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Contents
  1. 1Objectives and incident assessment
  2. 2Extinguishing mechanisms
  3. 3Portable and manual suppression
  4. 4Fixed systems and water supplies
  5. 5Access and operational information
  6. 6Ventilation and backdraft
  7. 7Management and reliability
  8. 8Evaluation and common misunderstandings
  9. 9See also
  10. 10Notes
  11. 11References

Firefighting is the work of controlling and extinguishing fires and carrying out related rescue and protection activities. It includes manual suppression with portable equipment and hoses, operation of fixed systems, and the access, water supply and information needed to use them. The objective can be extinguishment, control, exposure protection or support for safe evacuation.[1][2]

Firefighting can be performed by building occupants, trained on-site personnel or the fire service, depending on the situation and jurisdiction. It changes the fire and its environment, but it also exposes people to heat, smoke, structural damage and changing ventilation conditions. Operational decisions must therefore account for the actual incident rather than a generic attack sequence.[3][2]

Effective firefighting depends on a complete chain: detection, suitable agent, access, delivery and continued suppression. Extinguishing visible flame is not always proof of safety because hot fuel and deep-seated combustion can remain. Re-ignition, water supply, secondary agent hazards and firefighter egress must be considered.[4][2]

Objectives and incident assessment

The incident objective determines how performance should be judged. A small fire may be extinguished, while a larger fire may need to be controlled to prevent spread or protect escape routes. Exposure protection can also be valuable even where the initial fuel continues to burn.[5][6]

Assessment begins with fuel, form, location and development. A solid deep-seated fire, a liquid pool and a pressurised spray require different delivery methods. Building geometry and ventilation can change smoke movement, fire intensity and access to the burning region.[7][8]

The initial fire stage is different from a fully developed enclosure fire. Van Rossum distinguishes local development from a compartment fire whose conditions are often ventilation controlled. Firefighting assessment must identify which conditions exist at the time of intervention.[9][10]

A localised fire can spread to other objects before suppression arrives. The assessment must include heat transfer and exposure to nearby fuel, not only the first item. Water cooling or another suitable agent can protect those exposed materials and reduce spread.[5][6]

Firefighting also includes rescue and protection of the responders' egress. C/VM2 requires access to the fire floor, search of the general area and protection of the way out. These tasks cannot be evaluated only by water flow or agent quantity.[2]

Extinguishing mechanisms

Extinguishing mechanisms include cooling, fuel separation, oxygen removal or dilution, and chemical interference with combustion. Real agents often use several mechanisms together. Their effectiveness depends on reaching and remaining at the burning region in a suitable form.[6]

Water absorbs heat from fuel and flame and reduces pyrolysis and heat feedback. Steam can contribute to oxygen displacement in some confined conditions, and water fog can attenuate radiation. Water is nevertheless unsuitable for some reactive materials and does not form a blanket over lighter, immiscible liquids.[6][5]

Foam can cover a suitable liquid surface, reduce vapour release and limit radiant heating. It must spread and remain coherent despite heat, drainage and mechanical disruption. Running fuel and pressurised spray do not provide the same surface as a pool.[7][11]

Dry chemicals can inhibit flame chemistry, cool, coat and block radiation. They can also create residue, corrosion and reduced visibility. Gaseous agents can reduce oxygen or affect flame chemistry but require retention and attention to deep-seated combustion.[12][4]

Suppression can reduce heat release without immediately removing every flame. Control and extinction should therefore be distinguished. Post-discharge inspection must consider whether remaining fuel can support renewed burning after air returns or the blanket is disrupted.[5][4]

Portable and manual suppression

A Fire extinguisher provides a limited quantity of agent for manual application. Its label and tested use identify the intended fire types, but delivery and fire geometry still determine the outcome. Repeated discharge can also increase contamination and visibility problems without ensuring extinction.[13][14]

Manual suppression requires appropriate training and notification. NUREG's fire-watch description links extinguisher use with hazard recognition and proper notification procedures. Personnel must understand both the agent's intended purpose and its secondary effects.[15]

Bryan describes occupants choosing between fighting, fleeing, seeking refuge and warning others. A manual attack can be well intended but inappropriate if the fire is more developed or the agent is unsuitable. The response should be reassessed as information and conditions change.[3][16]

Portable equipment is not a substitute for developed-fire resources. Fire service access, pumping appliances, hoses and sustained water supplies may be needed as the incident grows. The threshold for safe and effective manual action must be part of the operational plan rather than assumed.[2][1]

