7.1 Primary & Secondary Search Operations

7.1 Primary & Secondary Search Operations

Structural Search Planning and Size-Up

Structural search and rescue is one of the most critical and hazardous operations performed by firefighters. It requires a disciplined combination of rapid decision-making, physical stamina, and technical proficiency. A successful search begins with size-up, which is an ongoing mental evaluation of the incident. Size-up starts at the moment of alarm receipt and continues until the incident is terminated. During size-up, firefighters must consider several critical variables:

• Building Construction: The building's construction type (Type I through Type V under NFPA 220) determines how the structure will behave under fire conditions. For example, Type V (wood-frame) construction presents a high risk of rapid fire spread and structural collapse, whereas Type I (fire-resistive) construction is more stable but can retain extreme heat.
• Occupancy Type: The occupancy type dictates the likely occupant load and behavior. Residential occupancies (single-family dwellings, apartments, hotels) pose the highest risk to life safety, particularly during night hours when occupants are sleeping. Commercial and industrial occupancies present larger open spaces, complex layouts, and unique hazardous materials.
• Fire Conditions and Dynamics: Firefighters must assess the location, size, and stage of the fire. High-heat and zero-visibility conditions severely restrict search capabilities.
• Risk-Benefit Analysis: Before entering a structure, firefighters must perform a risk-benefit analysis based on the survivability profile of the environment. If the fire is in a post-flashover stage and temperatures exceed human tolerance (typically above 300°F or 150°C), it is highly unlikely that any occupants are still viable. In such cases, search operations are delayed until suppression crews have cooled the atmosphere. Firefighters follow the rule: 'We will risk our lives a lot to save lives that can be saved; we will risk our lives a little to save property; we will not risk our lives at all to save what is already lost.'

Structural Search Priorities

Search operations are not random; they must be prioritized to target areas with the highest probability of victim survival. The standard search priority sequence is:

1. Most Severely Threatened: The area immediately surrounding the fire, typically starting on the fire floor itself and then moving to the floor directly above the fire, where heat and toxic gases accumulate.
2. Largest Number of Victims: Areas where large numbers of people are likely to gather or seek refuge, such as bedrooms, exit corridors, and assembly areas.
3. Remainder of the Hazard Zone: A systematic search of all remaining areas of the structure, starting from the fire area and working outward.
4. Exposures: Adjacent apartments, structures, or exterior areas that may become threatened by fire spread or toxic gas migration.

Primary vs. Secondary Search Operations

Search operations are divided into two distinct, sequential phases to ensure maximum safety and thoroughness.

Primary Search

A primary search is a rapid, systematic search performed immediately upon arrival, often before or during active fire suppression operations. The objective is to quickly locate and remove victims who are in immediate danger. Speed is critical; however, the search must be systematic so that no high-probability areas are overlooked. Key guidelines for conducting a primary search:

• Team Integrity: Search must always be conducted in teams of at least two. Firefighters must maintain visual, vocal, or physical contact with each other at all times.
• Stay Low: Crawling or crouch-walking keeps firefighters below the thermal layer, where visibility is better and temperatures are lower.
• Door Control: Check doors for heat using the back of a gloved hand before opening them. If a door is hot, it indicates fire on the other side. When entering a room, close the door behind you (or maintain control of the door) to prevent fire from being drawn into the search path.
• Search High-Probability Areas First: Focus on areas where victims are most likely to be found, such as bedrooms, hallways leading to exits, and bathrooms.

Secondary Search

A secondary search is a slow, thorough, and highly detailed search conducted after the fire is under control and the main hazards have been mitigated (e.g., structural stabilization, ventilation). Key guidelines for conducting a secondary search:

• Fresh Crews: To ensure 'fresh eyes' inspect the structure, the secondary search must be conducted by a crew that was not involved in the primary search.
• Thorough Inspection: Firefighters during this phase check every cupboard, closet, under furniture, inside bathtubs, and beneath piles of debris.
• Completeness: Speed is not a priority during a secondary search; completeness is the sole objective. The search is not complete until every square inch of the structure has been verified clear of victims.

