Combustibility - Revision history

Jan: Remove links to pages that do not exist; retain displayed text (wiki-wide link audit).

2026-11-02T21:32:47Z

Remove links to pages that do not exist; retain displayed text (wiki-wide link audit).

← Older revision		Revision as of 22:32, 2 November 2026
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	* [[Flame retardant]]		* [[Flame retardant]]
	* [[Photovoltaic system fire]]		* Photovoltaic system fire
	* [[Wildland-urban interface]]		* [[Wildland-urban interface]]
	* [[Large-scale facade fire test]]		* Large-scale facade fire test

	== Notes ==		== Notes ==

Thomas: Improve Combustibility: sourced explanations, calculations and internal links (Codex)

2026-11-02T17:59:01Z

Improve Combustibility: sourced explanations, calculations and internal links (Codex)

← Older revision		Revision as of 18:59, 2 November 2026
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	C/VM2 also uses critical radiant flux for flooring performance, with higher flux corresponding to better performance in its commentary. The criterion depends on occupancy, escape function and sprinkler protection. This illustrates how combustibility-related performance is evaluated against a scenario rather than as an isolated label.<ref name="CVM2-52" />		C/VM2 also uses critical radiant flux for flooring performance, with higher flux corresponding to better performance in its commentary. The criterion depends on occupancy, escape function and sprinkler protection. This illustrates how combustibility-related performance is evaluated against a scenario rather than as an isolated label.<ref name="CVM2-52" />

			New Zealand's C/VM2, second edition (2025), provides an example of a classification with a defined application. Its Group Numbers concern exposed interior wall and ceiling lining surfaces, and §4.7.2.2 refers determination of those numbers to the Building Product Specifications. The document's lists of material types illustrate the groups; they do not replace the specified classification process for a particular product.<ref name="CVM2-linings">Ministry of Business, Innovation and Employment (2025), §§4.7.1.5 and 4.7.2.2, pp. 50–52.</ref>

			This distinction separates a broad description such as combustible timber from evidence for a particular lining system. Backing, joints, coatings and exposed surfaces can change the tested product. A classification therefore describes the tested or assessed application within its stated conditions, rather than every installation containing the same base material.<ref name="CVM2-linings" /><ref name="Beyler-char">Beyler and Hirschler (2002), p. 1-113.</ref>

	== Composite products and installations ==		== Composite products and installations ==
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	Combustibility also says nothing about toxicity. Two materials can both burn, yet produce very different carbon monoxide, hydrogen cyanide, soot and irritant yields. Fire safety assessment must include those product yields as well as energy and spread.<ref name="Purser-2-85">Purser (2002), pp. 2-85–2-86.</ref><ref name="Gottuk-Lattimer-2-54">Gottuk and Lattimer (2002), p. 2-54.</ref>		Combustibility also says nothing about toxicity. Two materials can both burn, yet produce very different carbon monoxide, hydrogen cyanide, soot and irritant yields. Fire safety assessment must include those product yields as well as energy and spread.<ref name="Purser-2-85">Purser (2002), pp. 2-85–2-86.</ref><ref name="Gottuk-Lattimer-2-54">Gottuk and Lattimer (2002), p. 2-54.</ref>

			=== Softening, decomposition and residue ===

			Beyler and Hirschler distinguish thermal decomposition from a loss of physical performance. Decomposition changes chemical structure and can release volatile fuel, while degradation includes changes in useful properties. A material can therefore lose its original shape or strength before sustained flaming is observed.<ref name="Beyler-Hirschler-1-110" />

			Thermoplastics soften and can melt as they are heated. Cross-linked thermosetting materials do not follow the same melting behaviour, although they can decompose and release combustible products. This difference helps explain why specimens with similar chemical energy can expose different burning surfaces during a test.<ref name="Beyler-Hirschler-1-112" />

