Journal of Fire Sciences

Polyamide (nylon) 11 (PA11) were melt-blended by dispersing low concentrations of nanoparticles (NPs), namely nanoclays (NCs) and carbon nanofibers (CNFs) via twin-screw extrusion. To enhance their thermal and flame retardant (FR) properties, an intumescent FR additive was added to the mechanically superior NC and CNF PA11 formulations. For neat and NP-reinforced PA11 as well as for PA11 reinforced by both intumescent FR and select NPs (NC or CNF), decomposition temperatures by TGA, flammability properties by UL 94, and cone calorimetry values were measured. All PA11 polymer systems infused with both NPs and FR additive had higher decomposition temperatures than those infused with solely FR additive. For the PA11/FR/NC polymer blends, Exolit® OP 1312 (FR2) is the preferred FR additive to pass the UL 94 V-0 requirement with 20 wt%. For the PA11/FR/CNF formulations, all Exolit® OP 1311 (FR1), OP 1312 (FR2), and OP 1230 (FR3) FR additives passed the UL 94 V-0 requirement with 20 wt%.

The oxygen index test has been one of the basic materials’ fire tests since the 1960s, with a large number of applications being described, but it is mainly limited nowadays to the ranking of materials and production control without relating results to behavior in real fires. The test exists in a large number of versions, but only one is internationally standardized as ISO 4589-2. Nevertheless, determination of test uncertainty is not simple, as the result is a combination of qualitative and quantitative measurements. This article highlights the main verifications needed to ensure the accuracy (trueness and repeatability) of test results and proposes a method to calculate and estimate test uncertainty.

The glow-wire test has been one of the basic electrotechnical material fire tests since the 1970 s. Although the test exists in a large number of versions, only one is internationally standardized as IEC 60695-2, Parts 10–13. Test results are ignition or flame persistence of a material in contact with a glow wire at a given temperature. Since the measurement is qualitative, uncertainty can only be performed on the temperature measurement itself. This article demonstrates the main verifications needed to ensure trueness and repeatability of the test and proposes a method to calculate test uncertainty. It also summarizes the results of various round-robin inter-laboratory studies and presents an example application of uncertainty determination.

This article presents an experimental investigation of ignition and burning behaviors of intumescent coatings and nanoparticles applied on flaxboard using the cone calorimeter, single burning item (SBI) and reduced scale (one-third) ISO room. The effects of intumescent coatings and nanoparticles on time to ignition (TTI), mass loss rate (MLR), heat release rate (HRR), production of toxic gases (carbon monoxide and smoke) were investigated. The performance of intumescent coatings in under-ventilated condition was examined by performing tests in the one-third ISO room with reduced opening sizes. Results in the cone calorimeter and SBI indicated that (1) there is a substantial increase of TTI and decrease of MLR/HRR by intumescent coatings and (2) the addition of nanoparticles results in a further increase of TTI as well as a decrease of MLR/HRR owing to increased stability of the char. Tests in the one-third ISO room showed that although the intumescent coatings reduce the HRR the reduction is much less substantial than that in the cone calorimeter or SBI.

Natural ventilation was provided by tall vertical shafts such as solar chimney while designing some green buildings. For buildings with a tall vertical shaft located in very cold countries, measured pressure difference due to stack effect was up to 300 Pa. Air motion induced by stack effect would give adequate ventilation flow rate. However, stack effect would also give adverse effect if not utilized properly in this green design. Smoke would spread faster to other parts of the building in an accidental fire. Therefore, estimations of stack pressure by simple hydrostatic equation used to be criticized in performance-based design. Further studies are required and will be justified by scale model experiments in this article. Stack effect in a vertical shaft was studied experimentally by a model shaft of size 0.05 × 0.05 m² and height 2.0 m. Air temperature inside the model was kept at constant values above outdoor by wounding hot electric wires. Vertical air temperature profiles inside and outside of the model at different heights were measured. Measured air pressure difference profiles between indoor and outdoor were then compared with those estimated from the air temperature difference. Results were then applied to justify stack pressure estimations by the hydrostatic models. From this study, hydrostatic equations are confirmed to be acceptable for studying stack pressure in tall vertical shafts.

This article studies the cooling capabilities of the compressed air foam system (CAFS) in fuel- and ventilation-controlled compartment fires. Tests were conducted with the CAFS and the traditional suppression agent, water mist. Tests were video recorded and the development of temperature inside the units was recorded using thermocouples, based on which a comparative analysis between the results by the CAFS and water mist is conducted. Results indicate that (1) the CAFS is more efficient in fuel-controlled fires, whereas for ventilation-controlled fires there is no noticeable difference between the two agents and (2) the CAFS does not contribute to or cause backdraft in ventilation-controlled experiments.

It is very important to accurately predict the fire-induced air velocity, temperature, and smoke concentrations in tunnel fires to design efficient fire protection systems. In this study a scaled model of a tunnel was constructed based on Froude number scaling and wood sticks with different configurations which were burned in a controlled environment. Model vehicles having a square base were built according to the wood crib theory. The impact of varying longitudinal ventilation velocity and the cross-sectional area of the burning substances on the heat release rate and temperature distribution in the tunnel were measured.