Structural Search Techniques

Firefighters use specialized search techniques to maintain orientation and safety in low-visibility, high-heat environments.

Oriented Search Method

The oriented search method is an efficient, team-based technique that enhances searcher safety and speed.

• The Oriented Leader: One firefighter (typically the officer or team leader) remains at a fixed point, such as a doorway or hallway. This leader maintains orientation to the exit, monitors fire conditions, coordinates communication with the incident commander, and provides a continuous beacon (using a flashlight, thermal imager, or voice) for the search team.
• The Searcher(s): One or more firefighters enter the room to perform the physical search. They remain anchored to the oriented leader, using voice communication or search tethers. By separating the roles of navigation and searching, the team minimizes the risk of disorientation and speeds up the search process.

Wall-Following Method

Wall-following (sometimes called the left-hand or right-hand search) is a classic tactical navigation method. The search team chooses a wall upon entering (e.g., the left wall) and maintains physical contact with that wall throughout the search.

• Left-Hand Search: Keep the left hand on the wall. Walk, crawl, or slide along the wall, searching toward the center of the room with a tool or foot.
• Right-Hand Search: Keep the right hand on the wall. To ensure full coverage of the room, searchers extend their reach using tools (e.g., a Halligan bar or Pike pole) to sweep the floor and feel under beds or furniture. If the team encounters a doorway, they can either search the room and return to the main wall, or follow the wall into the room. Maintaining a consistent wall reference ensures the team can always trace their way back to the exit.

Thermal Imaging Cameras (TICs)

Thermal Imaging Cameras are invaluable tools that detect infrared radiation (heat signatures) and convert it into a visible image. TICs allow firefighters to see through dense smoke.

Applications in Search & Rescue

• Victim Location: TICs show the heat signature of human bodies, which typically appear as warm (white or colored, depending on the camera's palette) against cooler surroundings.
• Fire Spread and Hotspots: TICs identify hidden fire in walls, ceilings, or floors, helping crews locate the seat of the fire.
• Navigation and Hazard Detection: TICs reveal structural elements, doors, windows, and hazards like holes in the floor or weakened structural supports.

Limitations of TICs

Firefighters must not rely solely on TICs, as they have significant physical limitations:

• Reflective Surfaces: TICs cannot see through glass, water, or highly reflective surfaces (like mirrors or polished metal). The camera will display a reflection of the firefighter's own heat signature (thermal mirroring) or block the heat source behind the glass.
• Depth Perception: Viewing the world through a screen alters depth perception.
• Battery and Electronic Failure: If the device fails, firefighters must be able to navigate using traditional tactile search methods.

Search Marking Systems

To coordinate search efforts and prevent duplicate searches, departments use standardized marking systems. The Federal Emergency Management Agency (FEMA) / US&R (Urban Search and Rescue) system is widely recognized.

The FEMA/US&R Slash Marking System

Markings are made on the door, adjacent wall, or conspicuous location using chalk, paint, or marking tape:

1. Single Diagonal Slash (/): Initiated upon entering a room or area. This indicates a search is in progress. The slash is marked with the team name, date, and entry time.
2. Crossing Diagonal Slash (X): Completed when the team exits the room or area. This indicates the search is complete. The four quadrants of the 'X' contain specific information:
   • Left Quadrant: Team identifier (e.g., 'E-10' for Engine 10).
   • Top Quadrant: Date and time of departure (e.g., '7/19 1830').
   • Right Quadrant: Hazards found (e.g., 'Rats', 'Gas', 'HVAC collapse').
   • Bottom Quadrant: Number of victims located (e.g., '2 Live, 0 Dead' or '0 victims').

FEMA/US&R Structural Marking Quadrants