KEY TERMS FOR HEAVY EQUIPMENT FIRE PROTECTION
Fire suppression systems for heavy equipment use specialized terms related to system design, detection, actuation, suppression agents, fire hazards, components, and testing standards.
This glossary explains common fire suppression terms used in mobile equipment applications, including mining, construction, forestry, waste and recycling, oil and gas, transportation, ports, and other demanding industries.
Use this page to better understand the language of fire protection for heavy-duty mobile equipment.
A
ActivFire
ActivFire is an Australian fire equipment listing and certification scheme operated by CSIRO.
ActivFire helps verify that fire protection products meet relevant Australian standards, including standards such as AS 5062. For heavy equipment buyers, ActivFire listing can provide additional confidence that a system has been evaluated against recognized requirements.
Related terms: AS 5062:2022, FM 5970 HDME, Third-Party Testing
Related AFEX page: Third-Party Approvals & Certifications
Actuation Circuit
An actuation circuit is the part of the fire suppression system that activates the system and releases the suppression agent when a fire is detected.
The actuation circuit can be triggered automatically by the fire detection system or manually by an operator using a pushbutton or monitor panel. Once activated, it tells the system to discharge the suppression agent and respond to the fire.
Related terms: Detection Circuit, Manual Actuation, Automatic Discharge, Monitor Panel
AS 5062:2022
AS 5062:2022 is an Australian standard for fire protection systems used on mobile and transportable equipment.
The standard addresses system design, installation, detection, actuation, agent application, documentation, and ongoing maintenance. It is especially important in mining and heavy industry markets that follow Australian fire protection requirements.
Related terms: ActivFire, SAFE-X Liquid Agent, Fluorine-Free Agent, Third-Party Testing
Related AFEX page: Third-Party Approvals & Certifications
Automatic Discharge
Automatic discharge is the release of suppression agent without operator input after the system confirms a fire condition.
Automatic discharge is important because equipment fires can develop quickly, and the operator may not immediately see the fire. Automatic activation typically works alongside manual actuation, giving the system more than one way to respond during an emergency.
Related terms: Detection Circuit, Actuation Circuit, Discharge Delay, Manual Actuation, Linear Detection Wire
B
Battery Fire
A battery fire is a fire involving a machine’s battery system, wiring, charging components, or nearby electrical equipment.
On heavy equipment, battery fire risks may involve traditional lead-acid batteries, lithium-ion batteries, battery cables, charging systems, electrical faults, or heat generated near the battery compartment. Battery fires can be especially complex when lithium-ion batteries are involved because heat can spread within the battery pack and create additional safety concerns.
Fire suppression for battery areas should focus first on early detection, operator alerting, cooling where appropriate, and supporting safe operator egress. The right approach depends on the battery type, enclosure, machine design, and operating environment.
Related terms: Electrical Fire, Class C Fire, Detection Circuit, Linear Detection Wire, Spot Sensor, Operator Safety, Operator Egress, Fire Risk Assessment
Related AFEX page: Battery Fire Protection for Heavy Equipment
C
CE Marking
CE marking indicates that equipment meets applicable European health, safety, and environmental requirements for sale or use within the European Economic Area.
For fire suppression equipment, CE marking may be relevant when systems or components are supplied into European markets. It is one part of understanding product compliance for international equipment applications.
Related terms: FM 5970 HDME, Third-Party Testing
Related AFEX page: Third-Party Approvals & Certifications
Class A Fire
A Class A fire involves ordinary combustible materials such as wood, paper, trash, vegetation, or debris.
On heavy equipment, Class A fire risks may come from wood chips, dry leaves, brush, trash, or other combustible material that builds up around engine compartments, undercarriages, or work areas.
Related terms: Class B Fire, Class C Fire, Debris Fire, Dry Chemical Fire Suppression System
Class B Fire
A Class B fire involves flammable or combustible liquids.
On heavy equipment, Class B fire risks may involve diesel fuel, hydraulic fluid, engine oil, lubricants, or other liquid fuels. These hazards are common because fuel and hydraulic systems often operate near hot surfaces and ignition sources.
Related terms: Pooled Fuel Fire, Hydraulic Fire, Fuel Source, Liquid Chemical Fire Suppression System
Class C Fire
A Class C fire involves energized electrical equipment or wiring.
On heavy equipment, Class C risks may involve batteries, wiring harnesses, alternators, control panels, sensors, or electrical faults. Suppression agents used around energized electrical components must be appropriate for electrical fire hazards.
