| 1. |
- Stolen, Reidar, et al.
(författare)
-
Solcelleteknologi og brannsikkerhet
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Bruken av solcelleteknologi er i stor vekst i Norge. I denne studien er branntekniske utfordringer ved bruk av solcelleteknologi undersøkt, med hensyn på brannstart, brannspredning og brannslokking. Studien danner et kunnskapsgrunnlag for å ivareta brannsikkerheten under montering, drift og under slokkeinnsats, samt for å utforme et enhetlig og tydelig regelverk. Resultatene fra studien viser:Brannstart: Solcelleinstallasjoner inneholder mange koblingspunkt, som kan være potensielle tennkilder, og en liten mengde brennbare materialer. Dermed er det som trengs til stede for å starte en brann. Det er viktig at alle kontaktpunkter i solcelleinstallasjonen er robuste og tåler den påkjenningen de blir utsatt for gjennom sin levetid uten at det oppstår dårlig kontakt som kan føre til brann.Brannspredning: For utenpåmonterte solcellemoduler er det ofte en åpen luftspalte mellom modul og bygning. Dersom det er en brann i denne luftspalten, vil varmen kunne bli akkumulert, noe som kan føre til raskere og større brannspredning enn om bygningsoverflaten ikke hadde vært tildekket. I fullskalaforsøk med solcellemoduler montert på tak spredte brannen seg under hele arealet som var dekket av moduler, men stoppet da den nærmet seg kanten av dette arealet. Dette illustrerer viktigheten av at områder med solceller utenpå en bygning blir seksjonert for å unngå brannspredning. Eventuelt kan det benyttes mindre brennbare materialer på taket under solcellemodulene for å motvirke den økte varmepåkjenningen som solcellemodulene gir. Luftspalten mellom modul og bygning kan potensielt også gi endringer i luftstrømningen langs bygget, som igjen kan påvirke brannspredningen.Brannslokking: Brannvesenet har behov for informasjon om det er solcelleinstallasjon i bygget og hvilke deler av det elektriske anlegget som kan være spenningssatt. Under slokkeinnsats må brannvesenet ta hensyn til berøringsfare, og fare for at det kan oppstå lysbuer og andre feil som kan føre til nye antennelsespunkt. Ferskvann kan brukes som slokkemiddel, dette må spyles fra minimum 1 meters avstand med spredt stråle og minimum 5 meters avstand med samlet stråle. Solcellemoduler kan komplisere brannslokking ved at de danner en fysisk barriere mellom brannvesenet og brannen, samt fordi det må tas hensyn til plassering av spenningssatte komponenter. Når disse punktene er tatt høyde for, bør ikke utenpåmonterte solcelleinstallasjoner være et problem.Videre arbeid: For utenpåmonterte solcelleinstallasjoner, er det lite forskning på vertikal montering (på fasader), og hvordan en eventuell endret branndynamikk kan påvirke brannspredning og slokking. Videre er det i dag økende bruk av bygningsintegrerte solcelleinstallasjoner, noe som gir mange mulige nye utfordringer for brannsikkerheten og for regelverk, ettersom solcellen da er en del av bygningskroppen, samtidig som den er en elektrisk komponent. Tysk statistikk tyder på at brannrisiko for slike installasjoner kan være større enn for utenpåmonterte solcelleinstallasjoner, og dette vil det derfor være viktig å undersøke nærmere.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Fjellgaard Mikalsen, Ragni, et al.
