When it comes to Class D fires however. Because of their bromine content halons can destroy ozone moleculesO3 very effectively thereby contributing to the depletion of ozone and the creation of holes in the ozone layer of the stratosphere.
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Halons Halons are chemicals that contain carbon fluorine and bromine.
. Specifically it is ideal for Class B events involving flammable liquids. It was first introduced in 1983 but it has only been recently that they have gained popularity. However halon extinguishants have one major caveat theyre now illegal in many countries including the UK due to the devastating impacts they have on the environment.
C F Cl and Br where indicates the number of each kind of atom in the. The Halon fire extinguisher is a recent addition to the market. The Halons are clean agents leaving no corrosive or abrasive residues following their use.
Since that time recycled halons are the only supply of halons in the United States for specialty fire suppression applications. Halon based fire extinguishants were previously regarded as the most effective universal fire extinguishing agents working on 3 fire classes and leaving no toxic residue However halon extinguishants have one major caveat theyre now illegal in many countries including the UK due to the devastating impacts they have on the environment. Class D fire are those that involve metals like sodium potassium titanium magnesium and lithium.
For example the smaller units are not suitable for class A fires and halon is expensive. Recharge costs can approach or exceed the initial purchase price. Because of their strong ozone depletion potential the production and import of virgin halons in the United.
Halon is an effective agent on Class B and C fires the ones youre most likely to see in an aircraft. Because of its versatility across Classes it is overall a good choice for most environments where the risk of fire is present. Regulations governing the use of halons are likely to become more restrictive.
It can be used for Class A B and C fires with great effect. Halon uses a liquefied gas pressurized with nitrogen which discharges as a vapor causing no cold or static shock and no impairment of the operators vision. Worldwide there are many States and organizations testing alternatives to halon.
There are many benefits of using this type of fire extinguisher including less risk for operator injury and environmental damage as well the ability to be used on Class A fires. Start studying Final Exam. 28 Nov 2024.
On January 1 1994 production and import of virgin halons were phased out in the United States. They are used in fire extinguishers and other firefighting equipment. The numbering system for halons is in the following order.
Halon 1211 portable fire extinguishers are iimportantprotection for a wide range of fire hazards. They are used to fight fires with flammable liquids and solid combustible materials These are ineffective on fuels that have their own oxidizing agent The most favored Halon for fire extinguishers is Halon 1301 which involves electronic equipment. Unfortunately there is no single substance which can be used for all of the extinguishing applications.
The production and con-sumption of halons was successfully phased out in developed countries by the beginning of 1994. At present halons are used for fire suppression on civil aircraft in four extinguishing applications as shown above. Effectively cool and smother fires in class A and Class B fuels the agents noncoductive so they can be used on energized electrical equipment.
Although they are highly effective fire fighting agents and explosion suppressants halons are extremely potent ODS as well as significant global warming gases. Halon systems are effective on class a and class b fires but engineering judgement rather than numerical ratings is used for halon system selection and design. While alternatives are available for most halon-based fire extinguishing applications c halons are still employed for important applications such as.
Halon 1211 is a streaming agent and more commonly used in hand-held extinguishers because it discharges mostly as a liquid stream. Class C events involving electrical fires. Halon Extinguishers are used for fighting class B and class C fires And sometimes A Fires.
Class b protection automatic fire protection is not rated in the same manner. Halon should never be used. And it works well for most Class A events such as common combustible fires.
Both Halon 1211 and 1301 have Class A B and C ratings and have relatively low toxicity and electrical conductivity making them the agents of choice for extinguishing the type of fires most prevalent in aircraft. Halons have also been identified as contributing to the depletion of the ozone layer in the atmosphere. Learn vocabulary terms and more with flashcards games and other study tools.
Halons especially CF 2 ClBr Halon-1211 and CF 3 Br Halon-1301 are used as fire suppressants in situations where the use of water is not appropriate eg around electronic equipment and on civilian aircraft. It works in gas form so it will not obscure your vision like the powder emitted from dry chemical extinguishers. Halon based fire extinguishants were previously regarded as the most effective universal fire extinguishing agents working on 3 fire classes and leaving no toxic residue.
Fire suppression and explosion protection have used halons in many applications because they are electrically non-conductive dissipate rapidly without residue are safe for limited human exposure and are extremely efficient in extinguishing most types of fires. As a result they are ideally suited to protect areas such as libraries and museums where the use of water or solid extinguishing agents could cause secondary damage equal to or exceeding that caused by direct fire damage. Halon is one of the most effective fire suppression agents available today.
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