ASTM E4-15 pdf free download.Standard Practices for Force Verification of Testing Machines.
7.3. 1 Introduction of the new force measuring devices shall require that interchangeability be established per 7.3.
7.4 A Practices E4 Verification consists of at least two verification runs of the forces contained in the force range(s) selected. See 10.1 and 10.3.
7.4.1 If the initial verification run produces values within the Practices E4 requirements of Section 17, the data may be used ‘6as found” for run one of the two required for the new verification report.
7.4.2 If the initial verification run produces any values which are outside of the Practices E4 requirements, the beas found” data may he reported and may he used in accordance with applicable quality control programs. Calibration adjustments shall he made to the force indicator system(s), after which the two required verification runs shall be conducted and reported in the new verification report and certificate.
7.4.3 Calibration adjustments may he made to improve the accuracy of the system. They shall he followed by the two required verification runs, and issuance of a new verification report and certificate.
8. Gravity and Air Buoyancy Corrections
8.1 In the verification of testing machines, where standard weights are used for applying forces directly or through lever or balance-arm systems, correct the force for the local value of gravity and for nominal air buoyancy.
8.1.1 The force exerted by a weight in air is determined by:
where:
F = Force, N
M = true mass of the weight, kg
g = local acceleration due to gravity, m/s2,
d = air density (1.2 kg/m3), and
D = density of the weight in the same units as d.
8.1.2 For the purposes of this standard, g can be calculated with a sufficient uncertainty using the following formula.
I, = elevation above sea level in metres
Nom 2—Eq 3 correcs for the shape of the earth and the elevation above sea level. The first term, which corrects for the shape of the earth, is a simplification of the World Geodetic System 84 Ellipsoidal Gravity Formula. The resuks obtained with (he simplified formula dit1r twin those in the full version by less than 0.0(X)5%. The second term combines a correction thr altitude, the increased distance from the center of the earth, and a correction for the counter-acting Bouguer eflèct of localized increased mass of the earth. The second term assumes a rock density of 2.67 g/cm4. If the rock density changed by 0.5 g/cm3, an error of 0.003 % would result.
8.2 The force in customary units exerted by a weight in air is calculated as follows.ASTM E4 pdf download.