Class A: SOLIDS such as paper Chicago Blackhawks Hoodie , wood, plastic etc
Class B: FLAMMABLE LIQUIDS such as paraffin, petrol, oil etc
Class C: FLAMMABLE GASES such as propane, butane Customized Chicago Blackhawks Jerseys , methane etc
Class D: METALS such as aluminium, magnesium, titanium etc
Class E: Fires involving ELECTRICAL APPARATUS
Class F: Cooking OIL & FAT etc


Water Fire Extinguishers:
The cheapest and most widely used fire extinguishers. Used for Class A fires. Not suitable for Class B (Liquid) fires, or where electricity is involved.


Foam Fire Extinguishers:
More expensive than water, but more versatile. Used for Classes A & B fires. Foam spray extinguishers are not recommended for fires involving electricity Cheap Chicago Blackhawks Jerseys , but are safer than water if inadvertently sprayed onto live electrical apparatus.


Dry Powder Fire Extinguishers:
Often termed the 鈥榤ulti-purpose鈥?extinguisher, as it can be used on classes A, B & C fires. Best for running liquid fires (Class B). Will efficiently extinguish Class C gas fires, BUT BEWARE, IT CAN BE DANGEROUS TO EXTINGUISH A GAS FIRE WITHOUT FIRST ISOLATING THE GAS SUPPLY. Special powders are available for class D metal fires.


CO2 Fire Extinguishers:
Carbon Dioxide is ideal for fires involving electrical apparatus Calvin De Haan Blackhawks Jersey , and will also extinguish class B liquid fires, but has NO POST FIRE SECURITY and the fire could re-ignite.


Wet chemical
Specialist extinguisher for class F fires.


For Metal Fires: A specialist fire extinguisher for use on Class D fires - metal fires such as sodium, lithium, manganese and aluminium when in the form of swarf or turnings.


Colour Coding


Prior to 1st Jan 1997, the code of practice for fire extinguishers in the UK was BS 5423 Andrew Shaw Blackhawks Jersey , which advised the colour coding of fire extinguishers as follows:


Water - Red


Foam - Cream


Dry Powder - Blue


Carbon Dioxide (CO2) - Black


Halon - Green (now 'illegal' except for a few exceptions such as the Police, Armed Services and Aircraft).


New extinguishers should conform to BS EN 3, which requires that the entire body of the extinguisher be coloured red. A zone of colour of up to 5% of the external area can be used to identify the contents using the old colour coding shown above.

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For nitrogen fixation is the combination of molecular nitrogen or dinitrogen with oxygen or hydrogen to give oxides or ammonia that can be incorporated into the biosphere . Molecular nitrogen, which is the major component of the atmosphere is inert and does not directly usable by most living organisms. Nitrogen fixation can occur abiotically (without the intervention of living things) or by action of microorganisms (biological nitrogen fixation). The general setting is the incorporation into the biosphere of a significant amount of nitrogen that can be achieved globally about 250 million tons per year, of which 150 correspond to the biological fixation.


These reactions occur so abiotic natural conditions as a result of electric shock or processes of combustion and the water of rain is responsible for dragging down the compounds formed. Are also derived from the chemical synthesis industry conducted in fertilizer with a high consumption of energy .


The reduction of nitrogen to ammonia carried out by bacteria living outside or in symbiosis with some species vegetables ( legumes and some woody non-legumes) Robin Lehner Blackhawks Jersey , is known as biological nitrogen fixation (BNF). Organisms capable of fixing nitrogen are called diazotrophs .


This property is restricted only to prokaryotes and is well distributed among the different groups of bacteria and some archaea . It is an energy intensive process that occurs through the mediation of the enzyme nitrogenase using the following equation:


Ammonia, the process first stable compound, is assimilated by fasteners or transferred to the corresponding free host in the case of association with plants. Although ammonia (NH 3 ) is the direct product of this reaction is quickly ionized ammonia (NH 4 ). In free-living diazotrophs, the nitrogenase ammonium is assimilated into glutamate through the synthesis cycle glutamine synthetase glutamate.


The nitrogenase consists of two metalloproteins , molibdoferroprote铆na ferroprotein and is fairly well conserved in all fixing microorganisms. Presents a range of activities spread over molecules containing triple bonds which has created the basis for a practical method of detection and measurement of binding capacity Olli Maatta Blackhawks Jersey , and to think about the possible role of this enzyme in detoxifying the primordial atmosphere of the earth.


In many bacteria, the nitrogenase is very susceptible to destruction by oxygen (many bacteria stop producing fixed nitrogen in the presence of oxygen). Low oxygen tensions are used by different bacteria that live in anaerobic , low oxygen breathing, or by obtaining oxygen with a protein (eg leghaemoglobin ).


Nitrogen fixation has great economic and ecological interest. In fact, as an example Brandon Saad Blackhawks Jersey , high yields of soybean worldwide are caused by this process through the application of microbial inoculant quality. It occurs in all habitats and balances the biogeochemical cycling of nitrogen for the biosphere to recover the lost by denitrification . Involvement in the plant symbiotic fixation so important in human and animal food such as legumes, and the possibility of extending this property to other plant species of interest setting , thereby eliminating the need for fertilizer nitrogen, has made ??the FBN a subject of intense research over the years.