This resource is provided to help Australian businesses and organisations understand the issues surrounding stack testing.


What is Stack Testing?

A stack test is a procedure for sampling a gas stream from a single sampling location at a facility, unit, or pollution control equipment. It is used to determine a pollutant emission rate, concentration, or parameter while the facility, unit, or pollution control equipment is operating at conditions that result in the measurement of the highest emission or parameter values (prior to any control device) or at other operating conditions approved by the regulatory authority. A test is comprised of three (3) sampling runs for a specified sampling time span. Additional conditions may be required by applicable rules, permit, or enforcement order. The testing is performed using sampling and analytical procedures approved by the EPA for the specific pollutant or parameter and facility, unit, pollution control equipment, process, or operation. A Stack Tests is also known as an "Emission Test", "Source Sampling Test", "Compliance Test", or "Performance Test".

In addition, a Stack Test measures the amount of a specific regulated pollutant, pollutants, or surrogates being emitted; demonstrates the capture efficiency of a capture system; or determines the destruction or removal efficiency of a control device used to reduce emissions at facilities. Stack testing is an important tool used to determine a facility's compliance with emission limits, or capture or control efficiencies established.

Types of testing include:

  • Compliance tests
  • Trial-burn tests and engineering services
  • CEMS CGAs (Cylinder Gas Audits)
  • CEMS RATAs (Relative Accuracy Test Audits, Conventional and Mercury CEMS)
  • PSTs (Performance Specifications Tests)
  • Process tests and data collection
  • Emission factor/emission inventory tests
  • Emission characterization

Instrumental Emission Testing

  • Mobile CEMS Laboratories
  • Performance Specification Testing
  • CO, CO2, O2, SO2, and NOx
  • Total Gaseous Organics

Specialized Emissions Testing

  • 3-D Pilot Flow Studies
  • Capture Efficiency (CE) Determinations
  • Thermal Oxidizer Temperature Optimization
  • RCRA/TSCA Trial Burns
  • VOC Emissions Profiling
  • Dioxin/Furan, PAH, and PCB Emission Testing
  • Boiler MACT Testing
  • Mercury Speciation Determination

Air Pollution Control Equipment Testing and Optimization

  • On-Site Inspection
  • Performance Data Evaluation
  • Diagnostic Testing
  • Equipment Specification Data
  • Pilot Plant Tests

Different Test Methods

  • EPA Methods
  • NIOSH Methods
  • ASTM Methods
  • ASME Test Methods
  • NCASI Test Methods
  • CARB Methods
  • SW846 Methods

Specialized Emissions Testing

  • FTIR Spectroscopy - On Site
  • GC - On Site
  • 3-D Air Flow Studies
  • Fugitive Emission Quantification
  • RCRA / TSCA CPT/ Trial Burns
  • VOC/TGNMO Emissions Testing
  • Dioxin / Furan, PAH, and PCB Emissions Testing
  • BIF Emissions Testing
  • Multi-Metals Emissions Testing

Instrumental Emission Testing

  • Mobile CEM Laboratories
  • New Source Performance Standards Emissions Testing
  • CO, CO2, O2, SO2, and NOx
  • Total Hydrocarbons and VOCs

Air Pollution Control Equipment: Testing and Optimization

  • On-Site Inspection and Performance Data Evaluation
  • Diagnostic Testing
  • Equipment Specification Data
  • Pilot Plant Tests

Continuous Emissions Monitoring (CEM)

  • CEM System Preventative Maintenance Packages
  • Instrumental Mobile CEM Laboratories
  • Performance Specification Tests (PST)
  • Quarterly Cylinder Gas Audits (CGA)
  • Absolute Calibration Audits (ACA)
  • Monitor Selection Criteria
  • Monitor Location Selection
  • Performance Criteria Relative Accuracy Test Audits (RATA)
  • Relative Accuracy Audits (RAA)

Fourier Transform Infrared Spectroscopy (FTIR)

Commonly referred to as FTIR, Fourier Transform Infrared Spectroscopy is one of the most powerful tools in the Air Compliance Testing technological toolbox.

