| 1. |
- Barton, John, et al.
(författare)
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The effect of oxygen concentration on selected industrial products in the open controlled atmosphere cone calorimeter
- 2022
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Ingår i: Fire and Materials. - : Wiley. - 0308-0501 .- 1099-1018. ; 46:4, s. 617-627
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Tidskriftsartikel (refereegranskat)abstract
- Past research on the effect of oxygen concentration on the heat release rate and carbon monoxide yield has focused on materials in isolation and there is a lack of research that studies end-use products. This paper investigates the effect of oxygen concentration on the heat release rate per unit area (HRRPUA) and carbon monoxide yield for two different cables and a mineral oil used as an operating fluid for vacuum pumps. A standard cone calorimeter was used to conduct the tests at an ambient oxygen concentration of 21% and an open controlled atmosphere cone calorimeter (OCACC) was used for the tests conducted below 21%. The OCACC allows cone calorimeter tests to be run at different oxygen concentrations by attaching a chamber to the standard cone calorimeter. The effects of oxygen concentration on the HRRPUA and carbon monoxide yield for the cables were limited when there was flaming over the entire exposed surface area. For the mineral oil, there was a large decrease in the HRPPUA at a reduced oxygen concentration, but the carbon monoxide yield appeared to be unaffected.
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| 2. |
- Bray, Robert John, et al.
(författare)
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A comparison of carbon monoxide yields and particle formation at various global equivalence ratios in vitiated and under-ventilated conditions
- 2023
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Ingår i: Fire Safety Journal. - 0379-7112. ; 141
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Tidskriftsartikel (refereegranskat)abstract
- There have been previous studies comparing experimental methods for the purpose of capturing gaseous yields at a range of global equivalence ratios. However, no work has investigated the capability of the open controlled atmosphere cone calorimeter for collecting such data where its two modes of operation are directly compared. The aim of this study is to compare carbon monoxide yields collected using vitiated and under-ventilated modes of atmospheric control in order to identify the preferable method of replicating carbon monoxide yields reported from larger scale enclosure fire experiments. Cone irradiances of 30, 50 and 65 kW/m2 were applied to PMMA and plywood samples. Vitiated tests were conducted using a mixed air/diluent gas, with an inflow rate of either 100, 150 or 180 L/min, resulting in a reduced oxygen concentration of 17.5 vol. %. Under-ventilated tests were conducted using flow rates of 5, 10 and 20 L/min in an air atmosphere. Particle formations and emissions were also measured using a particle analyser and have been reported herein. Results indicate that the under-ventilated mode of equivalence ratio control offers a more promising method of capturing species yields with favourable comparisons to other bench scale methods.
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| 3. |
- Bray, Robert John, et al.
(författare)
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Burning material behaviour in hypoxic environments : An experimental study examining a representative storage arrangement of acrylonitrile butadiene styrene, polyethylene bubble wrap, and cardboard layers as a composite system
- 2022
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Ingår i: Fire and Materials. - : Wiley. - 0308-0501 .- 1099-1018. ; 46:1, s. 313-328
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Tidskriftsartikel (refereegranskat)abstract
- Cone calorimeter and controlled atmosphere cone calorimeter experiments were conducted on various samples. The intent of the tests was to examine the behavior of uniform and composite samples in a range of thicknesses, irradiances, and oxygen concentrations. Single, uniform layers of acrylonitrile butadiene styrene (ABS) were compared to a composite mix, comprising of ABS with a surface layer of cardboard and a secondary layer of polyethylene bubble wrap (intended to represent a potential storage arrangement). The horizontal samples have been tested at irradiances of 25 and 50 kW/m2 and oxygen concentrations of 20.95%, 17%, and 15% to examine a range of significant variables. Results for the uniform arrangement indicated various correlations, previously observed in the works of others, such as the relationships typically described between applied heat flux, ignitability, heat release rate and the effect of the introduction of hypoxic conditions. However, results were shown to change significantly when samples were arranged to feature composite layers. A hypothesized cause of the behavioral change, namely the soot and char residual introduced from the incomplete combustion of the cardboard layer, highlights further important variables that require consideration in material testing under hypoxic conditions. Such variables, namely specific material behaviors and sample orientation, must be sufficiently captured in the design methodologies of systems reliant upon the introduction of hypoxic conditions. It is concluded that sufficiently capturing a wider range of variables in burning materials under hypoxic conditions will introduce further design resilience and help optimize fire protection/prevention methods.
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| 4. |
- El Houssami, Mohamad, et al.
