What Is Vertical Flame?
Vertical flame test is a standard flame applied to a vertically suspended sample for a defined period of time; It is an experiment in which flame extinction time, burning length and burning drop formation are evaluated.
Purpose of Vertical Flame
The purpose is to verify that the material or cable limits flame spread in a vertical position and goes out when the igniter is removed.
Which Products Is Vertical Flame Applied To?
- Single cable insulation and sheaths
- Electrical product plastic housings
- Textile and curtain materials
- insulation films
In Which Sectors Is Vertical Flame Used?
Standards Related to Vertical Flame
- IEC 60332-1 (tek kablo dikey alev)
- UL 94 (V-0, V-1, V-2)
- ISO 6941 (tekstil)
- IEC 60695-11-10
- UL 94flammability class in plastic materials test
- EN 13501Fire classification of building products test
- ASTM E84flame spread on the surface test
- ASTM E119Fire resistance in building elements test
Vertical Flame Conditions
- Flame application
- Burner, flame length and application time defined in the standard
- Criteria
- Extinction time, combustion/carbonation length, ignition of cotton by burning drop
- Specimen orientation
- Vertical; hanging arrangement defined in the standard
- Conditioning
- Defined in the standard; UL 94 also has an aging requirement
Equipment for Vertical Flame
- Dikey alev test kabini
- Calibrated burner and gas system
- Timer and cotton pad layout
- Conditioning and aging oven
Sample Requirements for Vertical Flame
- Sample size and thickness must comply with the standard
- Thinnest and thickest thickness tested to UL 94
- Conditioning and aging conditions must be observed
- The number of specimens is defined in the standard
Duration of Vertical Flame
Typically 1–3 weeks including conditioning.
Vertical Flame Procedure
- 1Samples are prepared and conditioned.
- 2The burner flame is calibrated.
- 3The sample is hung vertically.
- 4Flame is applied and removed for a defined period of time.
- 5Extinction time and drop behavior are recorded.
- 6The combustion length is measured and the classification is given.
Vertical Flame Acceptance Criteria
Acceptance criteria are defined in the applicable standard: V-0/V-1/V-2 criteria in UL 94, maximum carbonization length in IEC 60332-1.
Evaluation of Results
UL 94 class applies to a certain thickness and color; If the thickness or pigment changes, the class becomes invalid. The single cable test (IEC 60332-1) does not represent the behavior of bundled cables; bundle requires IEC 60332-3.
Vertical Flame Report
- Applied standard and class
- Sample thickness and color
- Conditioning and aging
- Extinguishing times and burning length
- Drop behavior
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Electrical product standards
- Cable product standards
Fire Testing — What Does This Testing Field Cover?
The section below describes the field that the Vertical Flame test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Fire testing measures two different concepts, and confusing them is the most common mistake in the field. REACTION to fire describes how much a material contributes to the start and growth of a fire. RESISTANCE to fire is the ability of a building element to hold a fire back for a defined period. One is a material property, the other a property of an element.
On the reaction side, ignitability, flame spread, heat release, smoke production, flaming droplets and toxic gas release are measured. The result is translated into an EN 13501-1 class in Europe, ASTM E84 indices in North America and a UL 94 class for appliance plastics. These three systems cannot be converted into one another; their scales and set-ups differ.
On the resistance side, furnace tests are carried out. The element is exposed to a defined temperature-time curve and it is measured how long it maintains three functions: load bearing (R), integrity (E) and insulation (I). For a fire door, the designation EI 60 says the element maintains its integrity and insulating function for sixty minutes.
SCALE is decisive in this family and directly affects cost. Small flame tests are suitable for screening materials and are fast and inexpensive. But real fire behaviour changes with scale: a material that self-extinguishes on a small specimen may sustain a flame over a large surface. Large-scale set-ups such as the room corner test and full-scale facade tests are therefore indispensable in critical applications.
Facade systems have become the most sensitive subject in the field in recent years. The rapid spread of facade fires in tall buildings has led national regulations to require large-scale facade testing. What is assessed here is not a single material but the SYSTEM: insulation, cladding, air cavity, fixings and fire barriers are tested together.
Smoke and toxicity form a separate body of work, because most deaths in a fire are caused by smoke rather than flame. In rail systems and on ships, smoke density and gas toxicity measurements are mandatory items; in an enclosed space the time available for evacuation depends on these values.
Cables have a sub-body of their own. A cable bundle inside a building can form a serious path for fire to spread between floors; flame spread, smoke production, halogen content and circuit integrity are therefore assessed for cables under separate standards, and in Europe the EN 13501-6 classification is used.
Method groups in this field
Non-combustibility and calorific value
The EN ISO 1182 non-combustibility furnace and EN ISO 1716 gross calorific value; the determinants of classes A1 and A2.
Single burning item (SBI)
EN 13823; heat release, flame spread and smoke production are measured together in a medium-scale corner set-up.
Small flame
Ignitability with a single flame source to EN ISO 11925-2; UL 94 horizontal and vertical burning; needle flame and glow wire.
Cone calorimeter
ISO 5660 / ASTM E1354; heat release rate, total heat release and smoke production are measured. The most informative test in material development.
Fire resistance
Furnace tests with the standard temperature-time curve; separate set-ups for doors, walls, floors, glazing and service penetrations.
Large scale
Room corner test (ISO 9705, NFPA 286), facade fire tests and vertical flame spread tests on cable bundles.
Smoke and toxicity
Optical smoke density, smoke gas analysis and toxicity indices; mandatory in rail systems and marine.
Commonly confused in this field
- Reaction to fire and resistance to fire are different concepts; the specification must be explicit about which is required.
- UL 94, ASTM E84 and EN 13501-1 results cannot be converted into one another.
- A small-scale result is not evidence of large-scale behaviour; large-scale testing is required in critical applications.
- A class is valid together with the end-use installation of the product; a different substrate or air cavity changes the result.
- For facade systems a result for a single material is not sufficient; the system must be tested as a whole.
- The fire class of a product does not show the fire resistance of an assembly made from it.
Which decisions these results support
- The fire class in the declaration of performance for construction products
- Regulatory compliance in the selection of cables, flooring and interior linings
- Approval of interior materials for rail vehicles, ships and aircraft
- Approval of the facade system design
- Meeting insurance and project specification requirements
Related Tests
Frequently Asked Questions About Vertical Flame
Is UL 94 V-0 class valid for all thicknesses?
No. Grade applies to thickness (and colour/pigment) tested. A thinner section requires separate testing; Specifies the certificate thickness range.