A light and sound annunciator can become a convenient means of transmitting light and in case of emergency situations in buildings of various types and purposes. Light and sound annunciators provide timely signals about the start of evacuation, remaining active throughout the day, operating from a standard power supply.
Areas of application
Various models and modifications of light and sound alarms are actively used to ensure safety at industrial facilities, retail establishments, entertainment and public areas.
Each device must correspond to the characteristics and purpose of the room in which it is installed. Typically, a suitable light and sound siren is selected based on the noise level in the room. The type of activity of the people who are in it is also taken into account.
Features of operation
Before installing a light and sound alarm, it is necessary to determine the mode in which it should operate. This may be a general, simplified or special mode of operation. Last option Most often used at security posts and in medical institutions, in control rooms, when the fire alarm system is under the control of specially trained personnel.
In standard mode, sirens operate in public, residential and rented premises. To ensure comprehensive security, several devices are mounted on opposite walls, connected to the alarm system and operate from a regular power supply.
Installation
The light and sound siren (220V) can be connected to the security system either by soldering or by the standard, default screw method. The connection of input and output wires through the siren terminals is carried out by duplicating them.
Operation of the siren in standby mode involves installation, in which communication control is performed by connecting wires to the end element. Typically, such an element is a resistor with a diode. When installing sirens, external connection of diodes is prohibited.
Sounder types
If we talk about operational capabilities and design differences, here we highlight:
- external type of sirens that provide security in open areas;
- indoor sirens, widely used for indoor use.
Regardless of the type, a device such as a light-sound siren can be installed at facilities with fire and security alarms, not only to provide light and sound signals during the evacuation of people, but also if it is necessary to provide certain signals to personnel.
Standard and combined models
Despite the relatively limited functionality, which is dictated by the purpose of standard sirens, there are currently a sufficient number of various modifications of devices for this purpose. Modified sirens are intended for use in the most innovative integrated security systems and modern fire alarms.
Among the main advantages that distinguish the light-sound combined siren, it is worth highlighting modern design, availability of conditions for installation both outdoors and indoors, as well as the ability to issue sound and light signals simultaneously. This, in turn, becomes extremely important for ensuring safety at facilities with high level noise and smoke in the premises.
Light and sound annunciator: price
Cost of light and sound sirens domestic production belongs to the average price range. The price is the most simple models varies from 70 to 150 rubles. The cost of combined and modified devices can reach 350 rubles, which fully corresponds to their functionality.
Naturally, the same light and sound siren may have different prices depending on the pricing policy of a particular retail chain. However, for most consumers, the price of domestic and imported devices still remains more than acceptable. Therefore, such security systems are available to a wide range of interested buyers.
Light and sound annunciator "Mayak"
If we talk about the most popular models available to domestic consumers, then light and sound devices of the Mayak brand come out on top. Today, such relatively inexpensive, truly reliable, functional and durable systems are widely used in domestic industrial, retail, entertainment, exhibition and public facilities. If necessary, fire alarm systems in residential premises can be equipped with Mayak brand sirens.
"Mayak" alarms do an excellent job with their main task - notifying people about the occurrence of emergency situation using signals that can simultaneously affect a person’s vision and hearing. Mayak brand devices cope with this task perfectly well, which is confirmed by practice and numerous reviews from specialists.
In the event of an emergency, devices in this category light up with a bright pulsating light, which illuminates a special alarm or direction indicator. The light signal is accompanied by a loud siren, clearly audible in noisy conditions. Currently, such alarms are in demand not only when it comes to ensuring security in enterprises, but also among individuals.
However, giving preference to light and sound sirens of the Mayak brand, you need to understand that for them efficient work selection required the right type device corresponding to the features of the existing alarm system. It is also necessary to calculate in advance their sufficient quantity, based on the conditions and characteristics of the room. Therefore, you should approach the choice of alarms wisely, preferably relying on the advice and opinions of experienced specialists.
The purpose of this article is to introduce designers, installers and integrators of warning systems, sound systems, and public address systems with the basic principles and features of electroacoustic design. The main attention in this article is paid to the features of the placement of voice alarms (loudspeakers) in closed protected spaces.
One of the main tasks solved in the process of electroacoustic calculation, performed at the initial stage of designing fire warning systems - SOUE, is the task of selecting and placing voice annunciators (hereinafter referred to as loudspeakers). Loudspeakers can be installed both in open areas and in closed (protected) rooms. The purpose of this article is to propose and justify options for the optimal placement of voice alarms (hereinafter referred to as loudspeakers) in closed (protected) rooms.