Post-use conditions include residue, impaired visibility and possible reflash. NUREG's Point Beach example reports repeated dry-chemical use before water finally extinguished the fire, with residue spread over equipment and surfaces. That case illustrates why delivery and cleanup are part of suppression performance.[14]

Fixed systems and water supplies

Automatic systems can begin controlling a fire before personnel arrive. Sprinklers detect heat at individual heads and distribute water over the protected area. Wet, dry, deluge and preaction arrangements introduce different activation and delivery sequences.[17][18]

A Fire hydrant supplies water to a pumping appliance, which then delivers it through hoses. The source, connection, pump and hose route must all remain available. The hydrant itself is not a complete extinguishing system.[1]

Dry and wet risers distribute water to hose outlets inside a building. Wet risers are permanently charged, while manual standpipes rely on fire service supply. Classifications of those standpipes concern intended use and are distinct from fire-fuel classifications.[19]

Water supplies can include municipal mains, reserve tanks and pumps. NIST's WTC analysis shows how those components can support sprinklers and standpipes, but it also identifies possible loss through power failure, damage or infrastructure impairment. Redundancy must be evaluated for independence.[20][21]

Fixed systems also depend on maintenance and suitable hazards. Closed valves, blocked pipes, corroded heads and changed storage can prevent effective operation. A system designed for one commodity may not control a later, different fire challenge.[22][18]

Access and operational information

Fire service access includes vehicle hard-standing, unobstructed paths to the building and connections, and safe internal routes. C/VM2 addresses those provisions together with water delivery, firefighter reach and protected egress. Arrival at the site alone does not demonstrate operational access.[2]

Connection points must be accessible and understandable. Firefighters need to know which inlets, valves and zones serve the fire area. Clear information about the fire location, available systems and hazardous substances or processes is part of that access.[2][20]

Hose routes must be practical for the building layout. C/VM2 uses approximate hose lengths in one water-delivery method, but indirect routes and fire conditions can affect actual deployment. Structural stability must support access for the required period.[10]

The incident's fire environment affects safe operations. C/VM2 gives radiation and smoke-layer criteria for particular unsprinklered firecells when firefighters first apply water. Those are method-specific criteria and do not guarantee safe conditions for every subsequent stage.[2][10]

Operational information should be current. Altered storage, partitions, hazards or supply arrangements can invalidate previous instructions. Building management must preserve both the physical provisions and the knowledge needed to use them.[23][24]

Ventilation and backdraft

Positive pressure ventilation uses fans to blow fresh air into an enclosure, creating a pressure difference that drives combustion products through an exit opening. NUREG-1805 describes its use to influence ventilation and burning activity and to assist firefighting. The complete airflow path must be considered.[25]

Ventilation can change visibility and smoke distribution, but it also supplies oxygen and changes pressure-driven flow. Its effect depends on the inlet, outlet, enclosure and fire condition. It should not be assumed to improve every fire scenario merely because air is moving.[25][8]

Backdraft is explosive ignition of pyrolysis gases when oxygen suddenly enters an oxygen-limited room. Combustion has consumed oxygen and left hot, unburned gases, so a new air supply can trigger rapid burning. This is a distinct hazard from simply seeing smoke leave an enclosure.[26]

A Smoke explosion instead concerns rapid combustion of a reasonably premixed flammable gas cloud within explosion limits. Van Rossum distinguishes it from backdraft in the source sections. Ventilation decisions must therefore consider the mixture's history, not only the immediate visibility.[27]

Smoke control and firefighting ventilation can interact with sprinklers. Water sprays cool hot gases and can affect later heat-sensitive equipment, while fans change smoke paths. These interactions must be included when assessing the timing and sequence of operations.[28][29]

Management and reliability

Firefighting provisions must remain usable in the building's current condition. Routes should be clear, connections accessible, signs readable and emergency systems operational. Maintenance must preserve the complete functional chain rather than isolated components.[24][22]

Impairments require explicit management. Closed valves, disabled detectors, pump failures and maintenance shutdowns can change the protection available during an incident. Restoration should be verified by appropriate functional checks before the original assumptions are relied upon.[22][30]

Training should include the intended operating sequence and its limitations. Personnel need to understand agent compatibility, access, notification, changing fire conditions and withdrawal. A drill based only on ideal conditions may not reveal failures in those arrangements.[15][31]

