Dow's Fire & Explosion Index Hazard Classification Guide, Seventh Edition
by American Institute of Chemical Engineers
Copyright ©U.S.A. 1994
APPENDIX E
EOUATIONS FOR DAMAGE FACTOR DATA
The Damage Factor is to be determined using Figure 8, page 53. This data is differentfrom the data in the
other figures in this report inasmuch as the data was fit to equations giving the damage factors at Process
Unit Hazards Factors from 1.0 to 8.0 for each of the discrete Material Factors. Since there are nine
Material Factors - 1,4,10,14, 16,21,24,29, and 40 - there are nine equations.
It is important to note that there really is no meaning for the intermediate Material Factors other than the
nine defined cases. The data points were joined by lines solely for the purpose of allowing it to be easier to
follow along the lines of constant Process Unit Hazards Factors. The main value of this figure is to allow
for the interpolation of the Damage Factors between different values of the Process Unit Hazards Factors.
The nine equations derived for the nine Material Factors are as follows:
For the Material Factor of 1 the equation for the Damage Factors (Y axis) based on the Process Unit
Hazards Factors from 1 through 8 is as follows:
Y = 0.003907 + 0.0029570()
+ 0.004031(X2)- 0.00029(X3)
or
Y = 0.003907 + 0.002957*X + 0.004031*X"2 - O.00029*XA3
For the Material Factor of 4 the equation for the Damage Factors (Y axis) based on the Process Unit
Hazards Factors from 1 through 8 is as follows:
Y = 0.025817 + O.O19071(X) - 0.00081(S) + 0.000108(X3)
or
Y = 0.025817 + O.O19071*X - 0.00081*X"2 + 0.000108*X"3
For the Material Factor of 10 the equation for the Damage Factors (Y axis) based on the Process Unit
Hazards Factors from 1 through 8 is as follows:
Y = 0.098582 + O.O17596(X) + 0.000809(X2) - 0.000013(X3)
or
Y = 0.098582 + O.O17596*X + 0.000809*X"2- O.oooO13*X"3
For the Material Factor of 14 the equation for the Damage Factors (Y axis) based on the Process Unit
Hazards Factors from 1 through 8 is as follows:
Y = 0.20592 + O.O18938(X) + 0.007628(X2)- 0.00057(X3)
or
Y = 0.20592 + O.O18938*X + O.007628*XA2- O.00057*XA3
For the Material Factor of 16 the equation for the Damage Factors (Y axis) based on the Process Unit
Hazards Factors from 1 through 8 is as follows:
Y = 0.256741 + O.O19886(X) + 0.01 1055(X2)- 0.00088(X3)
or
Y = 0.256741 + O.O19886*X + 0.01 1055*X"2 - O.00088*XA3
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For the Material Factor of 21 the equation for the Damage Factors (Y axis) based on the Process Unit
Hazards Factors from 1 through 8 is as follows:
Y = 0.340314+ 0.076531(X)+ 0.003912(X2)- 0.00073(X3)
or
Y = 0.340314+ O.O76531*X + 0.003912*XA2- O.00073*XA3
For the Material Factor of 24 the equation for the Damage Factors (Y axis) based on the Process Unit
Hazards Factors from 1 through 8 is as follows:
Y = 0.395755+ O.O96443(X)- 0.00135(X2)- 0.00038(X3)
or
Y = 0.395755+ O.O96443*X - O.00135*XA2- O.00038*XA3
For the Material Factor of 29 the equation for the Damage Factors (Y axis) based on the Process Unit
Hazards Factors from 1 through 8 is as follows:
Y = 0.484766+ 0.094288(X)- 0.00216(X2)- 0.00031(X3)
or
Y = 0.484766+ 0.094288*X- 0.00216*X"2- O.00031*XA3
For the Material Factor of 40 the equation for the Damage Factors (Y axis) based on the Process Unit
Hazards Factors from 1 through 8 is as follows:
Y = 0.554175+ O.O80772(X)+ 0.000332(X2)- 0.00044(X3)
or
Y = 0.554175+ O.O80772*X + 0.000332*XA2- O.00044*XA3
The equations are given in both word processing format and text format. For reading this guide in text
format only, the figures and the word processing format equations will not appear. However, the equation
in text format will allow determination of the Damage Factor.
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