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newSchoolWorks.com › VoTechWorks › Agriculture, Environment & Public Service › Firefighting / Public Safety › Fire Suppression: Tactics, Hose Operations, and Structural Attack › Lesson 10
AGR-FIRE51-03 · Lesson 10 · 20 clock hours · field

Interior Structural Fire Attack: Initial Lines and Team Tactics

Objective. Students will execute a coordinated two-person interior attack on a training prop fire, advancing a charged 1.75-inch line from the door to the seat of fire using low-crawl technique and controlling the nozzle to protect the team.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed professional in the field or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

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Why the First Line Matters

The first hoseline placed inside a burning structure sets the outcome of the entire incident. It protects occupants from fire spread, protects the crew making entry, and begins the process of removing heat and smoke. A poorly placed or poorly managed line can push fire toward victims or cut off your own egress. Everything you do on an interior attack — from door approach to nozzle control — must be deliberate and coordinated with your partner.

Pre-Entry: Reading the Building Before You Go In

Before touching the door, gather information. Position yourself to the hinge side of the door — never directly in front. Look for smoke conditions: high-volume, dark, turbulent smoke pushing from seams suggests a ventilation-limited fire with significant heat buildup. A thermal imaging camera (TIC) used on the door and surrounding surfaces gives you a heat signature through the door before it opens. Hold the TIC against the door surface and read the color gradient — bright areas indicate concentrated heat.

Check the door with the back of your gloved hand for heat. A hot door does not automatically mean you cannot enter, but it demands that you open it in a controlled way and be ready to shut it again if conditions inside are untenable.

Charging and Controlling the Line

Your attack line should be charged and bled of air before you reach the door. A 1.75-inch line with a combination nozzle is the standard first attack line for most residential and small commercial structures — it delivers enough flow to knock down the fire while remaining manageable for a two-person crew. Bleed the line by briefly opening the nozzle away from the structure so you know water is flowing and there are no air locks.

The nozzle operator controls water application. The backup firefighter manages the hose behind the nozzle operator — feeding slack, preventing the line from kinking around corners, and keeping the team moving forward. Neither role is passive. The backup firefighter is also the nozzle operator's lifeline if anything goes wrong.

Low-Door Opening and Entry

Crack the door open slowly from the hinge side while staying low and to the side. This controlled opening allows you to check interior conditions without exposing yourself to a full rush of heat or a potential smoke explosion (backdraft). If conditions are acceptable — visible floor, manageable heat — signal your partner and enter in a low crawl.

The low-crawl position keeps you below the thermal layer and below rising hot gases. Stay below the level of smoke banking down from the ceiling. If the smoke layer drops to the floor and you lose visibility of your hand in front of your face, communicate to your partner immediately and consider backing out.

Advancing to the Seat of Fire

Move together. The nozzle operator advances first, staying low and reading the environment through the TIC or by feel — testing the floor ahead with a tool or the heel of your boot before fully weighting it. The backup firefighter stays close, maintaining voice or touch contact at all times.

When you reach the fire room door, do not charge in immediately. Pause at the threshold. Use a short burst of water fog directed at the ceiling to cool the gas layer — a technique sometimes called a ceiling stroke or gas cooling. This reduces the risk of igniting superheated gases above you. Then advance the line into the room and direct water at the base of the flames (the seat of fire), working from the nearest edge toward the far edge.

Use a straight or narrow fog pattern to reach the seat of fire. A wide fog in a doorway can push smoke and heat back onto the crew or create steam burns in a confined space. Apply water in short, controlled bursts rather than a continuous blast, allowing steam to clear before moving forward.

NFPA 1403 and Live-Fire Safety

All live-fire training is governed by NFPA 1403, Standard on Live Fire Training Evolutions. Key requirements include: a qualified safety officer with authority to stop any evolution at any time, a Rapid Intervention Team (RIT) staged and ready before ignition begins, SCBA for all personnel inside the structure, a pre-burn survey and documentation of the structure, accountability for all personnel, and controlled fuel — no accelerants, no unapproved materials. Never enter a live-fire evolution if any of these safeguards are absent.

Monitor your SCBA air supply continuously. Signal low-air to your partner and to the IC before your low-air alarm activates — do not wait for the alarm. If your SCBA malfunctions or you become separated from your partner, activate your PASS device, call a mayday, and attempt to exit or take a position of refuge near a window or door.

Communication and Egress

Keep a verbal or radio channel open with the incident commander. Report conditions when you enter, when you reach the fire room, and when fire is knocked down. Know your egress route before you enter — it is always the way you came in unless you are directed otherwise. Never allow the hose line to be kinked or trapped under a door because it blocks both your water supply and your path out. Back out of the structure in a controlled manner, maintaining hose control so the line remains available if the fire re-kindles.

