BS EN ISO 1716 Calorific Value Test - Essay Example

BS EN (ISO) 1716 Calorific Value Test This is a method of determining the maximum potential amount of heat that is released when product is totally consumed by burning it. Test specimen which is usually in powdery form is ignited in pressurized calorimetric bomb filled with oxygen and immersed in water. The change in temperature of water jacket is measured. Gross calorific potential is calculated from temperature change, specimen mass and the results is modified using calorimeter modification factor .The units of Gross calorific potential (PCS) is MJ/kg or MJ/m2 and depends on the product’s features and its composition (Bett etal 145-178). The gross calorific potential value which is obtained in computation is very important in classification of building materials. The most commonly used instrument in this test is called Bomb Calorimeter and is used to measure the heat of combustion or the amount of calories in the material. A test specimen is normally burned under controlled conditions and its mass must be specified before the test begins. The amount of heat is obtained by observing the change in temperature while factoring in the amount of heat loss. The combustion process takes place in a container with constant volume and under space filled with oxygen. Both temperature of water inside the calorimeter vessel and water used to immerse the vessel are closely monitored. Combustion reaction in calorimeter need to be considered hazardous since they involve explosive reactions therefore vigilance is highly recommended. Cone calorimeter test method On the other hand cone calorimeter test method is mostly used in determination of the heat release rate and other test on behaviors of materials when fire test is carried out. The method involves exposing insulating materials in electrical or optical cables to prescribed heating flux in cone calorimeter. The amount of heat released give data that useful for designing of electrical and optical cables and product design. Cone calorimeter is very useful instrument in the field of fire testing which utilizes bench scale. Technique called oxygen depletion Calorimetry has been used recently to measure the released heat using full scale testing which was not possible with the traditional ways. Gross heat of combustion of any organic material is directly related to the amount of oxygen required for combustion. (Huggett, 61-65) It derives its name from the shape of radiant heater which is conical and enables uniform heating over the surface of sample. The largest manufacturer of this instrument in UK is fire testing Technology Limited (FTTL).The source of energy is radiant exposure and has been used to compare with the rate at which heat is been released and spread of flame in materials used for insulation Comparison The following are similarities or dissimilarities of BS EN (ISO) 1716 Calorific Value Test and Cone Calorimeter Test; 1. Both BS EN (ISO) 1716 Calorific Value Test and Cone Calorimeter Test are used to determine fire behaviour for building material 2. Both tests methods derive their names from the shapes of the test apparatus used, in cone calorimeter test, the radiant heater is conical in shape while BS EN (ISO) 1716 Calorific Value Test or Bomb calorimeter test, the calorimeter vessel is bomb shaped 3. In BS EN (ISO) 1716 Calorific Value Test, there is determination of the potential maximum total heat released by a product when burned completely, in contrast; Cone Calorimeter Test does not determine the net heat of combustion 4. In BS EN (ISO) 1716 Calorific Value Test the important parameter to measure is prospective total heat release of a product, while in Cone Calorimeter Test, it stress importance of heat release rate (HRR) Classification of hazard The main factor being considered in classification under this standard is flammability of the building materials .Flammability is the ability of product to ignite, leading to fire breakout. The ability to cause fire is quantified through fire testing.BS En 1716 classifies the building materials in two broader categories, namely class A1 and Class A2. Class A1 building materials releases heat of combustion, Gross calorific potential (PCS) ≤ 2.0 MJ/kg. This class consists of materials that don’t contribute fire e.g. stones, concrete, bricks, ceramic, glass, steel and many metallic products which don’t support fire. The products in this class can be made of one or more of the materials which are classified as class without carrying out any testing, this was arrived in 1996. The second Class is A2 whereby, under BS En ISO 1716 are products that release the heat of combustion and Gross calorific potential (PCS) ≤ 3.0 MJ/kg. It produces less fire and produces a lot of Fumes, Fire droplets and particles e.g. Cable insulation . History of the test Long time each country in European Union had been developing their own fire test in supporting their building laws. In UK British standard was used while European Nations EN standard was used, but currently BS and EN references is used in the transitional period.BS EN ISO 1716 is European standard of determining the gross heat of combustion of product in a constant volume in bomb calorimeter. BS EN ISO 1716: 2000 was form in the year 2000 and was and still being used for fire tests for building materials. It replaced EN ISO 1716:200 The term calorimeter was first used in 1770 by Josef Black and ice-calorimeter was first designed by Lavoisier and Laplace. Pure oxygen was first used at high pressure in 1885.The burning sample is oxidized and the heat created during the reaction process is computed using the isoperibol, adiabatic or dynamic measuring procedure. In an isoperibol Calorimeter the temperature in the outer vessel (Tov) is kept constant throughout the whole experiment. Usefulness and its limitations for fire safety BS En 1716 has led to adoption of common fire codes and other regulations used in building materials as well as good ways of storing and handling highly combustible materials in and out of the building structures, for instance if one is to use the building for other use then the building permit need to be applied. This has created limitation for the change and use of the building. BS En 1716 has also increased the fire safety of building; this has reduced a lot of fire accidents and consequently has brought the cost of insurance and doing business down. BS En 1716 has encouraged a lot of research it terms of building materials. This has led to coming up of fire resistant building materials. This might also limit the design since the cost goes up to cover the cost of research. Also the standard has led to restriction of using any materials anywhere. non-flammable materials can be used without restriction anywhere in a building. Finally fire safety is to ensure that the right firefighting equipments are installed in the right points in the buildings as per the materials that are used in the construction of the building. This will ensure quick response and effective firefighting in case of any fire breakout Conclusion BS EN ISO 1716 test is currently the most important standard that governs fire safety in Buildings in all European nations. It also follows the international fire standards in building materials. The standardization has led to easy transfer of technology throughout the European nation and the rest of the world. It has played a vital role in ensuring the safety of buildings, stored materials and people who are living in the buildings. This summarizes the importance of the standardization and it’s therefore here to stay and will not be replaced in the near future. Work Cited Bett, George, Frith,Henkel,and James Robson.The Scottish Building Regulations:Explaed and illustrated.oxford:JohnWiley & sons,2007.print Hugget, C; Estimation of Rate of Heat Release by Means of Oxygen Consumption Measurements. Fire and Materials, 1980. Print Read More