(författare)
-
Fra bensinstasjon til energistasjon : Endring av brann- og eksplosjonssikkerhet
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- From petrol station to multifuel energy station: Changes in fire and explosion safetyA multifuel energy station is a publicly available station which offers refueling of traditional fossil fuels in combination with one or more alternative energy carriers, such as hydrogen or electric power to electric vehicles. The goal of this study is to survey how the transition from traditional petrol stations to multifuel energy stations affects the fire and explosion risk.Relevant research publications, regulations and guidelines have been studied. Four interviews with relevant stakeholders have been conducted, in addition to correspondence with other stakeholders. The collected information has been used to evaluate and provide a general overview of fire and explosion risk at multifuel energy stations. The scope of the project is limited, and some types of fueling facilities (in conjunction with supermarkets, bus- and industrial facilities), some types of safety challenges (intended acts of sabotage and/or terror), as well as transport of fuel to and from the station, are not included.Availability of different types of fuel in Norway was investigated and three types were selected to be in focus: power for electric vehicles, gaseous hydrogen, as well as hydrogen and methane in liquid form. The selection was based on expected future use, as well as compatibility with the goal of the National Transport Plan that all new vehicles sold from 2025 should be zero emission vehicles. Currently, the category zero emission vehicle includes only electric- and hydrogen vehicles.In facilities that handle flammable, self-reactive, pressurized and explosive substances there is a risk of unwanted incidents. When facilities with hazardous substances comply with current regulations, the risk associated with handling hazardous substances is considered not to be significant compared to other risks in society. When new energy carriers are added, it is central to understand how the transition from a traditional petrol station to a multifuel energy station will change the fire and explosion risk. Factors that will have an impact include: number and type of ignition sources, number of passenger vehicles and heavy transport vehicles at the station, amount of flammable substances, duration of stay for visitors, complexity of the facility, size of the safety distances, fire service’s extinguishing efforts, environmental impact, maintenance need etc. In addition, each energy carrier entails unique scenarios.By introducing charging stations at multifuel energy stations, additional ignition sources are introduced compared to a traditional petrol station, since the charger itself can be considered as a potential ignition source. The charger and connected car must be placed outside the Ex-zone in accordance with NEK400 (processed Norwegian edition of IEC 60364 series, the CENELEC HD 60364 series and some complementary national standards), in such a way that ignition of potential leaks from fossil fuels or other fuels under normal operation conditions is considered unlikely to occur. A potential danger in the use of rapid charging is electric arcing, which can arise due to poor connections and high electric effect. Electric arcs produce local hot spots, which in turn can contribute to fire ignition. The danger of electric arcs is reduced by, among others, communication between the vehicle and charger, which assures that no charging is taking place before establishing good contact between the two. The communication also assures that it is not possible to drive off with the charger still connected. There are requirements for weekly inspections of the charger and the charging cable, which will contribute to quick discovery and subsequent repair of faults and mechanical wear. Other safety measures to reduce risk include collision protection of the charger, and emergency stop switches that cut the power delivery to all chargers. There is a potential danger of personal injury by electric shock, but this is considered most relevant during installation of the charger and can be reduced to an acceptable level by utilizing certified personnel and limited access for unauthorized personnel. For risk assessments and risk evaluations of each individual facility with charging stations, it is important to take into account the added ignition sources, as well as the other mentioned factors, in addition to facility specific factors.Gaseous hydrogen has different characteristics than conventional fuels at a petrol station, which affect the risk (frequency and consequence). Gaseous hydrogen is flammable, burns quickly and may explode given the right conditions. Furthermore, the gas is stored in high pressure tanks, producing high mechanical rupture energy, and the transport capacity of gaseous hydrogen leads to an increased number of trucks delivering hydrogen, compared with fossil fuels. On the other hand, gaseous hydrogen is light weight and easily rises upwards and dilute. In the case of a fire the flame has low radiant heat and heating outside the flame itself is limited. Important safety measures are open facilities, safe connections for high pressure fueling, and facilitate for pressure relief in a safe direction by the use of valves and sectioning, so that the gas is led upwards in a safe direction in case of a leakage. For risk assessments and risk evaluations of each individual facility with gaseous hydrogen, it is important to take into account the explosion hazard, as well as the other mentioned factors, in addition to facility specific factors.Liquid hydrogen (LH2) and liquid methane (LNG, LBG) are stored at very low temperatures and at a relatively low pressure. Leakages may result in cryogenic (very cold) leakages which may lead to personal injuries and embrittlement