Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors Te-Chi Chen, Chia-Chun Yu, Cherng-Shing Lin
Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors 1
*1~3
Te-Chi Chen, 2 Chia-Chun Yu, 3Cherng-Shing Lin Department of Mechanical Engineering Yuan Ze University Taoyuan, Taiwan (R.O.C),
[email protected]
Abstract As metropolitan areas become densely populated in Taiwan, with high-rise buildings located everywhere; elevators are becoming essential transport tools in buildings. Elevators usually connect each floor with vertical transportation, and play a significant role in personnel and goods loading. However, a large elevator shaft can become a path to extend fire if fire happens. Large amounts of flame and smoke are produced during a fire and the rising characteristics of smoke mean it can go through channels, stairs, and pipes. With the stack effect of high-rise buildings, the entire building can fill with smoke in a very short time, causing the fire can quickly spread to each floor and cause serious personnel casualties. This study investigates fire door structural strength changes in high temperature situations by using ANSYS, finite element analysis software, to verify the resistance of fireproof elevator door. This study also investigates the influences of various parameters to explores the effect of fire resistance time and provide numerical reference data to designers.
Keywords: Elevator, Fire, Fire Door, Stack Effect 1. Introduction 1.1. Literature Review The elevator (lift) has become an essential tool for vertical transportation in high-rise buildings in Taiwan. Unfortunately, if fire occurs, the physical and chemical properties are changed and the structural strength decreased in elevator. When an elevator door is destroyed, fire smoke can spread through the elevator shaft as a stack effect to the top floor, for example: the MGM fire accident, and which caused heavy casualties. Therefore, to enhance the fireproof function for elevator door is an important task. This study develops numerical simulations and explores the fireproof and smoke-proof performance of various kinds of elevator door. Based on this analysis, we might have the reference for the elevator door in the fire protection and safety design. The high temperatures and toxic gas produced during a fire first pass through the elevator shaft to the top floor which makes it become the most dangerous area [1]. This phenomenon causes not only suffocation or poisoning, it also reduces visibility and possibilities to evacuate [2-3]. The toxic smoke is a much greater threat to human life than fire temperature. The Article 79 of local construction rules requires an elevator must be equipped with safety facilities to resist fire at least one hour [4-6]. According to CNS10594 requirements, the elevator entrance and exit on each floor must be made of uninflammable materials [7]. However, elevators on the market currently are always constructed from stainless steel or painted steel. Further study is necessary to determine whether this design can resist fire and smoke.
1.2. Elevator Construction and the High-Temperature Properties of Steel Most elevators include an elevator room, elevator shaft, elevator car, and elevator door. Elevator door (elevator fire door) can be constructed in closed form or free format form. The closed form is consistently made of steel plates 1mm to 1.5mm thick. The most common elevator in Taiwan is closed with a double field gate shown in Fig. 1.
Advances in information Sciences and Service Sciences(AISS) Volume4, Number19, Oct 2012 doi: 10.4156/AISS.vol4.issue19.65
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Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors Te-Chi Chen, Chia-Chun Yu, Cherng-Shing Lin
The tensile strength of steel will re duce 50% att temperaturee 1100 ℉ (5593 ℃) and the yiellding strengthh is far below w general dessign requirem ments, the exppansion rate iis approximaately 1%,, which resullts structure ddeformation aand or even collapse. In a general firee scenario, rooom tem mperature can reach 1100 ℉ (593 ℃) iin 5 min. Thherefore the eelevator doorr has to meett the fire resistance tim me requiremeents to ensuree the evacuation and fire rrescue. An analysis for steel de formation in high temperrature enviro nment must be based on the Euro steeel properties and temperaature. The folllowing discuussion providdes an overvview of the E stanndard EUROC CODE 3 [8]. About the firre and ANSY YS research reefer to the liteerature [9-15]]. Fig. 2 show the definitioon for the redduction coeffficient of the stress-strain value, the yyield stre ss is defined as the stress value at 2% strain, at 20 ℃. ℃ The effectivve yield stresss reduction factor again st the yield stress at 20℃ ℃ is definedd as folloows:
k y , f y , / f y The limit prooportional re duction factoor against the yield stress at a 20 ℃, is as a follows:
k p , f p , / f y The slope reeduction coeffficient of thhe linear elasstic range against the sloppe at 20℃ is as folloows:
k E , E a , / E a When the teemperature is below 400 ℃ and no crooss-section b uckling and strain increassing happpened, the strress-strain cuurve could bee extend alon g with the saame slop afterr the strain fiixed poinnt.