In enclosed spaces, it is recommended to install indoor loudspeakers, as they are the most optimal in terms of parameters and quality. Depending on the configuration of the room, these can be ceiling or wall types. Proper placement of loudspeakers allows for uniform distribution of sound in the room, hence achieving good intelligibility. If we talk about sound quality, it will be determined mainly by the quality of the selected speakers. So, for example, when using ceiling loudspeakers, it is necessary to take into account that the sound wave from the loudspeaker propagates perpendicular to the floor, therefore, the sounded area at the height of the listeners’ ears is a circle, the radius of which is taken to be equal to the difference between the installation height (mount) of the loudspeaker and the distance to the mark of 1.5 m from the floor (according to regulatory documentation). In most problems for calculating ceiling acoustics, sound waves are identified with geometric rays, while the directivity pattern (DP) of the loudspeaker determines the parameters (angles) of a right triangle; therefore, to calculate the radius of a circle (the leg of the triangle), the Pythagorean theorem is sufficient. To provide even sound throughout a room, speakers should be installed so that the resulting areas touch or slightly overlap each other. In the simplest case required quantity loudspeakers is obtained from the ratio of the size of the sounded area to the area sounded by one loudspeaker.
One of the main parameters that must be determined in the calculations is the pitch of the speaker chain. It will be determined by the size of the room, the installation height of the loudspeakers and their directional pattern (PDP).
When placing wall-mounted speakers in corridors along one wall, the recommended spacing is:
- excluding reflections from walls:
(Arrangement step, m) = (Corridor width, m) x 2
- taking into account reflections from the walls:
(Arrangement step, m) = (Corridor width, m) x 4
When placing wall speakers in rectangular rooms along two walls in checkerboard pattern placement step:
(Pitch, m) = (Width of the room, m) x 2
When placing back-to-back wall-mounted speakers in rectangular rooms along two walls, the placement step is:
(Arrangement step, m) = (Half the width of the room, m) x 2
Basic Requirements
Here is the main requirement of regulatory documentation (ND):
The number of sound and speech (loudspeakers) fire alarms, their placement and power must ensure the sound level in all places of permanent or temporary residence of people in accordance with the norms of this set of rules.
The installation of loudspeakers and other voice alarms (loudspeakers) in protected premises must exclude concentration and uneven distribution of reflected sound.
Voice annunciators (loudspeakers) must be located in such a way that at any point of the protected object where it is required to notify people about a fire, the intelligibility of the transmitted speech information is ensured.
The design of warning systems is accompanied by an electroacoustic calculation (EAC). The consequence of a competent EAR is optimization - minimization technical means, improving the quality of perception. The quality of perception, in turn, is characterized by sound comfort for background music and intelligibility for speech messages. The criterion for the correctness of the EAR is the requirements of regulatory documentation (ND), which can be divided into:
- requirements for a voice annunciator (loudspeaker);
- requirements for audio signal levels;
- requirements for the placement of voice alarms (loudspeakers).
It should be noted that the RD sets out only the necessary (minimum) requirements, while sufficient (maximum) requirements are ensured by the presence of competent techniques, and in their absence, by the literacy and responsibility of the designer.
Loudspeaker requirements
The following requirements are stated. Sounders must provide a sound pressure level such that:
The sound signals of the SOUE provided an overall sound level (the sound level of constant noise together with all signals produced by the sirens) of at least 75 dBA at a distance of 3 m from the siren, but not more than 120 dBA at any point in the protected premises.
This paragraph contains two requirements - the requirement for minimum and maximum sound pressure.
Minimum sound pressure
The loudspeaker must provide a (minimum) sound signal level at a distance of 1 m from the geometric center:
Maximum sound pressure
Let's define the design point:
Calculation point (PT) is the most critical place of possible (probable) location of people in terms of position and distance from the sound source (loudspeaker). RT is selected on the design plane - an (imaginary) plane drawn parallel to the floor at a height of 1.5 m.
Requirements for audio signal levels
The main requirement for the (necessary) sound signal level is set out in the ND:
Sound signals of the SOUE must provide a sound level of at least 15 dBA above the permissible sound level of constant noise in the protected room. Sound level measurements should be carried out at a distance of 1.5 m from the floor level.
Arrangement requirements
The main requirement for the placement of loudspeakers is set out in the ND:
The installation of loudspeakers and other voice alarms (loudspeakers) in protected premises must exclude concentration and uneven distribution of reflected sound.
Voice annunciators (loudspeakers) must be located in such a way that at any point of the protected object where it is required to notify people about a fire, the intelligibility of the transmitted speech information is ensured.
Taking into account the main characteristics of loudspeakers
According to , the placement of loudspeakers is part of the organizational measures carried out during the design of the SOUE and called electroacoustic calculation. The most relevant is not just the arrangement, but the optimal arrangement of loudspeakers, which allows minimizing the amount of estimated resources (time) and material resources.
