FIPEC Heat Release Rate Instrumentation
IEC 60332-3; EN 50399
The European Commission and The European Cable Industry (EUROPACABLE) are currently finalising Classification Systems for electric cables for use in support of the Construction Products Directive (CPD) throughout Europe. The Classification utilises the results obtained from traditional IEC 60332-3 test equipment fitted with heat and smoke release measurement instrumentation.
The measurement technique was developed as part of the recently concluded 3 year FIPEC (Fire Performance of Electric Cables) project, which was carried out by the 4 laboratories: SP (Sweden), ISSeP (Belgium), CESI (Italy) and Interscience (UK). FTT director Stephen Grayson managed this project and FTT’s Andrew Green was seconded to Interscience for its duration. Andrew’s contribution included instrument commissioning, software and data base development and maintenance.
Heat release rate is calculated by continuous measurement of the oxygen being consumed in the combustion process. Combustion products are sampled from the exhaust duct of the IEC 60332-3 chamber and used to determine the level of oxygen depletion. Additional measurements of mass flow rates and smoke temperatures are taken and used to calculate the heat release rates. Smoke release rates are similarly calculated from optical measurements and mass flow in the duct. Other combustion products can also be conveniently measured in the same process by use of appropriate analysers.
Conversion of existing IEC 60332-3 rigs is conveniently effected by fitting a small instrumented section of ducting into the exhaust system of the rig. The section houses all gas sampling, temperature and mass flow probes needed, and the smoke measuring system.