【 Weak current College 】 cable fire characteristics and several common extinguishing device

(A), Sol
Sol is a smoke fire extinguishing agent, also belongs to the chemical fire suppression, it relies on combustion smoke fire extinguishing, and also with the "hot" outlet temperature reaction in more than 80 degrees, and the generation of hazardous gases; because it is itself a source of ignition, and therefore not suitable for explosion and inerting; Sol fire extinguishing technology cannot make the pipe network system design, and generally does not apply to a large space to put out the fire, fire extinguishing remnants of corrosive and very difficult to clear in recent years, many industry disable Sol for fire protection.

Compared with ultra-fine powder, Sol has five obvious deficiencies: 1, fire-fighting slow; Sol by combustion smoke release to space, the formation of the whole process of submerged and space-related, far and ultra-fine powder instant fire. 2, Sol can only be fully submerged in the fire, the requirement is relatively closed space; ultra-fine powder can be completely submerged in the local application fire fighting and fire-fighting, in some big space for cable application sandwich or equipment, we can only fire-prone areas for local protection, reducing fire extinguishing time, saving costs, achieve early fire suppression, rapid fire extinguishing purposes. 3, resistance to a resumption of ultra-fine powder, special can be overridden on the cable, particularly for cable surface burning (smoldering) have very good off. When special ultra-fine powder powder and cable high temperature combustion of surface contact, a series of chemical reactions in the role of high-temperature cables surface was melted, resulting in a glass-like surface of the cable cover and separated from the surrounding air, so that combustion asphyxiation; at the same time, highly concentrated powder mixed with flame, produced by the decomposition of endothermic reaction effectively absorb the heat of the flame component. In cable protection, such as application Sol fire sprinklers, fire extinguishing time is extremely easy to form a deep-fire, fire-fighting is not successful, i.e. immediately comes alive. 4. Security: Sol outlet temperature of 80 degrees, on a m in and protect from harm, "thermal joint reaction" is Sol hidden dangers, such as in the iron and steel enterprise of underground hydraulic station and other places, the absolute to disable Sol. 5, Sol and ultra-fine powder while there are deposits of ultra-fine powder, but not conductive dust, non-corrosive, non-toxic and harmless to the human body, the residue is easy to clean; Sol residues more corrosive to the conductivity of metal salts caused power supply circuit, strong corrosion significantly reduces cable and equipment life, and adhesion on the surface is very hard to clear.

(Ii), water mist system
Water mist is a type of installation in the network system of open sprinkler control valve, the system and water connections, through the installation in the mist of the same region of the detection system open control valve for water mist systems. When the valve is open, the water flow into the pipeline system, and installed on the system of the nozzle churning out for fire-fighting.

Justice, water mist in open space than gaseous fire extinguishing system has a distinct advantage, the size of the fire, the water mist systems of fire extinguishing effect has a great effect on combustion fierce fire easily water mist fight, this is because the water mist is purely physical fire extinguishing, fire, oxygen consumption, accompanied by large amounts of steam and turbulence; and on cable class a fire burning slowly but poor, water mist system relatively fine dry powder fire extinguishing, fire-extinguishing system for a much longer time, the former is approximately 200 seconds, while the latter only 10 seconds.

A test certificate, medium pressure water mist produce larger water particles, deep in the fight against A class of fire (such as cotton and hemp warehouse, etc.), showed good results, because of the large flow of water can be protected from moisture, but weakened the obstructed the ability of the fire; in contrast, high pressure water mist as particle size smaller, improves off obstructed the ability of the fire, but weakened the fight A class effect of deep fire, so attention to water mist fire protection systems applied to fight large spatial warehouse (total area) has the advantage, but on a single protection area smaller, reserve large and dispersed cable dissection and underground tunnels no advantage, and also because the pipeline to complex, high volume, cost engineering.

Water mist systems are used for high-quality water fire extinguishing agent, while the resource-rich and affordable, but digging a pond and frequent replacement of water is also a smaller number of pipes, high-pressure water pumps, sprayers and valve and so on material requirements are very strict, later maintenance costs than gas fire extinguishing system is much higher. More for domestic water mist fire fighting equipment technology also does not cross the border, water fog particle size is far more than the international standard, in the application is restricted.

