BRIEF DESCRIPTION OF THE DRAWINGS
Below, a preferred embodiment of the process of the invention will be specified in greater detail with reference to the figures. The drawings show:
FIG. 1A illustrates the course over time of the oxygen concentration inside a protective room, when a preferred embodiment of the inertization process of the invention is used;
FIG. 1B illustrates the course over time of a quantitative measured value for the characteristic fire value and/or the smoke level inside the protective room, in which the oxygen concentration is lowered according to the curve shown in FIG. 1A, with the help of the preferred embodiment of the inertization process of the invention;
FIG. 2A illustrates the course over time of the oxygen concentration inside a protective room, with the execution of a preferred embodiment of the inertization process of the invention, whereby the fire is extinguished after the first preset time interval has elapsed;
FIG. 2B illustrates the course over time of the quantitative measured value of the fire characteristic and/or the smoke level inside the protective room according to FIG. 2A.
FIG. 3A illustrates the course over time of the oxygen concentration inside a protective room with the execution of a preferred embodiment of the inertization process of the invention, whereby the fire has not yet been fully extinguished by the time the first preset time interval has elapsed; and
FIG. 3B illustrates the course over time of the quantitative measured value of the fire characteristic and/or the smoke level inside the protective room according to FIG. 3A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1A and FIG. 1B each show the oxygen concentration and the quantitative measured value of the fire characteristic and/or the smoke level inside a protective room, in which a preferred embodiment of the inertization process of the invention is applied. In these, it is shown that at the time t0, the oxygen concentration is lowered to a base inertization level, where it is continuously maintained. The base inertization level in this preferred example corresponds to a concentration of 17.0 vol.-% oxygen in the air inside the monitored protective room.
The continuous maintenance of the oxygen concentration inside the protective room at the base inertization level up to time t0 is preferably accomplished via the continuous measurement of the oxygen concentration inside the protective room and via a controlled introduction of inert gas and/or fresh air into the protective room. As was mentioned above, the term “maintaining the oxygen concentration at a specific inertization level” refers herein to maintaining the oxygen concentration within a certain control range, in other words within a range that is defined by an upper and a lower threshold value. The maximum amplitude of the oxygen concentration within this control range can be established in advance and amounts, for example, to 0.1 to 0.4 vol.-%.
In the concentration sequences shown in the figures, the corresponding inertization level always represents the lower threshold value for the control range. Of course, this need not necessarily be the case. For example, it is also conceivable for the corresponding inertization level to represent the upper threshold value, and/or the medium range, in other words the value between the upper and the lower threshold range.
In the scenario represented in FIG. 1A, a fire alarm is emitted at the time t0 by a fire characteristic detector (not shown) to a control unit, which controls the execution of the inertization process of the invention on an inert gas system. Specifically, at this time t0, the smoke level and/or the quantitative measured value of the fire value, which is determined by the characteristic fire value detector, continuously or at preset time intervals, has exceeded a first threshold value (alarm threshold 1), as can be seen in FIG. 1B. As a reaction to this fire alarm, the oxygen concentration inside the protective room is reduced further from the base inertization level to the first lowered level. In the curve shown here, the first lowered level (lowered level 1) corresponds to an oxygen concentration of 15.9 vol.-%. As can be seen in the course over time in FIG. 1A, the lowering of the oxygen content to the first lowered level takes place within the shortest possible time. This is enabled by a rapid introduction of a quantity of inert gas which is determined in advance. Thus, shortly after the fire alarm is triggered, the oxygen concentration inside the protective room is lowered to lowered level 1.
The oxygen concentration is then maintained at this first lowered level for a first preset time ΔT1. At the same time, the quantitative value of the at least one fire characteristic in the air inside the protective room is determined continuously via the fire characteristic detector. In the scenario shown here, the quantitative value of the fire characteristic in the air inside the protective room increases steadily, despite the drop in the oxygen concentration to the first lowered level. This is an indication that, despite the reduced oxygen concentration, the fire inside the protective room has not been extinguished.