FTIR can be used to identify chemicals from paints, polymers, coatings, spills, drugs, and contaminants (qualitative analysis). FTIR is likely the most powerful tool for identifying types of chemical bonds (functional groups). The wavelength of light absorbed is characteristic of the chemical bond as can be seen in this annotated spectrum. Because the strength of the absorption is proportional to the concentration, FTIR can also be used for quantitative analyses.

FTIR Applications include:

  • Identifying Organic Compounds and many Inorganic Compounds
  • Hazardous Air Pollutant (HAP) Speciation
  • Ambient Air and Employee Exposure Monitoring
  • Contaminants Analysis
  • Analysing Oil and Lubricants
  • Thin Film Metrology and Composition
  • Chemical Process Monitoring and Optimization
  • Measuring Catalyst Efficiency
  • Real Time VOC Emission Analysis
  • Control Equipment Optimization
  • In-situ Chemical Vapour Monitoring
  • Blending Processes Optimization
  • Indoor Air Monitoring of VOC's and Semi-Volatiles at very Low Levels
  • Measuring Moisture in Corrosive Gases
  • On-Line Process Monitoring
  • Remote Sensing of Fugitive Emissions
  • Reaction End Point Determinations

FTIR Methods:

  • EPA Method 318 - Extractive FTIR Method for Measurement of Emissions from Mineral Wool and Wool Fibre Glass Industries
  • EPA Performance Specification 15 for Extractive FTIR CEMS in Stationary Sources
  • EPA Method 320 -Vapour Phase Organic and Inorganic Emissions by FTIR (extractive)
  • EPA Method 321 - Determination of HCl for Portland Cement Industries
  • EPA Protocol for Extractive FTIR for Analysis of Gas Emissions
  • NIOSH Method 3800 - Organic and Inorganic gases by Extractive FTIR Spectrometry
  • ASTM D6348 - 03 Standard Test Method for Determination of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy>

How FTIR Works:

Due to the fact that chemical bonds absorb infrared energy at specific frequencies (or wavelengths), the basic structure of compounds can be determined by the spectral locations of their IR absorptions. The plot of a compound's IR transmission vs. frequency is its "fingerprint" that can be compared to reference spectra to identify the material. FTIR spectrometers offer speed and sensitivity impossible to achieve with older wavelength-dispersive instruments. This capability allows rapid analysis of micro-samples down to the nanogram level is some cases, making the FTIR unmatched as a problem-solving tool in organic analysis.

Fourier Transform Infrared Spectroscopy is preferred over Dispersive or Filter Methods of Infrared Spectral Analysis for several reasons:

  • It is non-destructive
  • There are few sample constraints; solids, liquids and gases can be accommodated.
  • It provides a precise measurement method which requires no external calibration
  • Because all of the frequencies are measured simultaneously, most measurements by FTIR are made in a matter of seconds rather than several minutes.
  • It has greater optical throughput
  • Mechanical Simplicity: The moving mirror in the interferometer is the only continuously moving part in the instrument. Thus, there is very little possibility of mechanical breakdown.
  • Sensitivity is dramatically improved with FTIR for many reasons. The detectors employed are much more sensitive, the optical throughput is much higher (referred to as the Jacquinot Advantage) which results in much lower noise levels, and the fast scans enable the coaddition of several scans in order to reduce the random measurement noise to any desired level (referred to as signal averaging).
  • These instruments employ a HeNe laser as an internal wavelength calibration standard (referred to as the Connes Advantage). These instruments are self-calibrating and never need to be calibrated by the user.

Isokinetic Sampling

The purpose of Isokinetic sampling is to capture particulates or aerosols that pass through a defined area over a given time period without altering their travel paths. The velocity of the stack gas going into the sampling probe's nozzle is equal to the velocity of the moving stack gas at that point in the stack cross sectional area. The moving stack gas is disturbed as little as possible so that the same amount of particles and aerosols go into the probe nozzle as would have passed the area of the nozzle had it not been there.

Wet Chemistry Methods

Wet Chemistry methods employ either Isokinetic, Non-Isokinetic, proportional or non-proportional integrated sample techniques. These methods are used to determine various flue gas components such as Sulfur Dioxide, Sulfur Trioxide, Dioxins and Furans, Hydrochloric Acid, Chlorine and Multi Metals. These Wet Chemistry methods collect the targeted contaminant in specific chemical solutions held in the sample train's impingers. After the samples are collected, the impinger contents are analysed using a variety of advanced laboratory techniques (GC/MS, IC, GFASS, ICP, and others).