Common-cause failure can affect several provisions. Shared power, water supplies, detection or structural elements can disable access, suppression and information together. The assessment should identify what remains available after each relevant failure.[32][33]

Changes to the building or its use require re-evaluation. New fuel arrangements, partitions, storage or occupancy can alter fire growth, access and required supply. A previously effective provision may no longer match the hazard.[23][22]

Evaluation and common misunderstandings

Firefighting is not only the application of water. It includes agent selection, access, delivery, rescue, information and control of the fire environment. Water may be effective for one scenario and harmful or ineffective for another.[6][5]

Visible flame extinction is not proof of complete safety. Hot fuel, deep-seated combustion and damaged foam blankets can support renewed burning. Post-discharge inspection and retention of suitable suppression conditions are necessary.[4][34]

More ventilation is not automatically better. Fans can change smoke and oxygen conditions in ways that affect fire development and backdraft risk. Inlet and outlet paths, enclosure geometry and the mixture's history must be evaluated.[25][26]

A positive engineering result does not dictate a particular fire service action. Van Rossum notes that an interior attack remains a decision for firefighters at the scene. Models can inform that decision but cannot guarantee the conditions they will face.[35]

The complete assessment therefore connects the incident, people, agents and building. It identifies what must operate, which failures are credible and how responders can reach and leave the fire area safely. Firefighting performance belongs to that whole operational system.[2][1]

An incident review should identify which fire conditions drive the response. A growing local fire, a ventilation-limited enclosure and a fire threatening neighbouring property require different priorities. The chosen objective should determine which people need protection, which agent is appropriate and which conditions must be controlled first.[2][9]

Delivery time should be part of that review. Detection, notification, appliance travel, hose deployment and agent activation all occur before suppression can influence the fire. C/VM2's intervention times are method-specific inputs, and a separate brigade model must justify any alternative time.[10]

Protection measures can also change one another's effectiveness. Suppression can alter smoke temperature and buoyancy, ventilation can alter oxygen and pressure, and altered conditions can change detector or vent activation. The sequence should therefore be analysed as an interacting system rather than as independent actions on a checklist.[28][29]

Operational evidence should distinguish capacity from availability. A water network may have adequate design flow, but a closed valve or damaged main prevents its use. Personnel may have suitable equipment, but an obstructed or unsafe route prevents deployment. Both forms of limitation must be recorded.[21][2]

The response record should also preserve the basis for post-incident decisions. Hot fuel, damaged boundaries, residual agents and impaired structures can remain hazardous after visible flame is reduced. Review before re-entry or continued suppression should account for those conditions and for possible renewed burning.[4][10]

A final check should test whether the chosen measures remain compatible with one another. Agent delivery must suit the fuel, access must support deployment, and ventilation must not create unacceptable conditions elsewhere. The assessment should also state which provisions are required simultaneously and which independent backups exist if one fails.[32][33]

Uncertainty should remain visible in the operational record. Fire development, water availability and responder timing can differ from the model, and a calculated condition is not a guarantee of what personnel will encounter. The record should therefore identify the scenario, evidence and outstanding judgement required at the scene.[10][35]

See also

Notes

[32]