			Char formation changes the remaining fuel rather than proving that combustion has ended. A coherent residue can limit heat transfer and the escape of volatiles, while cracks or poor adhesion can reduce that protection. Carbonaceous char can itself oxidise after the main period of volatile release.<ref name="Beyler-char" />

			Consequently, the initial specimen and the material actually burning may have different density, surface geometry and permeability. Material identity alone cannot capture these changes. Fire testing follows the response of a specified specimen and exposure, including the residue or melt that forms during heating.<ref name="Beyler-Hirschler-1-110" /><ref name="Beyler-char" />

	== Use and limitations ==		== Use and limitations ==
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	Material comparisons should use consistent specimens and exposures. Thickness, backing, moisture and test scale can change the result, and full-scale installation can add further feedback. A generic combustibility label alone is not enough to rank products safely.<ref name="Quintiere-2-247" /><ref name="Babrauskas-3-3">Babrauskas (2002), p. 3-3.</ref>		Material comparisons should use consistent specimens and exposures. Thickness, backing, moisture and test scale can change the result, and full-scale installation can add further feedback. A generic combustibility label alone is not enough to rank products safely.<ref name="Quintiere-2-247" /><ref name="Babrauskas-3-3">Babrauskas (2002), p. 3-3.</ref>

	~~Finally,~~ combustibility does not describe how much harm a fire will cause. Harm depends on heat release rate, spread, smoke, toxicity, enclosure and occupants. The material is one part of that larger scenario.<ref name="Purser-2-85" /><ref name="IFEG-1.6-3">Australian Building Codes Board et al. (2005), p. 1.6-3.</ref>		combustibility does not describe how much harm a fire will cause. Harm depends on heat release rate, spread, smoke, toxicity, enclosure and occupants. The material is one part of that larger scenario.<ref name="Purser-2-85" /><ref name="IFEG-1.6-3">Australian Building Codes Board et al. (2005), p. 1.6-3.</ref>

	== Material evidence and comparison ==		== Material evidence and comparison ==
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	For product development, alternative formulations and installations can be compared using the same scenario. This shows whether a change improves the relevant outcome without introducing a new exposure path. Full product evidence is especially important where a facing or treatment protects combustible material.<ref name="Janssens-3-39" /><ref name="Beyler-Hirschler-1-110" />		For product development, alternative formulations and installations can be compared using the same scenario. This shows whether a change improves the relevant outcome without introducing a new exposure path. Full product evidence is especially important where a facing or treatment protects combustible material.<ref name="Janssens-3-39" /><ref name="Beyler-Hirschler-1-110" />

	For existing buildings, the actual installed condition should be established before relying on earlier data. Ageing, moisture, damage and altered contents can change both material properties and exposure. An older test result may therefore need confirmation rather than direct reuse.<ref name="Kodur-Harmathy-1-156" /><ref name="IFEG-2.4-3">Australian Building Codes Board et al. (2005), p. 2.4-3.</ref>

	A clear report therefore identifies the material, its intended function, the exposure and the criteria used. It also records which fire and structural consequences were assessed and which remain open. This makes combustibility a useful starting point for analysis without presenting it as a complete safety conclusion.<ref name="Janssens-3-39" /><ref name="CVM2-64" />		A clear report therefore identifies the material, its intended function, the exposure and the criteria used. It also records which fire and structural consequences were assessed and which remain open. This makes combustibility a useful starting point for analysis without presenting it as a complete safety conclusion.<ref name="Janssens-3-39" /><ref name="CVM2-64" />

	For final acceptance, the evidence should be weighed against the actual fire scenario rather than a generic material description. A product that performs as intended in one exposure can be unsuitable in another, and the governing criterion should determine which data are needed. This keeps combustibility tied to a measurable fire process.<ref name="Quintiere-2-247" /><ref name="Kanury-2-231" />		For final acceptance, the evidence should be weighed against the actual fire scenario rather than a generic material description. A product that performs as intended in one exposure can be unsuitable in another, and the governing criterion should determine which data are needed. This keeps combustibility tied to a measurable fire process.<ref name="Quintiere-2-247" /><ref name="Kanury-2-231" />

