Installation of light and sound alarms. Light and sound annunciator

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.

It is recommended to install loudspeakers in enclosed spaces internal execution, as 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) right triangle Therefore, to calculate the radius of a circle (side of a 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 very simple case the required number of 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 arranging wall-mounted speakers in rectangular rooms along two walls in a checkerboard pattern, the placement step is:

When placing back-to-back wall-mounted speakers in rectangular rooms along two walls, the placement step is:

Primary 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 annunciators (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:

SOUE sound signals provided general level sound (the sound level of constant noise together with all signals produced by the sirens) is not less than 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 annunciators (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 , speaker placement is part of organizational events, carried out during the design of 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.

Loudspeaker power

There are several main types of power:

Loudspeaker power rating– electrical power at which nonlinear distortion loudspeaker do not exceed the required values.

Loudspeaker rated power– defined as the highest electrical power at which a loudspeaker can long time work satisfactorily on a real audio 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 case 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 (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's use the well-known geometric concept, 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 various types 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 50 ms) 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 the 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 geometric beam, 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 wooden sheathing at a frequency of 4 kHz, K absorp = 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).

A 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 hallways with high ceilings without taking into account 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 loudspeakers 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 ШДН=90°, R=ШК we have Ш=4ШК.

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

1. Set of rules SP-3-13130-2009 of 2009 “Requirements fire safety to sound and voice warning and management of people evacuation.”
2. Kochnov O.V. “Features of designing warning systems” (Murom, Kovalgin publishing house, 2012).
3. Kochnov O.V. “Design of warning systems” (Tver 2016, Volume 1).

Good day.

We have already said that the requirements for SOUE (warning and evacuation control systems) are regulated by volume SP 3.13130.2009. "Set of rules. Systems fire protection. Warning and management system for evacuation of people in case of fire. Fire safety requirements."

The main requirement for sound systems- they must provide a minimum sound pressure level of 1.5 m from the floor (i.e. at the height of the average person’s ears) 15 dB above the average noise level in the room, but not less than 75 dB. Wherein maximum level The sound pressure created by the SOUE should not exceed 120 dB: this is the pain threshold, then it’s still useless - only harm can be done. Therefore, if the noise level at the facility is, say, 110 dB, then your SOUE should squeal no quieter or louder than 120 dB, and increased efficiency should be achieved through all sorts of lighting effects - stroboscopes, for example. In sleeping quarters, hotels, hospital wards, etc. The sound level is measured at the height of a sleeping person's head.

There are many options for placing sound sources. You can attach a horn-type “bell” loudspeaker of terrible power in the corner of the hall and let it scream “throughout the whole forest.” As a result, at the far end of the room the sound will meet the requirements, but near the sound source people will go deaf. So I forgot to add: the “Code of Rules” also requires uniform distribution of sound (clause 4.7. Installation of loudspeakers and other voice alarms in protected premises must exclude concentration and uneven distribution of reflected sound.).

Therefore, ceiling speakers are widely used in large rooms - they allow you to create just the same uniform distribution of sound pressure. There are many designs for installation in dropped ceilings, there are pendant speakers that look like chandeliers.

In corridors and small rooms, wall-mounted speakers are quite suitable; their placement is strictly regulated: not lower than 2.3 m from the floor, but not less than 15 cm from the ceiling. By the way, there are bidirectional loudspeakers: in the middle of the corridor I attached them to the wall, they speak back and forth.

It should be added that, in order to avoid large power losses on the wires, the amplifiers produce a high-voltage signal, 100-120 V. The speakers are equipped with step-down transformers.

About calculating the SOUE with ceiling speakers:

The number of ceiling speakers for sounding a room is calculated without taking into account power - pure geometry. We assume that the directional pattern of the speaker is 90 degrees; it is necessary that they evenly, without overlap, sound the rooms at a height of 1.5 m from the floor. Those who wish can draw, I’m too lazy, so without any details:

b Take the height of the room minus 1.5m, proudly call the resulting number “h”. We hang the speakers at a distance of 2h from each other, and from the wall - h.

The area covered by one ceiling speaker is approximately:

Now we take the area of ​​the room and divide it by this same S(op), we get the number of speakers. For example, we have a hefty warehouse of 7000 sq.m., height 6m. In this case, h=6m-1.5m=4.5m. S(op) is approximately 2x4.5x2x4.5 = 81 sq. m. Number of speakers:

N = 7000:81 = 86

Now about the power. Any normal speaker (loudspeaker), among its technical characteristics, has such an interesting parameter as sensitivity, measured in W/m. True, then, for the convenience of calculations, this is converted into dB, those who wish can look for themselves how to convert watts into decibels, this is already a theory, I don’t want to go into details. In short, sensitivity is the sound pressure created by a speaker at a distance of 1 m with a power dissipated at 1 W.

