Runway / Taxiway Incidents

Portable aluminium ground monitor · Deployed from ARFF appliance · 40–80 L/s · Under 1 min setup

Aircraft Hangar Protection

Fixed foam-water monitors (PL Series) + low-level foam deluge · NFPA 409 combined system

Governing Standards

ICAO Annex 14 · FAA AC 150/5210-6 · NFPA 409 · Local CAA requirements

Aerodromes — Volume 1: Aerodrome Design and Operations

ICAO Annex 14 classifies airports by category (CAT 1–10) based on the length and width of the largest aircraft regularly using the aerodrome. The airport category determines the minimum required fire fighting agent discharge rates — the total volume of foam solution (water + concentrate) that ARFF equipment at the airport must be capable of delivering per minute. These rates are specified in litres per minute and set the minimum capacity requirement for ARFF vehicle pumps, onboard water and foam tank volumes, and ground monitor flow rates.

Key: Airport categories 4–10 serving commercial jet aircraft require principal agents of 2,170–51,300 L/min foam solution capacity from ARFF vehicles and equipment combined.

Aircraft Fire and Rescue Facilities and Extinguishing Agents

The FAA Advisory Circular provides US-specific guidance on ARFF vehicle specifications, agent types, vehicle response standards and equipment requirements for airports certificated under 14 CFR Part 139. For ground monitors specifically, the AC addresses the foam application rates required for effective aircraft fuel fire suppression and the placement of any fixed monitors at fuel storage areas and hangars on airport property.

Standard on Aircraft Hangars

NFPA 409 is the primary standard governing fire protection in aircraft hangars. It classifies hangars into Groups 1–4 based on the aircraft accommodated and the hangar door opening height. Group 1 (large jet aircraft) and Group 2 (medium jet aircraft) hangars require a combined foam system: a low-level foam-water deluge system covering the floor slab plus high-level fixed foam-water monitors covering the aircraft body and engine zones from above. The monitors must discharge at specified application rates and must cover the entire protected floor area.

Standard for Low-, Medium-, and High-Expansion Foam

NFPA 11 governs the foam system design for fuel storage areas, fuel farm fire protection and any Class B fire protection involving foam-water monitors. At airports, fuel storage and dispensing areas — hydrant fuelling systems, fuel trucks, fuel storage tanks — are typically governed by NFPA 11 in conjunction with ICAO Annex 14 requirements for fuel storage fire protection.

No fixed infrastructure on runways

Runways have no fire water main — no pipe risers, no hydrants. All water and foam comes from the ARFF appliance tanks. The portable monitor is the only way to project a high-flow stream from the appliance’s water supply to a precise point at the aircraft.

Incident position is unknown in advance

An aircraft emergency can occur anywhere on the runway, taxiway or apron. A fixed monitor can only protect its pre-set coverage zone. A portable monitor can be positioned exactly where the incident has occurred, regardless of location.

Repositionable as the incident develops

Aircraft fires can shift as fuel spreads or as the fuselage structure collapses. ARFF crews reposition portable monitors mid-incident to follow the fire — something a fixed monitor cannot do.

Level 1 — Low-Level Floor Deluge

Open-head foam-water deluge nozzles at floor level (typically 300–600 mm above floor slab) covering the entire floor area. Activated by detection — immediately floods the floor with foam-water to suppress the burning fuel pool under and around the aircraft.

Level 2 — High-Level Fixed Monitors

Fixed foam-water monitors at high level (mounted on structural trusses or mezzanine level), aimed to cover aircraft fuselage, wings and engine zones. Discharge foam-water at the upper surfaces of the aircraft where the deluge floor system cannot reach effectively. CA-FIRE PL Series foam-water monitors are the standard specification for this application.

What foam concentrate is used for aircraft fuel fires?

ICAO Annex 14 and FAA standards specify AFFF (Aqueous Film-Forming Foam) or FFFP (Film-Forming Fluoroprotein) as the primary agent for aircraft fuel fire suppression. Protein-based foams are also permitted in some categories. The foam is proportioned at 3% or 6% concentrate-to-water ratio, depending on the specific product. Note that environmental concerns have driven significant changes to PFAS-based AFFF formulations in recent years — airports are increasingly transitioning to fluorine-free foam (F3) alternatives where regulatory requirements permit. The monitor system hardware (foam-water monitor body and nozzle) is compatible with all foam types — the concentrate selection is an operational and environmental compliance decision independent of the monitor specification.

Does the portable monitor replace the ARFF vehicle’s roof monitor?

No — the roof monitor on an ARFF vehicle and the portable ground monitor serve different purposes. The vehicle roof monitor is the primary first-attack tool — it can discharge while the vehicle is still moving towards the incident. The portable ground monitor is a secondary deployment tool: once the vehicle is positioned, a crew member removes the portable monitor, places it on the ground at the optimal angle to reach the fire and operates it independently of the vehicle’s position. This allows the vehicle to move to a new position while the portable monitor continues to discharge from a fixed point. Both are used simultaneously at a major incident.

How many portable monitors should an ARFF appliance carry?

Most ARFF appliances carry 1–2 portable ground monitors in the equipment lockers, though some operations at high-category airports carry more. The number depends on the number of crew available to deploy and operate the monitors simultaneously, the vehicle locker space available, and the airport’s emergency response plan. At a minimum, one portable monitor per ARFF appliance is standard practice at category 6 and above airports. The monitor flow rate (not the number of monitors) is the parameter set by ICAO Annex 14 — carrying two 40 L/s monitors may be less effective than one 80 L/s monitor if the appliance pump cannot supply both simultaneously.

What is the difference between an ARFF monitor and a standard industrial fire monitor?

Functionally they are the same device — a high-flow nozzle that delivers water or foam-water at a directed target. The key difference for ARFF use is material and weight: ARFF portable monitors are aluminium alloy to minimise carry weight. Standard industrial fixed monitors may be stainless steel because corrosion resistance over decades of outdoor installation is the priority and weight is not a constraint. The hydraulic performance (flow rate, throw range) is equivalent for the same model number in aluminium vs stainless steel — the “-L” suffix on CA-FIRE models (e.g. PS10/80W-L) designates the aluminium alloy variant.

Do hangar foam-water monitors need to activate automatically or can they be manual?

NFPA 409 requires that hangar foam-water systems be automatically operated for Group 1 and Group 2 hangars — detection triggers the floor deluge and the monitor system simultaneously, without requiring manual activation. The monitors open via automatically operated control valves when the system is triggered. Manual override — the ability to activate or stop the system from a manual control station — must also be provided. Manual-only operation is not acceptable for the primary hangar system in Group 1 and Group 2 classification. Remote control (RCFM electric) monitors may be used in certain hangar configurations where the automatic detection trigger also drives the monitor aim — confirm with the design engineer and the AHJ for the specific project.