  1. ↑ 1.0 1.1 1.2 1.3 U.S. Nuclear Regulatory Commission (2005), pp. F-25–F-26.
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 Ministry of Business, Innovation and Employment (2025), p. 53.
  3. ↑ 3.0 3.1 Bryan (2002), pp. 3-318–3-319.
  4. ↑ 4.0 4.1 4.2 4.3 4.4 U.S. Nuclear Regulatory Commission (2005), pp. B-43–B-44.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 Fleming (2002), p. 4-72.
  6. ↑ 6.0 6.1 6.2 6.3 6.4 U.S. Nuclear Regulatory Commission (2005), p. B-15.
  7. ↑ 7.0 7.1 Scheffey (2002), p. 4-88.
  8. ↑ 8.0 8.1 Australian Building Codes Board et al. (2005), p. 2.5-6.
  9. ↑ 9.0 9.1 Van Rossum (2027), §4.11.
  10. ↑ 10.0 10.1 10.2 10.3 10.4 10.5 Ministry of Business, Innovation and Employment (2025), pp. 54–55.
  11. ↑ U.S. Nuclear Regulatory Commission (2005), pp. B-58–B-59.
  12. ↑ U.S. Nuclear Regulatory Commission (2005), pp. B-55–B-56.
  13. ↑ U.S. Nuclear Regulatory Commission (2005), p. B-16.
  14. ↑ 14.0 14.1 U.S. Nuclear Regulatory Commission (2005), pp. H-28–H-29.
  15. ↑ 15.0 15.1 U.S. Nuclear Regulatory Commission (2005), p. F-29.
  16. ↑ Bryan (2002), p. 3-319.
  17. ↑ U.S. Nuclear Regulatory Commission (2005), pp. 10-1–10-2.
  18. ↑ 18.0 18.1 Fleming (2002), p. 4-73.
  19. ↑ U.S. Nuclear Regulatory Commission (2005), pp. F-61–F-62.
  20. ↑ 20.0 20.1 Hopkins, Schoenrock, and Budnick (2005), p. xxxv.
  21. ↑ 21.0 21.1 Hopkins, Schoenrock, and Budnick (2005), pp. xli–xlii.
  22. ↑ 22.0 22.1 22.2 22.3 U.S. Nuclear Regulatory Commission (2005), p. 10-2.
  23. ↑ 23.0 23.1 Australian Building Codes Board et al. (2005), p. 0.3-8.
  24. ↑ 24.0 24.1 Australian Building Codes Board et al. (2005), pp. 1.8-13–1.8-14.
  25. ↑ 25.0 25.1 25.2 U.S. Nuclear Regulatory Commission (2005), p. F-45.
  26. ↑ 26.0 26.1 Van Rossum (2027), §4.9.
  27. ↑ Van Rossum (2027), §4.10.
  28. ↑ 28.0 28.1 Evans et al. (2005), p. 70.
  29. ↑ 29.0 29.1 Cooper (2002), p. 3-239.
  30. ↑ Australian Building Codes Board (2020), pp. 129–130.
  31. ↑ Proulx (2002), p. 3-350.
  32. ↑ 32.0 32.1 32.2 Australian Building Codes Board (2020), p. 131.
  33. ↑ 33.0 33.1 Ministry of Business, Innovation and Employment (2025), pp. 58–59.
  34. ↑ U.S. Nuclear Regulatory Commission (2005), p. B-60.
  35. ↑ 35.0 35.1 Van Rossum (2027), §14.2.

References

  • Australian Building Codes Board. (2020). Fire safety verification method data sheets (Version 1.1). Author.
  • Australian Building Codes Board, National Research Council of Canada, International Code Council, & Department of Building and Housing New Zealand. (2005). International fire engineering guidelines (2005 ed.). Australian Building Codes Board.
  • Bryan, J. L. (2002). Behavioral response to fire and smoke. In P. J. DiNenno (Ed.), SFPE handbook of fire protection engineering (3rd ed.). National Fire Protection Association.
  • Cooper, L. Y. (2002). Smoke and heat venting. In P. J. DiNenno (Ed.), SFPE handbook of fire protection engineering (3rd ed.). National Fire Protection Association.
  • Evans, D. D., Peacock, R. D., Kuligowski, E. D., Dols, W. S., & Grosshandler, W. L. (2005). Active fire protection systems (NIST NCSTAR 1-4). National Institute of Standards and Technology.
  • Fleming, R. P. (2002). Automatic sprinkler system calculations. In P. J. DiNenno (Ed.), SFPE handbook of fire protection engineering (3rd ed.). National Fire Protection Association.
  • Hopkins, M., Schoenrock, J., & Budnick, E. (2005). Fire suppression systems (NIST NCSTAR 1-4B). National Institute of Standards and Technology.
  • Ministry of Business, Innovation and Employment. (2025). C protection from fire: Verification method C/VM2 (2nd ed.). New Zealand Government.
  • Proulx, G. (2002). Movement of people: The evacuation timing. In P. J. DiNenno (Ed.), SFPE handbook of fire protection engineering (3rd ed.). National Fire Protection Association.
  • Scheffey, J. L. (2002). Foam agents and AFFF system design considerations. In P. J. DiNenno (Ed.), SFPE handbook of fire protection engineering (3rd ed.). National Fire Protection Association.
  • U.S. Nuclear Regulatory Commission. (2005). Fire dynamics tools: Quantitative fire hazard analysis methods for the U.S. nuclear regulatory commission fire protection inspection program (NUREG-1805). Author.
  • Van Rossum, E. (2027). Introduction to Fire Safety Engineering. Fire Safety Academy.
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