The methods of placing loudspeakers are closely related to their design features. The most generalized classification is:
- by execution;
- by design features;
- by characteristics;
- according to the method of matching with the amplifier.
Taking into account the type and design features of loudspeakers
Based on their design, loudspeakers can be divided into internal and external. A characteristic feature internal design is IP protection class. For indoor loudspeakers, IP-41 is sufficient, for external speakers – at least IP-54. For indoor use, primarily for cost-saving purposes, indoor loudspeakers are used.
Depending on the tasks being solved, loudspeakers of different types can be used design. For example, depending on the configuration of the room, ceiling-mounted or wall-mounted speakers can be used. For sounding open areas, horn loudspeakers are used, due to their characteristics, protection class, high degree of sound directionality, and high efficiency.
Specifics of taking into account the main parameters of loudspeakers
To carry out proper placement of loudspeakers, we need the following characteristics (basic parameters) of the loudspeaker:
Calculation of loudspeaker sound pressure
The loudness of a loudspeaker cannot be measured directly, so in practice it is expressed in terms of sound pressure levels, measured in decibels, dB.
The sound pressure of a loudspeaker is determined by both its sensitivity and the electrical power supplied to its input:
Speaker sensitivity P 0 , dB (speaker sensitivity is sometimes called SPL from the English SPL - Sound Pressure Level) - sound pressure level measured on the working axis of the loudspeaker, at a distance of 1 m from the working center at a frequency of 1 kHz with a power of 1 W.
Speaker power
There are several main types of power:
Loudspeaker power rating– electrical power at which the nonlinear distortion of the loudspeaker does not exceed the required values.
Loudspeaker rated power– is defined as the highest electrical power at which a loudspeaker can operate satisfactorily for a long time on a real sound signal without thermal and mechanical damage.
Sinusoidal power– maximum sinusoidal power at which the loudspeaker must operate for 1 hour with a real music signal without receiving physical damage (cf. maximum sinusoidal power).
In general, the power setting should be the value specified by the speaker manufacturer.
Basic calculations
Sound pressure reduction depending on distance
To calculate the sound pressure level at the design point, it remains to determine one more important parameter - the amount of sound pressure reduction depending on the distance - divergence, P 20, dB. Depending on where the loudspeaker is installed - in interior spaces or in open areas, different formulas (approaches) are used.
Calculation of sound pressure level in RT
Knowing the parameters of the loudspeaker - its sensitivity - P 0, dB, the input sound power P W, W, and the distance to the RT, r, m, we calculate the sound pressure level L 1, dB, developed by it in the RT:
Sound pressure in the RT with simultaneous operation of n loudspeakers:
Calculation of effective range
The effective sound range of a loudspeaker is the distance from the loudspeaker to the point at which the sound pressure does not exceed (US+15) dB:
The effective sound range (loudspeaker) D, m, can be calculated:
Working with Templates
Let's divide all loudspeakers into three main classes, differing in the direction of emission of sound energy.
Ceiling– loudspeakers, the sound energy of which is directed perpendicular to the design plane (floor) [Sound energy is directed along the working axis of the loudspeaker].
Wall mounted– loudspeakers whose sound energy is parallel to the design plane (floor).
Horn– loudspeakers, the sound energy of which is directed at a certain angle to the design plane (floor).
Under templates We will understand the geometric region, which is the projection of the sound field of the loudspeaker onto the calculation plane:
- for ceiling loudspeakers – circle;
- for wall - sector;
- for horn – ellipse.
The loudspeaker is a wideband device. For the lower frequency of the standard range f=200Hz, the loudspeaker can be considered as a sound emitter of a spherical wave. As the frequency increases, the speaker pattern begins to narrow and concentrate inside a spherical cone with an opening angle [the angle between the generatrices of the spherical cone (in English coverage angle)], determined by the value of the spherical cone. This idea does not fully correspond to established practice, according to which the sound field at the output of a loudspeaker is usually approximated by a semi-ellipse. It is shown that for the (statistical average) SDN = 90 0 the quantitative estimates for the cone and ellipse coincide.
Estimation of the effective area voiced by loudspeakers of various types can be associated with the problem of finding the area formed by the intersection of a given spherical cone with the working plane. Let us use the well-known geometric representation, according to which the result of the intersection of a plane and a cone at different angles is various elliptical surfaces - hyperbola, parabola, ellipse and circle, Fig. 1.
Hyperbola is obtained as a result of the intersection of a cone and a plane intersecting one of its generatrices.
Parabola is obtained as a result of the intersection of a cone and a plane parallel to one of its generatrices.
