Understanding the language of industrial dust collection helps you make smarter decisions about air quality, worker safety, and regulatory compliance.
This glossary defines essential terms used in dust collection systems, from airflow measurements to filtration equipment. Whether you're specifying new equipment, troubleshooting system performance, or ensuring OSHA and NFPA compliance, these definitions provide the foundation for effective dust management in manufacturing environments.
Where relevant, we’ve linked to deep-dives and cited official/industry sources to help you go further.
ACFM (Actual Cubic Feet Per Minute) is the actual volume of gas flowing through a system per minute at operating temperature, pressure, moisture content, and composition conditions.
Why it matters: ACFM accounts for real-world conditions in your facility, unlike standard measurements. Equipment is typically rated at standard conditions (SCFM), so conversions between actual and standard conditions are required for proper sizing. Temperature and humidity variations directly impact system performance and filter efficiency.
The process where multiple dust particles cluster together through surface tension, moisture, static charge, or particle structure to form larger particles.
Why it matters: Agglomeration can improve dust collection efficiency by creating larger, easier-to-capture particles, but excessive agglomeration may cause filter blinding and reduced airflow.
The ratio of actual cubic feet per minute (ACFM) flowing through filters divided by the square footage of available filter area, typically expressed as CFM per square foot.
Why it matters: Proper air-to-cloth ratios prevent premature filter failure and help maintain consistent system performance. Too high creates excessive pressure drop; too low wastes filter capacity.
ASHRAE is American Society of Heating, Refrigerating, and Air-Conditioning Engineers, a professional organization establishing industry standards for ventilation system design and testing procedures.
Why it matters: ASHRAE standards guide proper design and operation of industrial ventilation systems, including dust collectors and fume hoods, ensuring worker safety and regulatory compliance.
Supply or makeup air delivered outside a fume hood's chamber to reduce total air consumption from conditioned building space.
Why it matters: Auxiliary air systems reduce energy costs by minimizing the amount of heated or cooled building air exhausted through ventilation systems, particularly important in climate-controlled manufacturing facilities.
Fabric blockage caused by dust, fume, or liquid that the cleaning mechanism cannot discharge, resulting in reduced gas flow due to increased pressure drop.
Why it matters: Blinding reduces system efficiency, increases energy consumption, and may require filter replacement. Understanding blinding helps in selecting appropriate filter media and maintenance schedules.
A sliding damper installed in ductwork to manually control or isolate airflow to specific collection points or equipment branches.
Why it matters: Blast gates allow operators to balance system airflow, isolate equipment for maintenance, and optimize collection efficiency by directing suction where needed. Proper blast gate management prevents over-ventilation and reduces energy waste.
Fine dust particles or fumes that migrate through filter media despite filtration, sometimes called filter leakage.
Why it matters: Excessive bleed indicates filter damage, improper installation, or inadequate filtration efficiency. This directly affects indoor air quality and regulatory compliance with OSHA exposure limits.
An air-moving device consisting of a motor, impeller, and scroll housing that creates the pressure required for dust collection.
Why it matters: The blower is the heart of any dust collection system. Proper blower selection ensures adequate airflow, energy efficiency, and the ability to maintain capture velocity throughout the system.
Explore our premium efficiency blowers / fans.
The upward gas velocity in the dust collector housing between filter elements, calculated above the hopper at the cross-sectional plane.
Why it matters: Proper Can Velocity prevents collected dust from re-entraining back into the airstream before settling into hoppers, maintaining collection efficiency and reducing filter cake buildup.
The minimum hood-induced air velocity required to capture and transport dust particles into the collection hood.
Why it matters: Insufficient capture velocity lets contaminants escape. Use ACGIH target ranges for your process to achieve effective source capture and reduce exposure.
Cubic Feet Per Minute, the standard unit measuring volumetric airflow through dust collection systems.
Why it matters: CFM sets capacity to capture and transport dust. Correct calculations are fundamental to design and sizing and support compliance with OSHA engineering controls.
The degree to which fumes and contaminants remain confined within a hood compartment rather than escaping into the work environment.
Why it matters: Effective containment protects workers from exposure to hazardous airborne particles. Poor containment can lead to exposures exceeding OSHA permissible exposure limits, creating health risks.
A mechanical device installed in ductwork to regulate or control air volume flowing through specific sections of a ventilation system.
Why it matters: Dampers balance system airflow, maintain proper static pressure, and allow system optimization without equipment modifications. They're essential for multi-branch dust collection networks.
A compressed-air-operated valve that delivers short, high-pressure air pulses to clean filters in pulse-jet dust collectors.
Why it matters: Diaphragm valves enable automated filter cleaning without stopping production. Valve failure leads to filter blinding, reduced airflow, and system inefficiency.
The difference between static pressures measured at a baghouse's inlet and outlet, typically expressed in inches of water column (in. W.C.).