	A final report should also distinguish observed behaviour from inferred risk. Test data describe combustion and material response, while risk additionally includes probability, occupants and consequences. Confusing those levels can make a combustible material appear to have a fixed risk independent of its setting. This also prevents a material's mere presence from being confused with its actual contribution to a particular fire and its consequences for occupants and property.<ref name="IFEG-1.6-3" /><ref name="Purser-2-85" />

	== See also ==		== See also ==

	* [[~~Large-scale facade fire test~~]]		* [[Flame retardant]]
	* [[Photovoltaic system fire]]		* [[Photovoltaic system fire]]
	* [[Wildland-urban interface]]		* [[Wildland-urban interface]]
			* [[Large-scale facade fire test]]

	== Notes ==		== Notes ==

Sanne: Add diagrams fse-combustibility-v1.svg, fse-combustibility-v2.svg, fse-combustibility-v3.svg (level-1 visual plan)

2026-11-02T07:02:07Z

Add diagrams fse-combustibility-v1.svg, fse-combustibility-v2.svg, fse-combustibility-v3.svg (level-1 visual plan)

← Older revision		Revision as of 08:02, 2 November 2026
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	Kodur and Harmathy distinguish burnable and nonburnable materials in their review, while noting that burnable structural materials can change from performing an intended role to adding to fire severity. This is why fuel contribution and structural contribution must be evaluated separately.<ref name="Kodur-Harmathy-1-157" />		Kodur and Harmathy distinguish burnable and nonburnable materials in their review, while noting that burnable structural materials can change from performing an intended role to adding to fire severity. This is why fuel contribution and structural contribution must be evaluated separately.<ref name="Kodur-Harmathy-1-157" />
			[[File:fse-combustibility-v1.svg\|thumb\|upright=1.5\|alt=One component shown as structure or insulation and as a fuel source.\|A material can have both a design function and a fuel role. Based on Kodur and Harmathy (2002), p. 1-157.]]

	== Ignition and flame spread ==		== Ignition and flame spread ==
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	Orientation and airflow matter. Upward spread can preheat material above the flame, whereas lateral or downward spread uses different forward heat-transfer paths. A material's combustibility should therefore be evaluated in the intended installation, not only in a convenient test orientation.<ref name="VR-4.3">Van Rossum (2027), §4.3.</ref><ref name="Quintiere-2-247" />		Orientation and airflow matter. Upward spread can preheat material above the flame, whereas lateral or downward spread uses different forward heat-transfer paths. A material's combustibility should therefore be evaluated in the intended installation, not only in a convenient test orientation.<ref name="VR-4.3">Van Rossum (2027), §4.3.</ref><ref name="Quintiere-2-247" />
			[[File:fse-combustibility-v2.svg\|thumb\|upright=1.5\|alt=Heat source, target material, orientation, backing and heat losses shaping ignition and spread.\|Combustibility is expressed through source, target and conditions. Based on Kanury (2002), pp. 2-230–2-232 and Quintiere (2002), p. 2-247.]]

