Regulatory documentation fire detectors ceiling space. Fire detector placement

Over the past three years, many regulations governing the placement of fire detectors have changed twice. Replaces NPB 88-2001* “Fire extinguishing and alarm installations. Design standards and rules” in November 2008, a new set of rules SP 5.13130.2009 “Fire protection systems” was published. Settings fire alarm and automatic fire extinguishing systems. Design Norms and Rules”, which for the first time regulated options for placing detectors in rooms with sloping ceilings, with decorative suspended lattice ceilings, etc. Change No. 1 to the set of rules SP 5.13130.2009, which came into effect on June 20, 2011, introduced significant adjustments, with some requirements returning from NPB 88-2001*. It is also necessary to note the fundamental differences in the requirements for the placement of fire detectors in our and foreign regulatory documents. Our standards, unlike foreign ones, contain only requirements; there is no explanation of physical processes. This gives rise to various interpretations, often erroneous, and the main provisions do not have a theoretical basis. There are no formal grounds for choosing the most effective solution taking into account the physical processes of detecting fire factors in specific conditions. As a rule, the probability of evacuation of people and property damage in the event of a fire is not assessed when designing systems fire automatics. Consequently, there will be a long process of harmonization of our standards in the field fire safety, and with a high probability we can expect in the near future the release of amendment No. 2 to the set of rules SP 5.13130.2009, then amendment No. 3, etc. For example, it is quite possible that clause 13.3.7 from SP 5.13130.2009 will be significantly adjusted, according to to which “the distances between the detectors, as well as between the wall and the detectors, given in tables 13.3 and 13.5, can be changed within the area given in tables 13.3 and 13.5.”

The first part of the article discusses the placement of point fire detectors in the simplest case, on a flat horizontal ceiling in the absence of any obstacles to the spread of combustion products from the fireplace.

Physical processes

In the European Standard BS 5839 Fire Detection and Alarm Systems for Buildings, Part 1, Code of Practice for the Design, Installation and Maintenance of Systems, each section and paragraph first sets out the physical processes to which attention should be paid and then how consequence, requirement. For example, why is it necessary to take into account the specifics of operation and the type of automatic fire detectors when arranging them.

“The operation of heat and smoke detectors depends on convection, which carries hot gas and smoke from the fire to the detector. The location and spacing of these detectors should be based on the need to limit the time spent on this movement and to ensure that there is sufficient concentration of combustion products at the location of the detector. Hot gas and smoke in general case will concentrate in the highest parts of the room, so this is where heat and smoke detectors should be located. Since smoke and hot gases rise upward from the fireplace, they are diluted with clean and cold air, which enters the convective stream. Consequently, as the height of the room increases, the size of the fire required to activate heat or smoke detectors increases rapidly. To some extent this effect can be compensated for by using more sensitive detectors. Linear optical beam smoke detectors are less sensitive to the effect high ceiling than point-type sensors, since as the smoke-filled space increases, the length of the beam affected by smoke increases proportionally...

The effectiveness of an automatic fire detection system will be affected by obstructions between the heat or smoke sensors and combustion products. It is important that heat and smoke detectors are not installed too close to obstructing the flow of heated gas and smoke to the detector. Near the junction of the wall and ceiling there is a “dead space” in which heat or smoke detection will not be effective. Since hot gas and smoke spread horizontally parallel to the ceiling, similarly there is a stagnant layer near the ceiling, this eliminates installation with the sensing element of a heat or smoke sensor located flush with the ceiling...”

Rice. 1. Smoke distribution model according to NFPA 72

In the American fire alarm standard NFPA 72, explanations, reference data and example calculations are given in appendices, the volume of which is almost 1.5 times the volume of the main text of the standard. NFPA 72 states that in the case of a flat horizontal ceiling and in the absence of additional air flows, the smoke forms a cylinder of a certain height centered on the projection of the hearth (Fig. 18). With distance from the center, the specific optical density of the medium and temperature decrease, which determines the limitation of the smoke-filled space at the first stage of the development of the source.

Spot detector placement requirements per BS 5839

According to BS 5839, the radius of protection for smoke detectors is 7.5 m, for heat detectors - 5.3 m in horizontal projection. Thus, it is easy to determine the placement of detectors in a room of any shape: the distance from any point in the room to the nearest smoke IP in the horizontal projection should be no more than 7.5 m, from the thermal one - no more than 5.3 m. This value The protected area is determined by the installation of smoke detectors every 10.5 m along a square grid, and heat detectors after 7.5 m (Fig. 2). Significant savings in the number of detectors (approximately 1.3 times) are achieved in large rooms when using arranging detectors along a triangular grid (Fig. 3).

Rice. 2. Location of smoke and heat detectors to BS 5839

Rice. 3. Arrangement of smoke detectors in a triangular grid

Rice. 4. Placement of smoke detectors in a rectangular room

In extended premises, it is also considered that the smoke detector controls an area at a distance of no more than 7.5 m in horizontal projection. For example, in a room 6 m wide, the maximum distance between detectors is 13.75 m and the distance from the detector to the wall is 2 times less, which is 6.88 m (Figure 4). And only for corridors whose width does not exceed 2 m, the following provision applies: only points closest to the center line of the corridor require consideration; accordingly, it is allowed to install smoke detectors at intervals of 15 m and at a distance of 7.5 m from the wall.

NFPA 72 Point Detector Location Requirements

According to NFPA 72, in the general case, on horizontal smooth ceilings, point detectors are placed on a square grid with a pitch S; the perpendicular distance from the wall to the detector should be no more than S/2. In addition, it is indicated that any point on the ceiling should be no further than 0.7S from the nearest detector. Indeed, the diameter of the circle of the area protected by one detector when they are arranged on a square lattice with a step S is equal to the diagonal of the square S x S, the size of which is S√2. Accordingly, the radius of the protected zone is S√2/2, which is approximately 0.7S.

Moreover, for thermal detectors, the pitch of the square grating S is calculated based on ensuring the detection of the source with power QCR, during the time tCR, so that by the time tDO extinguishment begins or the AUPT is turned on, its value does not exceed the specified power QDO, for example, no more than 1055 kW (1000 Btu/sec ). The calculations assume a quadratic dependence of the growth of the source power on time (Fig. 5). The appendices provide examples of calculations and reference data on various types materials and products.

Rice. 5. Dependence of fire source power on time

With an initial square grid pitch of S = 30 feet, i.e. 9.1 m, it is assumed that the detector protects an area in the form of a circle with a radius of 6.4 m (9.1 m x 0.7). Based on this concept, NFPA 72 provides examples of rectangle sizes that fit within a 6.4 m radius circle (Figure 6) and can be protected by a single centrally located detector:

Rice. 6. Rectangles inscribed in a circle with a radius of 6.4 m

A = 3.1 m x 12.5 m = 38.1 m 2 (10 ft x 41 ft = 410 ft 2)
H = 4.6 m x 11.9 m = 54.3 m 2 (15 ft x 39 ft = 585 ft 2)
C = 6.1 m x 11.3 m = 68.8 m 2 (20 ft x 37 ft = 740 ft 2)
D = 7.6 m x 10.4 m = 78.9 m 2 (25 ft x 34 ft = 850 ft 2)

The maximum area obviously corresponds to a square inscribed in a circle of 9.1 m x 9.1 m = 82.8 m 2 (30 ft x 30 ft = 900 ft 2). Placing detectors in rectangular rooms is recommended by dividing their area into rectangles that fit into a circle with a radius of 6.4 m (Fig. 6).

Rice. 7. Placement of detectors in rectangular rooms

In a non-rectangular room, the detector placement points can be determined as the intersections of circles with a radius of 6.4 m with centers in the corners of the room furthest from the center (Fig. 7). Then the absence of points outside circles of a radius of 6.4 m with centers at the points where the detectors are located is checked and, if necessary, additional detectors are installed. For the room shown in Fig. 8, 3 point detectors turned out to be quite sufficient.

Rice. 8. Placement of detectors in non-rectangular rooms

Fire extinguishing fire according to British standard

IN complex systems, where a false alarm could lead to significant property damage, apply additional measures, including work on 2 detectors. For example, in the British standard BS 7273-1 for gas fire extinguishing In order to avoid unwanted release of gas in the case of automatic operation of the system, the operating algorithm, as a rule, should involve the detection of a fire simultaneously by two separate detectors. Moreover, activation of the first detector should at least lead to the indication of the “Fire” mode in the fire alarm system and to the activation of an alert within the protected area. In this case, the arrangement of detectors, naturally, should ensure control of each point of the protected premises by two detectors with the ability to identify the activation of each of them. In addition, in this case, the fire alarm and warning system must be designed in such a way that in the event of a single break or short circuit the plume, it detected a fire in the protected area and, at least, left the possibility of turning on the fire extinguishing manually. That is, if maximum area, controlled by one detector, is X m 2, then in case of a single failure of the loop, each fire detector must provide control of an area of maximum 2X m 2. In other words, if in normal mode double control of each point in the room is provided, then in the event of a single break or short circuit of the loop, single control should be provided, as in the standard system.

This requirement is quite simply technically implemented, for example, when using two radial stubs with detectors installed in “pairs” or one ring stub with short-circuit insulators. Indeed, if there is a break or even a short circuit in one of the two radial loops, the second loop remains in in working condition. In this case, the placement of detectors must ensure control of the entire protected area by each loop separately (Fig. 9).

A higher level of performance is achieved when using ring loops in addressable and addressable analogue systems with short circuit insulators. In this case, when there is a break ring loop is automatically converted into two radial ones, the break point is localized, and all detectors remain in working order, which keeps the system functioning in automatic mode. If the analog address loop is short-circuited, only the devices between two adjacent short-circuit isolators are switched off. In modern analog addressable systems, short-circuit isolators are installed in all detectors and modules, so that even if the loop is short-circuited, operation is not affected.

It is obvious that the systems used in Russia with one two-threshold loop do not meet this requirement. In the event of a break or short circuit of such a loop, a “Fault” signal is generated, and the fire is not detected until the fault is eliminated; the “Fire” signal is not generated for one detector, which makes it impossible to turn on the fire extinguishing manually after receiving it.

Our standards: past and present

Our requirements for the placement of fire detectors were first defined a quarter of a century ago in SNiP 2.04.09-84 “Fire automatics of buildings and structures.” This document specified the standard distances between smoke and heat point detectors when installed on a square grid, which have not changed since then. According to 4.1 SNiP 2.04.09-84, fire alarm installations were required to generate an impulse to control fire extinguishing, smoke removal and fire warning installations when at least two automatic fire detectors installed in one controlled room were triggered. In this case, each point of the protected surface was required to be monitored by at least two fire detectors. Moreover, the maximum distance between duplicate detectors was equal to half the standard; accordingly, detectors in fire extinguishing systems were installed in “pairs” (Fig. 9), which ensured strict implementation of double control of the room area and close-in-time response of detectors in case of fire.