Ellipse is obtained as a result of the intersection of a cone and a plane intersecting both of its generatrices.
Circle is obtained as a result of the intersection of a cone and a plane parallel to its base.
Definition 1
The effective area sounded by a loudspeaker is the area on the working plane within which the sound pressure remains within the limits determined by the loudspeaker's radiation pattern.
Let's calculate the effective areas voiced by different types of loudspeakers.
Speaker placement
The problem of optimal speaker placement can be related to the results obtained in the previous chapter. Let's give a definition:
Definition 2
The placement of loudspeakers must be carried out in such a way that any potential design point necessarily falls within the limits covered by the radiation pattern of the nearest loudspeaker.
In the previous section, we received three basic geometric shapes [Which we will later use as tracing paper (figures) to fill (uniformly cover) the surface] - a circle, a sector and an ellipse. The placement problem can be reduced to uniform coverage [Cf. the problem of “tiling” the surface in mathematics] of the entire working plane.
Accounting for reflections
In practice, the placement of loudspeakers is carried out taking into account reflections from surfaces [Taking into account reflections is very relevant. It should be noted that the so-called direct sound (sound energy received by the listener in the first 50ms) consists of 80% reflected energy (the so-called primary reflections), and the clarity of perception (which, by the way, like intelligibility is not taken into account in the standards) directly depends on the proportion of direct diffusion energy of a closed room. Within the framework of an elementary EAR (see the previous chapter), it is proposed to take into account no more than one reflection (cf.)].
We will take reflections into account based on the geometric ray theory, in which sound energy is identified with a geometric ray reflected from the surface at the same angle and in the same plane, Fig. 2.
When colliding with a surface, some of the sound energy is lost. The fraction of absorbed sound energy Pabs., dB, can be determined by knowing the absorption coefficient Kabs. of the surface:
When taking reflections into account, it is necessary to check the following boundary condition, Fig. 2:
If condition (8) is met, the placement of loudspeakers can be carried out taking into account reflections.
Most surfaces such as parquet, laminate, wood, concrete practically do not absorb [So, for example, for wood paneling at a frequency of 4 kHz, K abs = 0.11, P abs = 0.5 dB]. In further examples of speaker placement, as a simplification, we will assume that sound energy is completely reflected from the surface.
Critical Speaker Spacing
From Fig. 3 it can be seen that the sound in the RT comes from 2 loudspeakers. Knowing the speed of sound in air v=340m/s and the delay time t=0.05s, it is easy to obtain the critical distance Rcr, m, at which the echo becomes possible: Rcr = vt = 340*0.05=17m, where v – speed of sound propagation in air (340m/s).
From Fig. 3, the stroke difference should be:
Depending on the directionality of the loudspeakers and their SDP, the spacing can be determined geometrically:
Classification of premises
We will consider two main types of premises:
- corridors;
- rectangular rooms.
By corridors we mean narrow, extended rooms with ratios of length a (m) and width b (m): a/b≥4.
Rooms with a/b ratios
Let's divide the premises into the following groups:
- corridors with low ceilings (height h ≤ 4m);
- corridors with high (h > 4m) ceilings;
- narrow corridors (b ≤ 3m);
- the corridors are wide (b > 3m and h ≤ 6m);
- medium rectangular rooms (b > 6m and b ≤ 12m);
- volumetric rectangular rooms (b > 12m).
Comment:
To determine the numerical value of the proposed coefficients (b, h), the average value of the effective sound range D (m) was used, which for P db = 95 dB, NS = 60 dB, will be ~ 10 m and SDN = 90 0.
The way speakers are positioned, with or without reflections, is determined by two factors:
- ceiling height (with high ceilings, the reflection effect can be ignored);
- type of reflective surface.
Corridors with low or high ceilings
We will consider the concepts of “low/high” ceilings in relation to the methods of placing ceiling speakers.
When placing speakers in low ceilings, it is advisable to take into account reflections from the floor. In this case, to determine the numerical value of the speaker spacing, the following criterion is used:
The sound energy emitted by the ceiling loudspeaker must 'reach' the floor and, reflected from it, to the 'design plane'.
When placing loudspeakers on high ceilings, reflections from the floor can be ignored or criterion (8) must be checked.
Narrow or wide corridors
We will consider the concept of “narrow/wide” corridors in relation to the methods of placing both ceiling and wall loudspeakers. In both cases we will have to take into account reflections from the floor or walls.
For wall speakers
To determine the numerical value of the spacing of wall-mounted speakers in the case of taking reflections into account, we will use the following criterion:
The sound energy emitted by a wall-mounted loudspeaker must reach the opposite wall and, reflected from it, to the wall on which the loudspeaker is installed.