	Thermal properties also influence the response. Conductivity, density, specific heat and thermal diffusivity affect how quickly a surface and its interior heat. Composite and anisotropic materials can have different properties in different directions.<ref name="Rockett-Milke-1-29">Rockett and Milke (2002), p. 1-29.</ref><ref name="Kodur-Harmathy-1-156">Kodur and Harmathy (2002), p. 1-156.</ref>		Thermal properties also influence the response. Conductivity, density, specific heat and thermal diffusivity affect how quickly a surface and its interior heat. Composite and anisotropic materials can have different properties in different directions.<ref name="Rockett-Milke-1-29">Rockett and Milke (2002), p. 1-29.</ref><ref name="Kodur-Harmathy-1-156">Kodur and Harmathy (2002), p. 1-156.</ref>
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	New Zealand's C/VM2 (second edition, 2025) describes Group Number 1 materials as noncombustible or limited-combustibility materials, with plasterboard and similar low-hazard materials as examples. Group Number 2 includes many fire-retardant-treated timbers, Group Number 3 ordinary timber products and Group Number 4 exposed polyurethane foams. These are classifications within that document, not universal categories.<ref name="CVM2-52" />		New Zealand's C/VM2 (second edition, 2025) describes Group Number 1 materials as noncombustible or limited-combustibility materials, with plasterboard and similar low-hazard materials as examples. Group Number 2 includes many fire-retardant-treated timbers, Group Number 3 ordinary timber products and Group Number 4 exposed polyurethane foams. These are classifications within that document, not universal categories.<ref name="CVM2-52" />
			[[File:fse-combustibility-v3.svg\|thumb\|upright=1.5\|alt=Four C/VM2 groups from limited combustibility to exposed polyurethane foam.\|Material groups in New Zealand C/VM2 (2025). Based on Ministry of Business, Innovation and Employment (2025), p. 52.]]

	C/VM2 also uses critical radiant flux for flooring performance, with higher flux corresponding to better performance in its commentary. The criterion depends on occupancy, escape function and sprinkler protection. This illustrates how combustibility-related performance is evaluated against a scenario rather than as an isolated label.<ref name="CVM2-52" />		C/VM2 also uses critical radiant flux for flooring performance, with higher flux corresponding to better performance in its commentary. The criterion depends on occupancy, escape function and sprinkler protection. This illustrates how combustibility-related performance is evaluated against a scenario rather than as an isolated label.<ref name="CVM2-52" />

Jan: New FSE wiki article: Combustibility (written by Kimi Code CLI)

2026-11-02T00:35:58Z

New FSE wiki article: Combustibility (written by Kimi Code CLI)

New page

'''Combustibility''' is the ability of a material to burn under specified conditions. A combustible material can act as fuel, contributing chemical energy and combustion products to a fire. The related term noncombustibility should also be applied with its test and regulatory context rather than treated as an absolute statement about every exposure.<ref name="Kodur-Harmathy-1-157">Kodur and Harmathy (2002), p. 1-157.</ref><ref name="CVM2-52">Ministry of Business, Innovation and Employment (2025), p. 52.</ref>

Combustibility is not a complete description of fire behaviour. It does not specify ignition temperature, heat release rate, flame spread, smoke yield or toxicity. Those properties require separate measurements and scenario conditions, including orientation, thickness, backing and ventilation.<ref name="Quintiere-2-247">Quintiere (2002), p. 2-247.</ref><ref name="Mulholland-2-259">Mulholland (2002), p. 2-259.</ref>

A material can have a structural or insulating role and still become fuel when exposed to sufficient heat. Its fire performance therefore depends on both its intended function and its contribution to the fire itself.<ref name="Kodur-Harmathy-1-157" />

== Combustible materials as fuel ==

Combustible materials store chemical energy that can be released through oxidation. [[Fire load]] describes the total energy potentially available from those materials in a defined inventory. Combustibility identifies the possibility of burning, while fire load quantifies potential energy.<ref name="VR-4.4">Van Rossum (2027), §4.4.</ref><ref name="Drysdale-1-92">Drysdale (2002), p. 1-92.</ref>

The heat of combustion provides one part of this energy description. Complete oxidation values are measured under controlled conditions and do not predict actual energy release in every fire. Incomplete combustion, protected contents and moisture can reduce the effective contribution.<ref name="Drysdale-1-95">Drysdale (2002), p. 1-95.</ref><ref name="IFEG-2.4-2">Australian Building Codes Board et al. (2005), pp. 2.4-2–2.4-3.</ref>