of materials such as steels. Critical installations which may be exposed to cryogenic leakages must be able to withstand these temperatures. In addition, physical boundaries to limit uncontrolled spreading of leakages should be established. Evaporation from tanks must be ventilated through safety valves. During a fire, the safety valves must not be drenched in extinguishing water, as they may freeze and seal. Leakages of liquid methane and liquid hydrogen will evaporate and form flammable and explosive gas clouds. Liquid hydrogen is kept at such a low temperature that uninsulated surfaces may cause air to condense and form liquid oxygen, which may give an intense fire or explosion when reacting with organic material. For risk assessments and risk evaluations of each individual facility with liquid hydrogen and liquid methane, it is important to take into account the cryogenic temperatures during storage and that it must be possible to ventilate off any gas formed by evaporation from a liquid leakage, as well as the other mentioned factors, in addition to facility specific factors.For the combination of more than one alternative energy carrier combined with fuels of a conventional petrol station, two areas of challenges have been identified: area challenges and cascade effects. Area challenges are due to the fact that risks to the surroundings must be evaluated based on all activity in the facility. When increasing the number of fueling systems within an area, the frequency of unwanted incidents at a given point in the facility is summarized (simply put). If two energy carriers are placed in too close proximity to each other, the risk can be disproportionately high. During construction, the fueling systems must be placed with sufficient space between them. In densely populated areas, shortage of space may limit the development. Cascade effects is a chain of events which starts small and grows larger, here due to an incident involving one energy carrier spreading to another. This may occur due to ignited liquid leakages which may flow to below a gas tank, or by explosion- or fire related damages to nearby installations due to shock waves, flying debris or flames. Good technical and organizational measures are important, such as sufficient training of personnel, follow-up and facility inspections, especially during start-up after installing a new energy carrier. The transition from a traditional petrol station to a multifuel energy station could not only give negative cascade effects, since sectionalizing of energy carriers, with lower storage volume per energy carrier, as well as physical separation between these, may give a reduction in the potential extent of damage of each facility. Apart from area challenges and cascade effects no other combination challenges, such a chemical interaction challenges, have been identified to potentially affect the fire and explosion risk.For future work it will be important to keep an eye on the development, nationally and internationally, since it is still too early to predict which energy carriers that will be most utilized in the future. If electric heavy transport (larger batteries and the need for fast charging with higher effect) become more common, it will be necessary to develop a plan and evaluate the risks of charging these at multifuel energy stations. For hydrogen there is a need for more knowledge on how the heat of a jet fire (ignited, pressurized leakage) affects impinged objects. There is also a general need for experimental and numerical research on liquid hydrogen and methane due to many knowledge gaps on the topic. During operation of the facilities and through potential unwanted incidents, new knowledge will be gained, and this knowledge must be utilized in order to update recommendations linked to the risk of fire and explosion in multifuel energy stations.
|
|
| 5. |
- Fjellgaard Mikalsen, Ragni, et al.
(författare)
-
Jet fires and cryogenic spills: How to document extreme industrial incidents
- 2019
-
Ingår i: <em>Sixth Magdeburg Fire and Explosion Days (MBE2019) conference proceedings, </em>.
-
Konferensbidrag (refereegranskat)abstract
- In industrial plants, such as oil platforms, refineries or onboard vessels carrying fuel, a rupture event of a pipeline could have dramatic consequences, as was demonstrated both in the Piper Alpha and Deepwater Horizon accidents. If surfaces are exposed to extreme conditions, both extreme cold (cryogenic spills) and extreme heat (jet fires), this can affect exposed surfaces, and can cause a domino effect of severe events.
|
|
| 6. |
- Jansson McNamee, Robert, et al.
(författare)
-
The function of intumescent paint for steel during different fire exposures
- 2016
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the present study the behaviour of four intumescent systems for steel was investigated experimentally. The main purpose of the study was to determine the behaviour of the systems during different fire scenarios including standardized furnace testing, tests in cone calorimeter and ad hoc tests including ceiling jets and fire plumes. The experimental campaign shows that two of the investigated systems did perform very poorly in the furnace tests compared to what they were designed for, despite being the systems having the best swelling in the cone calorimeter tests. This highlights the importance of adhesion at high temperature for this type of systems. Since adhesion is crucial a more relevant evaluation for this type of systems ought to be a test where the flows around the specimen can be characterized and controlled, i.e. a ceiling jet or a fire plume scenario. This is especially important as steel protected with intumescent systems are often used in large open spaces where local fire plumes and ceiling jets are expected.Key words: intumescent paint, steel, alternative exposure
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Stolen, Reidar, et al.