Control of technological, electrical and other equipment interlocked with the installation of a fire alarm was allowed to be carried out when one fire detector was activated. But in practice in simple installations For fire alarms, notification was triggered from a single detector with single control of the area of the premises and the placement of detectors at standard distances. A separate paragraph contained general requirement: “At least two automatic fire detectors should be installed in one room.” And so far, fulfilling this requirement implies a kind of redundancy of fire detectors, which is actually provided only in small rooms, the area of which does not exceed the standard for one detector. Moreover, the illusion of reservation creates the basis for the almost complete absence Maintenance, and even more so, there are no requirements for periodic monitoring of the sensitivity of detectors; accordingly, test equipment is not produced. For example, in a room measuring 9 m x 27 m with 3 non-addressable smoke detectors, to ensure redundancy, one detector must have a protected zone radius of more than 14 m and provide control of the entire room, i.e. 243 m 2. Any of the extreme detectors may fail uncontrollably, and the fault may not be detected for several years.

But in practice, equipment of the same type has approximately the same mean time between failures, which determines the almost simultaneous failure of all detectors in the room and building. For example, there is a loss of sensitivity of all smoke detectors due to a decrease in the brightness of the optocoupler LEDs. Moreover, such a massive failure of domestic fire detectors is defined by GOST R 53325-2009 “Fire fighting equipment. Technical means fire automatics. Are common technical requirements. Test methods”, since “the average time between failures of fire detectors must be at least 60,000 hours”, i.e. less than 7 years, and “ average term The service of the fire detector must be at least 10 years.”

The “area controlled by one detector” indicated in tables 4 and 5 of SNiP 2.04.09-84 is quite rightly indicated in today’s SP 5.13130.2009 as “the average area controlled by one detector.” However, over 25 years, we have not yet determined the maximum area protected by one detector in the form of a circle with a radius of 0.7 of the standard distance. Instead, in SP 5.13130.2009, a very strange in content clause 13.3.7 appeared, according to which “the distances between the detectors, as well as between the wall and the detectors, given in tables 13.3 and 13.5, can be changed within the area given in tables 13.3 and 13.5″?! That is, not, as in NFPA 72, rectangles inscribed in a circle with a radius of 0.7 from the standard distance, but any aspect ratio of a rectangle with a constant area. For example, for smoke detectors with a room height of up to 3.5 m and a width of 3 m, the distance between the detectors can be increased to 85/3 = 28.3 m! Whereas, according to NFPA 72, the average area controlled by the detector, in this case, is reduced to 38 m2, and the distances between detectors should not exceed 12.5 m (Fig. 6), moreover, clause 13.3 remains in SP 5.13130.2009. 10, according to which “when installing point smoke fire detectors in rooms less than 3 m wide, the distances between detectors specified in Table 13.3 may be increased by 1.5 times,” i.e. only up to 13.5 m.

Near future

Throughout the last decade, the development of our standards has been determined by the fight against false alarms of domestic fire detectors, moreover, without regular maintenance. Moreover, there are no plans to increase the requirements for protecting detectors from external influences, which have long no longer met operating conditions. But our DIPs are the cheapest in the world, however, they can only be certified by us according to GOST R 53325-2009. Even in the neighboring countries they have switched to European standards of the EN54 series, the scope of tests and requirements for which are an order of magnitude higher. But at the same time, installation requirements are simplified: effective protection and high reliability exclude mandatory requirement installation of at least two detectors of any type, and even detectors without automatic performance monitoring are installed one at a time in a room. For fire alarms, the placement of detectors is based on single monitoring of each point of the protected area; for fire extinguishing, double monitoring.

But it turns out that we have not yet implemented all the ways to increase the reliability of “Fire” signals. In project new edition GOST 35525, the “Fire” signal from any threshold fire detector is perceived by the control panel as false and can only identify it as “Attention”. Generating a “Fire 1” signal is only allowed either from one detector, if the “Fire” mode is confirmed after a re-request, or from 2 detectors without a re-request, if they are activated within a period of no more than 60 s. The “Fire 2” signal, which is required according to clause 14.1 of the set of rules SP 5.13130.2009 for generating signals for automatic control of fire extinguishing, smoke removal, warning or engineering equipment, in the general case should be generated only by two “Fire 1” signals per time no more than 60 s. Moreover, this algorithm for generating FACP signals “Fire 1” and “Fire 2” must be performed when working with threshold detectors of any type: thermal maximum and maximum differential, smoke linear, flame and thermal cable, since other algorithms are not provided for these detectors.

Thus, protection against false alarms is our highest priority and its increase is carried out by reducing the level of fire safety. When will the “Fire 2” signal be generated when implementing this algorithm? In most cases never and for several reasons. The set of rules SP 5.13130.2009 in this case prescribes the installation of detectors in increments of half the standard. That is, the detectors are located at different distances from the source, and their activation is with a difference of 1 - 2 minutes. unlikely. For a technically competent implementation of the proposed algorithm, the detectors must be in close proximity, i.e. they must be installed in “pairs”, and if one of them fails, in “triples”, and with the same orientation to the air flow to eliminate variation in sensitivity depending on the direction air flow, as shown in Fig. 10 Photoshop tools.

Rice. 9. Arrangement of detectors in “pairs” with inclusion in two loops

In addition, for simultaneous operation of detectors, it is necessary to install detectors with exactly the same sensitivity in “triples”. Even the permissible discrepancy between detectors in sensitivity by 1.6 times will determine the difference in response of several minutes with smoldering fires. Therefore, it will be necessary with high accuracy measure the sensitivity of each detector and indicate it on the label. The manufacturer will have to select detector packages with the same sensitivity. Naturally, it is necessary to ensure stability of the sensitivity level during operation not only through circuit design solutions and the choice of element base. Absolutely identical operating conditions must be ensured, down to the same dust content in the smoke chamber. Obviously, for smoke detectors it will be necessary to introduce mandatory precision dust compensation. Etc.

Moreover, our 2-threshold control panels issue one signal with one relay, whatever it is called, either one or two detectors and, as a rule, with a re-request. Moreover, the duration of the re-request, oddly enough, is not limited by the norms and is already found to be 2 minutes. and more. Consequently, when the first detector is triggered, even after a re-request in our 2-threshold control panels, the output signal is not generated, therefore, ventilation, air conditioning, thermal curtains etc. are not turned off, which significantly affects the distribution of smoke and will determine a significant delay in the response of the second detector if it is located at a large distance from the first. With open fires, the temperature in the room quickly increases, and with significant time spent on re-requests, it is likely that the “Fire” mode will not be confirmed by the detector due to the high temperature. It must be taken into account that most fire detectors have an operating temperature range of no more than 60 degrees C.

What happens if there is a false positive? Practice shows that low-quality detectors “false” normal conditions, even despite the re-request. In addition, any smoke detector, if there is no maintenance and a high level of dust in the smoke chamber, goes into operation, despite resets. According to this algorithm, after 60 seconds, subsequent signals from other detectors are considered false alarms. Thus, one faulty detector disrupts the operation of the entire loop, and possibly all loops, depending on the design of the control panel. Moreover, this is a well-known property of all threshold devices and it is not clear why it is not taken into account in the standards. Why is there no time limit for troubleshooting in threshold fire systems? In “Methodology for determining the estimated values of fire risk in buildings, structures and structures of various classes of functional fire danger“The probability of effective operation of the fire alarm system can be assumed to be 0.8. This means that during a service life of 10 years, it is completely inoperative for 2 years, or an average of 2.4 months each year. And according to statistics, the efficiency of fire alarm installations during fires is even lower: in 2010, out of 981 installations during a fire, only 703 completed the task, that is, they worked with a probability of less than 0.72! Of the remaining 278 installations, 206 failed, 3 did not complete the task (a total of 21.3%), and 69 (7%) were not included. In 2009, it was even worse: out of 1021 installations, only 687 completed the task, with a probability of 0.67!!! For the remaining 334 installations: 207 did not work, 3 did not complete the task (a total of 20.6%), and 124 (12.1%) were not included. Why not extend the effect of SP 5.13130.2009 of the application “Determination of the established time for detecting a malfunction and its elimination” to threshold systems? After all, here we are not talking about one room with one addressable analogue detector, but from several rooms to entire objects without automatic fire protection. How will the current situation change when the new edition of GOST 35525 comes into force? Will “Lozhnyak” finally defeat the fire?

So it seems that the development of fire systems in in this direction comes to its logical conclusion. The cost of cheap detectors will be too expensive. The draft new edition of GOST 35525 includes fire tests of fire detectors using test fires in the certification testing program. We will finally find out what level of fire protection our fire detectors provide. Moreover, if the requirements for re-queries in PPKP remain in GOST 35525, then tests must be carried out with two maximum re-queries in order to simulate fire detection by our false-proof devices.

Obstacles to the impact of fire factors on detectors

In the general case, with a horizontal overlap, due to convection, hot gas and smoke from the source are transferred to the overlap and fills the volume in the form of a horizontal cylinder (Fig. 10). When rising upward, the smoke is diluted with clean and cold air, which is drawn into the upward flow. Smoke occupies a volume in the form of an inverted cone with its apex at the location of the hearth. When spreading along the ceiling, the smoke also mixes with clean cold air, while its temperature decreases and the lifting force is lost, which determines the limitation of the space filled with smoke on initial stage fire in large rooms.

Obviously, this model is valid only in the absence of extraneous air flows created supply and exhaust ventilation, air conditioners and in a room free of any objects on the ceiling near the paths of distribution of the smoke-gas mixture from the fire. The degree of impact of obstacles on smoke flows from the fireplace depends on their size, shape and location relative to the fireplace and the detector.

Requirements for the placement of fire detectors in rooms with racks, with beams and in the presence of ventilation are present in various national standards, but vary significantly depending on the origin, despite the generality of physical laws.

Requirements SNiP 2.04.09-84 and NPB88-2001

Requirements for the placement of fire detectors were first defined in 1984 in SNiP 2.04.09-84 “Fire automatics of buildings and structures”; these requirements were set out in more detail in NPB 88-2001 “Fire extinguishing and alarm installations. Design standards and rules, as amended in NPB88-2001*. Currently, the set of rules SP 5.13130.2009 with Amendment No. 1 is in force. It is obvious that the development of new versions of documents each time was carried out on the basis of the previous one by adjusting individual paragraphs and adding new paragraphs and applications. As an example, we can trace the development of our requirements over a 25-year period regarding the placement of detectors on columns, walls, cables, etc.