Materials also differ in how readily they release that energy. Gases can mix directly with air, liquids generally evaporate, and many solids require thermal decomposition. A material can therefore be combustible without supporting immediate or sustained flaming under a particular exposure.<ref name="VR-4.1">Van Rossum (2027), §4.1.</ref><ref name="VR-3.1">Van Rossum (2027), §3.1.</ref>

Kodur and Harmathy distinguish burnable and nonburnable materials in their review, while noting that burnable structural materials can change from performing an intended role to adding to fire severity. This is why fuel contribution and structural contribution must be evaluated separately.<ref name="Kodur-Harmathy-1-157" />

== Ignition and flame spread ==

Combustibility becomes evident when a material ignites and sustains combustion, but the required exposure varies. Heat flux, exposure time, pilot arrangement and heat losses determine whether a critical condition is reached. No single universal ignition threshold applies to every material configuration.<ref name="Kanury-2-231">Kanury (2002), pp. 2-231–2-232.</ref><ref name="IFEG-3.3-3">Australian Building Codes Board et al. (2005), p. 3.3-3.</ref>

[[Flame spread]] is movement of a flame over or adjacent to condensed fuel as new regions are heated and decomposed. A material may be combustible but resist spread because of its thermal response, char formation or heat losses. Another can ignite readily and support rapid spread under the same exposure.<ref name="Quintiere-2-246">Quintiere (2002), p. 2-246.</ref><ref name="Quintiere-2-247" />

Orientation and airflow matter. Upward spread can preheat material above the flame, whereas lateral or downward spread uses different forward heat-transfer paths. A material's combustibility should therefore be evaluated in the intended installation, not only in a convenient test orientation.<ref name="VR-4.3">Van Rossum (2027), §4.3.</ref><ref name="Quintiere-2-247" />

Thermal properties also influence the response. Conductivity, density, specific heat and thermal diffusivity affect how quickly a surface and its interior heat. Composite and anisotropic materials can have different properties in different directions.<ref name="Rockett-Milke-1-29">Rockett and Milke (2002), p. 1-29.</ref><ref name="Kodur-Harmathy-1-156">Kodur and Harmathy (2002), p. 1-156.</ref>

== Reaction to fire and testing ==

[[Reaction to fire]] describes how a material or product responds to fire exposure, including ignition, heat release, spread and sometimes smoke or toxic products. Combustibility is one part of that response but does not replace the complete measurement. Test conditions and product form are essential to interpretation.<ref name="Janssens-3-38">Janssens (2002), pp. 3-38–3-39.</ref><ref name="Quintiere-2-247" />

The [[Euroclass system]] is an example of a regulatory classification framework for reaction to fire. Such a system uses defined tests and criteria, so its classifications must not be inferred from material name or generic combustibility alone. The applicable edition and jurisdiction should be stated when a class is used.<ref name="CVM2-52" /><ref name="Janssens-3-38" />

New Zealand's C/VM2 (second edition, 2025) describes Group Number 1 materials as noncombustible or limited-combustibility materials, with plasterboard and similar low-hazard materials as examples. Group Number 2 includes many fire-retardant-treated timbers, Group Number 3 ordinary timber products and Group Number 4 exposed polyurethane foams. These are classifications within that document, not universal categories.<ref name="CVM2-52" />

C/VM2 also uses critical radiant flux for flooring performance, with higher flux corresponding to better performance in its commentary. The criterion depends on occupancy, escape function and sprinkler protection. This illustrates how combustibility-related performance is evaluated against a scenario rather than as an isolated label.<ref name="CVM2-52" />

== Composite products and installations ==

A [[Sandwich panel]] combines facings, a core, joints and fixings, which can respond differently during heating. One component may provide insulation while another supplies fuel. Panel performance therefore cannot be deduced from a single constituent without considering the assembled product.<ref name="Kodur-Harmathy-1-156" /><ref name="Rockett-Milke-1-29" />