Roles and Accountability

Every student must complete the evolution as both nozzle operator and backup firefighter. These are distinct skill sets. The nozzle operator must control flow rate and pattern selection and keep water application focused. The backup firefighter must manage hose drag, feed slack on command, and be ready to take the nozzle if the nozzle operator is incapacitated. Swap roles cleanly on instructor signal during the rotation.

Key terms10

Seat of fireThe point of origin or the location where the main body of fire is burning; the primary target for water application during interior attack.
Combination nozzleA nozzle capable of delivering both a straight stream and a fog pattern, giving the nozzle operator flexibility to match water application to fire conditions.
Thermal imaging camera (TIC)A handheld device that detects infrared radiation to display heat signatures, used to locate fire, hot gases, and victims through smoke without requiring visible light.
Low-crawl techniqueA method of moving through a structure on hands and knees or on the belly to remain below the hot gas layer and reduce exposure to heat and toxic smoke.
NFPA 1403The NFPA standard that establishes minimum safety requirements for live-fire training evolutions, covering structure condition, fuel control, personnel accountability, and safety officer authority.
Rapid Intervention Team (RIT)A dedicated crew of firefighters, fully equipped and standing by outside the structure, whose sole mission is to locate and rescue a firefighter who becomes trapped or incapacitated.
Gas coolingThe technique of directing short bursts of water fog at superheated gases near the ceiling to lower their temperature and reduce the risk of ignition before advancing further into a fire compartment.
Backup firefighterThe second member of a two-person attack team who manages hose behind the nozzle operator, feeding slack, preventing kinks, and maintaining close contact to support or assist the nozzle operator.
PASS devicePersonal Alert Safety System — a device worn by firefighters that emits a loud alarm when the user is motionless for a set period or when manually activated, used to signal a downed or trapped firefighter.
Ventilation-limited fireA fire whose growth is restricted by the available oxygen supply rather than by fuel; opening doors or windows can cause rapid fire growth or a dangerous increase in heat release.
In class: Pre-burn classroom briefing using an incident command whiteboard: students review door approach, thermal imaging camera reading, door-opening technique, and nozzle pattern selection for an interior attack; students verbalize their individual role assignments. · Dry run (no fire, no SCBA): teams walk through the evolution in the training building—door approach, thermal check, low door-opening, hook-and-advance of hose line—with instructor role-playing IC on radio; debrief focuses on communication and hose management. · Live burn evolution (compliant with NFPA 1403): in full PPE and SCBA, two-person teams advance a charged line, make entry on instructor signal, reach the fire room door, apply water to extinguish a controlled burn, and back out maintaining hose control; rotation continues until every student has served as nozzle operator and backup firefighter.
Materials: NFPA 1403-compliant live-fire training structure, 1.75-inch attack line with combination nozzle, SCBAs for all participants, thermal imaging camera, rapid intervention team (RIT) staged per NFPA 1403, radio, NFPA 1403 Standard (current edition), safety officer documentation forms
Check: Instructor and safety officer independently score each student on a live-fire JPR checklist; all NFPA 1403 safety requirements must be met before ignition; student must demonstrate controlled nozzle technique, proper communication, and maintain a passable egress route—any uncontrolled SCBA event, failure to signal low air, or leaving a partner is a critical fail requiring full remediation before re-entry.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Firefighter I — Interior Attack and Structural Firefighting
1. When approaching a closed door in a structural interior attack, the nozzle operator should position on which side of the door before attempting to open it?
Firefighter I — Hose Operations and Team Tactics
2. A two-person team is advancing a 1.75-inch attack line toward a fire room. The backup firefighter's PRIMARY role during this advance is to:
Firefighter I — Live-Fire Safety and NFPA 1403
3. Before ignition of any live-fire training evolution under NFPA 1403, which of the following MUST be in place?
Firefighter I — Fireground Safety and Situational Awareness
4. A firefighter notices the smoke layer has banked down to floor level and visibility is lost even at crawl height. The correct immediate action is to:
Firefighter I — Nozzle Technique and Water Application
5. When applying water at the fire room threshold, a narrow fog or straight stream is preferred over a wide fog because a wide fog pattern directed into a doorway can:
Firefighter I — Interior Attack Techniques
6. The gas cooling technique involves directing short water bursts at the ceiling layer. The PRIMARY purpose of this action is to:
Firefighter I — SCBA and Air Management
7. During a live-fire evolution, a firefighter's low-air alarm activates. Under the team accountability requirements of NFPA 1403 and standard firefighting practice, the firefighter should:
Firefighter I — Fire Behavior and Reading Smoke
8. Which condition observed at a closed door during a structural attack MOST strongly suggests a ventilation-limited fire that could intensify rapidly upon door opening?
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