Poznan University of Technology ASSESSMENT OF PUBLIC SAFETY

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, 60 -965 Poznań, Poland e-mail: tomasz. lodygowski@put. poznan. pl, piotr. sielicki@put. poznan. pl 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) WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1 -3 September, 2010

Poznan University of Technology INTRODUCTORY REMARKS - Full spatial modeling covers 30 by 60 m 2 area and 3. 5 m high - Underground concrete office rooms with plant room in „p 1” - 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 Door heads are not included WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1 -3 September, 2010

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 Type of Charge Propane-Air Mixture Mass [kg] 330 Volume [m 3] 172. 8 Specific Energy [J/kg] 2. 73 e 7 Density [kg/m 3] 626 liquid 1. 9 mixture Detonation speed [m/s] 1680 - 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

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: Problem size: Element size: Analyzed time: Computational time: Boundary conditions: Abaqus 6. 9 Explicit code is used for calculation 2. 5 e 6 Finite Elements EC 3 D 8 R 0. 125 by 0. 125 m 3 0. 2 sec 3600 x 15 seconds (average time for one analysis) corridors rooms & (wall, floor, ceiling) are fixed with use of zero velocity condition 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. t= 0. 001 s t= 0. 005 s t= 0. 1 s WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1 -3 September, 2010

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 3 -340 -02, 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 Pressure – Time relation in the P 1 room Peak overpressure Duration time Specific Impulse* 0. 62 e 9[ Pa ] 0. 02 [ s ] 3. 1 e 6[ Pa s / W* ] Pressure contour lines 0. 001 s after detonation WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1 -3 September, 2010

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

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 1 m head high. The results are presented with use EARDRUMS RUPTURE criteria. 0. 5 m head vs. 1 m head for EARDRUMS RUPTURE criterion Movie represents EARDRUMS RUPTURE for 0. 5 m vs 1 m high doors head and badly wounded zone WORKSHOP 2010 ON CONSTITUTIVE MODELING IN APPLICATIONS FOR INDUSTRIAL PROCESSES KRAKÓW, 1 -3 September, 2010

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

Poznan University of Technology CONCLUSIONS Designer increases a value (square meters) of safety zone area in the structure after use of rigid 1 m 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