The requirements of SNiP 2.04.09-84 regarding smoke and heat fire detectors state that “if it is impossible to install detectors on the ceiling, they can be installed on walls, beams, columns. It is also allowed to hang detectors on cables under the roofs of buildings with light, aeration, and skylights. In these cases, detectors must be placed at a distance of no more than 300 mm from the ceiling, including the dimensions of the detector.” This paragraph incorrectly introduces the requirements for distance from the ceiling for various conditions placement of fire detectors relative to the directions of air flows and the maximum permissible distance for heat and smoke detectors. According to the British Standard BS5839, fire detectors must be installed on the ceiling so that their sensing elements are located below the ceiling, ranging from 25 mm to 600 mm for smoke detectors and from 25 mm to 150 mm for heat detectors, which is logical from the point of view of detection of various stages of lesion development. Unlike smoke detectors, heat detectors do not detect smoldering fires, and at the open fire stage there is a significant increase in temperature, accordingly, there is no stratification effect and, if the distance between the ceiling and the heat-sensitive element is more than 150 mm, this will lead to unacceptably late detection of the fire, i.e. i.e. will make them practically inoperable.

On the other hand, if detectors suspended by cables and mounted on the bottom surfaces of beams are exposed to horizontal air currents, then when placed on walls and columns, changes in air flow directions must be taken into account. These structures act as barriers to the horizontal spread of smoke, creating poorly ventilated areas in which fire detectors should not be placed. The NFPA provides a drawing indicating the area where detectors are not allowed to be installed - this is the angle between the wall and the ceiling with a depth of 10 cm (Fig. 11). When installing a smoke detector on a wall, its upper part should be at a distance of 10-30 cm from the ceiling.

Rice. 11. NFPA 72 Requirements for Wall Mounted Smoke Detectors

After adjustment two years later, in NPB 88-2001*, the requirements were divided: “when installing point detectors on walls, they should be placed<…>at a distance of 0.1 to 0.3 m from the ceiling, including the dimensions of the detector” and the maximum permissible distance of the detector from the ceiling when hanging detectors on a cable was separately introduced: “<…>the distance from the ceiling to the bottom point of the detector should be no more than 0.3 m.” Naturally, if the detectors are installed directly on the ceiling, then when hanging them on a cable there is no reason to move them 0.1 m from the ceiling, as when placing them on the wall.

Requirements SP 5.13130.2009

In SP 5.13130.2009, paragraph 13.3.4, which sets out the requirements for the placement of detectors, was significantly revised and significantly increased in volume compared to previous versions, but it is difficult to say that this added clarity. As in previous versions, all possible installation options are listed in a row: “if it is impossible to install detectors directly on the ceiling, they can be installed on cables, as well as walls, columns and other load-bearing building structures.” True, a new requirement has appeared: “when installing point detectors on walls, they should be placed at a distance of at least 0.5 m from the corner,” which fits well with European standards and with the general requirement introduced later in amendment No. 1 to SP 5.13130.2009 .

The range of distances from the ceiling of 0.1-0.3 m specified in NPB88-2001 for installing detectors on the wall was excluded, and now the distance from the ceiling when installing detectors on the wall is recommended to be determined in accordance with Appendix P, which contains a table with minimum and maximum distances from the ceiling to the detector measuring element, depending on the height of the room and the angle of inclination of the ceiling. Moreover, Appendix P is entitled “Distances from the top point of the floor to the measuring element of the detector,” based on which it can be assumed that the recommendations of Appendix P relate to the placement of detectors in the case of inclined floors.

For example, with a room height of up to 6 m and floor inclination angles of up to 150, the distance from the ceiling (the top point of the floor) to the detector measuring element is determined in the range from 30 mm to 200 mm, and with a room height of 10 m to 12 m, respectively, from 150 up to 350 mm. For floor inclination angles greater than 300, this distance is determined in the range from 300 mm to 500 mm for a room height of up to 6 m and in the range from 600 mm to 800 mm for a room height of 10 m to 12 m. Indeed, with inclined floors, the upper part of the room is not ventilated, and, for example, NFPA 72 in this case requires smoke detectors to be located at the top of the room, but only below 4” (102 mm) (Fig. 12).

Rice. 12. Placement of detectors for sloping floors per NFPA 72

It should be noted that clause 13.3.4 refers to point fire detectors in general, i.e., both smoke detectors and heat detectors, and significant distances from the ceiling are allowed only for smoke detectors. Apparently, Appendix P is applicable only for smoke point detectors, this is indirectly indicated maximum height protected premises - 12 m.

Installing Smoke Detectors on a Suspended Ceiling

The placement of detectors on a suspended ceiling is defined in the requirements of clause 13.3.15 of the set of rules SP 5.13130.2009, although initially we are talking about a perforated suspended ceiling, but in the absence of perforation, at least two conditions given in this paragraph are not met:

and as stated further: “If at least one of these requirements is not met, the detectors must be installed on a false ceiling in the main room< >. It is directly on the false ceiling.
Many smoke detector manufacturers produce mounting kits for embedding detectors into suspended ceilings, which improves appearance premises (Fig. 13).

Rice. 13. Embedding the detector into a suspended ceiling using an installation kit

In this case, the requirement given in clause 4.7.1.7 of GOST R 53325-2009 is usually met with a reserve, according to which the design of the smoke detector “must ensure the location of the optical camera at a distance of at least 15 mm from the surface on which the IPDOT is mounted” (fire smoke detector optical-electronic point). It may also be noted that British Standard BS5839 requires fire detectors to be ceiling mounted with their sensing elements below the ceiling ranging from 25mm to 600mm for smoke detectors and 25mm to 150mm for heat detectors. Accordingly, when installing foreign smoke detectors into a suspended ceiling, the installation kits ensure that the smoke outlet is located 25 mm below the ceiling.

Controversy in Change #1

On the other hand, according to new version clause 13.3.8, “point smoke and heat fire detectors should be installed in each ceiling compartment with a width of 0.75 m or more, limited by building structures (beams, purlins, slab ribs, etc.) protruding from the ceiling at a distance of more than 0.4 m”. However, to fulfill the absolute requirement of clause 13.3.6, the width of the compartment must be at least 1 m plus the size of the detector. With a compartment width of 0.75 m, the distance from the detector, even without taking into account its dimensions “to nearby objects,” is 0.75/2 = 0.375 m!

Another requirement of clause 13.3.8: “If building construction protrude from the ceiling at a distance of more than 0.4 m, and the compartments they form are less than 0.75 m in width, the area controlled by fire detectors, indicated in tables 13.3 and 13.5, is reduced by 40%”, also applies to floors with beams more than 0, 4 m in height, but the requirement of clause 13.3.6 does not allow detectors to be installed on the ceiling. And Appendix P, already mentioned here, from the set of rules SP 5.13130.2009 recommends a maximum distance from the top point of the floor to the measuring element of the detector of 350 mm at floor angles of up to 150 and with a room height of 10 to 12 meters, which excludes the installation of detectors on the lower surface of the beams. Thus, the requirements introduced in clause 13.3.6 exclude the possibility of installing detectors under the conditions given in clause 13.3.8. In some cases, this regulatory problem can be resolved by the use of linear smoke or aspiration detectors.

There is another problem when introducing the requirement “Distance from detectors to nearby objects” into clause 13.3.6<…>in any case it must be at least 0.5 m.” It's about protecting ceiling space. In addition to the mass of the cable, air ducts and fittings, the suspended ceiling itself is often located at a distance of less than 0.5 m from the ceiling - and how in this case can the requirement of clause 13.3.6 be met? Should I refer the suspended ceiling to 0.5 m plus the height of the detector? It’s absurd, but clause 13.3.6 does not say about excluding this requirement for the case of overhead space.

Requirements of British Standard BS 5839

Similar requirements in the British standard BS 5839 are set out in much greater detail. more points and with explanatory drawings. Obviously, in general, objects near the detector have different effects depending on their height.

Ceiling barriers and obstacles

First of all, a restriction is given on the placement of point detectors near structures of significant height, located on the ceiling and significantly affecting the detection time of controlled factors, in rough translation: “Heat and smoke detectors should not be installed within 500 mm of any walls, partitions or obstacles for flows of smoke and hot gases, such as structural beams and ducts, where the height of the obstacle is greater than 250 mm.”

The following requirement applies to structures of lower height:

Rice. 14. The detector must be separated from a structure whose height is up to 250 mm by at least twice its height

The next requirement, also absent from our codes, concerns beams: “Ceiling obstructions, such as beams exceeding 10% of the total height of the room, must be considered as walls (Fig. 15).” Accordingly, abroad, at least one detector must be installed in each compartment formed by such a beam, and our detectors must be 1, or 2, or 3, or even 4 according to SP 5.13130.2009, but this is the topic of a separate article.

However, it should be noted that the requirement of clause 13.3.8 “Spot smoke and heat fire detectors should be installed in each ceiling compartment...” leaves open the question of what is the minimum number of them in each compartment? Moreover, if we consider the 13th section of the set of rules SP 5.13130.2009, then according to clause 13.3.2 “in each protected room at least two fire detectors should be installed, connected according to the logical “or” circuit, and according to the 14th section for installation To have two detectors in a room, a number of conditions must be met, otherwise the number of detectors must be increased to 3 or 4.

Rice. 15. Beams exceeding 10% of the total height of the room should be considered as walls

Free space around the detector

And now we finally got to the analogue of our requirement, clause 13.3.6 of the set of rules SP 5.13130.2009, however, the only thing common with the requirement of the BS 5839 standard is the value of 0.5 m: “Detectors must be placed in such a way that free space within 500 mm below each detector” (Fig. 7). That is, this requirement specifies the space in the form of a hemisphere with a radius of 0.5 m, and not a cylinder, as in SP 5.13130.2009, and applies mainly to objects in the room, and not on the ceiling.

Rice. 16. Free space around the detector 500 mm

Ceiling protection

And the next requirement, also absent from SP 5.13130.2009 with amendment 1, is the placement of detectors in the ceiling space and under the raised floor: “In unventilated spaces, the sensitive element of fire detectors should be located in the upper 10% of the space or in the upper 125 mm, depending on , which is greater” (see Fig. 17).

Rice. 17. Placement of detectors in the ceiling or underground space

This requirement shows that this case should not be associated with the requirement of a free space of 0.5 m around the detector for rooms and excludes the possibility of “inventing” the detector to protect two spaces.

Critical air flow speed

For smoke fire detectors, the main characteristic is usually considered to be sensitivity, measured in smoke channel in dB/m. However, in real conditions, the effectiveness of detecting the source of a smoke detector in most cases depends on the so-called critical speed - the minimum air flow speed at which smoke begins to enter the smoke chamber of the detector, overcoming aerodynamic drag. That is, to detect a fire, it is necessary not only to have smoke of sufficient specific optical density at the location of the smoke detector, but also to have a sufficiently high air flow velocity in the direction of its smoke outlet. The American fire alarm standard NFPA 72 for smoke detectors provides calculations using the critical air velocity method. It is believed that if at the location of the smoke detector a critical speed of movement of the smoke-gas mixture from the source has been reached, then the smoke concentration is sufficient to generate an alarm signal.