Figurre 1. Elevatorr door
Figgure 2. Steel sttress-strain rellationship in a high temperaature environm ment
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Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors Te-Chi Chen, Chia-Chun Yu, Cherng-Shing Lin
2. R Research M Methods The study used the BS-4476 elevator door d fire resiistance test too measure strructural strenngth variiations underr high temperrature condittions, and theen used this data as the basis b of ANS SYS simuulation validdation analyysis to dete rmine the Base B Case fire resistannce. This sttudy inveestigated variious parametter changes, such as heigght, width, annd materials,, to simulate the struuctural effectss of fire doorr in various conditions. Fig. F 3 illustraates the reseaarch process and Bas e Case test prrocess studie s are as folloows:
F Figure 3. Elevvator door simuulation processs In heat tests , as shown inn Figure 4, in which elevattor door and frames were combined wiith a BS-476 heatinng curve (Figg. 5), the relaation furnnace through lifting and thhen heated fo llowing the B of teemperature vvariation withh time was as follows:
T 3445 log( 8 t 1 ) 20 ℃) and t is tiime (min). where T is teemperature (℃
Figure 4. Elevator doorr and furnace
F Figure 5. Heaating curve
As the tempperature increeased graduallly, the elevaator door beccame red andd deformed. T This studdy used the 122 points on thhe non-heatedd side to meaasure and recoord deformation changes ((Fig. 6 & Table1).
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Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors Te-Chi Chen, Chia-Chun Yu, Cherng-Shing Lin
Figurre 6. The elevaator door and measurement m points Table 1. Deflection tesst results
3. T The Study 3.1 Numerical Modeling The elevatorr door is madde by pieces of o metal sheetts combined w with upper, l ower and midddle reinnforcements. This study extends the 3D elevator door geomettric model thhen uses ANS SYS withh the materiaal properties and boundarry conditionss to calculatee the deformaation under hhigh tem mperature, Figgure 7 shows the 3D geom metric model and indicatees cross-sectiion dimensionn of the elevator dooor. Followinng the BS-4476 specificaation heating curve of thhe elevator ddoor surfface layer annd the expeerimental datta collected by Chow et e al. [16], the heated fface convvection coeffficient was set from 7.55 W/ ㎡ ℃ too 9.5 W/ ㎡ ℃ , and the non-heated fface convvection coeffficient was seet at 4.5 W/㎡ ㎡℃.