Composite and porous materials can contain solid, liquid and gaseous phases. Moisture affects thermal properties and energy consumption, while pores can support oxygen transport and smouldering. The material's microstructure consequently influences its macroscopic fire response.<ref name="Kodur-Harmathy-1-156" /><ref name="Ohlemiller-2-200">Ohlemiller (2002), p. 2-200.</ref>

A [[Facade fire]] adds external flame exposure, cavities, cladding geometry and possible spread between floors. Combustible facade components can contribute to this pathway, but their effect depends on installation and fire source. A material classified in one test arrangement still needs evaluation in the facade system.<ref name="IFEG-1.6-7">Australian Building Codes Board et al. (2005), p. 1.6-7.</ref><ref name="CVM2-52" />

Protected and encapsulated fuel also requires attention. Combustible insulation behind a facing can remain uninvolved until the facing fails or heats sufficiently. The inventory may then change abruptly, demonstrating why material presence and actual fire contribution differ.<ref name="IFEG-2.4-2" /><ref name="Beyler-Hirschler-1-110">Beyler and Hirschler (2002), p. 1-110.</ref>

== Properties that influence response ==

Conductivity affects how quickly energy moves into and through a material, while heat capacity affects storage. Density and moisture influence both. These properties can change during heating, so ambient values do not necessarily describe the material throughout a fire.<ref name="Rockett-Milke-1-29" /><ref name="Kodur-Harmathy-1-163">Kodur and Harmathy (2002), p. 1-163.</ref>

Char formation can reduce heat transfer to underlying material, but char can also oxidise and sustain smouldering. Its continuity, porosity, adherence and permeability affect whether it acts as an insulating barrier. These changing properties can alter the apparent combustibility over time.<ref name="Beyler-Hirschler-1-110" /><ref name="Beyler-Hirschler-1-114">Beyler and Hirschler (2002), p. 1-114.</ref>

Some materials melt, shrink or disintegrate before full decomposition. Thermoplastics and thermosets respond differently to heating, and those physical changes alter exposed area and heat transfer. A material that initially appears protected can therefore become exposed later.<ref name="Beyler-Hirschler-1-112">Beyler and Hirschler (2002), p. 1-112.</ref>

Combustibility also says nothing about toxicity. Two materials can both burn, yet produce very different carbon monoxide, hydrogen cyanide, soot and irritant yields. Fire safety assessment must include those product yields as well as energy and spread.<ref name="Purser-2-85">Purser (2002), pp. 2-85–2-86.</ref><ref name="Gottuk-Lattimer-2-54">Gottuk and Lattimer (2002), p. 2-54.</ref>

== Use and limitations ==

Combustibility is useful for screening fuel inventory and selecting scenarios. It tells the analyst to consider a material as potential fuel and to investigate its ignition and contribution. It does not remove the need for subsequent measurements and modelling.<ref name="VR-4.4" /><ref name="IFEG-2.4-4">Australian Building Codes Board et al. (2005), p. 2.4-4.</ref>

A noncombustible label should be tied to the test or regulation that assigns it. It should not be interpreted as proof that a material cannot melt, decompose, lose strength or transfer heat. Noncombustibility and fire resistance are different properties.<ref name="Kodur-Harmathy-1-155">Kodur and Harmathy (2002), p. 1-155.</ref><ref name="CVM2-64">Ministry of Business, Innovation and Employment (2025), p. 64.</ref>

Material comparisons should use consistent specimens and exposures. Thickness, backing, moisture and test scale can change the result, and full-scale installation can add further feedback. A generic combustibility label alone is not enough to rank products safely.<ref name="Quintiere-2-247" /><ref name="Babrauskas-3-3">Babrauskas (2002), p. 3-3.</ref>

Finally, combustibility does not describe how much harm a fire will cause. Harm depends on heat release rate, spread, smoke, toxicity, enclosure and occupants. The material is one part of that larger scenario.<ref name="Purser-2-85" /><ref name="IFEG-1.6-3">Australian Building Codes Board et al. (2005), p. 1.6-3.</ref>

