WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 Poznan University of Technology ASSESSMENT OF PUBLIC SAFETY AFTER GAS EXPLOSION INSIDE A CIVIL ENGINEERING STRUCTURE Tomasz Łodygowski and Piotr W. Sielicki Institute of Structural Engineering (ISE) Poznań University of Technology ul. Piotrowo 5, Poznań, Poland

WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 Poznan University of Technology PRESENTATION OUTLINE: - MOTIVATION - INTRODUCTORY REMARKS - NUMERICAL MODEL AND COMPUTATIONS - PUBLIC SAFETY - CONCLUSIONS

WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 Poznan University of Technology MOTIVATION PUBLIC SAFETY ASSESSMENT (during building employment for retrofitting) - SAFE - WOUNDED - BADLY WOUNDED FLOOR PLANNING (before built during a design process for changing floor configuration)

Poznan University of Technology INTRODUCTORY REMARKS - Full spatial modeling covers 30 by 60 m 2 area and 3.5m high - Underground concrete office rooms with plant room in „p1” - There is an open space without blast doors, and door heads are not included - Rigid walls represent the most risk scenario, where the reflection is the highest WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 Door heads are not included

Poznan University of Technology NUMERICAL MODEL - The analyzed scenario is: Escaping of propane from a broken installation in the plant room - Assumption: 50% propane-air concentration in the plant room before an explosion - The important property of propane-air mixture; an Initial Specific Energy value bases on Alternate Energy Systems, Inc. online data - Propane behavior is simulated by JWL equation of the state - Air behavior is simulated by IDEAL GAS equation of the state WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 Type of Charge Propane-Air Mixture Mass [kg]330 Volume [m 3 ]172.8 Specific Energy [J/kg]2.73e7 Density [kg/m3] 626 liquid 1.9 mixture Detonation speed [m/s]1680

Poznan University of Technology NUMERICAL MODEL Coupled Eulerian-Lagrangian is used to simulate a pressure evolution in the air space inside the office area Source code:Abaqus 6.9 Explicit code is used for calculation Problem size: 2.5e6 Finite Elements EC3D8R Element size:0.125 by by m 3 Analyzed time: 0.2 sec Computational time: 3600x15 seconds (average time for one analysis) Boundary conditions: corridors & rooms (wall, floor, ceiling) are fixed with use of zero velocity condition FE requested results: Over- Pressure values and velocity in time and space function Transferred requested results:Mean pressure-time dependency and impulse for every room WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010

Poznan University of Technology NUMERICAL MODEL Pressure maps in time function allows for assessment of real hazard for every room, only if some criterion is known. WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 t= st= s t= 0.05 st= 0.1 s

Poznan University of Technology NUMERICAL MODEL In the work: „Pressure Loading on Structure after Explosion” (ISIE 2010 Warsaw) the authors undertake a study on comparison of reflected pressure values with US standard (UFC 2-193). Presented conclusions allow for use of rigid walls in a good comparison of pressure values with reality. WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 Pressure maps for different angle (0~90deg) of incidenceComparison of reflected pressure coefficient

Poznan University of Technology PUBLIC SAFETY Human tolerance to the blast output of an explosion is relatively high. However, the orientation of a person (standing, sitting, etc.) is really important. The pressure tolerance for short-duration blast loads is significantly higher than that for long-duration blast loads. There are used two separate criteria, in agreement US standard i.e. Unified Facilities Criteria (UFC) UFC , for assessment public safety. 1. LUNG DAMAGE 2. EARDRUMS RUPTURE WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010

Poznan University of Technology PUBLIC SAFETY The mean properties are obtained for each office room and could be further compared with safety criteria. The results for one room (Plant Room) are presented below WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 Pressure – Time relation in the P1 room Peak overpressure0.62e9[ Pa ] Duration time0.02 [ s ] Specific Impulse*3.1e6[ Pa s / W* ] Pressure contour lines 0.001s after detonation

Poznan University of Technology PUBLIC SAFETY The mean values are obtained for each room and compared with both criteria. WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 Safe zone (below criteria) Wounded zone (50%) Badly wounded zone Safety zones base on EARDRUMS RUPTURE vs. LUNG DAMAGE criteria Movie represents EARDRUMS RUPTURE vs. LUNG DAMAGE for badly wounded zone

Poznan University of Technology PUBLIC SAFETY - RETROFITTING The structure model is upgraded by rigid door heads to increase public safety in the rooms. The results are presented below for two variants: 0.5 and 1m head high. The results are presented with use EARDRUMS RUPTURE criteria. WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, m head vs. 1m head for EARDRUMS RUPTURE criterion Movie represents EARDRUMS RUPTURE for 0.5m vs 1m high doors head and badly wounded zone

Poznan University of Technology PUBLIC SAFETY Because of using the rigid door heads there is a significant improvement of safety in the building WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010 Safety zones for basis and upgraded (1m door head) schemes of the floor under EARDRUMS RUPTURE criterion Safety zones for basis and upgraded (1m door head) schemes of the floor under LUNG DAMAGE criterion The safety area (green) increases 3 times after retrofitting process The safety area (green) increases 5 times after retrofitting process

Poznan University of Technology CONCLUSIONS Designer increases a value (square meters) of safety zone area in the structure after use of rigid 1m height door heading Obtained pressure values are comparable with real overpressure (in agreement with UFC) Approach may be useful for predicting blast resistant for new-designed or existing structures in relatively short time Mesh size sensitivity must be checked for analyzing of considerably complex structure including HVAC and elevator duct in the multi levels building WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010

Poznan University of Technology Thank you for your attention ! WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1-3 September, 2010