors such as industry, parameter and plant capacity. For cement, fertilizer, thermal plants, and other major air polluting units, stack sampling ranges from once a week to once in eight weeks. Emissions from cells should be monitored for total particulates and fluorides every week. Emissions from other stacks should be monitored once every four weeks.
Stack monitoring involves measuring the total volume, velocity, flow rate, and moisture content of released gaseous pollutants. The gases to be measured are specified by government agencies such as the CPCB and EPA.
According to CPCB guidelines, the prescribed minimum stack height is 30 meters. Nevertheless, there’s a provision for relaxation to H=74(Q) po 27, where Qp represents the particulate emission in tonnes per hour.