Dry chemical suppression agents are generally the preferred choice because they are non-conductive and can quickly interrupt the fire without increasing the risk of electrical shock or equipment damage from conductivity.
Related terms: Electrical Fire, Battery Fire, Detection Circuit, Dry Chemical Fire Suppression System, Control Unit
Compact Liquid Agent System
A compact liquid agent system is a space-saving fire suppression system that uses our SAFE-X liquid agent and can be mounted in any orientation, making it ideal for smaller or space-limited equipment.
Compact systems are used on machines such as skid steers, compact track loaders, forklifts, buses, deicers, and other equipment where a full-size tank may not fit. Smaller machines can still face serious fire risks, especially when they operate near people, buildings, production areas, other vehicles, or combustible materials.
Related terms: SAFE-X Liquid Agent, Compact Panel, Liquid Chemical Fire Suppression System, Automatic Discharge
Related AFEX page: Compact Fire Suppression for Critical Equipment
Compact Panel
A Compact Panel is a simplified fire suppression monitor panel installed inside the cab of smaller or space-limited equipment.
In the event of a fire, the Compact Panel provides audible and visual alerts to the operator. It monitors the fire suppression system and may use LED indicators, an audible horn, and an on-panel press-to-discharge button instead of a larger display.
Related terms: Control Unit, Compact Liquid Agent System, Manual Actuation, Horn and Strobe, Side Cartridge Design, Nitrogen Cartridge
Related AFEX page: AFEX Launches Next-Generation Compact Panel
Control Unit
A Control Unit is an advanced fire suppression monitor panel for larger or more complex equipment systems.
A Control Unit may include an LCD display, multiple detection and actuation circuits, internal event logging, relay outputs, and telematics connectivity. This makes it a strong fit for larger heavy equipment, complex installations, and operations that need more advanced system monitoring.
Related terms: Compact Panel, Telematics Connectivity, Detection Circuit, Linear Detection Wire
Related AFEX page: Detection & Monitoring
D
Detection Circuit
A detection circuit is the part of the fire suppression system that senses fire conditions and sends a signal to the monitor panel.
Detection circuits may use heat-sensitive detection wire, sensors, or other detection methods. They are typically routed through high-risk areas such as engine compartments, hydraulic zones, and electrical areas.
Related terms: Actuation Circuit, Control Unit, Compact Panel, Automatic Discharge, Spot Sensor, Linear Detection Wire
Related AFEX page: Linear Wire vs. Sensors
Discharge Delay
A discharge delay is a brief time lag between fire detection and agent discharge.
A discharge delay may give the operator time to recognize an alarm, stop the machine, prepare to exit, or take another immediate action before agent discharge occurs. The use and timing of a discharge delay depends on the system design, application, and applicable requirements.
Related terms: Detection Circuit, Automatic Discharge, Control Unit, Monitor Panel
Distribution Nozzle
A distribution nozzle releases suppression agent into a protected area.
Nozzle placement, type, and orientation affect how suppression agent spreads during discharge. On heavy equipment, nozzles are commonly positioned to cover engine compartments, hydraulic areas, turbochargers, electrical zones, and other fire-prone areas.
Related terms: Total Flooding, Fire Knockdown
Dry Chemical Fire Suppression System
A dry chemical fire suppression system uses a powder-based agent to quickly knock down flames.
A dry chemical system is commonly used on heavy equipment because it can provide fast fire knockdown and broad coverage in areas such as engine compartments, hydraulic zones, and other enclosed hazard areas.
Dry chemical systems are often used for Class A, Class B, and Class C fire risks, depending on the system design and application.
Related terms: Class A Fire, Class B Fire, Class C Fire, Total Flooding, Fire Knockdown, Dual Agent Fire Suppression System
Related AFEX page: Dry Chemical Fire Suppression System
Dual Agent Fire Suppression System
A dual agent fire suppression system uses both dry chemical and liquid agent in one installation.
Dual agent systems combine fast flame knockdown from dry chemical agent with cooling and reignition resistance from liquid agent. This makes them useful for larger machines or higher-risk applications where both immediate suppression and cooling are important.