== Material evidence and comparison ==

A useful comparison starts with the same exposure and product form. Heat flux, specimen orientation, backing, thickness and ignition method should be consistent, otherwise a measured difference cannot be assigned confidently to the material. Composite products also need their layers and mounting identified.<ref name="Kanury-2-231" /><ref name="Janssens-3-39">Janssens (2002), p. 3-39.</ref>

Heat release and mass loss should be evaluated together. A material can have high energy content but low combustion efficiency, while another can release energy rapidly despite a smaller inventory. Effective heat of combustion and fuel-consumption history therefore provide more insight than combustibility alone.<ref name="Babrauskas-3-1">Babrauskas (2002), p. 3-1.</ref><ref name="Drysdale-1-95" />

Soot and toxic yields need the same conditional treatment. Material chemistry and oxygen supply can change the quantities and the types of products, and those yields can vary during the test. Early well-ventilated results should not be used to represent a developed fuel-rich fire without checking.<ref name="Purser-2-96">Purser (2002), p. 2-96.</ref><ref name="Gottuk-Lattimer-2-55">Gottuk and Lattimer (2002), p. 2-55.</ref>

Physical integrity can be as important as combustion. A material may melt, shrink, delaminate, spall or lose strength before it contributes substantial flame. Those changes can expose new fuel or allow heat and smoke to bypass the original barrier. Reaction to fire and structural performance therefore have to be assessed together.<ref name="Beyler-Hirschler-1-112" /><ref name="Kodur-Harmathy-1-163" />

The scale of the test changes interpretation. Bench-scale specimens isolate material response, while room and system tests add hot-layer radiation, ventilation and assembly effects. Selecting evidence that matches the intended application is more defensible than choosing the largest or most convenient test.<ref name="Babrauskas-3-3" /><ref name="Janssens-3-39" />

== Scenario assessment ==

For an ignition assessment, the source and target must be described. A small pilot can ignite a suitable gas mixture, but a solid target needs enough heat to produce volatiles and maintain reaction. Combustibility does not remove the need to evaluate that source-target interaction.<ref name="Kanury-2-230">Kanury (2002), p. 2-230.</ref><ref name="IFEG-2.4-4" />

For a spread assessment, the relevant paths include direct flame contact, radiation, convection and conduction. Material boundaries and openings can change those paths during the fire. A product that resists early ignition can still become involved when the surrounding exposure grows.<ref name="IFEG-1.6-7" /><ref name="VR-5.1">Van Rossum (2027), §5.1.</ref>

For a smoke assessment, total mass burned and product yields must both be estimated. A lower heat release rate can reduce total production, but a higher yield per kilogram can offset part of that reduction. Receiver concentration and exposure duration should be calculated from the resulting atmosphere.<ref name="VR-6.2">Van Rossum (2027), §6.2.</ref><ref name="Purser-2-88">Purser (2002), p. 2-88.</ref>

For structural assessment, temperature and integrity must be linked to the material's function. A combustible member can lose section and strength, while a noncombustible member can transmit heat or deform. The required criterion determines whether the material's behaviour is acceptable.<ref name="CVM2-64" /><ref name="Kodur-Harmathy-1-155" />

For facades and cavities, installation should be treated as part of the fuel geometry. Joints, air gaps and coverings can alter oxygen access, heat transfer and the route to other floors. This makes system testing and analysis necessary even when the individual material properties are known.<ref name="IFEG-1.6-7" /><ref name="CVM2-52" />

For regulated performance, the jurisdiction and edition must be explicit. C/VM2's 2025 groups and critical-radiant-flux criteria belong to New Zealand, while other frameworks use different tests and classifications. A material should not be assigned a class from one system using evidence from another without an equivalence assessment.<ref name="CVM2-52" /><ref name="Janssens-3-38" />

Where uncertainty remains, alternatives should be compared rather than hidden. Exposure, backing, moisture and installation can be varied to see whether the material's ranking or the safety conclusion changes. This shows whether a combustibility claim is broadly applicable or limited to one test configuration.<ref name="VR-1.7">Van Rossum (2027), §1.7.</ref><ref name="Quintiere-2-247" />

