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A simplified methodology is proposed to estimate the dynamic pressures developed within partially filled cylindrical vertical tanks when subjected to earthquake-related horizontal accelerations. The total pressure at the bottom of the tank is calculated as the superposition of vertical and horizontal pressures. While the magnitude of the vertical pressure depends on the free surface height of the liquid, the horizontal pressure depends on the magnitude of the horizontal acceleration and on the diameter of the tank. The liquid free surface oscillation angle is simulated based upon the principles of the simple pendulum analogy for sloshing. The length of the pendulum, however, is set on the basis of a methodology to calculate the free sloshing frequency of partially filled containers. Such a methodology is experimentally verified in this work. The outputs of the model for full scale situations, suggest that the lateral perturbation - sloshing phenomenon (earthquake effect) can generate an increase in the total pressure of 56% above the no lateral perturbation situation, further suggesting that such an overpressure should be taken into account when designing tanks that could be potentially subjected to earthquake-related perturbations.
Several geometrical analytical tools can be used for assessing the potential benefits of any alternative tank shape. The quasistatic evaluation of the cargo-vehicle behavior represents a fast way to objectively determine the roll stability benefits of any potentially new tank shape. In this paper, the geometrical, quasistatic rollover performance of a convex bottom tank shape is compared with that of standard tank shapes, finding that in spite of the lower position of the cargo´s center of gravity in such a tank shape for the un-perturbed condition, it has the same performance as the elliptical tank shape when subjected to Steady lateral acceleration. That as a result of the large cargo´s lateral displacement. Consequently, the combination of a lower center of gravity for the cargo when it is not perturbed, and a Minimum lateral shift due to lateral accelerations inputs, define the conditions for an ideal tank shape.
Zur Charakterisierung von Brandschutzbeschichtungssystemen für Gas-
Lagertanks ist ein Großbrandversuch erforderlich. Zur Ermittlung der produktspezifischen Beschichtungsdicke sind Plattenbrandversuche notwendig. Für Brandprüfungen existieren verschiedene Brandkurven (z.B. ETK, Hydrocarbonkurve, Schwelbrandkurve, BAM-Kurve) um Prüfmuster je nach Anwendungsfall zu zertifizieren. Diese Brandkurven unterscheiden sich hinsichtlich des Temperaturgradienten. Zur Gewährleistung der Übertragbarkeit der BAM-Prüföfen (Kleinprüfstand DIN 4102-8 (Klep) und 1-m³ Ofen) auf die NORM ISO 21843 (2018-09) ist es erforderlich einen Wärmeintrag von 90 – 120 kW/m² in das Prüfmuster zu garantieren.
Liquefied propane gas (LPG) tanks in a fully engulfing accidental fire experience a fast increase in internal pressure. The result is often a Boiling Liquid Expanding Vapor Explosion (BLEVE) that can result in a large fireball and flying debris over a radius of more than 100 meters.
In the last 30 years BAM has carried out more than 30 real scale fire tests on propane storage vessels across three test sites. The primary research goal was to identify systems that can delay or prevent a BLEVE. Early studies started with water deluge systems, and have since moved on to consider alternative protection systems.
It has been shown that an unprotected vessel fails within 10 minutes or less. Tests with different oil and propane fueled fires have given an overview on possible real accidents involving full-engulfing scenarios. LPG tanks of various sizes (2.7 m³, 3.6 m³, 4.8 m³, 6.7 m³) were used with different filling levels. Numerous protection systems, ranging from active systems like water systems to passive thick- and thin-film layers. Also, the degree of thickness of these layers was variated. Pressure relief valves (PRV) have also been investigated, both alone and in combination with protection systems.
This paper gives an overview of the work performed by BAM in the field of BLEVE prevention of protecting system since the last 30 years. It has been shown that e.g. with a full applied coating degree on the tank with and without PRV can be reached an exposition in a test fire scenario a duration of more than 60min. For partly coated tanks with and without PRV the duration time is like an unprotected vessel. Furthermore, it could be shown that the active water system also protects with technically correct design.