In certain applications, NFPA standards also require dual agent systems. For example, NFPA 122, Standard for Fire Prevention and Control in Metal/Nonmetal Mining and Metal Mineral Processing Facilities, requires dual agent fire suppression systems on mobile equipment containing more than 150 gallons of hydraulic fluid. This requirement applies to large machines such as 250-ton haul trucks, 20-cubic-yard excavators, and 30-cubic-yard bucket wheel loaders, where elevated fire hazards demand comprehensive suppression strategies.
Related terms: Dry Chemical Fire Suppression System, Liquid Chemical Fire Suppression System, Fire Knockdown, Reignition, Hydraulic Fire, NFPA 122
Related AFEX pages: Dual Agent Fire Suppression System, The Case for Dual Agent Fire Suppression Systems
E
Electrical Fire
An electrical fire starts when wiring, batteries, control panels, or electrical components create enough heat to ignite surrounding material.
Electrical risks may involve short circuits, damaged wiring, battery failures, overloaded components, or faults in electronic systems. As mobile equipment becomes more advanced, electrical fire hazards are an increasingly important part of a fire risk assessment.
Related terms: Class C Fire, Detection Circuit, Control Unit, Battery Compartment, Battery Fire, Spot Sensor, Linear Detection Wire
Engine Compartment Fire
An engine compartment fire starts in or spreads through the engine area of a machine.
Engine compartments contain many common fire hazards, including hot surfaces, fuel, oil, electrical components, hydraulic lines, moving parts, and debris. Because fires can develop quickly in this area, engine compartments are often a primary protected zone in heavy equipment fire suppression design.
Related terms: Ignition Source, Fuel Source, Detection Circuit, Distribution Nozzle, Spot Sensor, Linear Detection Wire
Engine Shutdown Package
An engine shutdown package automatically shuts down a machine’s engine during a confirmed fire event.
Engine shutdown can help cut off fuel, hydraulic flow, or machine operation that could otherwise worsen a fire. This accessory may be used when stopping the equipment quickly is important to fire control and operator safety.
Related terms: Pooled Fuel Fire, Hydraulic Fire, Operator Egress, Fire Sleeve
Related AFEX page: Accessories for Mobile Equipment Fire Suppression, Should You Add an Engine Shutdown Package to Your Vehicle Fire Suppression System?
F
Fire Knockdown
Fire knockdown refers to how quickly and effectively a suppression system reduces or extinguishes visible flame.
Dry chemical agent does an excellent job of achieving rapid fire knockdown because it interrupts the chemical chain reaction that sustains combustion. When discharged, the agent quickly spreads throughout the protected area and attacks the fire at the flame level, helping suppress flames before they can spread to additional fuel sources.
Fast knockdown is especially important on heavy equipment because fires can spread quickly through fuel, oil, debris, wiring, and other combustible materials. By reducing flames rapidly, dry chemical agent can help limit fire growth and provide valuable time for operators to respond safely.
Related terms: Dry Chemical Fire Suppression System, Total Flooding, Distribution Nozzle, Dual Agent Fire Suppression System
Fire Risk Assessment
A Fire Risk Assessment is a systematic evaluation of a machine’s fire hazards, operating conditions, and protection requirements used to guide fire suppression system design.
A proper assessment identifies potential ignition sources, available fuel sources, high-risk areas, machine layout, environmental conditions, operator safety considerations, and the potential operational and financial impact of a fire. It also evaluates how a fire could start, spread, and affect critical components.
The findings help determine the most effective suppression strategy, including the appropriate agent type, detection coverage, nozzle placement, system configuration, and any supporting accessories needed to protect the equipment and its operators.
Related terms: Heavy-Duty Mobile Equipment, Hydraulic Fire, Engine Compartment Fire, Dual Agent Fire Suppression System, Battery Fire, NFPA 122, Linear Detection Wire, Spot Sensor
Related AFEX page: The Impact of Fire Risk Assessments on Suppression System Designs
Fire Sleeve
Fire sleeve is a heat- and flame-resistant protective wrap installed over hoses, wires, or critical lines.
Fire sleeve can help slow flame spread and protect important components from heat exposure during a fire event. It is often used as part of a broader fire protection strategy, especially around hydraulic lines, electrical wiring, or other vulnerable components.
Related terms: Engine Shutdown Package, Class B Fire, Hydraulic Fire, Hot Surface
Fire Suppression System
A fire suppression system is an engineered system that detects a fire, alerts operators, and automatically or manually discharges a suppression agent to control or extinguish the fire before it can spread.
