Measuring the heat release rate of PVC wall panels using ISO 5660

1.Test Principle

The ISO 5660 standard is an important standard used to measure combustion characteristics such as the heat release rate of materials during the combustion process. Heat Release Rate (HRR) refers to the amount of heat released per unit time when a material burns under specified test conditions. For PVC wall panels, measuring their heat release rate can assess their combustion performance in a fire.

The test principle is based on the oxygen consumption principle. During combustion, there is a proportional relationship between the heat released and the amount of oxygen consumed. Generally, the heat released per unit mass of oxygen consumed is approximately constant (about 13.1×10³ kJ/kg). By accurately measuring the oxygen consumption during combustion, the heat release rate can be calculated.

ISO 5660-1 Reaction to fire tests—Heat release, smoke production and mass loss rate—Part 1: Heat release rate (cone calorimeter method)

2.Test Equipment

The ISO 5660 heat release rate is tested using a cone calorimeter, which is the core equipment for ISO 5660 testing. It mainly consists of a combustion chamber, sample holder, ventilation system, oxygen analyzer, weighing system, and data acquisition system.

The combustion chamber provides a controlled burning environment, the sample holder is used to secure the PVC wall panel sample, and the ventilation system ensures the supply of air required for combustion and removes combustion products. The oxygen analyzer accurately measures changes in oxygen concentration during combustion, the weighing system records the mass loss of the sample during combustion, and the data acquisition system collects and processes various test data, such as heat release rate and mass loss rate.

3.Test Sample Preparation

The sample dimensions should comply with the requirements of the ISO 5660 standard. Generally, PVC wall panel samples are typically 100mm×100mm in size, with the thickness based on the actual wall panel thickness, but the flatness and consistency of the samples must be ensured.

Multiple samples are usually required to ensure the reliability and repeatability of the test results.

4.Sample Pretreatment

Before testing, the samples need to be pretreated, such as conditioning them to a constant weight under standard environmental conditions (temperature 23°C±2°C, relative humidity 50%±5%), to eliminate the influence of moisture and other volatile components in the samples on the test results.

5.Test Procedure

Mount the sample horizontally under a radiation cone with a specific radiant flux, insert the spark plug, and ignite the igniter.

Data collection is stopped under the following conditions:

a)Continuous combustion for 32 minutes

b)The sample does not ignite within 30 minutes

c)The sample mass becomes zero

d)XO2 returns to within 0.01% of the pre-test oxygen concentration value for 10 minutes