BURST FACTOR

Burst strength Measure of the ability of a sheet to resist rupture when pressure is applied to one of its sides by a specified instrument, under specific conditions. A burst factor is obtained by dividing the burst strength in grams per square centimeter by the basis weight of the sheet in grams per square meter. 

Burst factor. The pressure developed by a fluid, in pounds per square inch, required to split open a sample of the paper when it covers a circular hole 1.20 in. in diameter and is protected by a rubber diaphragm, is defined as burst (Ib/in. or g/cm ). When burst is divided by the basis weight (e.g., in g/m ), it is called burst factor. 

Paper samples Breaking length, m Burst factor Tear factor Water absorption, %... 

Fiber Pulping Process Yield UB B Breaking Length (km) Burst Factor Tear Factor Fold... 

Tsukagoshi, N., G. Tamura, and K. Arima A Novel Protoplast-Bursting Factor (Surfactin) Obtained from Bacillus subtilis lAM 1213.1. The Effects of Surfactin on Bacillus megaterium KM. Biochim. Biophys. Acta 196, 204 (1970). 

A difference between tank cars and most pressure vessels is that tank cars are designed in terms of the theoretical ultimate or bursting strength of the tank. The test pressure is usually 40 percent of the bursting pressure (sometimes less). The safety valves are set at 75 percent of the test pressure. Thus, the maximum operating pressure is usually 30 percent of the bursting pressure. This gives a nominal factor of safety of 3.3, compared with 4.0 for Division 1 of the ASME Pressure Vessel Code. 

This subject has received little attention in the context of pressure vessel bursts. Pittman (1976) studied it using a two-dimensional numerical code. However, his results are inconclusive, because the number of cases he studied was small and because the grid he used was coarse. Baker et al. (1975) recommend, on the basis of experimental results with high explosives, the use of a method described in detail in Section 6.3.3. That is, multiply the volume of the explosion by 2, read the overpressure and impulse from graphs for firee-air bursts, and multiply them by a factor depending on the range. 

This energy measure is equal to Brode s definition of the energy, multiplied by a factor 2. The reason for the multiplication is that the Brode definition applies to free-air burst, while Eq. (6.3.15) is for a surface burst. In a fiee-air burst, explosion energy is spread over twice the volume of air. 

Kf, = correction for Napier equation =1.0 when P[ = 1515 psig = (0.1906P, - 1000)/ (0.2292Pi - 1061) where Pj > 1515 psia and < 3215 psia, Table 7-6. Ksb = superheat correcUon factor, see Table 7-7. For saturated steam at any pressure, Ksb =1.0 Pb = stamped bursting pressure, psia... 

Burst Assumed external pressure gradient of saltwater = 0.465 psi/ft and formation pore (gas) pressure gradient = 0.65 psi/ft. Gas weight is neglected. Safety factor = 1.1. 

Have a safety factor with a burst pressure at a minimum of 4 times the rated working pressure. 

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