BS ISO 20463-2018 pdf free download.Rubber and rubber products — Determination of combustion energy and carbon dioxide emission from biobased and non-biobased materials
4 Principle
A sample from rubber or a rubber product is completely combusted in a pressure-proof sealed vessel (bomb) with high pressure oxygen gas settled in an insulated area. The combustion energy of the sample is calculated from the increased heat in the insulated area. The carbon dioxide emission amount is determined by measuring both the combustion gas volume collected from the used bomb and its carbon dioxide concentration. The biobased combustion energy and the biobased carbon dioxide emission can be calculated in proportion by multiplying the obtained values by the biobased carbon content.
NOTE There are two kinds of combustion energies, i.e. gross calorific value and net calorific value (see Annex A for information). This document specifies the determination of gross calorific value of rubber and rubber products.
5 Sampling For raw rubber, carry out sampling in accordance with ISO 1795. For vulcanized rubber, carry out sampling in accordance with ISO 4661-2. 6 Determination of the combustion energy of biobased and non- biobased materials
6.1 General
This method specifies how to determine the combustion energy of rubber or a rubber product using a bomb calorimeter. A high-pressure proof sealed bomb is used as a measuring vessel. A test sample is placed in the bomb filled with high-pressure oxygen with an ignition wire contacting the sample. The bomb is then placed in a water vessel the temperature of which is accurately controlled and measured. The test sample is combusted by igniting the wire and the calorific value is determined by the temperature increase, the volume of water in the water vessel (or the heat capacity of calorimeter) and the heat capacity of the bomb. The combustion system is calibrated by combusting the calorimetric standard, i.e. certified benzoic acid. If the carbon dioxide emission amount is to be measured in the later process, the combustion gas in the bomb shall be collected and used for the determination.
6.2 Reagents and materials
6.2.1 Oxygen, at a pressure high enough to fill the bomb to 3 MPa, pure, with an assay of at least 99,5 % volume fraction, and free from combustible matter. NOTE Oxygen made by the electrolytic process can contain up to 4 % volume fraction of hydrogen.
6.2.2 Benzoic acid, of calorimetric-standard quality, certified by (or traceable to) a recognized standardizing authority.
6.3 Apparatus
6.3.1 Bomb calorimeter The calorimeter (see Figure 1) consists of the assembled combustion bomb, the calorimeter can (with or without a lid), the calorimeter stirrer, water, temperature sensor and leads with connectors inside the calorimeter can required for ignition of the sample or as part of temperature measurement or control circuits. The calorimeter shall conform to ISO 1928 or provide the equivalent test results. During measurements, the calorimeter is enclosed in a thermostat. The manner in which the thermostat temperature is controlled defines the working principle of the instrument and, hence, the strategy for evaluating the corrected temperature rise.
6.3.2 Combustion bomb, capable of withstanding safely the pressures developed during combustion; see Figures 1 and 2. The material of construction shall resist corrosion by the acids produced in the combustion of rubber or a rubber product.
A suitable internal volume of the bomb is from 250 ml to 350 ml and it is preferred that the bomb is equipped with a relief valve or a bursting disc. WARNING — Bomb parts shall be inspected regularly for wear and corrosion; particular attention shall be paid to the condition of the threads of the main closure.
Manufacturers’ instructions regarding the safe handling and use of the bomb shall be observed. When more than one bomb of the same design is used, it is imperative to use each bomb as complete unit. Colour coding is recommended. Swapping of parts can lead to a serious accident.BS ISO 20463 pdf download