When placing loudspeakers in wide corridors, reflections from walls can be ignored or criterion (8) must be checked.
For ceiling speakers
To clarify the meaning of narrow/wide corridors in the case of using ceiling loudspeakers, let's consider the concept of a loudspeaker chain.
Figure 4 shows a wide corridor in which two strings of ceiling speakers are installed.
The number of chains, K c, pcs., will be determined from the ratio:
Let's look at examples of speaker placement for different types premises (cases) and conditions for determining the spacing W, m.
Ceiling speaker placement
Placing ceiling speakers in high-ceilinged hallways without considering floor reflections
The placement of ceiling speakers in corridors with high ceilings without taking into account reflections [As noted above, due to the height of the ceilings or the presence of reflective surfaces] from the floor should be done in increments, Fig. 5:
When ShDN=90 0, R=h–1.5:
Test condition 1
The loudspeaker, taking into account the ShDN, must reach the working plane.
When ShDN=90 0:
Placing ceiling speakers in hallways with low ceilings, taking into account floor reflections
The placement of ceiling speakers in corridors with low (less than 4 m) ceilings can be done taking into account reflections (from the floor) in increments, Fig. 6:
Arrangement of wall-mounted speakers placed along one wall, excluding reflections
The placement of wall-mounted speakers in (wide, over ~3 m) corridors, placed along one wall, without taking into account reflections, should be done with a step of W = 2R:
where ShK is the width of the corridor, Fig. 7.
With ShDN=90°, R=ShK we have Ш=2ШК.
Test condition 3
Effective range, for arbitrary long-distance traffic:
For ShDN = 90°:
Let us write down the criterion for determining the effective range, taking into account the installation height of the loudspeaker, H, m. For an arbitrary long-distance beam:
Arrangement of wall-mounted speakers placed along one wall, taking into account reflections
The placement of wall-mounted loudspeakers in (narrow, up to ~3 m) corridors, placed along one wall, taking into account reflections, can be done with a step W = 4R, where R is calculated by formula (16), Fig. 8.
With ShDN=90°, R=ShK we have Sh=4ShK.
Test condition 4
The loudspeaker, taking into account the ShDN, must reach the opposite wall twice, taking into account the ShDN.
Effective range, for arbitrary long-distance traffic:
For ShDN = 90°, excluding absorption:
Taking into account the installation height, see formula (18).
Arrangement of wall-mounted speakers in rectangular rooms, staggered along two opposite walls
It is advisable to arrange wall-mounted speakers in medium-sized rectangular rooms, with the possibility of placing them along two opposite walls, in a checkerboard pattern with a step W = 2R:
where b is the width of the room, Fig. 9.
With ШДН=90°, R= b we have Ш=2b.
Test condition 5
The loudspeaker, taking into account the ShDN, should reach the opposite wall.
Effective range, for arbitrary long-distance traffic:
For ShDN = 90°:
Arrangement of wall-mounted speakers in rectangular rooms, with placement along two opposite walls
Wall-mounted loudspeakers in large rectangular rooms can be placed on opposite walls, in any order, with a step determined by half the distance to the opposite wall, b/2 (m) W=2R.
Where b is the width of the room, Fig. 10.
With ШДН=90°, R= b we have Ш=b.
Test condition 6
The loudspeaker, taking into account the ShDN, should penetrate half the distance to the opposite wall, Fig. 10.
Effective range, for arbitrary long-distance traffic:
For ShDN = 90°:
Taking into account the installation height is carried out similarly to formula (18).
Placing loudspeakers in rooms with complex configurations
The placement of loudspeakers in rooms with complex configurations is carried out as follows. The sounded (designed) room is analyzed, divided into separate sections, for each of which an appropriate arrangement scheme is selected from the above. The main task, in this case, comes down to the optimal joining of individual sections.
Literature
- Set of rules SP-3-13130-2009 of 2009 “Requirements fire safety to sound and voice warning and management of people evacuation.”
- Kochnov O.V. “Features of designing warning systems” (Murom, Kovalgin publishing house, 2012).
- Kochnov O.V. “Design of warning systems” (Tver 2016, Volume 1).
Timely information about the outbreak of a fire helps to effectively evacuate people and begin operational measures to eliminate the source of the fire. This is especially true for structures in which a significant number of people live or work. For these purposes, sirens are used.
One type of such equipment is a light-sound alarm, where light and sound are used to transmit an alarm signal. With its help, fire and security systems are equipped that are responsible for the prompt evacuation of people in the event of a threat to their life.