In the American UL standard for smoke detectors, the sensitivity of the detector in the smoke duct is measured at a minimum air flow velocity of 0.152 m/sec. (30 ft/min). In NPB 65-97, the minimum air flow velocity in the smoke channel at which the sensitivity of the smoke detector was measured should have been set equal to 0.2 ± 0.04 m/s, as in the European standard EN 54-7 for smoke point detectors. However, in the currently valid GOST R 53325-2009 clause 4.7.3.1, this value was replaced by a range of air flow speeds of 0.20÷0.30 m/s, and in the draft new edition of GOST R 53325 the same range is defined as : “set the air flow speed to (0.25 ± 0.05) m/s.” On the basis of what experimental studies was this adjustment carried out, which determines the possibility of a significant reduction in the efficiency of domestic smoke detectors in comparison with European and American detectors? And some fire detectors with “high” protection from dust due to a reduction in the smoke outlet area, a critical speed of slightly less than 1 m/s, stop responding to smoke during real fires.
In a room with a flat horizontal ceiling, due to convection, hot gas and smoke from the fireplace rises, and it is diluted with clean and cold air, which is drawn into the upward flow. The NFPA 72 Smoke Detector Spacing Guide provides a smoke detector distribution model to account for the stratification effect. Smoke occupies a volume in the form of an inverted cone with an angle equal to 22 0, respectively, at a height H, the radius of the area filled with smoke is equal to 0.2 N. When spreading along the ceiling, the smoke also mixes with clean, cold air, and its temperature decreases, lift is lost and the air flow speed becomes below critical. These physical processes determine the impossibility of detecting a source with a point smoke detector at significant distances and limiting the maximum distance to the detected source, and not the area, as in our standards.

Rice. 18. Free divergence of smoke from the hearth

Room compartments, dedicated parts of the room, protected areas

The set of rules SP 5.13130.2009 clause 13.3.9 contains the requirement: “Point and linear, smoke and heat fire detectors, as well as aspiration detectors should be installed in each compartment of the room formed by stacks of materials, racks, equipment and building structures, the upper edges of which distanced from the ceiling by 0.6 m or less.” As already noted, this requirement is not new, but there is no clarity regarding the minimum number of detectors in each compartment. It is clear that if the room is divided into compartments, then the smoke accumulates in the same compartment with the fireplace, and, as in separate rooms, it is necessary to install at least 2 detectors with the “or” signal generation logic, or at least 3-4 detectors when generating signals when not triggered. less than two fire detectors connected according to the logical “and” circuit. Moreover, it is obvious that if in 3 compartments of the room one detector is installed in a two-threshold loop, then the system will be inoperative even if all detectors and the device are in full working order. However, what justification can be found in the requirements of the set of rules SP 5.13130.2009 for installing more than one detector in a compartment, if the distance requirements are met. After all, design is usually carried out based on the minimum cost of equipment, but rarely does anyone think about operational efficiency and operability.
According to clause 13.3.2, in a room, as 30 years ago, it is required to install at least two fire detectors, connected according to the logical “or” circuit without any reservations, although clause 13.3.3 allows for the installation of one detector not only in the protected premises, but also in “dedicated parts of the premises”. Clause 14.2 also states that at least two detectors according to the “or” logical scheme are installed “in the room (part of the room)<…>» with placement at standard distances. And in clause 14.3 already “in a protected room or protected area<…>» there must be at least 2-4 detectors. And in the 3rd section of clause 3.33 there is the term “fire alarm control zone (fire detectors)”, which is defined as “the totality of areas, volumes of premises of the facility, the appearance of fire factors in which will be detected by fire detectors.”
The variety of terms used in the set of rules SP 5.13130.2009 without their definition significantly complicates the fulfillment of the requirements set out in them. Excessive savings of equipment can only be limited by the general requirement given in clause 14.1: “The generation of signals for automatic control of warning systems, smoke removal or engineering equipment of the facility must be carried out in a time not exceeding the difference between the minimum value of the time of blocking of evacuation routes and the evacuation time after notification of a fire." And when one detector is installed in 3 compartments of the room, the “fire” signal will be generated only when the fire zone covers several compartments. If 2 detectors are installed in each compartment, then, provided that both detectors are operational, a “fire” signal will be generated adequately, but if one of them fails, the requirement will not be met. Conflicting requirements and confusion with terms could be avoided by defining, as in BS 5839, that when the protected space is divided by partitions or shelving the top edge of which is within 300mm of the ceiling (rather than 600mm as in SP 5.13130.2009), they should be considered as solid walls that rise to the ceiling (Fig. 19). If SP 5.13130.2009 contained a similar definition, then there would be certainty in determining the number of detectors depending on their type.

Rice. 19. Partitions are treated as walls to ceiling

Floors with beams

British Standard BS 5839 contains several requirements for the placement of fire detectors. By type, beams can be divided into at least 3 classes: single linear beams, frequent linear beams (Fig. 20) and beams forming cells like a honeycomb. For each type of beam, the corresponding requirements for installing detectors are given.

Rice. 20. Combination of shallow and deep beams

In change No. 1 to the set of rules SP 5.13130.2009 in clause 13.3.8 we returned to the wording from NPB 88-2001 clause 12.20, which was based on the requirements of SNiP 2.04.09-84 clause 4.4: “Smoke and heat fire detectors should be installed in each ceiling compartment limited by building structures (beams, purlins, slab ribs, etc.) protruding from the ceiling by 0.4 m or more.” And here, similarly to compartments formed by stacks, it is necessary to formulate the requirement of how many detectors of each type should be installed in each compartment and how. Due to the uncertainty of the requirements, one detector is often installed in each part of the room, divided by a high beam (Fig. 21).

Rice. 21. There is one detector in each compartment, at least 2 in the room.

In addition, the influence of the beam on the spread of smoke along the ceiling depends not only and not so much on the height of the beam, but on its relationship to the height of the ceiling. The British standard BS 5839 and the American standard NFPA 72 consider the ratio of beam height to slab height. If the height of an individual beam exceeds 10% of the height of the room, then the smoke from the fireplace will mostly fill one compartment. Accordingly, when placing detectors, the beam is treated as a solid wall, and the detectors are installed, as usual, on the floor.

Rice. 22. Placement of detectors in relation to beam according to BS 5839

In the case of frequent placement of beams, smoke and heated air are distributed along the ceiling in the form of an ellipse. Moreover, the upper part of the openings formed by the beams remains poorly ventilated, and the detectors are installed on the lower surface of the beams. According to NFPA 72, if the beam-to-ceiling height ratio D/H is greater than 0.1 and the beam pitch-to-ceiling height ratio W/H is greater than 0.4, detectors must be installed in each compartment formed by the beams. It is quite obvious that this value is determined based on the radius of smoke divergence at height H, equal to 0.2 N (Fig. 1); accordingly, smoke can actually fill one compartment. For example, detectors are installed in each compartment with a ceiling height of 12 m, if the beams are spaced more than 4.8 m, which is significantly different from our 0.75 m. Another requirement of NFPA 72: if the beam height to ceiling height ratio is D/H less than 0.1 or the ratio of beam pitch to ceiling height W/H is less than 0.4, then the detectors must be installed on the underside of the beams. In this case, the distance between detectors along the beams remains standard, but across the beams is reduced by half (Fig. 23).

Rice. 23. The distances along the beams are standard, but across them are reduced by 2 times

The British standard BS 5839 also discusses in detail frequent linear beams (Fig. 24) and longitudinal and transverse beams that form a honeycomb (Fig. 8).

Rice. 24. Ceiling with beams. M - distance between detectors

The requirements of BS 5839-1:2002 for permissible distances between detectors across beams depending on ceiling height and beam height are given in Table 1. As in NFPA 72, the maximum distance along beams remains the norm, no increase in 1.5 times as in we are not there, and the distances across the beams are reduced by 2-3 times.

Table 1
Where, H is the height of the ceiling, D is the height of the beam.

For beams in the form of a honeycomb, fire detectors are installed on the beam with a relatively small cell width, less than four times the height of the beam, or on the ceiling with a cell width greater than four times the height of the beam (Table 2). Here the limit for the height of the beam is 600 mm (as opposed to our 400 mm), but the relative height of the beam is also taken into account - an additional limit, 10% of the height of the room. Table 2 shows the radius of the controlled area of the smoke and heat detector; accordingly, the distance between the detectors with a square lattice is √2 greater.

Rice. 25. Longitudinal and transverse beams divide the ceiling into honeycombs

table 2
Where, H is the height of the ceiling, W is the width of the cell, D is the height of the beam.

Thus our regulatory requirements differ significantly from foreign standards, and the need to use several of our detectors instead of one detector not only makes it impossible to harmonize our standards, but also creates difficulties in determining the area protected by the detector and the logic of the system. As a result, in practice we get low efficiency of fire protection in the presence of a fire automatic system. According to statistics presented by VNIIPO in the collection “Fires and Fire Safety in 2010”, in 2,198 fires at facilities protected by fire automatics, 92 people were killed and 240 were injured, and in total there were 179,500 fires, in which 13,061 were killed and injured 13,117 people.

Igor Neplohov - expert, candidate of technical sciences
Published in the journal “Protection Technologies” No. 5, 6 - 2011

Design suspended ceiling allows you to hide exhaust ducts, wiring, electrical cables and other communications in the interceiling space, however, this increases the risk of fire. In this connection, the ceiling must be equipped with an automatic fire alarm system.

When is it necessary to install sensors?

Safety standards are constantly changing, so homeowners with suspended ceilings need to regularly monitor new regulations. Thus, some owners are confident that it is the ceiling height that is the fundamental factor in the need to install an alarm. However, this belief is incorrect - fire protection requirements do not depend on the height of the ceiling space, but solely on the presence and amount of flammable cable load. Legally, this is regulated by the following regulations:

set of rules 13130 of 2009 with mandatory Appendix “A”;
table “A2”, paragraph 11 and note to paragraph 11 (standard “Fire protection”).

How to determine the need for installation:

Step 1. Look behind the ceiling, find a cable that provides power, outlet wires or a power network.

Step 2. Select maximum large plot, carried out in one direction for more than a meter. Count the number of cables, taking into account their brands, write down the data.

Step 3. For each type of wire, determine the combustible mass indicators according to any directory of cable manufacturers, for example, the Kolchuginsky plant.

Step 4. Carry out calculations using the formula: A×B=C, where A is the number of wiring a certain model and grade, B is the combustible mass, and C is the desired flammability parameter. The calculation is performed separately for each cable type, then all results are summed up.