(författare)
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EUFireStat Project - Final report
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- EU FireStat project brings together the knowledge and experience of nine different international fire safety institutions. The project maps the existing fire data collected across Member States and proposed meaningful data sets to allow decisions on fire safety at Member State and at EU level. This project was carried out by a consortium composed of nine international fire safety institutions: Efectis, NFPA, DBI, University of Edinburgh, BAM, VFDB, CTIF, Unviersity of Lund and EuroFSA Further information: https://eufirestat-efectis.com/
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| 5. |
- Gephine, Sarah, et al.
(författare)
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Specific contribution of quadriceps muscle strength, endurance, and power to functional exercise capacity in people with chronic obstructive pulmonary disease : a multicenter study
- 2021
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Ingår i: Physical Therapy. - : Oxford University Press. - 0031-9023 .- 1538-6724. ; 101:6, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Various functional muscle properties affect different aspects of functional exercise capacity in people with COPD. The purpose of this study was to investigate the contribution of quadriceps muscle strength, endurance, and power to the 6-minute walking distance (6MWD) and the 1-minute sit-to-stand test (1STS) performance in people with COPD.METHODS: The study was a prospective, multicenter cross-sectional study. Anthropometrics, Medical Research Council (MRC) dyspnea scale, lung function, 6MWD and the 1STS number of repetitions were assessed. Isometric quadriceps strength (Strength-ISOM) and endurance (Endurance-ISOM), isotonic quadriceps endurance (Endurance-ISOT), isokinetic quadriceps strength (Strength-ISOKIN), and power (Power-ISOKIN) were assessed on a computerized dynamometer while functional quadriceps power was determined during 5 sit-to-stand repetitions (Power-5STS). Univariate and multivariate analyses were performed to determine the contribution of functional muscle properties on the 6MWD and the 1STS number of repetitions.RESULTS: The study included 70 people with COPD (mean % predicted FEV1 = 58.9 [SD = 18.2]). The 6MWD correlated with each functional muscle property, except the Endurance-ISOM. The number of repetitions during the 1STS correlated with each functional muscle property except isometric measurements. Multivariate models explained respectively 60% and 39% of the variance in the 6MWD and 1STS number of repetitions, with Power-5STS being the muscle functional property with the strongest contribution to the models.CONCLUSION: Except for isometric endurance, quadriceps strength, endurance, and power were associated with functional exercise capacity in people with moderate COPD. Among these functional muscle properties, muscle power contributed the most to the 6MWD and 1STS number of repetitions, suggesting that muscle power is more relevant to functional exercise capacity than muscle strength or endurance in people with COPD.IMPACT: Understanding the individual contribution of muscle properties to functional status is important to designing interventions. This study provides the guidance that muscle power may be more important to functional exercise capacity than muscle strength or endurance in people with COPD.
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| 6. |
- Huang, Yajun, et al.
(författare)
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Experimental study of flame spread over thermally-thin inclined fuel surface and controlling heat transfer mechanism under concurrent wind
- 2021
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Ingår i: International Journal of Thermal Sciences. - : Elsevier BV. - 1290-0729. ; 165
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Tidskriftsartikel (refereegranskat)abstract
- The fuel inclination and wind velocity play a significant role on the forward flame spread behavior. It deserves further study since the heat transfer mechanism and flame spread characteristics coupled these two factors are not clear yet. In this paper, a thermally thin slab of PMMA that could be inclined from a horizontal (0°) to a vertical (90°) angle is used to investigate flame spread behavior under the condition of the concurrent ambient airflow. A wind tunnel is utilized to provide a uniform concurrent airflow, ranging from 0 (quiescent) to 3 m/s with an interval of 0.5 m/s. Essential flame characteristic parameters are collected to quantify the flame spread process, including flame spread rate (FSR), burning rate, heat release rate as well as heat flux feedback both in the pyrolysis and preheating zones. A mechanism, including the competition between the acceleration of buoyancy brought by inclination and the cooling effect of ambient airflow for relatively high wind velocity, is developed. The relationship between flame length and pyrolysis length is investigated. Moreover, the evolution of both heat release rate per unit width and standoff distance as a function of pyrolysis length are analyzed. A dimensionless heat release rate for upward flame at different wind velocities is used to scale the dimensionless flame length with a power-law exponent of 0.77 and −1.92. In addition, the dimensionless heat flux in preheated zone decay with distance as a function of power law. A predictive formulation of FSR coupled with inclination angle and wind velocity is proposed. This study facilitates the understanding of the interaction of fuel inclination angle and horizontal ambient airflow from aspect of heat and mass transfer.