Liquefied propane gas (LPG) tanks in a fully engulfing accidental fire experience a fast increase in internal pressure. The result is often a Boiling Liquid Expanding Vapor Explosion (BLEVE) that can result in a large fireball and flying debris over a radius of more than 100 meters. In the last 30 years BAM has carried out more than 30 real scale fire tests on propane storage vessels across three test sites. The primary research goal was to identify systems that can delay or prevent a BLEVE. Early studies started with water deluge systems, and have since moved on to consider alternative protection systems. It has been shown that an unprotected vessel fails within 10 minutes or less. Tests with different oil and propane fueled fires have given an overview on possible real accidents involving full-engulfing scenarios. LPG tanks of various sizes (2.7 m³, 3.6 m³, 4.8 m³, 6.7 m³) were used with different filling levels. Numerous protection systems, ranging from active systems like water systems to passive thick- and thin-film layers. Also, the degree of thickness of these layers was variated. Pressure relief valves (PRV) have also been investigated, both alone and in combination with protection systems. This paper gives an overview of the work performed by BAM in the field of BLEVE prevention of protecting system since the last 30 years. It has been shown that e.g. with a full applied coating degree on the tank with and without PRV can be reached an exposition in a test fire scenario a duration of more than 60min. For partly coated tanks with and without PRV the duration time is like an unprotected vessel. Furthermore, it could be shown that the active water system also protects with technically correct design.
To save weight and resources lightweight tanks with complex geometries made of glass-fibre reinforced plastics (GFRP) are a promising innovation for the transportation of dangerous goods. To realise the use of polymer tanks for such applications, their fire safety must be guaranteed. This paper presents solutions to protect fibre-reinforced plastic tanks from fire. The fire resistance of six GFRP tanks with different fire protection systems was tested in an outdoor full-scale fire test facility according to the regulation stipulated in the ADR (European agreement concerning the national carriage of dangerous goods by road). All tanks feature a complex geometry and a holding capacity of 1100 litres. The fire protection systems are composed of specialised resins as well as two intumescent coatings. All systems had a protective impact. The best results were achieved by the epoxy based intumescent coating, which was able to prolong the time needed to reach 150 °C inside the tank by 20 min. The emergence of a temperature holding point inside the tank due to condensation effects was observed at temperatures around 100 °C.
The use of glass-fiber reinforced plastic (GRP) can reduce the weight of tanks significantly. By replacing steel with GRP in tanks for gases (propane, etc.) a weight reduction of up to 50 % was reached. In this project not only the material should be optimized, but also the design. Previous tanks consist of a double-walled structure with an insulation layer between the two shells (e.g. vacuum). Goal of this project is to realize a single-walled construction of GRP with an insulation layer on the outside.
To determine the temperature dependent material values, two different experiments are performed: In the first experiment, temperature dependent material properties of liquid nitrogen found in literature research are validated in a simple setup. The level of liquid nitrogen in a small jar is measured over the experiment time. Numerical simulation shows the change of nitrogen level with sufficient precision. In the second experiment, a liquid nitrogen is applied on one side of a GRP plate. Temperature is measured with thermocouples on top and bottom of the GRP plate, as well as in the middle of the plate. By use of numerical simulation, temperature dependent thermal conductivity is determined.
In the third experiment, a test stand is designed to examine different insulation materials. In this test stand, the insulation material can easily be changed. A numerical simulation, in which the determined material data is used, is performed as well for this test stand.
The experiments show, that GRP can be used in cryogenic environments. Multiphase simulations are a suitable tool to describe the energy absorption of thermal energy due to thermal phase change. Results on different insulation materials will follow.
The application of lightweight materials for tanks for transportation appears promising. Besides saving weight and therefore transportation costs, new complex geometries that depart from common cylindrical shapes of steel tanks can be manufactured. For transportation of dangerous goods, fire and explosion safety must be maintained to prevent accidents with serious consequences. In this work the fire behavior of lightweight tanks made from glass fiber reinforced plastics (GFRP) with complex geometries is investigated. Pretests on intermediate scale GFRP plates are conducted to identify suitable fire protection systems and surface treatments for composite tanks. The fire resistance is shown to be improved by addition of fire protective coatings and integrated layers. Finally, a complex rectangular GFRP tank with a holding capacity of 1100 liters is fire protected with an intumescent fire coating. The tank is filled up to 80 % with water and burned under an engulfing fully developed fire. It was shown that the intumescent layer could expand before the decomposition of the resin occurred. Furthermore, the adhesion between tank surface and coating was maintained. The structure could withstand a fire for more than 20 min.
A new tank design for Hazmat
(2016)
Initial studies have shown pre-deformed honeycomb structure
pressure vessels to have comparable burst pressure to straight steel vessels.
It was shown that honeycomp structured tanks have a higher energy absorption than straight steel tanks.
Future studies will investigate optimization of the deformed plate, to determine if increased payloads or a reduced wall thickness can be achieved.