Step 5. Compare the resulting indicator with legal standards:

up to 1.5 liters per meter – no need to install sensors on the ceiling;
from 1.5 to 1.7 l – fire safety is ensured in the form of an independent ceiling alarm loop;
1.7 l and more - must be installed automatic system fire extinguishing For ceiling heights less than 0.4 meters, a cable is installed.

In this case, the distance between the base ceiling and the suspended ceiling should be sufficient to accommodate the sensors. It is also important to identify the area with the most dense arrangement of wires and other communications - the cables should be at a distance of at least 30 cm from each other.

In what cases is a fire alarm not required?

The need to install an alarm is always determined solely by the combustible load indicator. However, the regulatory safety documentation also establishes a number of other factors under which installation of a fire alarm on a suspended or suspended ceiling is not required:

If there are wires hidden in insulated corrugated tubes or special steel boxes.
In the case of installation based on a single-core cable and an NG type electrical supply (non-flammable).
If there is a single strand of wiring in the suspended ceiling.

Types of fire detectors

Existing sensors have a fairly extensive classification system in accordance with the nuances of the structure of the device and the methods of its functioning. Each of the detectors has its own installation and operation features. So, depending on the type of transmitted signal, sensors are divided into the following categories:

Single-mode detectors. Signal danger upon exposure external factor, for example, temperature. Currently they are not used in everyday life.
Dual-mode with “Fire” and “No fire” alarms. At the same time, the absence of a fire signal confirms that the device is in working order and is operating normally.
Multi-mode with built-in notification programs about device failures.

In addition, detectors are conventionally divided into types according to their location:

Spot Appliances They have a single sensor, often built into the housing.
Multipoint devices are equipped with multiple detectors.
Linear sirens analyze the space along an arbitrary trajectory. They can be single or paired, autonomous or targeted.

Regardless of the classification, all fire detectors are divided into wired and wireless and differ in the type of detector itself - it is this division that is fundamental when choosing a warning system.

Heat detectors

Heat sensors were the first fire prevention devices. They appeared in everyday life at the beginning of the 19th century, and at that time they looked like two spring-loaded cables with a wax insert in the middle. As the temperature increased, the wax began to melt and the wires shorted, causing sound signal anxiety. New generation thermal sensors also have melting elements and often use an electrical effect based on the thermocouple principle.

Despite all the advantages of the device, including its low cost, such detectors have one serious drawback - they sound an alarm after the air temperature has risen and a fire has started. It is for this reason that with the development of technology, this type of device gradually lost its relevance.

Smoke detectors

Systems equipped with smoke detectors are by far the most popular fire protection devices for use in homes and work areas. Smoke is the first and main sign of a possible fire, which may appear before an open flame occurs. For example, a faulty electrical wiring is often accompanied by a long process of smoldering with a characteristic caustic fumes. Therefore, this type of sensor helps to identify the source of fire at its initial stage.

The smoke sensor operates on the principle of detecting changes in the transparency of smoky air. In this case, the device is classified depending on the methods of its operation into linear detectors (working with a directed beam in the optical or ultraviolet range) or point detectors (based on infrared radiation). Point detectors are usually simpler than linear ones, but less reliable - thick, dark smoke does not reflect infrared rays, so during such a fire the sensor may not respond.

Flame detectors

This type of siren is usually used to provide fire safety at production sites. In such rooms, the use of smoke or heat sensors will be difficult due to the constant dustiness of the air or its elevated temperature.

Types of detectors:

Infrared. Catch radiant heat open flame. If there are regularly operating sources of air heating, groundless alarm activation is excluded.
Ultraviolet. They are used if there are sources of infrared radiation in the room, for example, an electric heater.
Sensors that react to the electromagnetic component of the energy released from an open fire.
Security ultrasonic devices. Interact with fluctuations in air masses. The operating principle is based on the fact that hot air actively rises upward.

Rules for installation and placement of fire sensors on the ceiling

The placement of security and fire alarm systems (OPS or APS) is regulated by the normative act SP 5.13130.2009 as amended on 06/01/2011. In accordance with this document, installation of devices is carried out exclusively on load-bearing elements(stiffeners) or cables. It is important to consider that it is strictly prohibited to attach sounders to suspended ceiling slabs - this design has poor mechanical stability and low fire resistance.

Sometimes ceiling sensors are also used to ensure indoor security. This is possible in cases where false ceilings have large perforations. According to safety rules, installation of fire detectors behind a suspended ceiling is possible in the following cases:

in the presence of perforation with an area of 40% of the entire surface with a periodically repeating large pattern;
with a diameter of one perforation hole of at least 1 cm;
if the size of the suspended structure element does not exceed the minimum size of one cell (for example, Armstrong-type ceilings).

If these requirements are not met, fire detectors must be installed on the walls of the room or directly on the surface of the suspended ceiling. In addition, it is necessary to take into account the sensitivity radius of the devices.

Installation is carried out according to the “triangular grid” arrangement principle - this will save space and protect the entire surface.
When calculating the range of the device, the orientation of the sensitivity zone in the horizontal plane is used. For smoke sensors - 7.5 m, for heat sensors - 5.3 m.
The detector, mounted on the base of a suspended structure, must be positioned so that the sensitive element is below the ceiling level. For smoke - 2.5-60 cm, thermal - 2.5-15 cm.
The distance from the walls must be at least 0.5 m.

Calculation of the required number of detectors

Before installing smoke sensors, you need to correctly calculate them exact amount for a specific room. In this case, it is necessary to take into account the type of devices and the intended connection diagram. It is important to understand that each state's laws will have different installation standards.

IN Russian Federation It is mandatory to install at least 2 sensors per room. The regulations state that it is recommended to install detectors on each section of the ceiling with a width of 0.75 m or more, as well as on elements of building structures with a protrusion of 0.4 m.

Thus, a separate zone of the inter-ceiling space should be equipped with:

three sensors, if they are connected to a two-threshold response loop or to three separate loops with a single response threshold;
four detectors when connected in pairs to two different device loops with the same threshold;
two devices with an alternating operation circuit.

Despite the fact that point sensors are capable of monitoring up to 25 meters of a room, it is imperative to install at least two of them if they are addressable and at least three if they are analog. This is explained by the fact that the spread of smoke and fire in the ceiling area has its own characteristics, which means that this area is more difficult to control.

Installation procedure

When installing a device, the first thing to determine is required amount sensors and mounting locations, only then does the installation process begin.

In the suspended ceiling

Sensors are most often installed in suspended plasterboard ceilings using the insertion method - the most aesthetically pleasing and in a convenient way. It is recommended to use heat-resistant cables with NG type braid, copper conductors and a minimum cross-section of 0.5 mm. Please note that installing sensors in blind corners between the wall and ceiling is strictly prohibited.

Fire sensor installation diagram:

Step 1. Determination of the number of detectors, approximate location their location and distance from each other. It should be noted that smoke sensors must be installed both in the suspended structure itself and on it.

Step 2. Fixing sounders is only permissible on a frame or concrete floor in an overhead way. It is possible to insert into a suspended ceiling and fasten it using special mounting rings, but in this case the sensor is additionally fixed to the ceiling with a cable.

Step 3. The device is connected only in the absence of power and in accordance with the diagram indicated on the sensor packaging. Finally, you should check the accuracy of the connection and the performance of the entire system several more times.

In a suspended ceiling

Regulatory documents do not indicate the mandatory location of fire sensors in suspended ceilings, however, it is necessary to comply minimum distance from the walls. When installing the device, preference should be given to those areas where there will be the greatest coverage of room control, taking into account the range of the sensor.

Installation instructions:

Step 1. Prepare the embedded structure for suspended ceiling. To do this, flexible metal hangers are screwed to a flat plate of plastic or plywood, with the help of which the platform is attached to the concrete floor.

Step 2. Align the mortgage to the level with the future ceiling. Bring the wiring down.

Step 3. Stretch the fabric. At the location of the platform, glue a thermal ring so that the PVC film does not tear, then cut a hole to install the sensor.

Step 4. Connect the device and check its functionality. Screw the sensor to the platform.

Safety precautions and possible installation problems

Despite the fact that the fire alarm system must be installed by a qualified organization in compliance with all requirements and standards, sometimes apartment owners try to install the device themselves. Self-installation fire detectors is possible, but certain safety rules must be observed:

During installation work It is allowed to use only special stepladders or ladders - any improvised means are strictly prohibited.
Only specialists with knowledge of the instructions and specifics of the work are allowed to install and maintain the fire safety system.
Tools used in the process must have insulated handles.
First, you need to measure the voltage between phases using a portable voltmeter.
Before installing the system elements, be sure to check the strength of the fire detectors on the suspended ceiling or tension structure.

Common problems during installation and operation

Problem #1: malfunction of one detector while all others are working properly.

Remedy: check the installed smoke sensors and, if necessary, remove them. It should be taken into account that if the voltage indicators are different, then the wiring for fire extinguishing and alarm systems should be located in separate boxes. When laid open, the distance between cables and other communication systems should not be less than 0.5 m.

Problem #2: No alarm.

Remedy: check mounting surface, turn the optical indicator of the device towards the main entrance.

Problem #3: Battery failure.

Remedy: if the sensor is installed on the ceiling itself, then changing the power system will be quite easy - you just need to carefully unscrew the device from its platform. When installing the device inside a suspended ceiling, you will need to partially dismantle the ceiling panel.

Thus, the main requirement for installing a fire detector remains its effective subsequent operation. When choosing a device, it is advisable to give preference to reliable manufacturers whose models are guaranteed to last for several years.

It is better for the owner of the premises to rely on qualified specialists who can calculate the number of detectors and create correct scheme their location - only with proper installation is it possible to operate fire detectors without failures or malfunctions.

Over the past three years, many regulations governing the placement of fire detectors have changed twice. It is also necessary to note the fundamental differences in the requirements for the placement of fire detectors in our and foreign regulatory documents. Our standards, unlike foreign ones, contain only requirements; they do not contain any explanation of physical processes. Change No. 1 to the set of rules SP 5.13130.2009 made significant adjustments, with some requirements returning from NPB 88-2001 *, and some, introduced for the first time, partially coincide with the requirements of foreign standards. For example, in clause 13.3.6 Amendment No. 1 to SP 5.13130.2009 it is stated that “the horizontal and vertical distance from detectors to nearby objects and devices, to electric lamps, in any case must be at least 0.5 m,” but not it is indicated what size objects should be taken into account. For example, is the cable that runs to the detector covered by this clause?
The first part of the article examined the placement of point fire detectors in the simplest case, on a flat horizontal ceiling in the absence of any obstacles to the spread of combustion products from the fireplace. The second part examines the placement of point fire detectors in real conditions, taking into account the influence of surrounding objects in the room and on the ceiling.