Why it matters: Differential pressure indicates filter condition and system health. Rising ΔP signals filter loading or blinding, while low ΔP may indicate filter damage or leaks. Monitoring ΔP helps prevent energy waste and supports ongoing compliance.
Small solid particles created by mechanical breakdown of larger materials through crushing, grinding, drilling, or explosions, dispersed into the air through handling operations.
Why it matters: Understanding combustible dust types helps determine explosion hazards and appropriate controls. Many industrial dusts are combustible, requiring NFPA 652-compliant dust hazard analysis.
An air-cleaning device that removes particulate matter from air in industrial, commercial, and production facilities to improve air quality.
Why it matters: Dust collectors are OSHA's preferred "engineering control" for managing workplace dust exposure. Proper selection and maintenance help support compliance with permissible exposure limits and combustible dust standards.
The quantity of dust particles in an air stream, usually expressed as grains of dust per cubic foot of air.
Why it matters: Dust loading determines filter sizing, cleaning frequency, and system capacity requirements. High dust loading requires more aggressive filtration and frequent maintenance.
Pressure loss occurring when air enters a duct or hood, measured in inches of water column (in. H₂O).
Why it matters: Entry losses reduce system efficiency and must be calculated during design to ensure adequate airflow at collection points. Minimizing entry loss improves energy efficiency.
The Environmental Protection Agency (EPA) is the federal agency responsible for developing and enforcing environmental policy, including air quality standards throughout the United States.
Why it matters: EPA sets National Ambient Air Quality Standards (NAAQS) that affect industrial emissions. EPA Particulate Matter standards complement OSHA worker protection requirements.
The quantity of air exhausted by ventilation equipment, typically expressed in cubic feet per minute (CFM), required to maintain desired face velocity.
Why it matters: Proper exhaust volume ensures adequate contaminant capture without excessive energy consumption. Insufficient exhaust creates worker exposure; excessive exhaust wastes energy.
The speed of air entering a fume hood through the face opening, measured in feet per minute (FPM).
Why it matters: Face velocity must be sufficient to prevent contaminant escape but not so high that it creates turbulence. ANSI/ASSP Z9.5 and ASHRAE 110 provide guidance on appropriate face velocities for different applications to help maintain worker safety.
The layer of accumulated dust on the surface of filter media in a dust collector.
Why it matters: A stable filter cake actually improves filtration efficiency by providing additional filtration surface. However, excessive cake buildup increases pressure drop and requires cleaning.
The ratio of differential pressure across filters (in inches W.C.) to velocity through filters (FPM), indicating flow resistance.
Why it matters: Filter drag indicates how much resistance filters create to airflow. High filter drag reduces system performance and increases energy costs, signaling the need for cleaning or replacement.
The permeable membrane material used in filtration to separate particles from a fluid stream.
Why it matters: Filter media selection affects efficiency, longevity, and operating costs. Different dusts require specific media types for optimal capture efficiency and regulatory compliance.
The process of separating particles from a fluid stream using a permeable membrane that traps solids while allowing gas to pass.
Why it matters: Effective filtration is the core function of dust collection systems. Proper filtration protects worker health, ensures regulatory compliance, and prevents environmental contamination.
Small solid particles formed when vapors from solid materials condense into airborne particulate matter.
Why it matters: Fumes (like welding fumes) are typically smaller than mechanical dust, requiring higher-efficiency filtration. Many metal fumes are highly toxic, requiring strict exposure controls under OSHA standards.
Feet Per Minute (FPM) is the standard unit for measuring air velocity in ductwork and at collection points.
Why it matters: FPM measurements verify adequate transport velocity to prevent dust settling in ducts and ensure effective capture at hoods. ACGIH Industrial Ventilation Manual recommends minimum transport velocities for different dust types to maintain system effectiveness.
A pressurized pipe containing the compressed air supply that feeds pulse-jet cleaning systems in baghouse dust collectors.
Why it matters: Adequate header pressure and capacity ensure effective filter cleaning. Undersized headers cause uneven cleaning and premature filter failure.
An inlet device designed to capture contaminated air at the source and conduct it into the exhaust dust collection system.
Why it matters: Hood design and placement are critical for effective capture. Poorly designed hoods waste energy and fail to protect workers, potentially violating OSHA requirements.
A differential pressure gauge commonly used to measure and monitor pressure drop across baghouse filters.
Why it matters: Magnehelic gauges provide real-time system monitoring, alerting operators to filter loading or system problems before efficiency declines significantly.
A unit of length equal to 1/25,400 of an inch (or 1/1,000 of a millimeter), typically used to describe particle size in dust collection applications.
Why it matters: Particle size determines health hazards and filtration requirements. Particles under 10 microns (PM10) are respirable and regulated by EPA ambient air standards. Particles under 2.5 microns (PM2.5) pose the greatest health risks. OSHA enforces workplace exposure limits for respirable and total dust.