At present, water mist system is the biggest shortage is its security and to the electrical equipment and personnel injury, when a live devices experience water, because water conductivity, on the one hand may cause an electrical short, damage the device, on the other hand, it may cause damage to the field; at the same time, the current will pass through the water spray, water fog sprinkler from along the water supply pipeline transmission. According to the "NFPA70, national electrical standards and NFPA750 the water mist system specification:" the whole system components must be non-blocking and non-insulated, live devices between minimal electricity net margin (2.2M), basic insulation level (BIL) uncertainties and in the use of conventional voltage as a design standard, you should use this group may require a minimum distance of electric NET ceiling value, select ground spacing should meet the surge voltage larger values or BIL value instead of by electric system with rated voltage; device insulation between live parts and the net margin of a water mist system between the parts shall be not less than the net margin, wherever a single electrical components of the electrical system insulation provides minimum spacing. "Cable dissection or cable tunnel height is less than the nozzle 2.2 metres away from the cable distance far below the standard required.

(Iii), hanging automatic dry-powder fire extinguishing device pulse
The installation is Russia fire technology, product, also known as Brown-hanging automatic dry-powder fire extinguishing device pulses, such fire suppression equipment using gas-driven, propellant powder, when an explosive device receives a signal after the moment the high pressure gas explosion, breaking the aluminum foil sealing of vents, high pressure release extinguishing, and self-Used in conjunction with fixed alarm system, its advantages are spray distance, hanging height than other fire extinguishing device twice.

This type of fire fighting installations of ABC powder extinguishing agent for normal and easy caking, poor liquidity, while high pressure gas explosions can instantly would fire extinguishing agent spray out, reduce the problem of dry powder agglomeration, but due to powder particle size large (70 μ m or so), you cannot be all submerged fire extinguishing means unprotected vents to place cannot fire; as the injection time of less than one second, if the fire was extinguished, the fire was not easily seen, this is the Achilles heel of fire-fighting equipment.

Brown-hanging pulse automatic extinguishing device security defects than other fire extinguishing system, devices launch not only loud explosion, shock might lead system second disaster, it is conceivable that, in the underground cable dissection or tunnel, if more than at the same time, its power is sufficient to explosion destroyed the entire underground engineering, especially in the relatively closed narrow space, this fire suppression equipment General recommended to space the higher reserve, and once at the start number should not be more than three sites above, from a security perspective, this would not be appropriate to the fire suppression equipment more than at the start and use the small space in the underground.

(Iv), ultra-fine powder without network automatic fire extinguishing system
From a certain definition, ultra-fine powder is a kind of aerosol that is driven by inert gas dry particulate release to space the cold aerosol, automatic fire extinguishing device Superfine powder with nitrogen as dynamic, driven fire-fighting equipment in the ultrafine powder extinguishing agent for fire fighting; a quiet boot, how fire extinguishing gas, nitrogen pressure 1.2MPA, safe and reliable protection from any damage, the fill of ultra-fine powder extinguishing agent among the green features, the most efficient of its fire fighting, fire fighting fastest, fire extinguishing concentration minimum characteristics of fully complies with today's most demanding fire, hanging, Cabinet, wall-mounted, can interface with the fire alarm system, automatic fire extinguishing system comprising; its no pipe fire suppression system (hanging, Cabinet, wall-mounted) and ease of installation, low cost; to put out the fire of a larger space, the whole or partially submerged in the fire protection of fire-fighting applications flexibly select; there are three startup mode: fixed temperature-controlled start, start, warm start, according to the scene environment flexibility, a wide range of applications, especially suitable for iron and steel, electric power, chemical, oil and other enterprises of cable tunnels, mezzanine, hydraulic station and other places of the fire.

No pipeline to hanging as representative, easy installation, no wall punch, electronic control and warm start is able to achieve more than at the start; tank fire suppression equipment high automation, reliable safety, fire fighting power.

EFI boot: can the market's general alarm controller interface, we can set up when the alarm host receives a separate signal detector, the host only alarm; when a host to receive two separate signals, alarms and delay of 30 seconds, conveying gives fire suppression equipment 24 volt power start fire suppression equipment, and can realize the partition boot, feedback release signals, and the linkage with other devices, and many other features.

Temperature control startup: hanging fire suppression equipment installed fixed temperature shower, thermal components from 57 degrees to 141 ° c optional, ambient temperature from-40 ° to + 55 ° c, when a reserve no more than eight, the choice of fixed temperature-start.

Warm start: when a reserve of fire suppression equipment more than eight, or warm start; that is, use the thermal cable connection, the protective zone of a fire extinguishing devices connected together, to achieve at the start.

The requirements of modern fire is early suppression, fast response, high efficiency, fire-fighting; metallurgical industry of industrial fire in selecting products to be taken into account, the selected medium to suitable for protected material characteristics and requirements, while also considering their security, such as in flammable and explosive place and underground works in "hot joint reaction" fire suppression equipment, can only be increased fire loss; they want to consider economic, fire extinguishing concentration low dosage, late is low maintenance and installation is simple and reliable.