Obstacles to the impact of fire factors on detectors

In the general case, with a horizontal overlap, due to convection, hot gas and smoke from the source are transferred to the overlap and fills the volume in the form of a horizontal cylinder (Fig. 1). When rising upward, the smoke is diluted with clean and cold air, which is drawn into the upward flow. Smoke occupies a volume in the form of an inverted cone with its apex at the location of the hearth. When spreading along the ceiling, smoke also mixes with clean cold air, reducing its temperature and losing lifting force, which determines the limitation of the space filled with smoke at the initial stage of a fire in large rooms.

Rice. 1. Direction of air flows from the fireplace

Obviously, this model is valid only in the absence of extraneous air flows created by supply and exhaust ventilation, air conditioners and in a room free of any objects on the ceiling near the paths of distribution of the smoke-gas mixture from the fire. The degree of impact of obstacles on smoke flows from the fireplace depends on their size, shape and location relative to the fireplace and the detector.
Requirements for the placement of fire detectors in rooms with racks, with beams and in the presence of ventilation are present in various national standards, but vary significantly depending on the origin, despite the generality of physical laws.

Requirements SNiP 2.04.09-84 and NPB88-2001
Requirements for the placement of fire detectors were first defined in 1984 in SNiP 2.04.09-84 “Fire automatics of buildings and structures”; these requirements were set out in more detail in NPB 88-2001 “Fire extinguishing and alarm installations. Design standards and rules, as amended in NPB88-2001 *. Currently, the set of rules SP 5.13130.2009 with Amendment No. 1 is in force. It is obvious that the development of new versions of documents each time was carried out on the basis of the previous one by adjusting individual paragraphs and adding new paragraphs and applications. As an example, we can trace the development of our requirements over a 25-year period regarding the placement of detectors on columns, walls, cables, etc.
The requirements of SNiP 2.04.09-84 regarding smoke and heat fire detectors state that “if it is impossible to install detectors on the ceiling, they can be installed on walls, beams, columns. It is also allowed to hang detectors on cables under the roofs of buildings with light, aeration, and skylights. In these cases, detectors must be placed at a distance of no more than 300 mm from the ceiling, including the dimensions of the detector.” This paragraph incorrectly introduces requirements for the distance from the ceiling for various conditions for placing fire detectors in relation to the directions of air flows and the maximum permissible distance for heat and smoke detectors. According to the British Standard BS5839, fire detectors must be installed on the ceiling so that their sensing elements are located below the ceiling, ranging from 25 mm to 600 mm for smoke detectors and from 25 mm to 150 mm for heat detectors, which is logical from the point of view of detection of various stages of lesion development. Unlike smoke detectors, heat detectors do not detect smoldering fires, and at the open fire stage there is a significant increase in temperature, accordingly, there is no stratification effect and, if the distance between the ceiling and the heat-sensitive element is more than 150 mm, this will lead to unacceptably late detection of the fire, i.e. i.e. will make them practically inoperable.
. On the other hand, if detectors suspended by cables and mounted on the bottom surfaces of beams are exposed to horizontal air currents, then when placed on walls and columns, changes in air flow directions must be taken into account. These structures act as barriers to the horizontal spread of smoke, creating poorly ventilated areas in which fire detectors should not be placed. The NFPA provides a drawing indicating the area where detectors are not allowed to be installed - this is the angle between the wall and the ceiling with a depth of 0 cm (Fig. 2). When installing a smoke detector on a wall, its upper part should be at a distance of 10-30 cm from the ceiling.

Rice. 2. NFPA 72 Requirements for Wall Mounted Smoke Detectors

A similar requirement was introduced later in NPB 88-2001: “When installing point fire detectors under a ceiling, they should be placed at a distance from the walls of at least 0.1 m” and “when installing point fire detectors on walls, special fittings or fastening them on cables should be placed at a distance of at least 0.1 m from the walls and at a distance of 0.1 to 0.3 m from the ceiling, including the dimensions of the detector.” Now, on the contrary, the restrictions for placing detectors on the wall also apply to detectors suspended on a cable. In addition, often the mention of “special fittings” for some reason was associated with the installation of detectors on the wall and special brackets were designed to mount detectors in a horizontal position, which, in addition to additional costs, significantly reduced the efficiency of the detectors. In order for the air flow to enter the horizontally oriented smoke chamber of a wall-mounted detector, it must seem to go “into the wall.” At relatively low speeds, the air flow smoothly flows around obstacles and “turns around” near the wall, without going into the corner between the wall and the ceiling. Consequently, a horizontally positioned smoke detector on the wall is transverse to the air flow, as if the detector were installed on the ceiling in a vertical position.
After adjustment two years later, in NPB 88-2001 *, the requirements were divided: “when installing point detectors on walls, they should be placed<…>at a distance of 0.1 to 0.3 m from the ceiling, including the dimensions of the detector" and the maximum permissible distance of the detector from the ceiling when hanging detectors on a cable was separately introduced: "<…>the distance from the ceiling to the bottom point of the detector should be no more than 0.3 m.” Naturally, if the detectors are installed directly on the ceiling, then when hanging them on a cable there is no reason to move them 0.1 m from the ceiling, as when placing them on the wall.

Requirements SP 5.13130.2009
In SP 5.13130.2009, paragraph 13.3.4, which sets out the requirements for the placement of detectors, was significantly revised and significantly increased in volume compared to previous versions, but it is difficult to say that this added clarity. As in previous versions, all possible installation options are listed in a row: “if it is impossible to install detectors directly on the ceiling, they can be installed on cables, as well as on walls, columns and other load-bearing building structures.” True, a new requirement has appeared: “when installing point detectors on walls, they should be placed at a distance of at least 0.5 m from the corner,” which fits well with European standards and with the general requirement introduced later in amendment No. 1 to SP 5.13130.2009 .
The range of distances from the ceiling of 0.1-0.3 m specified in NPB88-2001 for installing detectors on the wall was excluded, and now the distance from the ceiling when installing detectors on the wall is recommended to be determined in accordance with Appendix P, which contains a table with minimum and maximum distances from the ceiling to the detector measuring element, depending on the height of the room and the angle of inclination of the ceiling. Moreover, Appendix P is entitled “Distances from the top point of the floor to the measuring element of the detector,” based on which it can be assumed that the recommendations of Appendix P relate to the placement of detectors in the case of inclined floors. For example, with a room height of up to 6 m and floor inclination angles of up to 150, the distance from the ceiling (the top point of the floor) to the detector measuring element is determined in the range from 30 mm to 200 mm, and with a room height of 10 m to 12 m, respectively, from 150 up to 350 mm. For floor inclination angles greater than 300, this distance is determined in the range from 300 mm to 500 mm for a room height of up to 6 m and in the range from 600 mm to 800 mm for a room height of 10 m to 12 m. Indeed, with inclined floors, the upper part of the room is not ventilated, and, for example, NFPA 72 in this case requires smoke detectors to be located at the top of the room, but only below 4"" (102 mm) (Fig. 3).

Rice. 3. Detector placement for sloped floors per NFPA 72

In the set of rules SP 5.13130.2009, there is apparently no information regarding the placement of detectors on the wall in a room with a horizontal ceiling in Appendix P. In addition, it can be noted that in the set of rules SP 5.13130.2009 there is a separate paragraph 13.3.5 with requirements for the placement of detectors in rooms with sloping ceilings: “In rooms with steep roofs, for example, diagonal, gable, hipped, hipped, serrated, having a slope of more than 10 degrees, some detectors are installed in the vertical plane of the roof ridge or the highest part of the building<…>" But in this paragraph there is no reference to Appendix P and, accordingly, there is no prohibition on installing detectors literally “in the highest part of the building,” where their efficiency is much lower.
It should be noted that clause 13.3.4 refers to point fire detectors in general, i.e., both smoke detectors and heat detectors, and significant distances from the ceiling are allowed only for smoke detectors. Apparently, Appendix P is applicable only for smoke point detectors, this is indirectly indicated by the maximum height of the protected room - 12 m.

Installing Smoke Detectors on a Suspended Ceiling

Clause 13.3.4 of the set of rules SP 5.13130.2009 states that “if it is impossible to install detectors directly on the ceiling, they can be installed on cables, as well as on walls, columns and other load-bearing building structures.” It is enough to classify a suspended ceiling as a load-bearing building structure, and to formally fulfill this requirement, the bases of point detectors are sometimes screwed onto the corners of the amstrong tiles. However, point detectors, as a rule, are lightweight; these are not linear smoke detectors, which actually have not only significant mass and dimensions, but also must maintain their position throughout their entire service life to avoid false alarms.
The placement of detectors on a suspended ceiling is defined in the requirements of clause 13.3.15 of the set of rules, although initially it refers to a perforated suspended ceiling, but in the absence of perforation, at least two conditions given in this paragraph are not met:
- perforation has a periodic structure and its area exceeds 40% of the surface;
- minimum size each perforation in any section is at least 10 m,”
and as stated further: “If at least one of these requirements is not met, the detectors must be installed on a false ceiling in the main room< >. It is directly on the false ceiling.
Many smoke detector manufacturers produce mounting kits for embedding detectors into suspended ceilings, which improves the appearance of the room (Fig. 4).

Rice. 4. Embedding the detector into a suspended ceiling using an installation kit

In this case, the requirement given in paragraph 4.7.1.7 of GOST R 53325-2009 is usually fulfilled with a reserve, according to which the design of the smoke detector “must ensure the location of the optical camera at a distance of at least 15 mm from the surface on which the IPDOT is mounted” (fire smoke detector optical-electronic point). It may also be noted that British Standard BS5839 requires fire detectors to be ceiling mounted with their sensing elements below the ceiling ranging from 25mm to 600mm for smoke detectors and 25mm to 150mm for heat detectors. Accordingly, when installing foreign smoke detectors into a suspended ceiling, the installation kits ensure that the smoke outlet is located 25 mm below the ceiling.