If, as is the case in the scenario shown in FIGS. 1A and 1B, when the first preset time ΔT1 has elapsed the quantitative measured value of the fire characteristic exceeds a second preset alarm threshold, it is assumed, that the fire has not yet been extinguished, so that the fire alarm triggered at the time t0 is again confirmed. The confirmation of the fire alarm at the time t1 causes the oxygen concentration inside the protective room to be rapidly lowered from the first lowered level (at the level of, for example, 15.9 vol.-% oxygen) to the second lowered level. This is accomplished again via the rapid introduction of a certain quantity of inert gas, so that, immediately following confirmation of the fire alarm at the time t1, the oxygen concentration reaches the second lowered level, at approximately 13.8 vol.-%.
At this second lowered level, the oxygen concentration inside the protective room is maintained for a second preset time ΔT2. This is again accomplished via the controlled subsequent introduction of inert gas and/or via the controlled introduction of fresh air.
However it can be assumed from the curve shown in FIG. 1B, that the repeated introduction of inert gas to establish the second lowered level has not resulted in a complete damping of the fire which has broken out inside the protective room. Although the quantitative measured value of the fire characteristic exhibits stagnation in this window of time ΔT2, meaning that the spreading of the fire inside the protective room has at least been successfully suppressed, after a certain time the smoke level and/or the quantitative measured value of the fire characteristic again rises, and even exceeds the alarm threshold 3, at which a main alarm is triggered. In the scenario shown in FIG. 1B, the alarm threshold 3 is exceeded already before the time t2.
When the second preset time ΔT2 has elapsed, in other words at the time t2, it is determined in the inertization process of the invention, whether the current quantitative measured value of the fire characteristic lies above the third alarm threshold (alarm threshold 3). If this is the case, as in FIG. 1B, for example, the fire alarm is confirmed, meaning that the fire that has broken out inside the protective room has not yet been extinguished, despite the reduction in the oxygen concentration to the second lowered level.
The reconfirmation of the fire alarm at the time t2 now causes the oxygen concentration inside the protective room to be further reduced from the second lowered level to the full inertization level, which is again accomplished via a rapid introduction of an appropriate quantity of inert gas. This appropriate quantity of inert gas can be determined in advance based upon the spatial parameters inside the protective room, such as the fire load and the size of the room, along with the density and the air exchange rate inside the room. It can be seen from the curve in FIG. 1A that, immediately following the time t2, in other words immediately following the reconfirmation of the fire alarm, the oxygen concentration has reached the full inertization level, which was determined in advance.
The full inertization level is configured, such that it corresponds to an oxygen concentration that lies below the ignition threshold for the materials present inside the protective room (fire load). By establishing the full inertization level inside the protective room, the fire is therefore completely extinguished by a removal of oxygen, while at the same time a re-ignition of the materials inside the protective room is effectively prevented.
It can be seen in the curve shown in FIG. 1B, that, after the full inertization level has been established (at time t2), the quantitative measured value of the fire characteristic continuously decreases, meaning, that the fire is being extinguished and/or has been extinguished. The full inertization level should be maintained at least until the temperature inside the protective room has dropped below the critical ignition threshold for the material. However, it would also be conceivable for the full inertization level to be maintained until forces have been reached and until the inert gas extinguishing system, which operates according to the inertization process of the invention, is taken out of its automatic fire extinguishing mode, for example via a manual release.
In the execution of the inertization process of the invention, as is shown by way of example in FIGS. 1A and 1B, the full inertization level is therefore established via two intermediate stages, namely the first and the second lowered level. In other words, this means that with the process of the invention, the quantity of inert gas required to effectively extinguish a fire is released only in partial quantities, so that decompression openings inside the protective room can be completely eliminated, or that decompression openings having significantly smaller dimensions need be provided inside the protective room.
