Fauske’s method

It is reeommended that a safety faetor of at least 2.0 be used [34]. In eertain eases, lower safety faetors may be employed. The designer should eonsult the appropriate proeess safety seetion in the engineering department for adviee. Table 12-4 lists the applieability of both Leung and Fauske s methods. 

If Fauske s method yields a signifieantly different vent size, then the ealeulation should be reviewed. 

The answer obtained from the Leung s method should not be signifieantly smaller than that of Fauske s method. 

Fauske s method for vapour pressure systems (see A5 3) and-the sizing method for gassy systems (see Chapter 7) have been, used to do a very.approximate relief sizing. Alternatively for screening purposes, nomographs153 could be used. "... 

For case (ii), Fauske s method (assuming homogeneous venting) is ... 

The version of Fauske s method given in A5.3.2 below is simplified by assuming that two-phase relief occurs until the reactor is empty (a safe assumption for vapour pressure systems). This makes the results directly comparable with those from Leung s method (in 6.3). The full version of Fauske s method14,51 allows account to be taken of vapour/ liquid disengagement before the vessel has emptied. This method is given in A5.3.4 below. 

Fauske s method has the stated condition of applicability that the absolute... 

Once it has been checked that1 the method is applicable (see above), it can be used for relief system sizing. Fauske s method is14,51 -... 

FRICTIONAL CORRECTION FACTORS FOR USE WITH FAUSKE S METHOD. ... 

A worked example of the use of Fauske s method for relief sizing is given below. 

As the safety valve has a de-rated discharge coefficient of 0.87, then A=0.0383/0.87 = 0.044 m2. In this case, Fauske s method gives a slightly higher relief area than the 0.0378 m2 given by Leung s method. 

A5.3.5 Worked example of Fauske s method with disengagement... 

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