Sprays produced by injecting water into quiescent air by three different types of nozzles were characterised by optical methods. The droplet velocities and droplet size distributions were assessed by the use of high speed shadowgraphs.

This report presents both small scale laboratory tests and tunnel fire tests carried out in a FORMAS project. Four series of small scale laboratory tests were conducted to obtain the material properties, burning properties, water spray distributions, and spray droplet size distributions. The main efforts were, by adopting the Froude scaling, seven series of tests conducted in a about 50 m long container tunnel with a scale of 1 to 3. This report presents results on the influence of low pressure, medium pressure and high pressure water-based fixed fire fighting systems (FFFSs) on fire development, fire spread to adjacent vehicles, structural protection, tenability, smoke control, spray deflection and spray resistances. The focus is to compare the performance of three default FFFSs and to evaluate the efficiency of each of the FFFS. The results show that the default low pressure FFFS performs well in term of suppressing the fire development, preventing the fire spread to nearby vehicles, providing tenable conditions for evacuation and rescue service, protecting tunnel structure and easing the problem with spray deflection due to tunnel ventilation. The default high pressure FFFS is usually on the opposite side while the default medium pressure FFFS usually lie in between.

Low pressure, medium pressure and high pressure water-based fire suppression systems were tested in a medium scale tunnel (scale 1:3). The primary objective was to investigate which of these systems are most effective in the suppression or control of different types of tunnel fires. The default low, medium and high pressure systems refer to full scale water flow rates of 10 mm/min, 6.8 mm/min and 3.7 mm/min, respectively. Some other water densities were also tested to investigate the effects, as well as different ventilation velocities and activation criteria. Several series of fire tests were conducted for different fire scenarios. The fire scenarios considered included idle wood pallet fires, loosely packed wood crib fires, loosely packed wood and plastic crib fires, and pool fires, with or without a top cover on the fuel load. Comparisons of the three default systems based on the three parameters: heat release rate, energy released and possibility of fire spread, show that the performance of the default low pressure system is usually the most effective based on the parameters studied. The default high pressure system usually yields results less effective in comparison to the default low pressure system. The performance of the default medium pressure system usually lies in between them. The high pressure system behaves very differently in comparison to the others, in terms of tunnel ventilation velocity, water density, operating pressure, and the presence of the top cover. © 2024 The Authors

Scheimpflug lidar is a compact alternative to traditional lidar setups. With Scheimpflug lidar it is possible to make continuous range-resolved measurements. In this study we investigate the feasibility of a Scheimpflug lidar instrument for remote sensing in pool flames, which are characterized by strong particle scattering, large temperature gradients, and substantial fluctuations in particle distribution due to turbulence. An extinction coefficient can be extracted using the information about the transmitted laser power and the spatial extent of the flame. The transmitted laser power is manifested by the intensity of the ‘echo’ from a hard-target termination of the beam located behind the flame, while the information of the spatial extent of the flame along the laser beam is provided by the range-resolved scattering signal. Measurements were performed in heptane and diesel flames, respectively. © 2023 The Author(s). 

This study provides an analysis on the fire safety of passengers and the fire protection of coaches and buses. A brief review of major bus fire incidents, an overview of current regulations in Europe, and their limitations are presented. The study finds that the current small-scale fire test methods described in UN ECE Reg No. 118 need to be replaced by test methods that can assess the reaction to fire of materials when exposed to ignition sources of varying sizes. To address these shortcomings, the study proposed an expert recommendation to update the material fire safety requirements and testing for buses. Additional measures are proposed, derived from objectives and strategies applied in other transport sectors, and can be tested through existing European and international standards, which are widely used by several industries. These measures aim to extend the time with tenable conditions for a safe evacuation in case of fire, reduce the degree of damage to buses, reduce the risk for fast and excessive thermal exposure on modern energy carriers needed for a more sustainable transport sector. © 2023 The Authors. 

The ignition of natural fuels by sparks from strikes between metals and hard rock is far from understood and the ignition potential of sparks from rock strikes during heavy machinery operations is disputed in the scientific literature. This study utilises a spectrally resolved technique to study the temperature evolution of metal sparks from rock strikes. The study shows that initial temperature after collision can easily reach 1500 °C and this temperature can increase additionally by several hundred degrees as rapid oxidation processes are initiated, often leading to further disintegration of the fragment. The average temperature of fragments from such collisions is here measured to 1400 – 2000 °C and the combination of temperature, size and exothermic processes makes them viable for forest litter igniting. However, ignition on forest lands is always an unlikely, although possible outcome of heavy machinery operations and should be considered in risk assessment of the activity.

