Office of Nuclear Reactor Regulation Division of Systems Safety and Analysis Plant Systems Branch Fire Protection Engineering
and Special Projects Section
CHAPTER 15. ESTIMATING PRESSURE INCREASE AND EXPLOSIVE ENERGY RELEASE ASSOCIATED WITH EXPLOSIONS
Version 1805.0
The following calculations estimate the pressure and energy due to an explosion in a confined space. Parameters in YELLOW CELLS are Entered by the User. Parameters in GREEN CELLS are Automatically Selected from the DROP DOWN MENU for the Fuel Selected. All subsequent output values are calculated by the spreadsheet and based on values specified in the input parameters. This spreadsheet is protected and secure to avoid errors due to a wrong entry in a cells(s). The chapter in the NUREG should be read before an analysis is made.
INPUT PARAMETERS
EXPLOSIVE FUEL INFORMATION Adiabatic Flame Temperature of the Fuel ((Tad) Heat of Combustion of the Fuel (DHc) Yield (a), i.e., the fraction of available combustion 1 percent for unconfined mass release and 100 percent for confined vapor release energy participating in blast wave generation Mass of Flammable Vapor Release (m F) Ambient Air Temperature (Ta) Initial Atmospheric Pressure (Pa)
THERMAL PROPERTIES FOR FUELS
FLAMMABILITY DATA FOR FUELS Fuel Acetylene Carbon Monoxide Ethane Ethylene Hydrogen Methane n-Butane n-Heptane n-Pentane n-Octane Propane Propylene User Specified Vlaue Adiabatic Flame Temperature Tad (F) 4779 4329 2244 4152 4085 2143 2442 2586 2356 2478 2338 4050 Enter Value
Reference: SFPE Handbook of Fire Protection Engineering, 2 nd Edition, 1995, Page 1-86.
METHOD OF ZALOSH
Reference: SFPE Handbook of Fire Protection Engineering, 2 nd Edition, 1995, Page 3-312.
Office of Nuclear Reactor Regulation Division of Systems Safety and Analysis Plant Systems Branch Fire Protection Engineering and Special Projects Section
Pressure Rise from an Confined Explosion (Pmax)/Pa = (Tad/Ta) Where Pmax = maximum pressure developed at completion of combustion (kPa) Pa = initial atmospheric pressure (kPa) Tad = adiabatic flame temperature (K) Ta = ambient temperature (K) Pmax = (Tad/Ta) Pa Pmax = 528.57 kPa
Blast Wave Energy Calculation E = a DHc mF Where E = blast wave energy (kJ) [E is the Trinitrotoluene (TNT) equivalent energy] a = yield (a is the fraction of available combustion energy participating in blast wave DHc = heat of combustion (kJ/kg) mF = mass of flammable vapor release (kg) E= TNT Mass Equivalent Calculation W TNT = E/4500 Where WTNT = W TNT = weight of TNT (kg) E = explosive energy release (kJ) 224.78 kg 1011490.91 kJ
NOTE
The above calculations are based on principles developed in the SFPE Handbook of Fire Protection Engineering, 2nd Edition, 1995. Calculations are based on certain assumptions and have inherent limitations. The results of such calculations may or may not have reasonable predictive capabilities for a given situation, and should only be interpreted by an informed user. Although each calculation in the spreadsheet has been verified with the results of hand calculation, there is no absolute guarantee of the accuracy of these calculations. Any questions, comments, concerns, and suggestions, or to report an error(s) in the spreadsheet, please send an email to nxi@nrc.gov or mxs3@nrc.gov.
Office of Nuclear Reactor Regulation Division of Systems Safety and Analysis Plant Systems Branch Fire Protection Engineering and Special Projects Section
Prepared by: Checked by: Additional Information
Date Date
Revision Log Description of Revision 1805.0 Original issue with final text.
Office of Nuclear Reactor Regulation Division of Systems Safety and Analysis Plant Systems Branch Fire Protection Engineering and Special Projects Section
E AND EXPLOSIVE ENERGY
sion in a confined space.
P DOWN MENU for the Fuel Selected. n values specified in the input o a wrong entry in a cells(s).
2338 F 46360 kJ/kg 100.00 %
1281.11 C 1554.11 K
48.00 lb 77.00 F 14.70 psi
21.82 kg 25.00 C 298.00 K 101.35 kPa
Calculate
Heat of Combustion DHc (kJ/kg) 48,220 10,100 47,490 47,170 130,800 50,030 45,720 44,560 44,980 44,440 46,360 45,790 Enter Value
Select Fuel Type
Propane
Scroll to desired fuel type then Click on selection
Office of Nuclear Reactor Regulation Division of Systems Safety and Analysis Plant Systems Branch Fire Protection Engineering and Special Projects Section
at completion of combustion (kPa)
76.66 psi
Answer
rinitrotoluene (TNT) equivalent energy] combustion energy participating in blast wave generation)
957983.04 Btu
Answer
495.55 lb
Answer
the SFPE Handbook of Fire Protection
erent limitations. The results of such abilities for a given situation, and should
ed with the results of hand calculation,
report an error(s) in the spreadsheet,
Office of Nuclear Reactor Regulation Division of Systems Safety and Analysis Plant Systems Branch Fire Protection Engineering and Special Projects Section
Organization Organization
Date January 2004