On heavy equipment, fire suppression systems are commonly installed in high-risk areas such as engine compartments, hydraulic systems, electrical enclosures, battery compartments, and fuel system zones. These systems typically include fire detection devices, a monitor panel, actuation components, agent storage tanks, distribution hose or tubing, and strategically placed discharge nozzles.
Heavy equipment operates in demanding environments where heat, combustible fluids, electrical faults, and accumulated debris can increase fire risk. A properly designed fire suppression system helps protect operators, reduce equipment damage, minimize downtime, and support business continuity by responding quickly when a fire is detected.
Depending on the application and hazard profile, a fire suppression system may use dry chemical agent, liquid agent, or a dual-agent configuration that combines the strengths of both technologies.
Related terms: Automatic Discharge, Detection Circuit, Actuation Circuit, Dry Chemical Fire Suppression System, Liquid Chemical Fire Suppression System, Dual Agent Fire Suppression System, Fire Risk Assessment, Spot Sensor, Linear Detection Wire, Nitrogen Cartridge, System Recharge
Related AFEX page: What is a Fire Suppression System for Heavy Equipment?, The Ins and Outs of Vehicle Fire Suppression Systems
Fire Triangle
The fire triangle explains that fire needs three things to start and continue burning: heat, fuel, and oxygen.
On heavy equipment, heat can come from turbochargers, exhaust components, brakes, electrical faults, or hot engine surfaces. Fuel can come from diesel, hydraulic fluid, engine oil, grease, debris, or other combustible materials. Oxygen is present in the surrounding air.
Fire suppression systems help control fire by interrupting one or more parts of the fire triangle. Dry chemical agents can interrupt the chemical reaction of the fire, while liquid agents can help cool hot surfaces and reduce the chance of reignition.
Related terms: Hot Surface, Dry Chemical Fire Suppression System, Liquid Chemical Fire Suppression System, Reignition
Related AFEX page: Understanding the Fire Triangle and Why It Matters for Heavy Equipment
Fluorine-Free Agent
A fluorine-free agent is a fire suppression agent formulated without fluorinated compounds such as PFAS.
Fluorine-free agents are becoming more important as industries evaluate environmental requirements, regulatory expectations, and long-term chemical use. For heavy equipment fire suppression, a fluorine-free liquid agent must still meet performance needs in demanding environments.
Related terms: SAFE-X Liquid Agent, Liquid Chemical Fire Suppression System, AS 5062:2022, Third-Party Testing
Related AFEX page: AFEX Liquid Agent Fire Suppression System Receives FM 5970:2022 Certification for Mobile Equipment
FM 5970 HDME
FM 5970 HDME is an FM Approvals standard developed specifically for fire suppression systems used on heavy-duty mobile equipment.
Unlike standards designed for fixed fire protection systems, FM 5970 HDME was created to address the unique hazards and operating conditions of mobile equipment. Heavy-duty machines are exposed to constant vibration, shock, extreme temperatures, dust, moisture, corrosion, and the day-to-day wear and tear that come with demanding industries such as mining, construction, forestry, waste and recycling, and oil and gas.
To achieve FM 5970 approval, fire suppression systems are evaluated through rigorous third-party testing that may include vibration resistance, mechanical shock, environmental exposure, corrosion resistance, and fire suppression performance. The standard helps verify that a system can withstand the harsh conditions experienced by heavy-duty mobile equipment while continuing to perform as intended.
Related terms: Heavy-Duty Mobile Equipment, Third-Party Testing, ActivFire, AS 5062:2022
Related AFEX page: Third-Party Approvals & Certifications
H
Heavy-Duty Mobile Equipment
Heavy-duty mobile equipment refers to large off-road or industrial machines that operate in demanding environments.
Examples include mining haul trucks, loaders, excavators, drills, dozers, graders, forestry machines, waste handlers, and other equipment exposed to heat, vibration, dust, debris, hydraulic fluid, fuel, and long operating hours.
These machines face fire risks that are different from buildings, fixed facilities, or standard vehicles.
Related terms: FM 5970 HDME, Fire Risk Assessment, Mobile Equipment Fire Suppression, NFPA 122
Related AFEX page: Industries Served
Horn and Strobe
A horn and strobe is an audible and visual alarm accessory used to alert people that a fire suppression system has activated.
This can be important when people near the machine, not just the operator, need to know that a fire event or system discharge is occurring.