A final comparison should distinguish necessary from sufficient evidence. A combustible label identifies the need for analysis, but it does not prove ignition or sustained fire. Demonstrating those outcomes requires suitable exposure, fuel production, oxygen and heat feedback.<ref name="Kanury-2-230" /><ref name="VR-4.2">Van Rossum (2027), §4.2.</ref>

Material selection should likewise be based on the complete performance profile. Heat release, spread, smoke, toxicity, integrity and structural response can each favour a different product. A single combustibility statement cannot resolve those trade-offs or establish which consequence should dominate.<ref name="Purser-2-85" /><ref name="CVM2-64" />

For product development, alternative formulations and installations can be compared using the same scenario. This shows whether a change improves the relevant outcome without introducing a new exposure path. Full product evidence is especially important where a facing or treatment protects combustible material.<ref name="Janssens-3-39" /><ref name="Beyler-Hirschler-1-110" />

For existing buildings, the actual installed condition should be established before relying on earlier data. Ageing, moisture, damage and altered contents can change both material properties and exposure. An older test result may therefore need confirmation rather than direct reuse.<ref name="Kodur-Harmathy-1-156" /><ref name="IFEG-2.4-3">Australian Building Codes Board et al. (2005), p. 2.4-3.</ref>

A clear report therefore identifies the material, its intended function, the exposure and the criteria used. It also records which fire and structural consequences were assessed and which remain open. This makes combustibility a useful starting point for analysis without presenting it as a complete safety conclusion.<ref name="Janssens-3-39" /><ref name="CVM2-64" />

For final acceptance, the evidence should be weighed against the actual fire scenario rather than a generic material description. A product that performs as intended in one exposure can be unsuitable in another, and the governing criterion should determine which data are needed. This keeps combustibility tied to a measurable fire process.<ref name="Quintiere-2-247" /><ref name="Kanury-2-231" />

A final report should also distinguish observed behaviour from inferred risk. Test data describe combustion and material response, while risk additionally includes probability, occupants and consequences. Confusing those levels can make a combustible material appear to have a fixed risk independent of its setting. This also prevents a material's mere presence from being confused with its actual contribution to a particular fire and its consequences for occupants and property.<ref name="IFEG-1.6-3" /><ref name="Purser-2-85" />

== See also ==

* [[Large-scale facade fire test]]
* [[Photovoltaic system fire]]
* [[Wildland-urban interface]]

== Notes ==

<references />

== References ==

* 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.
* Babrauskas, V. (2002). Heat release rates. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Beyler, C. L., & Hirschler, M. M. (2002). Thermal decomposition of polymers. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Drysdale, D. D. (2002). Thermochemistry. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Gottuk, D. T., & Lattimer, B. Y. (2002). Effect of combustion conditions on species production. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Janssens, M. (2002). Calorimetry. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Kanury, A. M. (2002). Flaming ignition of solid fuels. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Kodur, V. K. R., & Harmathy, T. Z. (2002). Properties of building materials. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Ministry of Business, Innovation and Employment. (2025). ''C protection from fire: Verification method C/VM2'' (2nd ed.). New Zealand Government.
* Mulholland, G. W. (2002). Smoke production and properties. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Ohlemiller, T. J. (2002). Smoldering combustion. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Purser, D. A. (2002). Toxicity assessment of combustion products. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Quintiere, J. G. (2002). Surface flame spread. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Rockett, J. A., & Milke, J. A. (2002). Conduction of heat in solids. In P. J. DiNenno (Ed.), ''SFPE handbook of fire protection engineering'' (3rd ed.). National Fire Protection Association.
* Van Rossum, E. (2027). ''Introduction to Fire Safety Engineering''. Fire Safety Academy.

[[Category:Materials & Fire Testing]]