Aspiratsionnyiy the method dyimoopredeleniya removes fire-prevention systems qualitatively to more high level. Compulsory selection of air from the protected volume with monitoring ultrasensitive laser smoke izveschatelyami supplies superearly detection of a critical situation. Aspiratsionnyie smoke firemen izveschateli allow to protect objects in which it is impossible to place directly the fireman izveschatel. In many cases it is expedient to use cheaper variant aspiratsionnogo izveschatelya with standard smoke izveschatelem. It is possibl to predict scope expansion aspiratsionnyih smoke firemen izveschateley with occurrence in the market of inexpensive laser models LASD-1, LASD-2 and cheaper light-emitting diode models not address ASD-PRO and address ASD-LEO company productions "Systems the Sensor control".

Work principle

Aspiratsionnyiy the smoke fireman izveschatel consists of system of pipes (from ABS or UPVC plastic, copper, stainless steel in diameter of 25 mm or 3/4 ") with apertures (fig. 1) diameter 2 – 3 mm through which air from a controllable zone acts in the central block (fig. 2) where smoke firemen izveschateli and the turbine for maintenance of a stream of air are established . Formation of the directed air streams in the protected volume considerably reduces influence of conditioners, stratifications of air, reduction of specific optical density in premises with high ceilings in comparison with dot smoke izveschatelyami etc. the Length of pipes is limited to time of transportation and can reach 75 metres that allows to protect premises with the big areas.

Fig. 3. A design laser izveschatelya 7251

In aspiratsionnyih izveschatelyah series LASD (Laser Aspirating Smoke Detector) the Sensor control with the tiny laser (fig. 3) as a radiator is used laser smoke izveschatel 7251 Systems. Brightness of radiation raises approximately on two order (in 100 times) above in comparison with a light-emitting diode, and beam focusing supplies practically complete absence of reflexions from walls of the smoke chamber and, accordingly, zero level of a background signal. As a result laser izveschatel supplies the control of environment with optical density less than 0,065 % of/m, that 0,0028 db/m. Ultrahigh sensitivity approximately are equal allows to generate preliminary signals on which the attendants can exclude possibility of development of a critical situation. In table 1 significances of specific optical density the environments corresponding to indications of the graphic display (fig. 4) are resulted.

Table 1

Optical density

Fig. 4. The graphic display izveschatelya LASD

Levels of preliminary signals and signal the FIRE, speed of rotation of the turbine, border of admissible change of an air stream and other parametres are programmed installyatorom by means of the buttons possessed on a lateral part of the block. The green light-emitting diode zero diskreta displays a mode on duty. At increase of optical density of environment yellow light-emitting diodes with numbers 1, 2, 3, …, 9 consistently join. At achievement of the programmed thresholds the additional red steams of light-emitting diodes possessed over the graphic display and join contacts of the relay the PREVENTION, the FIRE are switched. Relay exits izveschateley series LASD allow to connect them to any traditional PKP. The additional relay MALFUNCTION supplies translation on PKP signals of system of the automatic control of working capacity of system.

The active method of the control of environment with compulsory selection of air in zones where ultrahigh sensitivity is not required, and is enough to supply formation of a signal the FIRE at standard level probably use threshold smoke izveschateley with sensitivity stabilisation. In aspiratsionnyih systems of series ASD (Aspirating Smoke Detector) not address PROS (IP 212-73) in ASD-PRO (fig. 5) and address LEONARDO (IP 212-60A) in ASD-LEO are used light-emitting diode smoke izveschateli. These izveschateli have function of stabilisation of sensitivity and possibility of updating of its level – three fixed significances: 0,08 dB / m, 0,12 dB / m (factory installation), 0,16 dB / m that defines adaptation possibility aspiratsionnyih systems of series ASD.

Fig. 5. The central block aspiratsionnogo izveschatelya ASD-2

On the light-emitting diode display aspiratsionnogo izveschatelya series ASD speed of an air stream and the established borders of its change (fig. 6) is displayed. Malfunction signals at achievement of change of speed of an air stream of one of borders are formed by the special relay. Izveschateli series ASD-PRO with the gauge of the PRO will be connected to any not address PKP under the usual scheme with inclusion of the relay MALFUNCTION on switching-off of a terminal element of a loop. Izveschateli series ASD-LEO with LEONARDO gauge will be connected in LEONARDO address tyre of address module AM-99 or PPKOP "Signal-99" with connection of the relay MALFUNCTION in not address loop.

Fig. 6. Indication of speed of an air stream and admissible borders in izveschatelyah ASD-LEO, ASD-PRO

Aspiratsionnyie systems ASD-LEO and ASD-PRO do not form preliminary signals, their sensitivity is equivalent 6 – 7 diskretu laser LASD (tab. 1). But with standard sensitivity they can supervise the significant area and can be used in such operating conditions where it is impossible to realise higher sensitivity because of false operations, or prevention signals are not required. On the other hand, application of more simple izveschateley allows to lower system cost, saving thus advantages aspiratsionnogo dyimoopredeleniya.

Aspiratsionnyie systems of series LASD and ASD are manufactured in two variants: single-channel - with one vzduhozabornoy a pipe to 75 metres and two-channel – with two pipes to 50 metres. In single-channel aspiratsionnom the system the second can be established additional izveschatel for acknowledgement of a signal "Fire" that is an obligatory request for management of systems of fire automatics. So, for example, LASD - 1 it is single-channel aspiratsionnyiy izveschatel in which central block it is established  one  or two laser izveschatelya 7251 (fig. 7), ASD - 2   two-channel izveschatel, with two traditional izveschatelyami, each of which is possessed  a separate compartment that increases the protected area approximately to 1000 m².