Related terms: Compact Panel, Control Unit, Manual Actuation
Hot Surface
A hot surface is any component hot enough to ignite nearby fuel, oil, debris, or other combustible material.
Common hot surfaces on heavy equipment include exhaust manifolds, turbochargers, diesel particulate filters, brakes, engine blocks, and aftertreatment components.
Hot surfaces are one of the most common ignition concerns in mobile equipment fire risk.
Related terms: Hydraulic Fire, Tier 4 Aftertreatment Component
Hydraulic Fire
A hydraulic fire occurs when hydraulic fluid leaks, sprays, or collects near a hot surface or ignition source.
Hydraulic systems are a major fire concern on heavy equipment because they operate under pressure and are often routed near engines, pumps, hoses, and high-temperature components.
A small hydraulic leak can become a serious fire risk if it reaches a hot surface.
Related terms: Class B Fire, Pooled Fuel Fire, Dual Agent Fire Suppression System, Fire Risk Assessment, Spot Sensor, Linear Detection Wire
I
ISO 9001:2015
ISO 9001:2015 is an international quality management system certification.
For manufacturers, ISO 9001:2015 confirms that documented quality processes are in place across areas such as design, production, inspection, and customer support.
In fire suppression, quality management matters because system reliability depends on consistent components, manufacturing processes, and support.
Related terms: Third-Party Testing, FM 5970 HDME
Related AFEX page: Third-Party Approvals & Certifications
L
Liquid Chemical Fire Suppression System
A liquid chemical fire suppression system uses a liquid agent to suppress fire, cool hot surfaces, and help reduce reignition risk.
Liquid systems are especially useful around high-heat components such as turbochargers, exhaust systems, aftertreatment components, and other areas where residual heat can remain after flames are knocked down. However, liquid chemical agents are generally not effective for Class C fires involving energized electrical equipment and are typically used in conjunction with other suppression strategies when electrical hazards are present.
Related terms: SAFE-X Liquid Agent, Reignition, Pooled Fuel Fire, Fluorine-Free Agent, Dual Agent Fire Suppression System
Related AFEX page: Liquid Chemical Systems Suppress Equipment Fires
Linear Detection Wire
Linear detection wire is a heat-sensitive cable used to detect fire conditions along a protected area of the machine.
On heavy equipment, linear detection wire is commonly routed through high-risk areas such as engine compartments, hydraulic zones, battery compartments, electrical areas, and other spaces where heat or fire may develop. When the wire is exposed to a set temperature or fire condition, it signals the monitor panel or control unit.
Linear detection wire is useful because it can cover irregular spaces and long hazard areas where a single point sensor may not provide enough coverage.
Related terms: Detection Circuit, Monitor Panel, Control Unit, Automatic Discharge, Battery Fire, Engine Compartment Fire, Hydraulic Fire
Related AFEX page: Linear Wire vs. Sensors
M
Manual Actuation
Manual actuation allows an operator or nearby person to intentionally activate the fire suppression system.
Manual actuators may be pushbuttons, panel-mounted controls, or external activation devices. They are often protected by a cover or seal to help prevent accidental activation.
Related terms: Automatic Discharge, Actuation Circuit, Compact Panel, Operator Egress
Mobile Equipment Fire Suppression
Mobile equipment fire suppression is fire protection designed for machines that move, work in harsh environments, and face equipment-specific fire risks.
These systems are used on machines such as haul trucks, loaders, dozers, excavators, drills, graders, skid steers, compact track loaders, forklifts, buses, deicers, forestry machines, and waste handling equipment.
Unlike building fire protection, mobile equipment fire suppression must be rugged enough to perform while the machine is operating in demanding conditions.
Related terms: Heavy-Duty Mobile Equipment, Engine Compartment Fire, Hydraulic Fire, Fire Risk Assessment
Monitor Panel
A monitor panel is the control center of an automatic fire suppression system.
The monitor panel watches detection circuits, alerts the operator to fire or fault conditions, and may support automatic or manual discharge.
Depending on the system, the panel may use lights, sounds, display messages, or other indicators to communicate system status.
Related terms: Control Unit, Compact Panel, Detection Circuit, Linear Detection Wire
Related AFEX page: Detection & Monitoring
N
NFPA 122
NFPA 122 is a fire prevention and control standard for metal and nonmetal mining and mineral processing facilities.