We must create a sound pressure 15 dB higher than the noise level in the room. In order not to run around with a sound level meter, we will use a table of typical noise levels in rooms:

Since we have a warehouse, we take the noise level to 70 dB. Let's take the LPA-6 speaker from Louis-Plus; it has a sensitivity of 94 dB, i.e. with a power of 1 W at a distance of 1 m from it, it creates a sound pressure = 94 dB. We need to obtain sound pressure at a distance of 4.5 m (our distance “h”)

70dB+15dB = 85dB

Let's use the graph of sound pressure attenuation c depending on the distance from the speaker, provided by the same company Louis-Plus:

At a distance of 1 m, the attenuation = 0, and at the 4.5 m we need, it is about 13 dB. Those. from the original 94 dB (speaker sensitivity or sound pressure at a distance of 1 m), we need to subtract 13 dB. We get that with a power of 1 W, our speaker will pump us at a level of 1.5 m from the floor with a pressure of 81 dB. But you need 85 dB.

Let's look at the characteristics of our speaker:

Look, in the column “Inclusion power” there are 3 connection options: 6 W, 3 W and 1.5 W. Those. its matching transformer has several taps, allowing, with a voltage on the transformer of 100 V, to develop a power of 6 W, 3 W or 1.5 W.

And, for complete happiness, one more sign - gain in dB depending on the power dissipated by the speaker:

We need to drive 85 dB at a distance “h” from the speaker. We received a calculated 81 dB, i.e. you need to add 4 dB. Let's see - with a power of 3 W, the sound pressure gain will be 4.8 dB, so if we connect the speaker at a power of 3 W, we will have 85 dB with some margin.

We multiply the speaker power by their number and get the minimum sufficient amplifier power. In our case it is 3W x 86 = 258 W.

Overall, quite confusing at first, but let's recap briefly.

1. Without being tied to any powers, stupidly based on geometry, we calculate the area that one speaker should sound at a given room height. Then, based on the area of ​​the room, we calculate the number of speakers.
2. We select a speaker and, based on its sensitivity, calculate what sound pressure it can create at a height of 1.5 m from the floor with a power of 1 W
3. And, finally, we calculate how much power needs to be developed on the speaker in order to obtain the sound pressure we need at that magical height of 1.5 m. Naturally, if this power is higher than the maximum power of the speaker, we will have to choose another model.

Well, that’s basically all the horror. The second approach is no longer so scary.

And here is the very first formula:

I recommend memorizing it by heart, since it’s not difficult. Imagine, you are inspecting a facility, the customer asks how much the notification will cost. With this formula, you can count on your fingers the number of ceiling speakers and plus or minus bast shoes, adding to them the cost of amplifiers and cables, and at least indicate the scale of prices. The customer likes this efficiency.

Questions - in comments or by email [email protected], news subscription form is below.

The first light and sound alarms in fire systems, burglar alarm were applied separately. Associated with the low development of electronic technology and previous legislation.

Now, in an effort to convey a disturbing message to everyone, regardless of their physical features, they began to use a combined light and sound siren. They are positioned so 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 used wireless devices, then the savings are greater, one battery is required. In addition, less materials (cables, fasteners) and labor costs for installation work are used.

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; here we need multi-zone security systems with precise definition scene of the incident.

Application area

Light and sound alarms are an integral element of any security system. In accordance with the law, all premises are equipped with fire detectors 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. How additional element a light detector is used that duplicates 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 company is a world leader among manufacturers of security and fire alarm.

Its products are of high quality and reliability, awarded many prizes, and are produced in factories in eight countries, including Russia.

Combined (light and sound) devices CWSS-RB-W7 among the sirens produced by the company have an optimal price/quality ratio.

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 of outdoor installation, it is necessary to provide a canopy to protect against direct rainfall.

It is powered by 12 V DC, with a 24 V modification available. The device has a 1-year warranty, a low price, and 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 production 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 housing 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 the technical specifications before ordering equipment.

Video: Light and sound fire alarm

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 they are equipped fire and security systems 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 to mean a complex electronic device, sending simultaneous visual and audible alarm signals. 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.

Advantage light and sound alarm is the use of a duplicated signal to notify of 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; additionally, blue and 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 outdoors, 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 protective properties housing, 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 different compact 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 an LED line that illuminates the display on a three-dimensional scale.

To operate the device, you will need a 12 or 24 V DC source.

For communication 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%.