Capture/Control Efficiency

Pollution Control Efficiency testing for Scrubber Inlet & Outlets, Electostatic Precipitators, Baghouses, Cyclone Collectors, Thermal, Catalytic and Regenerative Thermal Oxidizers (RTOs) for VOC Capture, Removal and Destruction Efficiency.

Instrumental Analysers

Instrumental Analysers are used in conjunction with EPA Protocol 1 Calibration Standard Gases to determine gaseous emissions from Stationary and Mobile Sources. A variety of analyser technologies are employed to accomplish this, including Non-Dispersive Infrared, Gas Chromatography (with Flame Ionization and Thermal Conductivity Detectors), Chemiluminescence, Hand-Held Portable Monitors, and other techniques determined to be equivalent and approved by State and Federal Regulatory Authorities. We also provide Performance Specification Testing (PST), Relative Accuracy Test Audits (RATA), Opacity Audits, and Calibration Gas Audits (CGA) for SO2, CO, NOx, THC/VOC, O2, CO2 and Opacity CEM or COM systems regulated by CFR Title 40 Part 60 and Part 75 standards.

Gas Flow Distribution Studies (3-D Flow)

A 3-D Pilot is used to determine the velocity pressure, yaw and pitch angles of the flow velocity vector in a stack or duct. Yaw angle is determined directly by rotating the probe to null the pressure across a pair of symmetrically placed ports (2 & 3) on the probe head. The pitch angle is calculated using probe specific calibration curves. From these values, and a determination of stack gas density, the average axial velocity of the stack gas is calculated. The average gas volumetric flow rate in the stack or duct can then be determined from the average axial velocity.

Stack and Stationary Source Emission Services

Flow rate, temperature and velocity USEPA Method 2, ISO10780
Particulate matter USEPA Method 5, USEPA Method 17, AS4323.2
PM10 USEPA Method 201A
Odour AS4323.3
Volatile organic compound (VOC) USEPA Method 18
Nitrogen oxides (NOx) USEPA Method 7E, USEPA Method 20
Carbon monoxide (CO) USEPA Method 10
Carbon dioxide (CO2) USEPA Method 3A
Oxygen (O2) USEPA Method 3A
Sulphur dioxide (SO2) USEPA Method 6, USEPA Method 6C
Sulphur trioxide (SO3) and sulphuric acid mist (H2SO4) USEPA Method 8
Halides (e.g. chlorides and fluorides) USEPA Method 26, USEPA Method 26A
Metals USEPA Method 29
PAH's CARB 429, USEPA Method 23, SW846-0010
Dioxins and Furans USEPA Method 23
Total organic compounds (TOC) USEPA Method 25A
Aldehydes and ketones SW846-0011

Additional Services

  • Stack gases (NOx, SO2, CO, CO2, O2)
  • Permanent gases (He, H2, Ar, O2, N2, CO, CO2)
  • Sulfur gases (H2S, sulfides & mercaptans)
  • CFC's & HCFC's
  • Total reduced sulfur compounds
  • Volatile organic compounds (aliphatic, aromatic, halogenated, oxygenated)
  • Total organic compounds
  • Dioxins, furans, PAH's, PCB's
  • Aldehydes and ketones (including formaldehyde)
  • Phenols & cresols
  • Isocyanates (MDI, TDI, HDI)
  • Phthalate esters (DIOP, DOP)
  • Anions (nitrate, sulfate, phosphate)
  • Halogens and halides (including fluoride)
  • Acidity, alkalinity & pH
  • Ammonia & amines
  • Cyanide (total soluble & gaseous)
  • Metals (including chromium VI)
  • Odour - concentration, intensity, hedonic tone, character
  • CEM calibrations (continuous emission monitors)

Mobile instrumentation & equipment:

  • Isokinetic and non-isokinetic source sampling equipment
  • Stack gas analysers - NO, NO2, SO2, CO, CO2, O2
  • FID analysers - Hydrocarbons
  • Dew point meter
  • Gas chromatographs - Hydrocarbons, sulfur gases, He, H2, Ar, O2, N2, CO, CO2
  • Dilution probe - up to 200 times dilution, thermostatically controlled to 350°C
  • Dynamic olfactometer - Odour concentration & intensity

Odour Sampling

Odour sampling techniques employed include isolation flux, fugitive, and point source sampling. Consultants can also arrange preparation and hire of odour sampling containers to clients with their own sampling capabilities. Most consultants offer a same day analysis service to minimise sample storage times.

