The Analysis of Fire

The Cone Calorimeter is the most significant bench scale instrument in the field of fire testing. Heat release is the key measurement required to assess the fire development of materials and products. Traditionally it has been very difficult to measure and more recently full scall testing of items (e.g. furniture) has been possible by burning these articles and measuring the evolved heat using a technique called oxygen depletion calorimetry. In the early 1980's workers at NIST (formerly NBS), in the USA, decided to produce an improved bench scale heat release test which would overcome the deficiencies of existing small scale heat release tests which relied on the measurement of the outflow enthalpy of enclosed systems. Oxygen depletion calorimetry was identified as the best measurment method. This is based on the empirical observation that heat released by burning materials is directly proportional to the quantity of oxygen used in the combustion process. The instrument was called a Cone Calorimeter. This name was derived from the shape of the truncated conical heater that is used to irradiate the test specimen with fluxes up to 100 kW/m2 in the test. The FTT Cone Calorimeter has been produced to meet all existing Standards (including ISO 5660, ASTM E 1354, ASTM E 1474, ASTM E 1740, ASTM F 1550, ASTM D 6113, NFPA 264, CAN ULC 135 and BS 476 Part 15) and can also be purchased in modular form so that those laboratories with particular interests such as heat release, mass loss, smoke production, etc. can initially purchase the sections they require and later add further instrumentation into the same cabinets in order to complete a full specification instrument. This is just one of the advantages of the FTT Cone Calorimeter.

Ignitability Smoke obscuration Heat release rates Kw Gas analysis(toxicity) Mass loss rates Soot sampling Effective heat of combustion MJ/Kg Corrosivity

A full system consists of:

Conical Heater - the conical heater, wound in the form of a truncated cone, is rated 5000 W at 230 V with a heat output of up an equivalent of 100 kW/m2 and for use in the horizontal and vertical orientation. Temperature control is achieved using 3 type K thermocouples and a 3-term (PID) temperature controller. Split Shutter Mechanism - protects the sample area before the beginning of the test. In this way, the initial mass measurement can stabilise before beginning the actual test and the operator has additional time for system checks before starting the test. This added time is very important for easily-ignitable samples, which often ignite irreproducibly if a shutter mechanism is not in place. Specimen Holders - for specimen 100 X 100 X 50 mm thick, in the horizontal and vertical orientation. Load Cell - Mass measurements are conducted via a strain gauge load cell with an accuracy of 0.1 g and a total weight range of 2 kg, with a quick electronic tare facility. The load cell is housed in an enclosed case, to reduce the effect of temperature changes. Spark Ignition - By 10kV spark generator fitted with a safety cut-out device. Exhaust System - Manufactured from stainless steel for long life. This comprises of a hood, a gas sampling ring probe, an exhaust fan (with adjustable flow controls from 0-50 g/s, at a resolution of at least 0.1 g/s) and orifice plate flow measurement (thermocouple and differential pressure transducer). Normal operation is at a nominal 24 l/s. Gas Sampling - this comprises of a ring sampler, refrigerated cold trap, pump, drying columns and flow control. Oxygen Analysis - paramagnetic oxygen analyser, which has a range of 0-25% and an accuracy of better than 50 ppm oxygen. Smoke Obscuration - measured with a laser system, using photodiodes, and an 0.5 mW Helium Neon laser, with main and reference (compensating) photo detectors, complete with alignment cradle and 0.3, 0.8 neutral density filters for calibration. Heat Flux Meter - for setting the irradiance, on the surface of the specimens, from of the conical heat. Calibration Burner - to calibrate the rate of heat release measured by the apparatus using methane of 99.5% purity. Data Collection - 16 channel A/D interface and Windows software for use on IBM or compatible computers.

Options

Carbon Dioxide and Carbon Monoxide - NDIR gas analysers optionally available. Low Ambient Oxygen Attachment- for low oxygen sample analysis. Protection Doors - to screen the operator from smoke generated by hazardous samples. The doors allow normal air influx from the bottom for natural test area ventilation and test air input. The protection doors enclose three sides of the test area, a steel panel covers the back side, the exhaust covers the top side, and the test area floor covers the bottom side.