For mining operations, NFPA 122 includes guidance related to fire prevention, fire protection, mobile equipment, fuel hazards, hydraulic systems, and emergency planning. It can be an important reference when evaluating fire suppression requirements for heavy equipment used in mining environments.
NFPA 122 also requires dual agent fire suppression systems on certain diesel-powered mobile equipment in underground mining applications, recognizing the need to address both flame knockdown and reflash prevention in high-risk environments.
Operations should review NFPA 122 along with applicable local regulations, insurance requirements, site standards, and equipment-specific fire risk assessments.
Related terms: Fire Risk Assessment, Heavy-Duty Mobile Equipment, Hydraulic Fire, Dual Agent Fire Suppression System, Third-Party Testing, FM 5970 HDME
Nitrogen Cartridge
A nitrogen cartridge stores the pressure used to discharge suppression agent through the system when it activates.
In cartridge-operated fire suppression systems, the agent tank is not continuously pressurized. Instead, the nitrogen cartridge pressurizes the system during actuation, pushing the suppression agent through the distribution tubing or hose and out through the nozzles.
This design can support serviceability and system reliability, especially on mobile equipment that experiences vibration, heat, and harsh operating conditions.
Related terms: Side Cartridge Design, Actuation Circuit, Distribution Nozzle, System Discharge, System Recharge
O
Operator Egress
Operator egress means the operator’s ability to safely exit the machine during an emergency.
During an equipment fire, the first priority is protecting the operator. A fire suppression system can help alert the operator, suppress the hazard, and support safer exit from the machine.
This is especially important on large equipment, elevated cabs, underground machines, buses, and machines working in remote or high-risk areas.
Related terms: Manual Actuation, Automatic Discharge, Operator Safety
Operator Safety
Operator safety refers to protecting the person operating the machine before, during, and after a fire event.
On heavy equipment, fires can develop quickly and may involve fuel, hydraulic fluid, electrical components, hot surfaces, debris, or confined engine compartments. A fire suppression system helps support operator safety by detecting fire conditions, alerting the operator, discharging suppression agent, and helping create time for the operator to stop the machine and exit safely.
Operator safety is the first priority in any equipment fire. Protecting the machine, reducing downtime, and limiting damage are important, but the system’s most important role is helping reduce risk to the person in or near the equipment.
Related terms: Operator Egress, Automatic Discharge, Manual Actuation, Monitor Panel, Fire Suppression System, Fire Risk Assessment, Battery Fire
Related AFEX page: 4 Steps for Operator Safety Using an Onboard Suppression System
P
Pooled Fuel Fire
A pooled fuel fire is a fire fueled by liquid that has collected on or around equipment surfaces.
Pooled fuel may come from diesel, hydraulic fluid, engine oil, lubricants, or other combustible liquids. These fires are dangerous because the fuel source can spread across surfaces and continue burning after ignition.
Liquid fire suppression agents are often effective against pooled fuel fires because they can quickly cover the burning liquid, help cool hot surfaces, and reduce the release of flammable vapors that sustain combustion. This makes them well suited for many Class B fire hazards commonly found on heavy equipment.
Related terms: Class B Fire, Liquid Chemical Fire Suppression System, Hydraulic Fire
R
Reignition
Reignition happens when a fire restarts after it appears to have been suppressed.
Reignition can occur when hot components, such as turbochargers, exhaust systems, or aftertreatment components, remain hot enough to ignite nearby fuel, oil, or debris.
Liquid agent and dual agent systems can help reduce reignition risk by cooling hot surfaces after initial fire knockdown.
Related terms: SAFE-X Liquid Agent, Liquid Chemical Fire Suppression System, Tier 4 Aftertreatment Component, Hot Surface
S
SAFE-X Liquid Agent
SAFE-X is AFEX’s fluorine-free liquid suppression agent designed for heavy equipment fire suppression applications.
SAFE-X is formulated to suppress fire, cool hot surfaces, and help reduce the risk of reignition. It is used in AFEX liquid agent and compact liquid agent systems.
Because it is fluorine-free, SAFE-X also supports operations looking for fire suppression solutions without fluorinated compounds such as PFAS.
Related terms: Fluorine-Free Agent, Liquid Chemical Fire Suppression System, AS 5062:2022, Compact Liquid Agent System
Related AFEX page: AFEX Liquid Agent Fire Suppression System Receives FM 5970:2022 Certification for Mobile Equipment
Side Cartridge Design
A side cartridge design places the nitrogen cartridge on the side of the agent tank rather than directly above or below it.