The work involves fabrication of natural fibre/Elium® composites using resin infusion technique. The jute fabrics were treated using phosphorus-carbon based flame retardant (FR) agent, a phosphonate solution and graphene nano-platelet (GnP), followed by resin infusion, to produce FR and graphene-based composites. The properties of these composites were compared with those of the Control (jute fabric/Elium®). As obtained from the cone calorimeter and Fourier transform infrared spectroscopy, the peak heat release rate reduced significantly after the FR and GnP treatments of fabrics whereas total smoke release and quantity of carbon monoxide increased with the incorporation of FR. The addition of GnP had almost no effect on carbon monoxide and carbon dioxide yield. Dynamic mechanical analysis demonstrated that coating jute fabrics with GnP particles led to an enhanced glass transition temperature by 14%. Scanning electron microscopy showed fibre pull-out locations in the tensile fracture surface of the laminates after incorporation of both fillers, which resulted in reduced tensile properties. © 2019 by the authors.

Det sker en snabb teknikutveckling i den elektriska miljön i byggnader, framförallt i våra bostäder. Ett exempel är lokal produktion av el, där solcellsinstallationer blir alltmer populära. Sådan elproduktion medför även förändringar i övriga delar av byggnaders elektriska infrastruktur, såsom DC-nät och i vissa fall energilagring i batterisystem. Utvecklingen sker till stor del som ett svar på behovet av mer hållbara lösningar, ur ett växthuseffektperspektiv, för vår elförsörjning, och förstärks bland annat av statligt stöd och ökad tillgänglighet på marknaden.Ny elektrisk teknologi kan leda till ökad brandrisk och denna förstudie har haft som mål att undersöka denna problematik. Metoden har varit workshops med intressenter och experter inom området, intervjuer, samt litteraturstudier.Av de studerade områdena förefaller solcellsanläggningar skapa störst utmaningar i framtiden om inget görs. Detta beror dels på bristfälligt regelverk men även på att dessa system är distribuerade i byggnaderna med flera delar som kan orsaka brand och att delar är exponerade för utomhusklimat vilket får stora konsekvenser vad gäller uppkomst av fel.Brandsäkerheten i samhället har sett ur ett långt tidsperspektiv väsentligt förbättrats. Detta har huvudsakligen drivits fram med hjälp av ett förbättrat regelverk, som ofta inkluderat förbättrade provnings- och kvalificeringsmetoder. En generell observation i detta projekt är att regelverket inte hinner utvecklas i samma takt som tekniken. Detta är en ofta återkommande utmaning inom brandsäkerhet, men gäller speciellt för de teknikområden som behandlas i denna rapport där utvecklingen går mycket snabbt, och de ingående komponenterna nästan uteslutande har stor inneboende brandpotential. Rapporten konstaterar att för att skapa ett relevant regelverk behövs tillämpad forskning, så kallad prenormativ forskning, inom prioriterade områden för att besvara de frågor som ställs vid formulerandet av nya regler och standarder. Exempel på områden som bör prioriteras är 1) komplettering av det än så länge magra statistiska underlaget för bränder i solcellsinstallationer med olycksutredningar, och studier av redan befintliga olycksutredningar, 2) studier av branddynamiken i solcellsinstallationer, såväl byggnadsapplicerade som integrerade, och såväl tak- som fasadmonterade sådana, 3) studier av ljusbågars uppkomst och hur dessa kan undvikas, alternativt hur det kan undvikas att de ger upphov till bränder, 4) skapa underlag för säker installation av batterilager, samt 5) kvalitetssäkring av så kallade second-life batterier, dvs. begagnade batterier, som används i batterilager.

The effect of thermochromic coatings of vanadium dioxide (VO₂) on the fire performance of windows was experimentally tested. Prototypes were subjected to radiant heat and the radiation transmitted through the specimens was measured as a function of time. The results indicate that windows coated with VO₂ can reduce radiative heat transfer from fires and thereby also reduce or prevent fire spread. The results clearly show that VO₂coatings on BK7 substrates hinder approximately 30% of the transmission of radiation from fire sources when compared with the performance of uncoated windows. It is expected that VO₂ will not be solely implemented for the purpose of increasing fire performance of windows, but it will rather provide a secondary positive effect if such windows are realized for energy‐saving purposes.