(författare)
-
BRAVENT – Tetting av ventilasjonsfilter med brannrøyk
- 2021
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the series of BRAVENT projects, the goal is to generate documentation and answers to issues related to ventilation and fire by investigating these experimentally. In ventilation systems where the smoke will be extracted through the ventilation system in the event of a fire, it is common practice to install so-called bypass solutions to send the smoke past the ventilation filter in the event of a fire. This is done to avoid clogging the filters with smoke particulates and maintain the airflow through the ventilation ducts. If the airflow in the ventilation system stops, smoke can spread freely in the ventilation ducts between different fire cells. For ventilation systems that will be stopped and sealed by fire rated dampers, this challenge is not relevant. Even though this is a common solution, it has been difficult to find documentation that ventilation filters can be clogged by smoke from a fire. As part of BRAVENT, RISE Fire Research has conducted two test series to investigate this problem by drawing fire smoke through a ventilation filter and measuring how quickly the filter clogs. In most experiments that were carried out, it took about an hour before the filter was clogged, but there were also experiments where the filter was clogged within a few minutes. This shows that there can be a big difference in how efficiently fire smoke can clog a ventilation filter, but that under certain conditions this can happen very quickly. For example, an experiment where a small amount of polyether foam was burned in addition to wood showed that the filter was clogged quickly. This shows that the clogging rate is highly dependent on the type of fuel. However, in another test where only wood was burned, the filter was clogged in a similar time frame, indicating that also other factors than the fuel are important. It is thus necessary to secure the smoke an alternative route outside the filter if it is necessary to maintain a certain amount of air in the ventilation system in the event of a fire since the ventilation filter can become clogged within a few minutes.
|
|
| 10. |
- Stolen, Reidar, et al.
(författare)
-
Heat flux in jet fires : New method for measuring the heat flux levels of jet fires
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Jet fires are ignited leakages of pressurized liquid or gaseous fuel. In jet fire testing for the offshore industry, heat flux is the defining factor for the accidental loads. NORSOK S001 [1] defines two different heat flux levels of 250 kW/m2 and 350 kW/m2 depending on the leak rate of hydrocarbons. These heat flux levels are used in risk analysis and define what type of fire load bearing structures and critical equipment need to be able to resist in a given area. Examples of such ratings can be “250 kW/m2 jet fire for 60 minutes”, “350 kW/m2 jet fire for 15 minutes” or any other combination based on calculations in the risk assessment. Combined with critical temperatures this defines the performance criteria for the passive fire protection. Each configuration of the passive fire protection needs to be tested and verified. Manufacturers of passive fire protection request fire tests to document their performance against jet fires with these various heat flux levels. The challenge is that the standard for testing passive fire protection against jet fires [2] does not define any heat flux level or any method to define or measure it. We have developed a method for defining and measuring the heat flux levels in jet fires. This method can be used when faced with the challenge of testing passive fire protection against specific levels of heat flux. The method includes a custom test rig that allows jet fire testing with different heat flux levels. A large number of tests have been performed to verify the reproducibility and repeatability of the method. Heat flux is defined as the flow of energy through a surface. The heat flux from a fire to an engulfed surface of an object is dependent on both the engulfing flame and the properties of the surface. The properties of the surface may change during the exposure to the flame as it heats up and changes its surface properties. At some point the object inside the flame will reach a thermal equilibrium with the flame where the net flow of energy into the object is balanced by the energy emitted from the object. The heat flux for an object can be calculated as incident heat flux, emitted heat flux or net heat flux. A definition of heat flux needs to include parameters of the receiving object. These variations give a lot of degrees of freedom when calculating heat flux in a fire. Special water cooled gauges are designed to measure heat flux to a cooled surface, but these have proved to be very unreliable when placed inside a large fire. A more robust and easily defined method is to measure the equilibrium temperature inside an object placed inside the flame. This is the principle used in plate thermocouples used in fire resistance furnace testing [3]. In our experience, these plate thermocouples are often damaged during high heat flux jet fire tests. This raises questions to how long into the tests such measurements are reliable. Several other types of objects have been tested and the most convenient and reliable type was found to be simply a small 8 mm steel tube that is sealed in the end and has a thermocouple inside. One key difference between this small tube thermocouple and the plate thermocouple is that the plate thermocouple is directional and the tube is omnidirectional. Current works and tests will optimize the measuring objects in order to get the most relevant equilibrium temperature while still maintaining the robustness of the sensor during the test. The suggested heat flux calculation is to follow the Stefan-Boltzmann relation of temperature and heat flux. For a black body this gives 350 kW/m2 for 1303 °C and 250 kW/m2 for 1176 °C. A lower emissivity may be defined for the surface of the sensing object giving higher temperatures for the same flux levels. This method gives a simple, robust and reproducible correlation between heat flux levels and temperatures that can be measured during jet fire tests. The method does not differ between the varying convective and radiative heat transfer in the flame, but it is a representative measurement for the temperature that an object would reach when placed inside the flame.
|
|