Controversy in Change #1

When adjusting clause 13.3.6 of the set of rules SP 5.13130.2009, a new and categorical requirement was introduced: “The horizontal and vertical distance from detectors to nearby objects and devices, to electric lamps in any case must be at least 0.5 m” . Notice how the phrase “in any case” aggravates this requirement. And one more general requirement: “Fire detectors must be placed in such a way that nearby objects and devices (pipes, air ducts, equipment, etc.) do not interfere with the impact of fire factors on the detectors, and sources of light radiation and electromagnetic interference do not affect the detector’s ability to remain operational.” "
On the other hand, according to the new version of clause 13.3.8, “point smoke and heat fire detectors should be installed in each ceiling compartment with a width of 0.75 m or more, limited by building structures (beams, purlins, slab ribs, etc.) , protruding from the ceiling at a distance of more than 0.4 m." However, to fulfill the absolute requirement of clause 13.3.6, the width of the compartment must be at least 1 m plus the size of the detector. With a compartment width of 0.75 m, the distance from the detector, even without taking into account its dimensions “to nearby objects,” is 0.75/2 = 0.375 m!
Another requirement of clause 13.3.8: “If building structures protrude from the ceiling at a distance of more than 0.4 m, and the width of the compartments they form is less than 0.75 m, the area controlled by fire detectors, indicated in tables 13.3 and 13.5, is reduced by 40%” also applies to floors with beams more than 0.4 m in height, but the requirement of clause 13.3.6 does not allow detectors to be installed on the floor. And Appendix P, already mentioned here, from the set of rules SP 5.13130.2009 recommends a maximum distance from the top point of the floor to the measuring element of the detector of 350 mm at floor angles of up to 150 and with a room height of 10 to 12 meters, which excludes the installation of detectors on the lower surface of the beams. Thus, the requirements introduced in clause 13.3.6 exclude the possibility of installing detectors under the conditions given in clause 13.3.8. In some cases, this regulatory problem can be resolved by using linear smoke or aspirating smoke detectors.
There is another problem when introducing the requirement “Distance from detectors to nearby objects” into clause 13.3.6<…>in any case it should be at least 0.5 m.” We are talking about protecting the ceiling space. In addition to the mass of the cable, air ducts and fittings, the suspended ceiling itself is often located at a distance of less than 0.5 m from the ceiling - and how in this case can the requirement of clause 13.3.6 be met? Should I refer the suspended ceiling to 0.5 m plus the height of the detector? It’s absurd, but clause 13.3.6 does not say about excluding this requirement for the case of overhead space.

Requirements of British Standard BS 5839

Similar requirements in the British standard BS 5839 are set out in more detail in a significantly larger number of clauses and with explanatory drawings. Obviously, in general, objects near the detector have different effects depending on their height.

Ceiling barriers and obstacles

Rice. 5. The detector must be separated from a structure whose height is up to 250 mm by at least twice its height

“Where beams, ducts, lights or other structures adjacent to the ceiling and obstructing the flow of smoke do not exceed 250 mm in height, detectors should not be installed closer to these structures than twice their height (see Figure 5).” . This requirement, which is absent in our standards, takes into account the size of the “dead zone” depending on the height of the obstacle that the air flow has to go around. For example, if the height of an obstacle is 0.1 m, it is allowed to move the detector away from it by 0.2 m, and not by 0.5 m, according to clause 13.3.6 of the set of rules SP 5.13130.2009.
The next requirement, also not in our code, concerns beams: “Ceiling obstructions, such as beams, exceeding 10% of the total height of the room must be considered as walls (Fig. 6).” Accordingly, abroad, at least one detector must be installed in each compartment formed by such a beam, and our detectors must be 1, or 2, or 3, or even 4 according to SP 5.13130.2009, but this is the topic of a separate article. However, it should be noted that the requirement of clause 13.3.8 “Spot smoke and heat fire detectors should be installed in each ceiling compartment...” leaves open the question of what is the minimum number of them in each compartment? Moreover, if we consider the 13th section of the set of rules SP 5.13130.2009, then according to clause 13.3.2 “in each protected room at least two fire detectors should be installed, connected according to the logical “or” circuit, and according to the 14th section for installation To have two detectors in a room, a number of conditions must be met, otherwise the number of detectors must be increased to 3 or 4.

Rice. 6. Beams exceeding 10% of the total height of the room should be considered as walls

Free space around the detector

And finally we got to the analogue of our requirement, clause 13.3.6 of the set of rules SP 5.13130.2009, however, what is common with the requirement of the BS 5839 standard is practically only the value of 0.5 m: “Detectors must be placed in such a way that free space within 500 mm below each detector (Fig. 7).” That is, this requirement specifies the space in the form of a hemisphere with a radius of 0.5 m, and not a cylinder, as in SP 5.13130.2009, and applies mainly to objects in the room, and not on the ceiling.

Rice. 7. Free space around the detector 500 mm

Ceiling protection

Rice. 8. Placement of detectors in the ceiling or underground space

Quote grek 01/25/2011 14:03:42

Are my questions being deliberately ignored?

--End quote------- Let your questions not be ignored, dear.
There is simply no clear answer to your questions.
We all read the same text in Table A.2 of Appendix A to SP5, but we each understand it differently.
The standard setter deliberately confused us so much with his delights of the Russian language that the MPH will figure it out.
For example:
-- in footnote No. 1 the concept of a cable structure is given, which also lists double floors. But right there, in footnote No. 2, they list cable structures and separate double floors. For what? Error? Or deliberately? Unclear. But this is just a saying.
-- clause 11 of Table A.2 tells us clearly and specifically about the NG and PRGP1 cables. But then in subclause 11.1 there are already any cables (regardless of NG and PRGP1), and in subclause 11.2 cables are indicated only with the letters NG, but without PRGP1. It's the same story with the exceptions specified in paragraph 1 of footnote No.-2. When choosing a protection method, do you need to take into account the design of the cables (simply NG or NG+PRGP or any)? Or should we assume that the footnote refers to the entire paragraph 11? But this is only the second saying.
-- if, to simplify understanding, we talk only about cables, then paragraph 2 in footnote No. 2 will look like this: “In the event that the building (room) as a whole is subject to protection by automatic fire protection devices, the spaces behind suspended ceilings and under double floors when laid in them ...cables with a volume of combustible cable mass of more than 7 liters per 1 meter of cable must be protected with appropriate installations." What are the relevant...? Indeed, for these conditions (7 liters or more), subclause 11.1 has already been written, which clearly requires AUPT. Why write the same thing a second time?
-- we remove this ridiculous repetition and then paragraph 2 in footnote No. 2 will look like this: “In the event that the building (room) as a whole is subject to protection by AUPT, but the height is from the ceiling to the suspended ceiling or from the level of the subfloor to the level of the double floor does not exceed 0.4 m, an AUPT device is not required even when laying cables in them with a volume of combustible mass of cables of more than 7 liters per 1 meter cable line. Now it becomes clearer. But not quite. This AUPT can not be inserted into this narrow space, but Is it just that AUPS is needed or not for these =less than 0.4 m=, but =more than 7 l=? It’s not clear.
-- It is not clear because clause 11.2 considers only the specific case for NG type cables with a total volume of combustible mass from 1.5 to 7 liters per meter of cable line. Here, if you please, AUPS, regardless of area and volume, as for paragraph 11.1. But for clause 11.1 an exception was made in the case of a height of up to 0.4 m.

Among other things, in all of this paragraph 11, when listing elements and conditions, several different meanings of phrases =and=, =and also= and =or= are used. If norm-setters use these various expressions consciously, then it turns out that, for example:
-- in subclause 11.1, as well as in clause 2 of footnote No. 2, the condition for protecting space is one of two things - OR laying pipelines... OR laying cables...
But in paragraph 11 itself the phrase =and also= is used. It turns out that spaces need to be protected only if both pipelines and cables are laid.

The absurdities and ambiguities can be continued, but they will no longer relate to your question.
So to answer your specific question, you need to know:
-- the suspended ceiling itself is made of materials of what flammability group?
-- type of cables used - no version, just NG or NG+PRGP. And if PRGP, then which one?
-- method of laying cables (pipes, ducts (which ones?) or openly?
-- purpose of cables? Maybe you can use point c) of paragraph 1 of footnote No. 2?
- and, of course, =liters per meters= are definitely needed.

That’s why no one wanted to contact you and answer your question unambiguously.
In short - SO THAT THEY ALL BE HEALTHY!!!

Several years ago, many publications appeared in the industry media and on fire safety portals devoted to the problem of implementing technical solutions for fire protection of the ceiling space. The so-called two-way fire smoke detectors have been subject to serious criticism, and traditional way protection of the ceiling space using detectors installed on the main ceiling had known difficulties in servicing such detectors.

An innovative solution to this problem was patented in 2005 by the private enterprise “Arton”, first as Ukrainian invention No. 73398 “Smoke fire detector”. Then similar technical solutions were patented both in Russia and in the Eurasian Patent Office (patents No. 2265888 and 007944). And the main thing was that consumers were offered several options for a two-point smoke detector, each of which had two processing units separated in space.

The claims also presented several design options for a two-point detector. Distinctive features among other technical solutions are that, in addition to the main processing unit, the two-point detector contains another additional smoke processing unit. Both processing units are located on the same vertical axis, their bases are turned towards each other and they are rigidly connected to each other.

The design of two-point detectors IP-2.1, IP-2.2 turned out to be the most suitable for implementation in mass production conditions (Fig. 1). These detectors differ from each other only in the connection diagram to the fire alarm loop: IP-2.1 is connected using a two-wire circuit, and IP-2.2 is connected using a four-wire circuit.

Fig.1

To implement this task, it was necessary to develop special base bases that would ensure not only the connection of the detectors to the alarm loop, but also the passage of the upper processing unit of the two-point detector through them.

The IP-2.1 is connected to the fire alarm loop using the base B103-02 (Fig. 2), which uses contacts corresponding to Ukrainian patents for inventions No. 85211 and 87554. IP-2.2 is connected according to four-wire circuits using the B103-03 base (Fig. 3) with one breaking contact.


Rice. 2	Rice. 3

These base bases have a significant through hole to allow the upper processing unit of the two-point detector to be inserted through it. And for this it is necessary that the inequality be satisfied:

Ø A ≥ Ø B, Ø A ≥ Ø C,

where Ø A is the minimum transverse size of the through hole of the base base;

Ø B - maximum transverse size of the additional processing unit;

Ø C - maximum transverse dimension of the rod.

The block diagram of a two-point detector is shown in Fig. 4, where

1 - main processing unit;

2 - base;

3 - electronic unit;

4 - detector contacts;

5 - indicator;

6 - optical-electronic sensor;

7 - smoke chamber;

8 – base base;

9 - fire alarm loop;

10 - external indicator;

11 - base contacts;

12 - additional processing unit;

13 - the basis of the additional processing unit;

14 electronic unit of the additional processing unit;

15 - optical-electronic camera of an additional processing unit;

16 - smoke chamber of the additional processing unit;

17 - conductors connecting electronic units;

18 bar.

Rice. 4

The lower point-to-point detector processing unit interfaces with the base base using traditional fire detector contacts. The base base can be installed in a decorative ring (see Fig. 1), which hides the unevenness of the hole in the suspended ceiling. The fire alarm loop wires are laid and secured into the base base so that the through hole in it remains free and the conductors do not interfere with the insertion and location of the two-point detector in it.