Read Our Blog: What is MERV Rating and Why is It Important?
Pressure conditions below atmospheric pressure (less than one atmosphere), typically found inside dust collector housings and ductwork.
Why it matters: Negative pressure systems prevent fugitive emissions but require leak-tight construction. Leaks in negative pressure systems pull in outside air, reducing efficiency.
A pressure-equalizing chamber within dust collection equipment that ensures uniform airflow distribution across filters.
Why it matters: Properly designed plenums prevent uneven filter loading and localized high velocities that can cause premature filter failure or dust re-entrainment.
Pressure conditions above atmospheric pressure (greater than one atmosphere), typically found downstream of blowers in positive-pressure systems.
Why it matters: Positive-pressure systems simplify ductwork construction but allow fugitive emissions through any leaks. Sealed construction and proper gaskets are essential for compliance.
Resistance to airflow through system components, expressed in inches of water column, which may refer to individual components or the entire system.
Why it matters: Pressure drop determines blower sizing and energy consumption. Monitoring pressure drop reveals filter condition and helps optimize maintenance schedules for efficiency and compliance.
Pounds per Square Inch (PSI) is a unit measuring pressure in compressed air systems; 1 PSI equals 27.68 inches of water gauge (at 4°C) or 2.04 inches of mercury.
Why it matters: PSI measurements indicate compressed air pressure available for pulse-jet cleaning. Insufficient PSI results in inadequate filter cleaning and system degradation.
The time interval between consecutive cleaning pulses in a pulse-jet baghouse dust collector.
Why it matters: Proper pulse timing balances filter cleaning with air consumption and filter life. Too frequent cleaning wastes compressed air; insufficient cleaning causes blinding.
Standard Cubic Feet per Minute (SCFM) is the volume of dry gas flow per minute at standard conditions (typically 70°F at sea level with standard air density of 0.075 lb/ft³), excluding moisture.
Why it matters: SCFM provides a standardized measurement for comparing equipment and calculating system requirements regardless of operating conditions. Equipment is typically rated at standard conditions, so converting between SCFM and ACFM is essential for proper sizing and performance prediction.
Air pressure or resistance within dust collectors, fume hoods, or ductwork, expressed in inches of water column.
Why it matters: Static pressure measurements reveal system balance and fan performance. Excessive static pressure indicates restrictions or undersized ductwork; insufficient static pressure suggests leaks or inadequate fan capacity.
Read Our Blog: What is Static Pressure in a Dust Collector?
A fume hood exhaust system that varies exhaust volume to maintain a target face velocity by automatically adjusting blower motor speed or balance dampers as sash position changes.
Why it matters: VAV systems reduce energy consumption while maintaining safety at the target face velocity setpoint. They're particularly effective in laboratory and pharmaceutical applications where hoods operate at varying sash heights.
The speed of airflow through ducts or collection points, measured in Feet Per Minute (FPM).
Why it matters: Maintaining minimum transport velocity prevents dust settling in ductwork. Different materials require different velocities; inadequate velocity causes buildup and potential combustible dust hazards.
The kinetic energy component of moving air, expressed as force per square inch applied by airflow.
Why it matters: Velocity pressure measurements calculate actual airflow rates and verify system performance. Understanding the relationship between static, velocity, and total pressure is fundamental to troubleshooting.
The quantity of air moved by a system, typically measured in cubic feet per minute (CFM).
Why it matters: Proper volume calculation ensures adequate contaminant capture and dilution. Insufficient volume creates exposure hazards; excessive volume wastes energy and may violate NFPA requirements for spark transport.
Understanding these terms is the first step toward effective dust management, but implementing the right solutions requires expertise.
Whether you're upgrading an existing system, ensuring compliance with OSHA and NFPA standards, or designing a new dust collection system, ACT Dust Collectors has the knowledge and experience to help.
Contact our team today to discuss your dust collection needs. We'll help you select the right equipment, optimize system performance, and maintain regulatory compliance while protecting your workers and your bottom line.
Talk to our team to learn more about and ask about our ready-to-ship industrial dust collectors.
This glossary provides general educational information about dust collection terminology. It is not a substitute for professional engineering consultation, compliance auditing, or regulatory guidance. Always consult with qualified professionals and refer to the most current versions of applicable standards and regulations for your specific application.
For additional information, please consult the following resources:
U.S. Occupational Safety and Health Administration (OSHA)
U.S. Environmental Protection Agency (EPA)
American Conference of Governmental Industrial Hygienists (ACGIH)
American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
Air Movement and Control Association (AMCA) International
American National Standards Institute (ANSI) / American Society of Safety Professionals (ASSP)
National Fire Protection Association (NFPA)
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