ISO15911:2000(E) method. IP 338/98, Determination of hydrogen content of aviation turbine fuels - Low resolution nuclear magnetic resonance spectrometry method. magnetic resonance spectroscopy. 3 Term and definition For the purposes of this International Standard, the following term and definition applies. 3.1 net specific energy amount of heat liberated when a unit mass or volume of fuel is burnt in air saturated with water vapour under constant pressure, and the products of combustion are cooled to a specified temperature NOTE 1 The net specific energy is the gross specific energy less the latent heat of the water produced during combustion. NOTE 2 The terms "calorific value" and "heat of combustion" are synonymous with specific energy. 2 Principle 4 The hydrogen content, sulfur content and density of the sample are determined by experimental test methods and the net specific energy is calculated from these test data using known correlations. 5 Procedure 5.1 procedure described in IP 338 or ASTM D 3701. NOTE material. 5.2 described in ISO 3675 or ISO 12185, using the corrections given in ISO 91-1 if appropriate. 5.3 Determine the mass fraction of sulfur in the sample, to the nearest 0,02 % (m/m), in accordance with the procedure described in ISO 4260 or ISO 8754. 6 Calculation 6.1 Calculate the net specific energy at constant pressure on a mass basis, ep in megajoules per kilogram, by ep = 37,2889+0,5561730H - 0,326 6s -0,0023003p (1) where oH is the mass fraction of hydrogen, expressed as a percentage by mass; os is the mass fraction of sulfur, expressed as a percentage by mass; is the density at 15 C, expressed in kilograms per cubic metre. p 2 ISO 15911:2000(E) ,(c)TheBritishStandards Institution2013 6.2 Calculate the net specific energy at constant pressure on a volume basis, epv, in megajoules per cubic metre, bymeansofequation(2). (2) epv = ep×p 7 Expression of results Report the result, to the nearest 0,01 MJ/kg or 10 MJ/m3, as the net specific energy on a mass or volume basis respectively. applies, results should be reported on a volume basis to the nearest 10 MJ/m3. Precision 8.1 General when using the data from IP 338, ASTM D 3701, ISO 3675 and ISO 4260, is given in 8.2 and 8.3. 8.2Repeatability, r The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the following value in only one case in 20: r = 0,05 MJ/kg on a mass basis 8.3Reproducibility, R exceedthefollowingvalueinonlyonecasein2o: R = 0,06 MJ/kg on a mass basis NOTE 1 The precision for this International Standard was derived for fuels on a mass basis only. As a guide, an estimate of precisiononavolumebasishasbeencalculatedforafuelwithadensityof810,okg/m3asfollows: 40 MJ/m3 Repeatability: 50 MJ/m3 Reproducibility: These values have been rounded off to the nearest 10 MJ/m3. NOTE 2 Use of fuel property data obtained with greater or lesser precision than that of the test methods indicated will have a 3 ISO 15911:2000(E) 3 201 9 Test report The test report shall contain at least the following information: a) a reference to this International Standard; the type and complete identification of the product tested; (q rds tandar the result of the test (see clause 7); C) d) S British e) the date of the test. (c) The Licensed copy: Lee 4