Basic functions of the device
A light and sound siren is understood as a complex electronic device that sends simultaneously visual and audio signals. alarms. Almost all modern security and fire alarm systems are equipped with such devices, which are responsible for the prompt evacuation of people when the first signs of danger appear.
Sounders are usually installed at the following facilities:
- educational and medical institutions;
- retail outlets and entertainment centers;
- public catering facilities;
- hotels;
- industrial buildings and structures.
The advantage of light and sound signaling is the use of a duplicated signal to notify about danger. This allows you to attract as much attention as possible when there is heavy smoke, or when the building is very noisy.
Often devices are placed in an explosion-proof housing, which facilitates their uninterrupted operation in fire conditions. There are intrinsically safe models designed for installation in hazardous areas, and conventional devices.
Design Features
To signal a danger, the light and sound annunciators use red and yellow lights; blue and yellow lights can be additionally provided. green colors. The light can be either flashing or constant. The sound mode and character of the sound signal may also vary depending on the model of the device.
A modern light and sound siren consists of several modules:
- high-strength metal shell that can resist aggressive influences;
- a reinforced glass display for light information with the inscriptions “exit”, “powder go away”, “do not enter” and others (there may be no inscriptions);
- a source of sound pulsating signals having a certain sound spectrum and a sound level of at least 85 dB;
- special connectors that make it possible to connect the system wiring.
The design of the light and sound alarm is designed in such a way that it can continue to operate under extreme and aggressive influences. To prevent unauthorized opening, the device is equipped with a special access contact. There are special mounting holes and openings for the power and control cables.
Installation
Due to the extensive warning coverage area, light and sound equipment is most often mounted on walls and other premises structures. This allows you to achieve the greatest visual and acoustic coverage of the surrounding space.
It is important to do everything possible to ensure that there are no obstacles in the directions of sound waves, and that the human eye can clearly perceive the inscriptions on the scoreboard or light indication in conditions of both natural and artificial lighting.
The specifics of installation of light and sound signaling equipment are influenced by its type, place of application and type of housing.
Wireless devices are more convenient in this regard: their installation involves simply attaching the base, while other parts are located on the board under the cover. If the siren is powered by a cable, then special channels will have to be used to lay it. If the alarm system is installed in street conditions, it is recommended to place the wiring inside corrugated metal pipes. To prevent the operation of the device from being affected by precipitation, protective visors are used.
Popular models
There is a wide range of light and sound explosion-proof sirens available for sale. Considering the fact that a person’s life directly depends on their work, it is better to give preference to proven models with an optimal price/quality ratio. The higher the protective properties of the case, the wider the capabilities of the device, the higher its price, which can reach 8-10 thousand rubles.
Mayak-12-KP
The purpose of this combined fire protection device is to notify people of emerging danger through sound and light signals.
Installation and maintenance activities may only be carried out if you have the appropriate experience.
This light and sound alarm is not intended for use in explosive areas. When carrying out installation, it is important to ensure reliable protection equipment from climatic and atmospheric influences.
Mayak-12-KP has a sound pressure of 105 dB. The disadvantage of the device is the inability to change the volume level. In cases where the signal strength is not enough, it can be strengthened using a howler. The material used to make the case is steel. The siren is compact in size and modern design. The equipment may be used in temperature conditions from -30 to +55 degrees.
Molniya-12-3
This siren looks like a sign with the inscription “Exit” on a red or green background. The convenience of this device lies in its ability to not only signal the start of a fire, but also indicate the direction of evacuation. The volume of the sound signal is set at 100 dB.
The collapsible design makes it possible to install any inscription on the display. The body is made of polycarbonate with a transparent insert in front made of acrylic glass.
The functioning of the light and sound siren "Molniya-12-3" is guaranteed at temperatures from -30 to +55 degrees. To simplify installation, the device body is equipped with special holes. This allows for surface mounting on the wall surface. The light source is a ruler LED type, illuminating the scoreboard on a three-dimensional scale.
To operate the device you will need a source. DC for 12 or 24 V.
For switching with external sources, the siren has a special terminal block.
Visual and light warnings can operate in parallel or separately; the operating mode of the device is set depending on the operating conditions.
Biya-S
The Biya brand light and sound annunciator provides an acoustic pressure level of 85 dB, and is capable of continuously sending alarm signals throughout the day.
For power supply, an alternating voltage of 220 V and 50 Hz is used, light signals are sent by a 25 W electric lamp. Sound notification is provided by an electrodynamic circuit that operates at temperatures from -40 to +50 degrees and air humidity up to 98%.
The main purpose of fire alarms and warning safety systems of any modification, designed to protect residential or complex industrial and explosive facilities, is to prevent the occurrence of a fire situation, to identify a fire at the initial stage as quickly as possible and to avoid casualties and material damage. Aggravating factors - the release of significant thermal energy and combustion products dangerous to human life - must be stopped as quickly as possible.