Scope

Laser aspiratsionnyie systems LASD are ideal for archives, museums, warehouses, server, switching premises of electronic communication centres, control centres, "pure" industrial zones, hospital premises with the hi-tech diagnostic equipment, television cents and broadcasting stations, computer halls and other premises with the expensive equipment. I.e. for the most important premises where material assets are stored or where the means enclosed in the equipment or where the damage from a stop of production or functioning interruption is great are huge, or the missed benefit from information loss is great. On such objects imperative authentically to find out and liquidate the centre at the earliest stage of development, at a decay stage – long before occurrence of open fire, or at occurrence of an overheat separate a component of the electronic system. Thus, considering, that such zones are usually equipped by the temperature and humidity monitoring system, in them air filtration is made, there is a possibility considerably to increase sensitivity of the fireman izveschatelya, having avoided thus false operations.

Other big class of objects where it is extremely important to supply at least 10 times higher sensitivity in comparison with traditional systems are large objects with a mass congestion of people: the trading and entertaining centres, exhibition halls, theatres, cinemas, stadiums etc. On objects of such type the preliminary signal about the fire-dangerous situation, acting only to attendants allows to liquidate a critical situation before notification inclusion about a fire. It allows to avoid evacuation of a considerable quantity of the people, the panic connected at risk occurrence, a crush and human victims even in the absence of threat of a life from a fire. Besides, filling of ways of evacuation with people creates significant problems for attendants at liquidation even rather small centre of ignition: even to reach it begins difficultly vyipolnimoy a problem.

Often there are increased requirements to design of premises, in this case depending on required level of fire protection can be used both laser, and traditional aspiratsionnyie systems. Vozduhozabornyie pipes with additional capillary tubes in length to 1,5 m can place behind a false ceiling, or in elements of furnish of a premise. And the availability of the air stream created aspiratorom allows to possess inputs of capillary tubes or directly pipe with vozduhozabornyimi apertures in premise corners (fig. 9).

The design aspiratsionnoy systems with vozduhozabornyimi pipes allows to realise antivandalnuyu system: metal pipes 3/4 "with the open or latent placing can be used, the central block which takes places together in a separate premise is subject to protection only.

Often there are the zones which control traditional dot smoke izveschatelyami is hindered because of complexity of installation and service, because of availability of a dust, because of air streams from ventilating systems or conditioners which deform smoke distribution indoors, the big premises high ceilings where concentration of a smoke under a ceiling is insignificant at early stages of ignition.

Aspiratsionnyie systems are effective method of protection of cable structures (fig. 10), spaces under falshpolom, for example, cabeles in a floor of the computer centre where speed of movement of air can be enough high as usually such "double" floor is used for giving of cooling air to equipment installation sites (fig. 11). Aspiratsionnyiy a method of the control of the air environment – constant compulsory selection of air through system of pipes considerably reduces influence of air streams indoors.

Fig. 11. Protection of spaces under falshpolom

Aspirator supplies zasasyivanie air through each aperture from enough great volume of a premise that compensates influence of air streams from a forced-air and exhaust ventilation, systems konditsionirovniya etc. Furthermore probably placing vozduhozabornyih pipes on lattices of air inlets (fig. 12) and even is direct in channels of air lines.

Fig. 12. An arrangement of pipes on lattices of air inlets

Protection of servers by means of laser aspiratsionnyih systems of series LASD allows to fix an overheat of separate electronic components. The control of directly internal volume of equipment (fig. 13) is thus made.

Fig. 13. Protection of servers by means of laser izveschatelya LASD-2

Fig. 14. The system for protection of the central block against a condensate

Aspiratsiya as considerably reduces influence of effect of stratification (stratification) of air in a high premise when the layer of warm air under a ceiling interferes with smoke receipt in the top part of a premise. On the other hand, in a high premise the smoke under a ceiling has low concentration, but extends on the big area and acts simultaneously through some apertures that compensates concentration decrease. Furthermore, use of flexible plastic pipes in diameter of 25 or 15 mm allow to protect a premise with any form of a ceiling, up to the spherical.

Modern microprocessor aspiratsionnyie systems well adapt for operation difficult conditions. For use in dusty zones on pipes additional filters are established. In zones with high humidity systems for protection of the central block against a condensate (fig. 14) are used. The probability of false operation of the system in dusty premises is minimised by means of programming of corresponding levels of operation and stabilisation of a range of measurements. Degree of protection of a cover of the central block is usually realised at level IP50 and can be raised to IP65, that allows to use the given systems in explosive zones of class V-Ia, V-Ib, V-Ig, V-IIa. And, if the central block is established out of a protected zone at use of an additional target pipe it is possible to create continuous air circulation in a controllable premise.

Important significance in some cases has absence of conductors of a loop in a controllable zone. Plastic vozduhozabornyie pipes are not submitted to influence of electromagnetic hindrances and can be maintained in the conditions of high levels of electromagnetic radiation. On the other hand aspiratsionnyie systems with the born central block do not create electromagnetic hindrances in a controllable premise.

CONCLUSIONS

1. Aspiratsionnyie firemen izveschateli considerably raise level of fire protection of objects and structures of various type.