In FIGS. 2A and 2B, a different scenario is shown, in which, when the first preset time ΔT1 has elapsed, the fire inside the protective room is already extinguished. As is illustrated especially in the curve in FIG. 2B, after the fire alarm has been triggered, at the time t0, the quantitative measured value of the fire characteristic first stagnates and then continuously decreases, which is an indication that the fire inside the protective room has been extinguished.
At the time t1, in other words when the first preset time ΔT1 has elapsed, the quantitative measured value of the fire characteristic (see FIG. 2B) thus lies below the first alarm threshold, so that at the time t1, the fire alarm is not confirmed. Because at the time t1 the fire alarm remains unconfirmed, the oxygen concentration inside the protective room can be raised back to the base inertization level, because the fire inside the protective room has been extinguished. This can be accomplished, for example, via the controlled introduction of fresh air.
In the inertization process of the present invention it is provided, that raising the oxygen concentration inside the protective room to the base inertization level, if the fire alarm is unconfirmed, can occur automatically, for example being initiated by the inertization system with which the inertization process according to the invention is implemented. Alternatively, however, it would also be conceivable for the oxygen concentration to be raised to the base inertization level, if the fire alarm is unconfirmed, only via a supplementary (independent) release. This independent supplementary release can, for example, be a manual release of forces. However, it would also be conceivable to use a parallel system which is completely autonomous in relation to the inertization system, in order to determine whether the fire detected inside the protective room at the time t0 has actually been extinguished, and whether a re-ignition of the fire can be ruled out.
In FIGS. 3A and 3B, a further scenario is represented, in which, after the decrease in the oxygen concentration inside the protective room to the first lowered level at the time t0 and after the oxygen concentration has been maintained at the first lowered level for the first preset time ΔT1, the fire that has broken out inside the protective room has not yet been extinguished, which is detected because the quantitative measured value of the fire characteristic does not continuously decrease within the window of time ΔT1, rather it stagnates or even increases slightly. In contrast to the previously described scenarios, however, this involves a fire that has been only partially extinguished and/or has transitioned into a low-temperature fire. The fire, however, is not large enough, that at the time t1, in other words when the first preset time ΔT1 has elapsed, the quantitative measured value of the fire characteristic has exceeded the second alarm threshold, which serves to confirm the fire alarm.
In this case, with the preferred embodiment of the inertization process of the invention, it is provided, that the first lowered level is again maintained for a first preset time ΔT1, in order then to be able to draw a conclusion, at time t2, regarding the fire status inside the protective room. If at time t2, in other words after the second elapse of the first preset time, the quantitative measured value of the fire characteristic continues to lie above the alarm threshold, it is provided in this represented embodiment, that the oxygen concentration is further reduced from the first lowered level to the second lowered level, as is shown in FIG. 3A.
However, it would also be conceivable for the first lowered level to again be maintained for an additional first preset time ΔT1, and for a decision regarding future measures to then be made.
As was already described above, the first and second preset times ΔT1 and ΔT2 are selected based upon the specific application. Furthermore, it is mentioned, that the oxygen concentrations, which in the represented exemplary embodiments correspond to the respective inertization level, are, of course, merely examples. It is further noted, that the decision criteria and the scenarios described above in relation to the first lowered level can naturally also be applied in a similar manner in connection with the second lowered level.
At this point it is mentioned, that, for example, the inertization system described in the German Patent Specification DE 198 11 851 C2 can be used to implement the inertization process according to the invention.
The process of the invention assumes the regular or continuous monitoring of the oxygen concentration and the fire characteristic content inside the target room. To this end, the oxygen concentration and/or the inert gas concentration and the quantitative value of the fire characteristic and/or the concentration of the smoke level inside the target room are regularly and/or continuously determined via corresponding sensors, and are fed to a control unit of an inert gas fire extinguishing system, which in response to this controls the supply of extinguishing agent and/or the supply of fresh air into the target room.
Although the process of the invention has been described in the preceding as having two intermediate stages (first and second lowered level), it is, of course, also possible for the process of the invention to have more than two intermediate stages, in order to enable an even better adaptation of the process to the protective room.
From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.