The increased level of constant danger dictates the development and construction of various signaling devices that prevent the development of force majeure fire situations. In addition to thermal linear, speech, gas and combined types of sirens, light and sound systems, signal beacons, and light and sound columns are very common and popular. The security and fire alarm light is used to indicate directions for evacuation of people in premises for various purposes - the light alarm “Exit” is the most common among such devices.
Visual and audio signaling devices have found application in both industrial and domestic spheres of life.
Areas of application for sirens
A light and sound alarm is a complex electronic device that allows you to visually display a pulsating or constantly glowing light signal on a display and simultaneously hear an audible alarm and is used in almost all modern systems fire safety and burglar alarm for the purpose of immediate evacuation of people from the premises.
Light and sound alarms are also widely used to inform about the expected occurrence of emergency situations - for example, the activation of water, gas or powder fire extinguishing systems.
Objects with large crowds of people must be equipped with annunciators:
- educational and medical institutions;
- administrative buildings and government bodies;
- shopping centers and catering establishments;
- hotel complexes;
- industrial facilities - plants, factories, production workshops.
Light and sound devices with a wide signal coverage area are installed on walls or other structures of large areas in places that provide maximum visual and acoustic coverage of the audience. It is necessary to ensure that there are no obstacles in the path of propagation of the sound channel and to ensure that the human eye perceives the inscription on the scoreboard or a light bulb in a contrasting manner in natural and artificial lighting.
Light and sound signaling device
A modern fire alarm is a monoblock or a collapsible structure that has several key elements:
- explosion-proof and impact-resistant metal shell;
- multilayer glass shockproof light display, equipped with an inscription on a bright red or green background and/or a pictogram, illuminated by LEDs. Depending on the settings, there may be a constant or pulsed glow;
- sound pulsating emitter with a set tone and sound pressure over 85 dB.
- connection compartment for connecting the cable directly to the connectors of the siren electronic board.
The design of the siren must provide for continued operation of the device in extreme conditions of aggressive environments, as well as under the influence of critically low and high temperatures.
Models of common sirens
Mayak-12-KP
The light and sound annunciator Mayak 12KP of a combined type is designed for optical and audio output of signals about the state of an object equipped with an alarm. The light and sound annunciator Mayak 12KP must be installed by qualified personnel; when installed outdoors, it is necessary to provide the device with a protective canopy from precipitation. There is no provision for adjusting the volume of the sound signal. Placement in explosive areas is prohibited.
The cost of Mayak sirens, depending on the modification, varies from 150 to 450 rubles.
Molniya-12
Light annunciator “Exit” Molniya 12 is used to indicate escape routes and exits for people in premises of any type. The design, which has a collapsible body with a latch, allows for the possibility of replacing the inscription.
An explosion-proof sound annunciator (abbreviated as ZOV), with appropriate markings, provides optical and sound alarms in explosive premises and open areas of class 1 and below to draw attention to the fire, radiation and other dangers that have arisen. 
A climatic version of the design is provided for location outside buildings and has a high sound pressure level of 105 dBA. Designed for operation in a temperature range of -55°С…+55°С and Rh up to 93% at a temperature of 40°С.
Any room where people are present must be equipped with appropriate fire and security alarm devices. Specialists responsible for ensuring the safety of people should choose the proposed siren models based on the categories of premises, technical regulations and regulations, installation features and functionality of the warning devices themselves.
The first light and sound alarms in fire and security alarm systems were used separately. Associated with the low development of electronic technology and previous legislation.
Now, in an effort to convey an alarming message to everyone, regardless of their physical characteristics, they began to use a combined light and sound siren. They are positioned in such a way that the area of effect covers the entire control zone.
Advantages and disadvantages of light and sound signaling
In public places, sound and light alarms are installed to notify of fire and other emergency situations. This is necessary to reliably attract people's attention to the incident.
When combining the siren in one device, the cost of the device is reduced; one housing is required instead of two.
If wireless devices are used, the savings are greater; one battery is required. In addition, it is used less materials(cables, fasteners), labor costs for installation work.
The advantage is that light and sound alarms are very easy to do yourself. It is enough to use a light and sound detector together with an autonomous motion sensor.
The result is a simple, cheap alarm system that will scare off intruders with light and sound and notify security of unauthorized entry into the facility.
Simplicity is good within a small object. When providing security for large buildings, such a system is unsuitable; multi-zone security systems with precise location of the incident are needed here.
Scope of application
Light and sound alarms are an integral element of any security system. In accordance with the law, all premises are equipped with fire sensors and warning devices.
