FDNY Training Notes on Low Expansion Foam and Tactical Delivery

Introduction to Low Expansion Foam

• Definition: Low expansion foam is a specialized fire-extinguishing agent designed for unusual-type incidents, specifically Class "B" fires and spills involving flammable and combustible liquids.
• Primary Functions: It provides both extinguishment and vapor control when selected and applied correctly.
• Advantages Over Other Agents: Foam offers advantages over dry chemical, carbon dioxide ($CO_2$), and halons:     * Progressive Extinguishment: Firefighters begin at the edge of the fuel and project the boundary of the foam blanket further away.     * Agent Stability: Unlike "transient" agents that disperse (allowing fire to burn back), foam provides long-lasting control due to the relatively long life of the foam blanket.     * Ignition Prevention: On open-air liquid spills, foam minimizes vapor release, preventing vapors from reaching their explosive range—a task not possible with halon or $CO_2$ in open air.
• Critical Requirement: Fire must be completely extinguished; if the foam breaks down before completion, the fire will burn back across the surface, and applied foam will be wasted.

Foam Concentrate

• Composition: A mixture of foaming agents formulated to produce air-filled bubbles. When mixed with water and air in proper proportions, it floats on fuel surfaces.
• Variety and Selection: Different concentrates are needed for different fuels. There is no single concentrate for every problem.     * FDNY Standard: The Department utilizes Universal Gold $1\%-3\%$ Alcohol Resistant - Aqueous Film Forming Foam (AR-AFFF).     * Note: This specific product surpasses all other concentrates investigated by the Department.
• Compatibility Rules:     * Different foam concentrates are incompatible and must never be mixed during storage or operations (e.g., in Foam Tanker or Foam Tender tanks).     * Mixing different brands or types can cause the foam to gel into a semi-solid mass, requiring the storage tank to be placed out-of-service and disposed of.     * Simultaneous Application: Two different low expansion foams may be applied simultaneously via different appliances (e.g., handlines and deck guns) if quantities of the primary foam are insufficient.     * Hi-Ex Foam Restriction: High Expansion foam (Class "A" confined spaces) is not to be used with low expansion foam for flammable liquid fires.
• Protein Foam: Not used by FDNY but may be found at bulk oil storage plants. It has fair burn-back resistance but lacks fuel-shedding properties and is slow to control fires. It is ineffective on gasohol or polar solvents.

Foam Solution and Finished Firefighting Foam

• Foam Solution: The mixture of foam concentrate and water proportioned at a specific rate.     * Method 1: Eduction: Uses a foam eductor to draw concentrate into water. This relies on the Venturi Effect, where water moves through a narrow throat, creates low pressure, and draws concentrate through a pick-up tube.     * Method 2: Injection: Uses a portable Foam Injection Metering Module (FIMM) carried by Satellite Units and Foam Tankers to inject concentrate into a pumper receiving water.
• Finished Firefighting Foam: The aerated product applied to the fire.     * Aeration: FDNY primarily uses aerated foam at a $3\%$ setting to produce a blanket with superior flashback and burn-back resistance.     * Buoyancy: Designed to be lighter than fuel to float on the surface.
• Four Primary Methods of Extinguishment:     1. Smothers: Prevents air from mixing with flammable vapors.     2. Suppresses: Stops or reduces the release of flammable vapors.     3. Separates: Separates flames from the fuel surface to reduce boiling and vapor generation.     4. Cools: The water content cools the fuel and adjacent metal (like tank walls), and extinguishes Class "A" materials in the spill area.
• AFFF vs. AR-AFFF: Port Authority crash trucks use AFFF, which drains fast. FDNY members should avoid entering these areas until a stable AR-AFFF blanket is established to control vapors.

Universal Gold $1\%-3\%$ AR-AFFF Characteristics

• Dual Function: Formulates a protective membrane between fuel and foam and provides stability/heat resistance for burn-back protection.
• Environmental Stability: It is freeze/thaw stable with no performance loss after thawing.
• Water Type: Can be generated using either fresh or salt water.
• Shelf Life: Remains effective for up to $25\,years$ if stored properly.
• Color Coding: Containers are color-coded with a red band around the top to prevent mixing.
• Distribution Levels:     * Engine Company: Three ($3$) red-banded $5\,gallon$ containers.     * Ladder Company: Two ($2$) red-banded $5\,gallon$ containers.     * Foam Tankers: Each of the $5$ tankers carries $1500\,gallons$ of concentrate.     * Foam Depots: $19$ locations citywide, each stocking $50$ five-gallon containers.     * Marine Division: "343" and "Firefighter 2" carry $3000\,gallons$ each. "The Bravest" holds $200\,gallons$. Ten $33'$ boats carry $25\,gallons$ each.