In FIG. 1A
Sauerstoff Konzentration=Oxygen Concentration
Grundinertisierungs Niveau=Base Inertization Level
Absenkungsniveau 1=Lowered Level 1
Absenkungsniveau 2=Lowered Level 2
Vollinertisierungsniveau=Full Inertization Level
Feueralarm=Fire Alarm
Feueralarm bestätigt=Fire Alarm Confirmed
Feueralarm erneut bestätigt=Fire Alarm Reconfirmed
Zeit t=Time t
In FIG. 1B
Quantitativer Messwert der Brandkenngrosse bzw. Rauchpegel (dimensionslos)=Quantitative measured Value of the Fire Characteristic and/or Smoke Level (dimensionless)
Alarmschwelle 3 (Hauptalarm)=Alarm Threshold 3 (Main Alarm)
Alarmschwelle 2 (Voralarm 2)=Alarm Threshold 2 (Cautionary Alarm)
Alarmschwelle 1 (Voralarm 1)=Alarm Threshold 1 (Cautionary Alarm
Feueralarm=Fire Alarm
Feueralarm bestätigt=Fire Alarm Confirmed
Feueralarm erneut bestätigt=Fire Alarm Reconfirmed
Zeit t=Time t
In FIG. 2A
Sauerstoff Konzentration=Oxygen Concentration
Grundinertisierungs Niveau=Base Inertization Level
Absenkungsniveau 1=Lowered Level 1
Absenkungsniveau 2=Lowered Level 2
Vollinertisierungsniveau=Full Inertization Level
Feueralarm=Fire Alarm
Feueralarm unbestätigt manuelle Freigabe=Fire Alarm Unconfirmed, Manual Release
Zeit t=Time t
In FIG. 2B
Quantitativer Messwert der Brandkenngrosse bzw. Rauchpegel (dimensionslos)=Quantitative measured Value of the Fire Characteristic and/or Smoke Level (dimensionless)
Alarmschwelle 3 (Hauptalarm)=Alarm Threshold 3 (Main Alarm)
Alarmschwelle 2 (Voralarm 2)=Alarm Threshold 2 (Cautionary Alarm)
Alarmschwelle 1 (Voralarm 1)=Alarm Threshold 1 (Cautionary Alarm
Feueralarm=Fire Alarm
Feueralarm unbestätigt=Fire Alarm Unconfirmed
Zeit t=Time t
In FIG. 3A
Sauerstoff Konzentration=Oxygen Concentration
Grundinertisierungs Niveau=Base Inertization Level
Absenkungsniveau 1=Lowered Level 1
Absenkungsniveau 2=Lowered Level 2
Vollinertisierungsniveau=Full Inertization Level
Feueralarm=Fire Alarm
Feueralarm unbestätigt/Schwellbrand bestätigt=Fire
Alarm Unconfirmed/Low-Temperature Fire Confirmed
Feueralarm unbestätigt/Schwellbrand unbestätigt=Fire
Alarm Unconfirmed/Low-Temperature Fire Unconfirmed
Zeit t=Time t
In FIG. 3B
Quantitativer Messwert der Brandkenngrosse bzw. Rauchpegel (dimensionslos)=Quantitative measured Value of the Fire
Characteristic and/or Smoke Level (dimensionless)
Alarmschwelle 3 (Hauptalarm)=Alarm Threshold 3 (Main Alarm)
Alarmschwelle 2 (Voralarm 2)=Alarm Threshold 2
(Cautionary Alarm)
Alarmschwelle 1 (Voralarm 1)=Alarm Threshold 1
(Cautionary Alarm)
Feueralarm=Fire Alarm
Feueralarm unbestätigt/Schwellbrand bestätigt=Fire Alarm Unconfirmed/Low-Temperature Fire Confirmed
Feueralarm unbestätigt/Schwellbrand unbestätigt=Fire Alarm Unconfirmed/Low-Temperature Fire Unconfirmed
Zeit t=Time t
Patent Application
20080087445
