ISO 1716 Reaction to Fire Tests for Products - Determination of Gross Heat of Combustion (Calorific Value)

The International Organization for Standardization (ISO) standard ISO 1716 Reaction to fire tests for products — Determination of gross heat of combustion (calorific value) describes a method for determining the gross heat of combustion of products at a constant volume in a bomb calorimeter. This method is intended for application to solid products. Liquids can be tested using the test equipment described in ISO 1928 Solid mineral fuels — Determination of gross calorific value and calculation of net calorific value by the bomb calorimetric method in accordance with IEC 61039 Classification of insulating liquids and using similar equipment and conditions described in ASTM D240-00 Standard test method for heat of combustion of liquid hydrocarbon fuels by bomb calorimeter. The appendix to the standard describes the calculation of the net heat of combustion when necessary (Annex A). Information on the sensitivity of the test method is given in Annex B.

For the purposes of this standard, the following terms and definitions apply:

• Product refers to the material, element or component for which information is required.
• Material refers to a single basic substance or a uniformly dispersed mixture of substances, such as stone, timber, concrete, mineral wool, uniformly dispersed binders and polymers.
• Homogeneous product, the product is composed of a single material and has uniform density and composition throughout the product.
• A non-homogeneous product is a product composed of more than one component, whether significant or insignificant, that does not meet the requirements of a homogeneous product. If a non-homogeneous product cannot be easily separated into its component parts, the individual components must be provided separately by the sponsor.
• A non-essential component is a component that does not constitute a significant part of a material non-homogeneous product and has a layer with a mass/unit area of ​​less than 1,0 kg/m2 and a thickness of less than 1,0 mm. If the non-essential layers do not comply with the above requirements, they are considered together as non-essential. Two or more adjacent non-essential layers (i.e., with no significant components between the layers) are considered as a single non-essential component when they collectively comply with the requirements for a layer to be a non-essential component.
• A significant component is a component that forms a significant part of a non-homogeneous material product and has a layer with a mass/unit area of ​​1,0 kg/m2 or more or a thickness of 1,0 mm or more. Two or more adjacent minor layers (i.e., no major components between the layers) are considered a single major component when they collectively comply with the requirements for a layer to be a major component.
• An internal non-trivial component is a non-trivial component that is covered on both sides by at least one non-trivial component.
• An external minor component is a minor component that is not covered on one side by a major component.
• Calorific value is the thermal energy produced by burning a unit mass of a given substance.
• Gross heat of combustion is the heat released when combustion of a substance is complete and the water produced is completely condensed under specified conditions.
• Net heat of combustion is the heat released when combustion of a substance is complete and the water produced is in the vapor state under specified conditions.
• The latent heat of vaporization of water is the heat required to change water from liquid to gas.
• Surface density is the mass per unit area.

In principle, this test involves burning a test sample of a given mass in a calibrated bomb calorimeter under standardized conditions, at a constant volume, in an oxygen atmosphere, by burning certified benzoic acid. The heat of combustion determined under these conditions is calculated based on the observed temperature rise, taking into account the heat loss and the latent heat of vaporization of water. This is a test method for determining the absolute value of the heat of combustion for a product and does not take into account any inherent variability of the product.

The calorimetric bomb used in these tests is manufactured to have the following features:

• Volume, 300 plus/minus 50 ml
• Mass not greater than 3,25 kg
• Case thickness at least 1/10 of the inner diameter of the body

The lid is designed to receive the crucible and electric ignition device. The lid, including all seals, must be able to withstand an internal pressure of 21 MPa.

These conditions define a bomb in which 3 g of coal, under an initial oxygen pressure of not more than 1 MPa (pressure gauge method), can withstand with a sufficient safety factor the maximum amount of pressure developed during combustion without the need for a calorimetric bomb of excessively large mass.

The internal surface of the bomb must be resistant to attack by combustion products and must be resistant to pitting and intercrystalline corrosion by acids formed during combustion, even when sulfur-rich fuels are used.

These tests also require the following equipment: calorimeter, temperature measuring device, crucible, timing device, electric power source, pressure gauge and needle valve, balance, “cigarette” making device and pellet making device.

Our organization has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. Among the numerous test, measurement, analysis and evaluation studies provided for businesses in various sectors, there are also test services in accordance with the standard “ISO 1716 Reaction to fire tests for products - Determination of gross combustion heat (calorific value)”.