The circuit solutions used in these detectors are also protected by patents for inventions of Ukraine No. 81529, 85270 and 85273. The first of them is devoted to temperature stabilization of infrared radiation power. The second is to stabilize the current consumption in various operating modes of the detector, while generating various optical signals with yellow and red indicators. And the third patent is responsible for matching the analog inputs of the microcontroller with the outputs of infrared photodetectors. The detectors provide periodic self-diagnosis, monitor the condition of the smoke sensor chambers, which provide compensation for drift (dust content of the smoke sensor chambers) and, if necessary, generate optical “Fault” signals with a yellow indicator. This indication indicates that the detector requires maintenance.

In total, the two-point detector can be in seven operating modes, and the yellow and red indicators display these operating modes of both sensors:

Duty;
Upper sensor fire;
Lower sensor fire;
Fire of upper and lower sensors;
Top sensor malfunction;
Lower sensor malfunction;
Malfunction of the upper and lower sensors.

IP-2.1 and IP-2.2 detectors are manufactured in three versions according to the distance between the sensors of the main and additional processing units: 200, 400 and 600 mm. It is this size that limits the height of the suspended ceiling in those rooms where such detectors can be used. The procedure for removing the product for maintenance is no different from removing a conventional point detector.

Connection of IP-2.1 detectors to the control panel with a constant current loop is carried out according to the diagram shown in Fig. 5. Thanks to the use of current stabilization at outputs 1 and 2 of the detector, the number of elements that are installed on base bases is minimized.

Rice. 5

IP2-1 detectors are connected to the control panel with an alternating loop according to the diagram shown in Fig. 6. By connecting contacts 1 and 2, the current from the positive phase of the loop state is doubled.

Rice. 6

If IP2-2 detectors are used, it is necessary to install a resistor Rв in each base, which is connected in parallel with the detector relay contacts. In addition, it is imperative to install a UK-4 terminal device at the end of each loop. Only when the detector is disconnected from the base base will a fault signal be generated on the control panel.

Rice. 7

The use of two-point detectors in Ukraine is also reflected in government building codes. Thus, Appendix B of DBN V.2.5-56: 2010 provides the definition:

"A two-point fire detector is a fire detector that contains in its design two sensitive elements located on the same vertical axis and structurally fastened together so that when installed in the base, one of them will be located above the base, and the second, on which the indicators are located the state of both sensitive elements is under the base."

And in paragraph 6.2.13 of this document there is a note: “To protect premises with suspended ceilings up to 0.9 m high inclusive, two-point fire detectors can be used.”

Literature:

Popov M. “What do you have in the ceiling space?” 03.12.2002
"Explain to a newbie" discussion on the Security-bridge forum
Bakanov V. "Innovative solution for fire protection of premises with suspended ceilings", g. Pozhezhna Bezpeka, 2008 No. 6, - p. 28.
Ukrainian patent for invention No. 73398 “Smoke fire detector”, Bulletin. No. 7, 2005
Ukrainian patent for invention No. 85211 “Fire detector base contact”, bul. No. 1, 2009
Ukrainian patent for invention No. 87554 “Fire detector base contact”, bul. No. 14, 2009
Maslov I. "Contact? There is contact! For how long..." w. BDI, 2005, No. 1, - p. 17
Ukrainian patent for invention No. 81529 “Smoke fire detector”, bul. No. 1, 2008
Ukrainian patent for invention No. 85270 “Smoke fire detector”, bul. No. 1, 2009
Ukrainian patent for invention No. 85273 “Smoke fire detector”, bul. No. 1, 2009
DBN V.2.5-56:2010 Engineering equipment buildings and structures. Fire protection systems.

Part 2

Returning again to the topic of protecting the ceiling space, it is advisable to recall that innovative solutions - two-point detectors IP-2.1 and IP-2.2 have already passed certification tests more than once both in Ukraine for compliance with the DSTU EN 54-7 standard, and in Russia for technical regulations and the relevant sections of GOST R 53325.

The fate of these products in Russia was very difficult, since pseudo-innovative solutions already existed there - bidirectional detectors. Moreover, they existed contrary to the laws of physics and thanks to the “letters of happiness” issued by officials from the Ministry of Emergency Situations. Thus, the manufacturer IP212-3SU advertised the mentioned product as the only detector in Russia that can be used for simultaneous monitoring of both the main room and the inter-ceiling space up to 1 m high thanks to special slots in the detector body (Fig. 8), where:

IP212-3SU detector;
lower slits;
upper slits;
suspended ceiling;
mounting device.

Rice. 8

This possibility was confirmed by letter from VNIIPO, St. Petersburg branch No. 06-03/97 dated 02/03/99 “On the possibility of protecting the space behind a suspended ceiling with IP 212-3SU detectors.” However, one of the authors of the mentioned VNIIPO letter, namely Sergey Vasilievich Sychev, in his letter to the Internet newspaper OXPAHA.ru stated that VNIIPO specialists conducted comparative tests of detectors on a suspended ceiling at different heights - from 0.5 to 1 m. Results These tests were negative (the detectors did not work). And the only fact confirmed by experiments, which is mentioned in the VNIIPO letter, is that these detectors detect smoke better than thermal ones. By the way, the negative test results were confirmed not only by observations, but also by measurements and video recording of the spread of smoke behind the suspended ceiling!

Probably because such a pseudo-innovative solution was not patented, the number of fire detector manufacturers quickly increased, who at the beginning of the century sought to quickly introduce such a “new product” into circulation. The real struggle of business owners with the elementary laws of physics for possible profit has begun. And it no longer matters that smoke as a combustion product has high temperature than the surrounding air, and in rooms it spreads along the ceiling.

It turns out that you can get a completely legal solution that for a particular detector, in a particular case, the laws of physics do not apply: for this detector, smoke spreads across the floor. This is how new “letters of happiness” appeared for new manufacturers...

Several good reasons why a bidirectional detector with vertical purge cannot be used to control not only the inter-ceiling space, but also the main room, were discussed in the article by Maxim Popov. However, this publication did not propose a single new solution to this problem of protecting the ceiling space.

An attempt to solve this problem was proposed by specialists from ARGUS-SPECTR JSC, who patented invention No. 2178919 “Device for detecting fire in rooms with an interceiling space.” They proposed using one detector 1 to monitor two spaces separated by a suspended ceiling (Fig. 9). This detector 1, installed on the main ceiling 5, was connected to a smoke channel - pipe 2 of the appropriate length and a given internal diameter. Pipe 2 was installed vertically between detector 1 and hole 3 in the suspended ceiling. From the side of the suspended ceiling, a special deflector 4 was installed in the smoke channel, which ensured the unhindered passage of smoke from the main room through the smoke channel 2 to the detector 1. A gap of the appropriate size between the upper end of the pipe 2 and the detector 1 provided access to it for smoke that could arise in ceiling space. The state of the detector was monitored using an external optical signaling device (VUOS) 6 located on outside false ceiling.

However, over ten years, JSC ARGUS-SPECTR, which is developing many new products, has not been able to bring this technical solution to the serial production of technical means suitable for protecting separated spaces. Perhaps, the mentioned technical solution is unsuitable for practical implementation, since the problem of maintaining a detector installed in the ceiling space is not solved by this patent.

Rice. 9

The real beginning of the use of two-point detectors in Russia was facilitated by the publication of Igor Gennadievich Neplohov. And to meet the requirements regulatory documents The Russian Federation also developed a special version of a two-point detector - IP-2.4, which was connected to two fire alarm loops, galvanically separated from each other. These detectors use additional innovative solutions. First, there is a basic base with two break contacts. If the detector was disconnected from the base base, a malfunction occurred in two fire alarm loops. Secondly, the detector had two independent red indicators for the fire alarm state for each processing block and a yellow indicator for indicating other detector states. Thirdly, to return the detector to its original state, it was necessary to reset the supply voltage on both loops simultaneously or separately on each loop that was in a fire alarm state. Of course, such a detector was more expensive than the IP-2.1 detector, which was connected to one fire alarm loop. There is simply no other way out. If the detector must fulfill more additional conditions, then it becomes more complex and its price naturally increases. However, this path does not suit all manufacturers.

Once again there are those who want to ignore the objective laws of physics and economics. So, on the website of one well-known manufacturer in Ukraine and Russia, a new pseudo-innovative solution of a “ceiling detector” appears (see Fig. 10). Studying the installation instructions for the “Ceiling detector mounting kit” allows us to conclude that the consumer is provided with a combination of certified products, which itself could never be certified.

Rice. 10

The installation kit for the ceiling detector includes two certified fire smoke detectors. But in this set the location of the smoke detectors in the space is not the same! I just want to ask the manufacturer of this “new product”: do the laws of physics again apply in the ceiling space?

The fact that the manufacturer of this kit did not carry out certification tests of such a product as a type 1 component according to GOST pr EN 54-13: 2004 is obvious. There is no certificate presented on the manufacturer’s website, but there should be one for a product of this type!

This manufacturer did not conduct qualification tests of the kit, because during testing according to clause 5.3 “Dependence on direction” of DSTU EN 54-7:2003 or according to clause 4.7.2.7 of GOST R 53325-2009 for a smoke detector it would not be possible to obtain positive results. A detector located in the smoke duct, like the top one of the set, would show a figure-of-eight radiation pattern in which the ratio of the response threshold values would be guaranteed to be greater than 1.6. If the detector is returned to the air flow by its base, then its sensitivity will be 3 - 4 times less than in the direction of maximum sensitivity. It is also known that this asymmetry will manifest itself even more when the air flow speed decreases. Thus, even when tested for test fires, according to clause 5.18, this kit will not meet the suitability criteria.

Knowing how difficult it is to test detectors using test fires, one can only guess what the test results of such a kit could be. These inconsistencies with DSTU EN 54-7:2003 and GOST R 53325-2009 could be avoided by changing the position of the top detector so that both detectors face each other with their base bases. But such a solution falls within the scope of the claims UA73398. But the manufacturer of the kit does not plan to purchase a license from the patent holder, so he offers consumers - installers and designers - an uncertified technical solution based on certified detectors. But responsibility for the use of such a pseudo-innovative solution rests with those who will use it in their projects.

From the above examples it is clear that not all inventions are implemented, but truly innovative solutions are supported by one or more patents for inventions, but pseudo-innovative solutions do not have such support.

Literature

DSTU EN 54-7:2004 Fire alarm systems. Part 7.
GOST R 53325-2009 Fire fighting equipment. Fire automatic equipment. General technical requirements. Test methods
Letter regarding the article by M. Popov. 02/05/2003.
Russian patent for invention No. 2178919 “Device for detecting fire in rooms with interceiling space”, bul. No. 4, February 2002
Two-point fire smoke detector for separated spaces IP-2.4. MCI passport 425239.004 PS
Installation instructions AKPI.425921.004IM3. Set of mounting parts for a ceiling detector.
Bakanov V. "A look at Fire smoke detectors through the prism of test fires" g. F+S: Safety and fire protection technologies. – 2010, - No. 1, p. 26.