Shopping and entertainment centers, sports facilities, office buildings, museums, theaters have alarm systems and fire fighting devices. No school or hospital is put into operation without a fire warning.
When servicing large buildings with a huge number of rooms, in addition to all kinds of sensors, devices are required that notify a person about an emergency. The most dangerous thing is a fire on a ship.
Therefore, all sea and river vessels are also equipped with light and sound warning and fire fighting systems.
Mining, chemical, and oil refineries must install light and sound alarms.
Operating principle of a light and sound detector
The essence of the work of a light and sound alarm is to create a sound of a certain tone and volume, which warns others about a fire or unauthorized access to a protected area. As an additional element, a light detector is used, duplicating the siren with bright flashes.
The device is turned on by simply connecting to the supply voltage through an electronic or relay key that can be opened from the control panel.
When using an addressable device, the siren and light flashes are launched by the siren control unit upon command from the central console via cable or radio channel.
Design
Depending on the installation location of the device, detectors can be wall or ceiling, indoor or outdoor. The body shape is usually rectangular or round.
Super bright LEDs or lamps are used as light sources. The sound alarm is made on the basis of a piezoelectric transducer or an electrodynamic device.
The body is made of metal, polycarbonate or other plastic, depending on the operating conditions.
To protect against opening, a special contact for unauthorized access is provided. There are holes for fastening and entering power and control cables.
Features of installation of a sound detector
Installation of the siren depends on its type, installation location, and type of housing. If a wireless device is used, then it is enough to secure the base of the device, and the remaining elements will be located on the board under the cover.
With a wired power supply and control circuit, the cables will have to be laid in channels or externally mounted. When laying outdoors, it is better to use corrugated metal pipes.
To protect against precipitation, sirens should be located under the canopy. In large rooms, devices are positioned in such a way as to ensure visibility and audibility in all areas.
TOP 5 models of sound detectors
System Sensor is a world leader among manufacturers of security and fire alarm devices.
Its products high quality and reliability, awarded many prizes, produced in factories in eight countries, including Russia.
Combined (light and sound) devices CWSS-RB-W7 among the sirens produced by the company have optimal ratio price/quality.
The device is powered by direct current voltage from 12 to 29 volts. The siren creates an acoustic pressure of up to 109 dB.
The wide directivity pattern of the light emitter and excellent optics allow you to install the device in any position, regardless of spatial orientation.
The device provides 32 tones and a red flash.
It has a housing protection degree of IP65, which allows outdoor use at temperatures -25 +70 ⁰С, air humidity up to 96%.
The Electrical Engineering and Automation company produces a whole line of light, sound and combined sirens. The Mayak-12-K model is popular.
This is an all-weather device that operates at temperatures of -50 +55 ⁰С.
The siren creates an acoustic pressure of 105 dB and consumes 20 mA, as does the light unit.
The device is made in a metal case 2 cm thick.
Mounted on the wall, in case street installation It is necessary to provide a canopy to protect against direct rainfall.
Powered by 12 V DC, a 24 V version is available. The device has a 1 year warranty. low price, is in demand.
Light and sound alarm 220 V "Biya-S" is produced by the company "Spetsavtomatika".
The device creates an acoustic pressure of 85 dB and can operate in alarm mode for up to 24 hours. Powered by alternating voltage 220 volts 50 Hz.
The role of the light emitter is performed by a 25 W electric lamp. An electrodynamic unit acts as a sound alarm; it operates at temperatures of -40 +50 ⁰С, air humidity up to 98%.
The manufacturer provides a 2.5 year warranty. The service life is 10 years. Tamper-proof protection is provided.
The Spetspribor company produces light and sound sirens in explosion-proof housing. They are used in mines, chemical plants and other enterprises of a similar level of danger.
The devices have a metal housing in IP67 design and a siren with a sound pressure of 105 dB. They are powered by a constant voltage of 12 or 24 volts.
The combined siren BC-07e-I 12-24 from Eridan is designed for use in the chemical, oil and gas and oil refining industries. The acoustic emitter produces 100 dB and is powered by 12/24 volts.
The body is made of aluminum, the cables are enclosed in metal corrugated pipes. Operates at temperatures -55 +70 ⁰С.
Conclusion
Fans of making alarms with their own hands should take into account when searching and buying on the Internet that a siren and a surface sound detector, for example, Arfa IO 329-3, are fundamentally different devices.
The first informs people about a fire, a violation of the security regime, after the second discovers the fact of this incident.
The security sound detector is a glass break sensor, and the exit light signaling device is a panel with a corresponding inscription and backlight.
To avoid confusion, be sure to read technical specifications before ordering equipment.
Video: Light and sound fire alarm