Testing by Industry

Adhesives and Sealants
Air, Water, & Solid Waste Management
Aircraft Engines and Engine Parts
Alkalies and Chlorine
Aluminum Sheet, Plate, and Foil
Asphalt Felts and Coatings
Asphalt Paving Mixtures and Blocks
Automotive Services
Bags: Plastics, Laminated, & Coated
Bags: Uncoated Paper & Multiwall
Blast Furnaces and Steel Mills
Brick and Structural Clay Tile
Broadwoven Fabric Mills
Carbon and Graphite Products
Cheese, Natural and Processed
Chemical Preparations
Cold Finishing of Steel Shapes
Colleges and Universities
Combination Utilities
Commercial Laundry Equipment
Commercial Printing, Gravure
Commercial Printing, Lithographic
Concrete Products
Construction Sand and Gravel
Copper Rolling & Drawing
Corrugated & Solid Fiber Boxes
Crushed and Broken Limestone
Crushed and Broken Stone
Current-Carrying Wiring Devices
Custom Compound Purchased Resins
Cut Stone and Stone Products
Cyclic Crudes and Intermediates
Electric Lamps
Electric Services
Electrical Equipment & Supplies
Electrical Industrial Apparatus
Electrometallurgical Products
Electronic Components
Ethanol Plants
Fabricated Metal Products
Fabricated Rubber Products
Fabricated Structural Metal
Fertilizers, Mixing
Gasoline Service Stations
General Medical & Surgical Hospitals
Gray and Ductile Iron Foundries
Gypsum products
Hardwood veneer and plywood
Industrial Inorganic Chemicals
Industrial Machinery
Industrial Organic Chemicals
Inorganic Pigments
Internal Combustion Engines
Lubricating Oils and Greases
Machine Tools, Metal Forming
Manufacturing Industries
Metal Cans
Metal Coating and Allied Services
Metal Doors, Sash, and Trim
Metal Heat Treating
Metal Sanitary Ware
Metal Stampings
Metal Work
Mineral Wool
Motor Vehicle Parts and Accessories
Motors and Generators
Natural Gas Transmission and Distribution
Nonclay Refractories
Nonferrous Forgings, Rolling & Drawing
Nonmetallic Mineral Products
Packaging Machinery
Paints and Allied Products
Paper Coated & Laminated
Paperboard Mills
Petroleum Refineries
Plastics Materials and Resins
Plastics Products
Plating and Polishing
Plumbing Fixture Fittings and Trim
Pottery Products
Primary Copper
Primary Metal Products
Primary Nonferrous Metals
Printing and Writing Paper
Pumps and Pumping Equipment
Refuse Systems
Scrap and Waste Materials
Secondary Nonferrous Metals
Sewerage Systems
Soap and Other Detergents
Soybean Oil Mills
Steam and Air-Conditioning Supply
Steel Foundries
Steel Pipe and Tubes
Steel Wire and Related Products
Synthetic Rubber
Telephone and Telegraph Apparatus
Vegetable Oil Mills
Wet Corn Milling
Wood Household Furniture
Wood Products

Testing by Source

  • Baghouses
  • Baking Ovens
  • Boilers (Parts 60 and 75)
  • Calciners
  • Can Coating Lines
  • Electric Arc Furnaces (EAF's)
  • Engines
  • Extruders
  • Fluidized Catalytic Crackers
  • Glycol Dehydrators
  • Heaters
  • Incinerators
  • Lime Kilns
  • Metal Coating Lines
  • Paint Booths
  • Paper Coating Lines
  • Parametric Emission Monitoring Systems (PEMS)
  • Printing Presses
  • Reverbatory Furnaces
  • Regenerative Thermal Oxidizers (RTO's)
  • Scrubbers
  • Sewage Slugde Incinerators
  • Thermal Oxidizers
  • Turbines
  • Vapour Combustors
  • Vapour Condensers
  • And more...