flammability test data in risk assessment

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72 THE ANNALS OF UNIVERSITY “DUNĂREA DE JOS“ OF GALAŢI FASCICLE VIII, 2008 (XIV), ISSN 1221-4590 TRIBOLOGY and the procedure. Even if the test is, in principle, simple and the results are quantified in only three possible ways, the procedure was well established in order to obtain repeatability, a desired characteristic of the test results but hard to obtain for test involving fire or flammability characteristics [26]. Discussions at ISO/TC 28 from 2000 also set the test parameters accuracy, in order to give the possibility of ranking fluids based on a well established procedure. For instance, there was introduced three temperature sensors, with imposed position on the manifold (two on its opposite sides – near the ends of the rod and one at the center of it), and not one as in the first version of the standard, in order to have a better control of the temperature uniformity that has to be at all these three points within 700°C±5°C (or other selected temperature, but with same accuracy) Several specifications are related to the fluid sample: the temperature, the volume and the state (including the fact that “any air bubbles which may have arise on mixing shall be allowed to escape from the fluid before testing”). It is interesting to notice that the majority of comments were done by countries that are big manufac-turers and users of hydraulic fluids (United Kingdom, Canada) [45]. This international test method and tester has the highest degree of resemblance to the American Hot Manifold Ignition Test (Federal Test Method 791, Method 6053.1) [40], the results of the test being also quantified in a similar way (Tab. 2). Even the tester dimensions are very close to those of the tester describes in EN ISO 20823:2003. This ISO testing method is mainly used for assessing the resistance to ignition of the fire-resistant fluids that are, by definition, difficult to be ignited. The procedure given in this standard is also specified in ISO 12922-1999, Lubri-cants, industrial oils and related products (class L). Family H (hydraulic systems). Specifications for categories HFAE, HFAS, HFB, HFC, HFDR and HFDU. Many specifications related to hydraulic fluids and oils include the results of some others tests concerning the fire resistance and flammability, the shear stability and the determination of extremepressure and anti-wear properties, taking into account other standards than those involved in this study [20, 21, 43] The FM Standard 6930 [2] was intended to test only hydraulic fluids. A sample of the hydraulic fluid being tested was pressurized to 6.89MPa and heated to a fixed temperature starting from 60°C. There were performed four tests: test for determining the chemical heat release rate of the fluid, flame propagation test, test for measuring critical heat flux for ignition, hot surface ignition test. The latest was designed to mimic hydraulic fluid leaking under high pressure from a hose in an environment where hot surfaces are common. Hydraulic fluid was sprayed from a nozzle onto a steel surface heated to 700°C. FM will also work with the American Petroleum Institute to include the new specification test standard within a new hydraulic fluid flammability standard being developed by the International Organization for Standardization (ISO) [34]. The objectives of the grant CEEX-M4-452 includes applicative research concerning the three testing methods that now are not performed in our country for technical fluid assessment conformity by taking into account the requirements of the European directives [6-9, 14]. As far as the authors could have investigated, the test included in SR EN ISO 20823:2004 has not been not performed in Romania till nowadays. This affirmation is based on the negative answers received from 10 laboratories having RENAR (Asociatia de Acreditare din Romania, Romanian Accreditation Association) accreditation for analysing, testing and research on fuels, oils, lubricants. These laboratories confirm that they can not perform any one of the three tests under the requirements of the European standards, as imposed by the Directive 92/104 [7]. These laboratories are: ICERP SA Ploieşti, ICMET Craiova, INCERP - CERCETARE SA Ploieşti, LAREX CNIEP - Centrul Naţional pentru Încercarea si Expertizarea Produselor, ROMPETROL QUALITY CONTROL SRL, PETROTEL LUKOIL SA Ploieşti, RULMENTUL SA, PETROM SA (ARPECHIM). Some laboratories explain the reasons why they could not do these tests, especially the absence of the necessary equipment and some of them could do one or two of these tests but in accordance to other standards. For instance, Total Lubrifin SA can perform two of the above-mentioned tests but following the requirements of ASTM standards. 4. THE TESTER The tester design meets the requirements imposed by SR EN ISO 20823:2004, comprising (fig. 2) a robotic system 1 that automatically ensures the positioning of the fluid dispenser 5 above the simulated manifold, at a position desired by the operator, within a high temperature enclosure 4. The manifold is made of corrosion resistant steel and it could be heated by an electric system up to 700°C. The temperature control is done by the help of three digital thermocouples mounted on a transversal guiding system 3 that allow them to be in contact with the manifold and then withdrawn during the fluid dropping. All the above mentioned subsystems are enclosed in the ventilated enclosure 2. 5. PRELIMINARY RESULTS Table 3 presents three tests done at elevated temperature and in the last column there are presented comments that could give supplementary characteristics of the tested fluids. For instance, a
THE ANNALS OF UNIVERSITY “DUNĂREA DE JOS“ OF GALAŢI FASCICLE VIII, 2008 (XIV), ISSN 1221-4590 TRIBOLOGY 73 characteristic that is not mentioned in ISO standard, but was recorded during these preliminary tests, was the time interval till the fluid starts to burn, time measured from the starting of the fluid dispensing process. From Table 3, one may notice that the grade oil ACEA-2002 A2/B2 – API SL/CF had the largest time interval between drop starting and burn starting on the hot manifold. This larger time may be crucial in activating the fire suppression systems. Another important aspect noticed during these tests was the quality and quantity of the residues left on the manifold, in the tray and on the metal box walls. Varying the manifold temperature and repeating the test methodology it is possible to establish a temperature (or a very narrow range of temperature) to ignite the fluid, under the test conditions. This temperature could be compared to the ignition point or flash point, this comparison being a criterion for establishing the degree of hazardous probability for the fluid. Fig. 2. Tester for determining the flammability characteristics of fluids in contacts with hot surfaces. Table 3 Preliminary results in determining the flammability characteristics of fluids in contacts with hot surfaces (methodology as required by EN ISO 20823:2003) Average high 300± 10 mm, Oil volume 10±0.5 ml. Number Tested oil of test Comments Oil grade H.G. 46 Manifold temperature ( o C) Dropping time (sec) 1 620 45 2 620 45 3 620 45 1 700 50-60 Oil grade T 90 API 2 700 50-60 GL-2 3 700 o C 50-60 Oil grade ACEA- 2002 A2/B2 – API SL/CF 1 700 o C 50-60 2 700 50-60 3 700 50-60 Permissible deviation of parameters ±20 o C; ± 10 sec; ±20 o C; ± 10 sec; ±20 o C; ±0.5 ml; ± 10 sec; - the fluid ignites after 5-7 sec and after dropping 1…1,5 ml of fluid; - test result: I(T), when the fluid flashes or burns on the tube but does not continue to burn when collected in the tray below. - the fluid ignites on the manifold after 5…10 sec of start dropping and it burns in the tray below. - test result: I(D), when the fluid flashes or burns on the tube and continues to do so when collected in the tray below - the fluid ignites and burns after 22 sec from drop starting; it burns on the manifold, during its dripping but it does not burn in the tray, - a lot of residue was noticed after burning on the tube but also on the walls of the high-temperature metal enclosure, - test result: I(D), when the fluid flashes or burns on the tube and continues to do so when collected in thetray below
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