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| 7. |
- Jiao, Enmiao, et al.
(författare)
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Further Insight into Extractable (Organo)fluorine Mass Balance Analysis of Tap Water from Shanghai, China
- 2023
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 57:38, s. 14330-14339
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Tidskriftsartikel (refereegranskat)abstract
- The ubiquitous occurrence of per- and polyfluoroalkyl substances (PFAS) and the detection of unexplained extractable organofluorine (EOF) in drinking water have raised growing concerns. A recent study reported the detection of inorganic fluorinated anions in German river systems, and therefore, in some samples, EOF may include some inorganic fluorinated anions. Thus, it might be more appropriate to use the term "extractable fluorine (EF) analysis" instead of the term EOF analysis. In this study, tap water samples (n = 39) from Shanghai were collected to assess the levels of EF/EOF, 35 target PFAS, two inorganic fluorinated anions (tetrafluoroborate (BF4-) and hexafluorophosphate (PF6-)), and novel PFAS through suspect screening and potential oxidizable precursors through oxidative conversion. The results showed that ultra-short PFAS were the largest contributors to target PFAS, accounting for up to 97% of ΣPFAS. To the best of our knowledge, this was the first time that bis(trifluoromethanesulfonyl)imide (NTf2) was reported in drinking water from China, and p-perfluorous nonenoxybenzenesulfonate (OBS) was also identified through suspect screening. Small amounts of precursors that can be oxidatively converted to PFCAs were noted after oxidative conversion. EF mass balance analysis revealed that target PFAS could only explain less than 36% of EF. However, the amounts of unexplained extractable fluorine were greatly reduced when BF4- and PF6- were included. These compounds further explained more than 44% of the EF, indicating the role of inorganic fluorinated anions in the mass balance analysis.
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| 8. |
- Johansson, Nils, et al.
(författare)
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ANLAGD BRAND i skolor och förskolor : Trender och uppföljning av åtgärder
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In 2007, a research program was launched to provide an overview of research needs coupled to arson in Swedish schools. A total of six different Swedish universities and research institutes were involved in different projects in the ensuing research program. These projects involved both technical aspects such as fire detection and fire protection as well as sociological issues related to individual neighbourhoods and fire-setters. The work presented in this report represents an updated investigation of the school arson problem in Sweden with a focus on technical aspects of fire safety in schools. The work includes a detailed study of statistics, a case study and an interview study. It is identified that there are slightly fewer costly exterior fires during nights and weekends than in the previous study; however, there has been a clear increase of less severe fires in recent years. This is worrying as these fires occur during school hours when there is a greater risk of personal injury. It is noted that the trend of arson fires follows the development of police reports for vandalism. This may indicate that fires in the school environment are not an isolated problem, but an expression of a societal problem with increasing vandalism. Even so, the interview study shows that there is a great awareness of the problem in many municipalities and there efforts are being made to reduce the problem. Finally, a risk assessment methodology is presented as means to identify at risk objects which might require additional prioritised attention to mitigate existing heightened risks.
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| 9. |
- Karyaparambil, Dheeraj Dilip, et al.
(författare)
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Flame heights and charring on a particle board – An experimental study
- 2022
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Ingår i: Fire Safety Journal. - : Elsevier BV. - 0379-7112. ; 134
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Tidskriftsartikel (refereegranskat)abstract
- Vertically oriented particle-board samples were exposed to external venting flames to study the fire spread and charring behaviour along a timber façade. Variation in flame height and the height, volume, area, density, and depth of the char layer were studied to determine the impact of heat-release rate and experiment duration. There was a peak flame height after which the flame returned to steady height approximately equal to the value before the ignition of the particle board and flame heights with inert panels. Flames did not spread to the top of the panel with increased experiment duration. Char height and area were found to increase with heat-release rate but were not affected significantly by experiment duration. Char depth and volume increased with both experiment duration and heat-release rates. Char density decreased with increased experiment duration and heat-release rate.
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| 10. |
- Li, Ying Zhen, et al.
(författare)
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Numerical modelling of water sprays and fire suppression in tunnels
- 2024
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This work aims to validate numerical modelling of water sprays against experiments carried out in this project. The focus has been on the influence of ventilation on water distributions on the tunnel floor, the influence of water sprays on control of smoke flow, and the modelling of pool fires and crib fires. Besides, full scale tunnel fires with FFFS in tunnels using longitudinal ventilation and point extraction ventilation systems are simulated and compared, as well recommendations for numerical modelling of such scenarios.
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