In fact, the obligation to raise the alarm at the sight of uncontrolled fire was first imposed on traditional day and night guards. When exactly this happened, no one will say for sure. But in ancient Greece and the Roman Empire, guards who changed every three hours were trained to signal fire alarms. Much later in Dresden, the guards went around the zone of responsibility in the city eight times in one hour, which was a fairly effective method of fire supervision. A typical means of warning about a fire in the city was the bell, which not only raised the alarm, but also made it possible to transmit information about the place of fire. With a special bell code, it was possible to convey to the fire brigade the location of the fire, as well as its intensity.
Fire horn at the Vienna Museum
Also, over time, a bugler appeared in the team of guards, announcing the danger with a horn. As the centuries passed, cities grew higher and higher, and even observations from simple heights became ineffective. The next stage in the evolution of the fire warning system was the watchtower, from which during the day the place of fire was indicated by a flag, and at night - by a lantern. For cities built of wood, such preventive measures were particularly relevant. Here is what Tsar Alexei Mikhailovich pointed out in 1668 in his charter regarding the procedure for giving a fire signal in Moscow: “If the city will light up in the Kremlin, in some place, and at that time it’s time to strike all three alarm bells in both edges at speed. And if it will light up in China, in some place, and at that time both edges are more polite …"
The problems of orienting fire brigades to burning houses in cities were first encountered in Europe - the large areas of the capitals affected. In Riga, for example, fires were announced by the simultaneous ringing of bells from four churches at once, and the direction to the fire was indicated by a conditional number of blows. And the Viennese observers used the crosses on the towers for accuracy as reference points. In addition, in European capitals, they began to use optics for visual control of urban areas. At first, these were classic telescopes, later they were replaced by toposcopes, which made it possible to detect a fire even on the outskirts of the city.
Firefighter's toposcope from the Vienna Firefighting Museum
But from a high tower it was still necessary to promptly deliver information to the fire brigade about the nature of the fire and the place of its appearance. For this purpose, a pneumatic mail was invented, an analogue of which can be observed in the network of modern supermarkets - cashiers receive cash from them. The emergence of this method of communication dates back to the 70s of the 18th century and since then it has long become the standard equipment of fire departments around the world. In small towns, special fire alarm bells have become widespread, which were made from amalgam (mercury alloys with various metals).
Russian alarm bells used, among other things, to raise a fire alarm
The strength of the sound of such a bell was explained by the fact that the diameter of the bell was greater than the height. But a special howler, which was an iron cylinder with a piston, injected air from which, under pressure, fell into a horn with a squeaker, was much louder to notify all the neighborhood about the fire. Eyewitnesses mention that such a siren was heard at a distance of 7-8 km. If the fire in the city was serious and the efforts of several fire brigades from different parts of the city were required, then a system of conventional signs was used. For example, a red flag during the day or a red lantern at night meant the collection of all units in a predetermined location, and a white flag or green lantern required reinforcements.
Over time, automation elements began to appear in the fire warning system - under Peter I, a fire-conducting cord with gunpowder began to be used on ships. How effective this technique was and whether it aggravated the consequences of the fire, history is silent. In England in the mid-19th century, according to the Russian edition of Otechestvennye Zapiski, a metal weight was hung on a long cord in residential buildings. The cord was pulled through the rooms and if it burned out from the fire, then the weight fell on a miniature explosive device. A similar technique was used in industry, only in this case the weight fell on the trigger mechanism of the alarm bell spring factory. In the Russian version of such a technique, the inventor Carl Dion was able to achieve such sensitivity that the system reacted even to hot air. Such "toys" began to be gradually replaced by electric sirens, which since 1840 came into use in America and Germany. In fact, these were the simplest electrical calls, later replaced by telegraphs. In crowded places in European capitals of the middle of the 19th century, Morse devices could now be seen, through which a specially trained person informed the fire department about the fire. The Berlin detector, which is located on the streets of the capital every 100-160 meters, simplified the calling process even more. Any passer-by could, in case of danger, twist the handle a couple of times to signal the alarm. As a result, all the innovations by the beginning of the 20th century reduced the arrival time of the best fire brigades to 10 minutes. The real perfection of that time was the telegraph apparatus "Gamavell & Co", which displayed the location of the fire during an alarm on the indicator, and also recorded the time and date of the call on the tape. It is noteworthy that the system woke up not only the firefighters on duty, but also transmitted an alarm call to the firemaster's apartment. In Russia, this technique appeared only in 1905 in the Lithuanian part of St. Petersburg. But despite all the efforts, many fires managed to spread over large areas during the response time of the firefighters squads. The fact was that when observers from the outside recorded a fire, it already covered most of the interior of the building. Therefore, it became necessary to promptly inform firefighters even about a simple increase in the temperature in the premises. For this purpose, the closure (opening) of the circuit of various electrical systems by changing the volume of liquid, the shape of the spring, and the like was excellent.
A variant of a mechanical fire alarm from England, mid-19th century
One of the first was Gelbort, who in 1884 proposed a kind of liquid boiling at 40 degrees for this. It was poured into a metal container with a contact system located in the lid. As soon as the liquid from the fire boiled, the vapors pressed on the lid and the electrical circuit was closed. And then - either just a loud bell, or immediately an alarm to the fire post. It is noteworthy that the inventor lived and worked in St. Petersburg. A similar operating principle was borrowed by the German company Siemens-Halske for its mass of fire detectors.
A patent for a mechanical fire alarm for several "loops". USA, 1886
As it evolved, fire alarms became more and more sophisticated in technical performance. Differential systems have appeared that respond to an increase in room temperature. Since the end of the 19th century, privileges have been given to such structures in Russia - in 1886 M. Schwambaum and G. Stykopulkovskiy thus designed their "Electro-automatic apparatus for signaling a fire." In many detectors of those times, fusible inserts began to be widely used, which interrupted electrical contacts, as well as metal plates that deform under the influence of heat.
Siemens differential detector: a - general view; b - connection diagram
So, in 1899, a Moscow peasant Yakov Kazakov developed an automatic fire contact, which was made of a material that expands when heated. But with all this, in St. Petersburg from the middle of the 19th century, the overwhelming majority of all fire alarms were of imported origin. In 1858, a hand-held alarm from the German Siemens was installed at the hay scales on the Kalashnikovskaya embankment. And in 1905, Gamewell became the winner of the competition for the installation of electrical detectors in St. Petersburg. And only by 1907 the fire alarm appeared in Moscow and Tsarskoe Selo. The firstborn of domestic production was a valve beam signaling device, which began to be produced at the Kozitsky plant in 1924. And in 1926 JSC "Sprinkler" (from the English sprinkler - sprinkler or irrigation head) appeared - the founder of the Soviet engineering school of fire-prevention automation. And on a global scale, the next important milestone in the history of firefighting technology was the automated extinguishing systems.
To be continued….