Modern systems Alerts are complexes of equipment, the correct operation of which allows us to guarantee the timely submission of alarm information and the organization of an effective evacuation process. Depending on the characteristics of the facility, warning systems can be quite simple and built using a minimum number of devices, or they can be a complex and multi-component set of equipment. However, regardless of the complexity and type of emergency warning system, the installation of sirens is an integral part of any warning system. According to the requirements of SP 3.13130.2009, installation sound alarms required for installation of warning lights - . And this is quite justified, because fairly simple and inexpensive alarms allow you to effectively convey information about a fire and indicate the nearest evacuation routes, and therefore save the health and lives of people. There are many more standards for installing fire alarms , prescribed in regulatory documentation and mandatory compliance. All these requirements, as well as key features We will consider each type of siren below.

Most often, the installation of sound alarms is carried out in structurally simple buildings belonging to the first type of SOUE, or in separate rooms of buildings with SOUE system 2-5 types that do not imply the possibility of permanent residence of people. As a rule, in such cases there is no need to additional devices and the purpose of the system is reduced to giving a sound signal informing about the need to immediately leave the room. Correct operation of the sound alarm can only be ensured by observing all the rules and current standards for installing sound alarms.

Standards for installing sound alarms

1. The sound pressure level at any point in the room should not exceed 120 dBA, but be at least 75 dBA at a distance of 3 m from the siren. When the sound level decreases, a person in the building may not hear the alarm signal, while exceeding the norm leads to a deafening effect and creates unnecessary panic during evacuation.

2. The sound level of the warning signal, created at a level of 1.5 m from the floor, must exceed the permissible constant noise level by at least 15 dBA. This item allows you to install sound alarms taking into account the differences in noise pollution of different buildings and premises.

3. In rooms intended for sleeping, the sound level is measured at the level of the head of a lying person and must be at least 70 dBA and exceed the constant noise level by 15 dBA.

4. Installation of sound alarms must be carried out taking into account the uniform distribution of sound over the entire area. Concentration of sound at one point and insufficient sound at others is unacceptable.

5. Sounders must be attached exclusively to non-combustible capital structures, because in the event of a fire, flammable walls and ceilings may ignite or collapse along with the sounders installed on them. Naturally, in this case, the operation of the warning system will be disrupted.

6. Installation of sound alarms on the wall must be carried out in such a way that the distance from the top of the device to the ceiling is at least 0.15 m, and to the floor - more than 2.3 m. There is a lot of debate on this point, because the ceiling level is not always stated at the design stage coincides with the final one. And here the question arises - what to do if the ceiling height is less than 2.45 m and it is simply impossible to ensure the required installation height of sound alarms? The answer is very simple - install the sirens on the ceiling, ensuring reliable fastening to a non-combustible base (main ceiling).

Signal lights in one form or another can be seen in almost any building. These can be simple light alarms used in combination with a sound alert, or various light displays with inscriptions or arrows. The installation of light warning signs "EXIT" is mandatory for all types of SOUE (except the first), light signs for the direction of movement - for SOUE types 4 and 5. Also, warning systems often use special displays that inform about the launch of gas and powder fire extinguishing systems and the need to urgently leave the premises. Naturally, installing illuminated signs does not solve the warning problem as a whole, but it allows people to focus their attention on the presence of a threat and effectively organize evacuation by directing everyone to emergency exits.

Standards for installing warning lights

1. The height of installation of light alarms must be at least 2 m. This condition guarantees excellent visibility of the device and minimal risk of damage due to accidental mechanical impact.

2. Installation of illuminated “EXIT” signs is carried out directly above emergency exits leading outside or to a safe area of ​​the building.

3. Installation of illuminated traffic direction indicators is mandatory in corridors longer than 50 m (interval up to 25 m), in places where corridors turn, as well as in all smoke-free areas stairwells. Additional installation locations to be determined design organization based on the planning decisions of the building and possible evacuation scenarios.

4. While people are in any auditoriums and demonstration halls, the illuminated “EXIT” signs installed in them must be turned on.

This type of sirens combines the capabilities of light and sound sirens and, as a rule, is used to reduce the number of equipment and cable routes in order to generally simplify and reduce the cost of the system. So, if the noise level in a room exceeds 95 dBA or people in it are wearing noise-protective equipment, SP 3.13130.2009 regulates the combination of light and sound alarms. In this case, it would be most appropriate to install light and sound alarms. For small premises in which it is necessary to combine light and sound notification, the most the right decision There will be installation of a light and sound signaling device "EXIT" (display). In this way, it is possible to reduce the amount of equipment and cable products while maintaining all functionality systems.

Order installation of sirens

All work on the installation of sirens must be carried out exclusively by certified specialists with experience in carrying out such work and all necessary permits. to our company, you will receive high-quality advice, calculation of the cost of work and any Additional information, and you can also order high-quality installation and connection of sirens.