Analysis of EN 45545 R24 oxygen index test method

Prevention of fire , Elimination of disasters , This is an eternal theme of human social security . With the development of synthetic materials in chemical industry at home and abroad 、 light industry 、 Spin 、 Building material 、 Electronics 、 mining 、 automobile 、 The universal promotion and application of space flight and various fields of people's life , People have higher and higher requirements for flame retardant materials .

Insiders have repeatedly called for , In order to reduce the fire hazard , All walks of life before the use of materials , Flammable and combustible materials must be treated with flame retardance

EN 45545 R24 Experimental principle of oxygen index test

In oxygen 、 In the nitrogen mixed gas stream , Determine the minimum oxygen concentration just needed to maintain the combustion of the sample , The result is defined as the oxygen index .

EN 45545 R24 Type of oxygen index test method

EN 45545-2:2020 R24 The oxygen index of the project has 3 Methods ： Method A、B and C.

One way is A、B They are the top ignition method and the diffusion ignition method , All are not simple methods , The oxygen index of the material can be measured and calculated , The main difference between the two lies in the way of ignition . The method C Is a simple method , Whether the oxygen index of the material is higher than a specified value can be quickly determined , Its ignition mode can be top surface ignition A Or diffusion ignition B.

notes ： Method C It can be applied to any type of material , The choice depends mainly on the customer . But the way A and B The choice of depends mainly on the shape of the specimen or the test standard .

EN 45545 R24 Sample specification for oxygen index test

The test sample shall be at least 15 individual . However, if the sample is anisotropic or fabric , Double the number of samples , path （ cross ）、 weft （ longitudinal ） Test separately , CO measurement 2 Group .

Sample size requirements are as follows ：

Film or film ：140mm*52mm* The thickness of the ≤10.5mm

Moulding materials ： Long （80-150mm）* wide 10mm* The thickness of the 4mm

Foam material ： Long （80-150mm）* wide 10mm* The thickness of the 10.5mm

Sheet receiving status ： Long （80-150mm）* wide 10mm* The thickness of the ≤10.5mm

（ For electrical appliances ） Moulding material or sheet ： Long （80-150mm）* wide 6.5mm* The thickness of the 3mm

Fiber reinforced plastics ： Long （80-150mm）* wide 6.5mm* The thickness of the 3mm

Rubber materials ： Long （80-150mm）* wide 6.5mm* The thickness of the 3mm

EN 45545 R24 Brief introduction of oxygen index test method

Method A - Top surface ignition method

The top surface ignition is to ignite with an igniter on the top surface of the sample .

Apply the lowest part of the flame to the top surface of the specimen , If needed , It can cover the whole top surface , However, the flame shall not face the vertical or edge of the specimen . Apply flame 30 s, every other 5s Move once , There is just enough time to observe whether the entire top surface of the sample is in the burning state when it is removed . In every increase 5 s after , Observe the continuous burning of the entire top surface of the sample , Remove the igniter immediately , At this time, the sample is ignited and the burning time is recorded and the burning length is observed .

Method B - Diffusion ignition method

Diffusion ignition method is to make the flame generated by the igniter move down to the vertical plane of the sample through the top surface .

Move down the igniter to apply the visible flame to the top surface of the sample and move down to the vertical plane 6 mm. Apply flame continuously 30 s, Include every 5s Check the combustion interruption of the sample , Until the vertical plane is in steady-state combustion or the visible combustion part reaches the upper mark of the supporting frame . If you use I、II、III 、Ⅳ and Ⅵ Type specimen , Then the burning part reaches the upper marking line of the sample .

In order to measure the burning time and burning length , When the burning part reaches the superscript line , It is considered that the sample is ignited .

EN 45545 R24 Relevant standards for oxygen index test

ISO 4589-2 plastic - Determination of combustion behavior by oxygen index method - The first 2 part : Room temperature test

ISO 4589-2 Plastics-Determination of burning behavior by oxygen index –Part 2: Ambient-temperature test

GB/T2406.2 plastic - Determination of combustion behavior by oxygen index method - The second part ： Room temperature test

GB/T2406.2 Plastics-Determination of burning behavior by oxygen index-Part 2:Ambient-temperature test

ASTM D2863 Measure the minimum oxygen concentration that supports the burning of plastic like candles （ Oxygen index ） Test method for

ASTM D2863Standard Test Method for Measuring the Minimum Oxygen Concentration to Support Candle-Like Combustion of Plastics (Oxygen Index)

GB/T 10707 Rubber - Determination of flammability

GB/T 10707Rubber-Determination of the burning

GB/T 8924 Test method for flammability of fiber reinforced plastics - oxygen index method

GB/T 8924Fiber Reinforced Plastics-Burning behavior-Oxygen index method

come from GF2022