Foam Equipment and Delivery Systems

• Eductors: Standard for Engine companies; used with $1\frac{3}{4}"$ or $2\frac{1}{2}"$ hoselines.
• Handline Operation Limits: Useful for small spills approximately $600\,sq\,ft$ (e.g., car fires, oil burners, gas pumps).
• Self-Educting Nozzles: Built-in eductors used with Foam Tankers for medium spills (over $600\,sq\,ft$, tanker trucks, loading racks).
• Master Stream Nozzles: Used for large operations (tank farms, spills over $2000\,sq\,ft$).
• First Alarm Capabilities:     * Assignment typically provides $13$ containers ($65\,gallons$).     * At a $3\%$ setting, an eductor consumes $3.75\,gpm$ of concentrate.     * Total duration of foam at a $3\%$ setting is approximately $17\,minutes$.
• Foam Tankers: Specialized units carrying $1500\,gallons$ of concentrate (no water). Equipped with pre-connected deck guns ($500, 750, 1000\,GPM$).     * A single $1500-gallon$ tanker duration at 3\% \tn:         * $1000\,GPM\,nozzle$: $50\,minutes$         * $750\,GPM\,nozzle$: $66\,minutes$         * $500\,GPM\,nozzle$: $100\,minutes$     * A single $1500-gallon$ tanker duration at 1\% \tn:         * $1000\,GPM\,nozzle$: $150\,minutes$         * $750\,GPM\,nozzle$: $200\,minutes$         * $500\,GPM\,nozzle$: $300\,minutes$
• Satellite Units: Carry portable FIMMs, $500\,GPM$ and $1000\,GPM$ aerating nozzles, and the Modified Angus Foam Cannon. They carry $6"$ large-diameter hose.
• Foam Tender: Transports $3000\,gallons$ in three $1000-gallon$ compartments. Features a $200\,GPM$ pump for concentrate transfer.

Strategic and Tactical Considerations for Spills and Fires

• General Rules:     * Apparatus positioning: Upwind and Uphill.     * Eliminate ignition sources, starting downwind/downhill.     * Request Haz-Mat and take explosive readings.     * Vapor awareness: Many vapors are heavier than air and collect in cellars.
• Spill Tactics:     * Containment: Dike and dam the spill to prevent sewer entry. If fire enters the sewer and there is no exposure hazard, it may be better to let it burn off; extinguishing it might lead to a larger problem later.     * Application: Aim to bounce foam off the ground or deflect it against objects to slide gently over the liquid. If not possible, rain foam skyward to fall gently.     * Flowing Spills: Work against the run of the spill towards the source. Establish a heavy foam blanket below the fire in ditches/gutters.
• Confined Area Fires (Tanks/Pits):     * Use the tank wall to break the stream velocity.     * Adequate Supply: Do not start operations until enough concentrate is on scene; otherwise, fire will burn back and waste all agent.     * Window Management: Aim for the "WINDOW" in the plume (upwind side) where flames are shorter and convection currents are lower.     * Product Level: If a tank is full, remove product until it is within $5\,feet$ of the top. If levels are too low, a "chimney" effect carries foam away, and tank walls may curl.

Tank Truck and Aircraft Incidents

• Tank Trucks:     * Modern tankers carry over $14000\,gallons$ and are often aluminum.     * BLEVE Risk: High in steel tanks; reduced in aluminum because the shell melts at approximately $1220\,^{\circ}F$.     * "Water Leak" Tactic: If product specific gravity is $< 1$, adding water to a bottom-leaking tank can force the product to float, creating a water leak instead of a fuel leak.     * Roll-overs: Never upright a loaded vehicle; it must be off-loaded.
• Aircraft Incidents:     * Fuels: Aviation Gasoline (volatile) vs. Jet A (kerosene-based).     * Port Authority Cooperation: Port Authority uses AFFF for knockdown. FDNY should apply AR-AFFF over it for a more stable, burn-back resistant blanket.     * Water Supply: Port Authority vehicles can re-supply foam $5\,times$ but need FDNY to supply water.

Bulk Oil Storage and Safety

• Fixed Systems: FDNY must augment facility systems which may need water, concentrate, or solution. Signs on pump houses can be misleading; verify via pre-fire plans.
• Exposure Cooling: Only use water if a tank is steaming. Shut down when steaming stops to preserve water for foam and prevent filling dikes.
• Pressurized Containers: Recognized by rounded ends. If a pressure relief valve increases in noise or the flame jet heightens, withdraw immediately due to BLEVE potential.
• Dike Management: Monitor water levels in dikes to prevent overflow and fuel runoff. Drains may need to be opened with plant personnel permission.
• Blanket Entry Safety: Entry is limited to rescue. Members must wear full PPE and SCBA facepieces. Constant reapplication of foam is mandatory while members are in the blanket.