On compact or space-limited equipment, side cartridge design can help make installation easier by reducing the overall height of the system assembly. This can be especially useful when a fire suppression system needs to fit into tight compartments or smaller equipment layouts.
Side cartridge systems still use the nitrogen cartridge to pressurize the agent tank during system actuation.
Related terms: Nitrogen Cartridge, Compact Liquid Agent System, Actuation Circuit, System Recharge
Related AFEX page: Fire Suppression Systems: Side Cartridge vs. Stored Pressure Operation
Spot Sensors
A spot sensor is a detection device that monitors a specific location for heat, flame, or other fire conditions.
On heavy equipment, spot sensors may be used in targeted hazard areas where a specific component or compartment needs focused monitoring. Examples may include engine compartments, battery areas, electrical enclosures, hydraulic zones, or other high-risk locations.
Unlike linear detection wire, which can monitor a longer path or irregular area, a spot sensor is positioned to watch a defined point or zone. The right detection approach depends on the machine layout, fire hazards, environment, and system design.
Related terms: Linear Detection Wire, Detection Circuit, Monitor Panel, Control Unit, Battery Fire, Engine Compartment Fire, Electrical Fire, Hydraulic Fire
Related AFEX page: Linear Wire vs. Sensors
Stainless Steel Tubing Distribution
Stainless steel tubing distribution routes suppression agent from the tank to the nozzles using rigid stainless steel tubing.
Stainless steel tubing can provide durable agent distribution on equipment that experiences vibration, heat, debris, and harsh operating conditions.
It can also reduce reliance on long flexible hose runs that may wear over time.
Related terms: Distribution Nozzle, Discharge Network, Dry Chemical Fire Suppression System
System Recharge
System recharge is the process of restoring a discharged fire suppression system so it is ready for service again.
After a system discharges, it must be inspected, serviced, and recharged before the machine returns to operation. Recharge may include refilling or replacing the suppression agent, replacing the nitrogen cartridge, inspecting the distribution network, checking detection and actuation components, and confirming that the system is functioning correctly.
System recharge should be completed by trained personnel or an authorized service provider so the system is properly reset and ready for the next event.
Related terms: Automatic Discharge, Nitrogen Cartridge, Detection Circuit, Actuation Circuit
T
Telematics Connectivity
Telematics connectivity allows a fire suppression control unit to communicate system status and event data to a vehicle or fleet management platform.
Telematics can help operations monitor system condition, receive alerts, review events, and connect fire suppression information to broader fleet data.
This can be especially valuable for large fleets, remote sites, and equipment that operates across multiple shifts.
Related terms: Control Unit
Related AFEX page: Telematics: When Do You Want to Know Your Machine is On Fire?
Third-Party Testing
Third-party testing means a system has been evaluated by an independent organization rather than only by the manufacturer.
Independent testing helps verify whether a system meets recognized performance, safety, and reliability requirements.
For heavy equipment fire suppression, this matters because systems must perform in harsh conditions where vibration, heat, debris, fuel, and hydraulic hazards are common.
Related terms: FM 5970 HDME, AS 5062:2022, ISO 9001:2015, ActivFire
Related AFEX page: Third-Party Approvals & Certifications
Tier 4 Aftermarket Component
A Tier 4 aftertreatment component is emissions-control hardware found on many modern diesel engines.
Examples include diesel particulate filters, selective catalytic reduction systems, and related exhaust aftertreatment components. These components can operate at very high temperatures.
Because of that heat, Tier 4 aftertreatment components can increase concern around hot surfaces and reignition after a fire is knocked down.
Related terms: Reignition, Liquid Chemical Fire Suppression System, Hot Surface, Engine Compartment Fire
Total Flooding
Total flooding is a suppression method that fills an enclosed hazard area with agent rather than targeting one single point.
On heavy equipment, total flooding is commonly used in engine compartments and other enclosed areas where agent needs to spread broadly across multiple hazards.
In dry chemical fire suppression systems, strategically placed distribution nozzles discharge dry chemical agent throughout the protected space. The agent disperses rapidly, helping to interrupt the combustion process, suppress flames across a wide area, and reach multiple fire sources within the enclosure.
This approach helps provide fast, wide-area coverage in spaces where fire may spread around fuel sources, hot surfaces, and debris.
Related terms: Dry Chemical Fire Suppression System, Fire Knockdown, Distribution Nozzle