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- 2014 (4) (entfernen)
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- Cone calorimeter (1)
- Controlled-atmosphere cone calorimeter (1)
- Excess air (1)
- Flame retardant (1)
- Heat release rate (1)
- Layer-by-layer assembly (1)
- Oxygen consumption (1)
- Polyurethane foam (1)
- Real scale mockup (1)
- Sodium montmorillonite (1)
Ventilation vs. Vitiation Effects on the CO Pruduktion in a Controlled-atmosphere Cone Calorimeter
(2014)
The standard cone calorimeter according to ASTM E 1354 and ISO 5660 enables reaction-to-fire tests to be performed in ambient atmospheric conditions. A controlled-atmosphere chamber modifies the standard apparatus in a way that allows tests to be performed in nonambient conditions as well. The enclosed chamber is placed underneath the standard exhaust hood and does not have a closed connection to the hood. With this open arrangement, the exhaust gases are diluted by excess air drawn in from the laboratory surroundings. Heat-induced changes in the consequential dilution ratio affect the calculation of fire quantities and, when neglected, lead to deviations of up to 30% in heat release rate. The paper introduces a test protocol and equations to calculate the heat release rate taking dilution effects into account. A mathematical correction is shown that compensates for the dilution effects while avoiding extensive mechanical changes in the equipment.
Layer-by-layer (LbL) assembly coatings reduce the flammability of textiles and polyurethane foam but require extensive repetitive processing steps to produce the desired coating thickness and nanoparticle fire retardant content that translates into a fire retardant coating. Reported here is a new hybrid bi-layer (BL) approach to fabricate fire retardant coatings on polyurethane foam. Utilizing hydrogen bonding and electrostatic attraction along with the pH adjustment, a fast growing coating with significant fire retardant clay content was achieved. This hybrid BL coating exhibits significant fire performance improvement in both bench scale and real scale tests. Cone calorimetry bench scale tests show a 42% and 71% reduction in peak and average heat release rates, respectively. Real scale furniture mockups constructed using the hybrid LbL coating reduced the peak and average heat release rates by 53% and 63%, respectively. This is the first time that the fire safety in a real scale test has been reported for any LbL technology. This hybrid LbL coating is the fastest approach to develop an effective fire retardant coating for polyurethane foam.
Bei der Ermittlung von Brandursachen und bei der Rekonstruktion von Brandverläufen kommt der Frage, ob und wie bei der Entstehung und Entwicklung des betreffenden Brandes Brandbeschleuniger beteiligt waren, eine bedeutende Rolle zu. Dennoch stehen umfangreiche experimentelle Daten zu originalmaßstäblichen Raumbrandversuchen, die den Einfluss von Brandbeschleunigern untersuchen, oder zumindest beiläufig berücksichtigen, kaum bis nicht zur Verfügung. Dieser Artikel berichtet über eine originalmaßstäbliche Versuchsserie, die diesen Einfluss auf den Verlauf von Raumbränden zum Gegenstand hatte. Es zeigt sich, dass die Beteiligung von Brandbeschleunigern einen unwesentlichen Einfluss auf die Ausprägung einzelner brandtechnologischer Kenngrößen, wie Wärmefreisetzungsrate, Brandraumtemperatur, Kohlenmonoxidfreisetzung uvm. hat, sich die Zeitspannen zum Eintreten von Ereignissen oder zum Erreichen bestimmter Kriterien jedoch erheblich verändern.