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Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors Te-Chi Chen, Chia-Chun Yu, Cherng-Shing Lin
L
H
t
Length
Unit
Maaterial
5799
38
1.5
2400
mm
Stainlless steel
Figu ure 7. Elevattor door geo metrical mo odel
3.2 Case Studyy Plan This study uuses the defo rmation resuult of the fire experimentaal data then ccalculate the fire resi stance time from ANSY YS strength simulation then set thee result as the Base C ase. Sim mulating the other effectiive factor coombinations in ANSYS to t compare and analyze the variiation of firee resistance time with ddifferent facttor. Table 2 shows the simulation case c plannning: Table 2. S Simulation casse planning Elevator ddoor height: 24000 mm Elevator ddoor width: 1100 mm Base Case
Elevator ddoor material: sttainless steel SU US304 Elevator ddoor middle reinnforcement quanntity: 2 Elevator ddoor middle reinnforcement locaation: center
Case A1
Elevator ddoor width: 800mm
Case A2
Elevator ddoor width: 1500mm
Case A3
Elevator ddoor height: 20000mm
Case B1
Elevator ddoor material: C Carbon steel (AIISI 1020)
Case B2
Elevator ddoor material: C Carbon structuree steel (ASTM A A36)
Case B3
Elevator ddoor material: E Electro galvanizeed steel (SECC)
4. S Simulation Results and d Discussioons 4.1 Simulation n Results An nalysis T This study uuses the 12 ppoints (D1-D12) shown inn Figure 6 too measure thhe elevator fl floor defoormation caused by fire teemperature dduring the dooor fire resistaance test. AN NSYS simula tion show ws that D6 annd D7 were thhe weakest (F Fig. 8), there fore, we onlyy discussed foor D6 and D77. In the Base Case, m maximum defflection exceeeded 31.8 mm m when the elevator door was heatedd for apprroximately 1132 min. Th is value reppresents the maximum alllowed valuee in regulatioons. Theerefore, specuulated fire ressistance time is 132 min. T availablee sizes of elevvator door inn market are generally 8000 mm to 15000 mm wide, and The 200 0 mm to 240 0 mm high. A Among these dimensions, a common s tainless steell elevator dooor is abouut 800 mm orr 900 mm widde, 2100 mm m high, and 1. 5 mm thick. Changes in size s and mateerial of t he door can have a substtantial effect on fire resisstance perform mance. This article discusses
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Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors Te-Chi Chen, Chia-Chun Yu, Cherng-Shing Lin
Case A1, in which points D6 and D7 were the weakest areas. Other simulation results are presented in Tables 3. D6 measurement point: Fig. 9 shows the deformation difference between Case A1 and the Base Case. The figure shows that the maximum deflection at D6 was 36 mm after a 4-h heating test, which is lower than the maximum deflection 38.8 mm for the Base Case. The deformation for D6 is much higher than other measurement points. Because it is located in the center of the lift entrance and is a long distance from the upper and lower enforcements, deformation for D6 is the most serious. D7 measurement point: Fig. 10 shows the deformation difference between Case A1 and the Base Case. The figure shows that the maximum deformation at D7 was 35.3 mm after a 4-h heating test, which is lower than the maximum deformation of 36.8 mm in the Base Case. D7 was located in the center of the lift entrance and was a long distance from other enforcement pieces. Thus, its deformation was much higher than that found from other points. In Case A1, the elevator door width was reduced which shortened the distance in between D7 and the middle reinforcement limited D7 flexural deformation. This enhanced the structural strength of D7. Therefore, the Case A1 D7 maximum deflection was lower than that Base Case.
Figure 8. Base Case deformation difference amounts for D6 and D7
Figure 9. Deformation difference between Base Case and Case A1 D6
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Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors Te-Chi Chen, Chia-Chun Yu, Cherng-Shing Lin
Figure 10. Deformation difference between Base Case and Case A1 D7
4.2 Case A and B Simulation Results and Discussion. The following conclusions can be drawn from the elevator door fire simulation (Tables 3): Case A: Simulation results indicate that the geometry of the elevator door has a significant effect on fire resistance time. In case A1, elevator door width decreased from 1100 to 800 mm and fire resistance time increased 22 min. By contrast, in Case A2, the width increased to 1500 mm then the fire resistance time decreased 49 min. In Case A3, the height decreased from 2400 to 2000 mm and additional 21 minutes in fire resistance time. Therefore, Case A simulation shows that a small elevator door design is a priority. Avoiding an increase elevator door in the height and width can enhance fire resistance capability and increase evacuation time. Case B: Simulation results show that the door material has a significant effect on door fire resistance time. Elevator door are commonly made of four types of material: stainless steel, carbon steel, carbon structure steel, and electro galvanized steel. Among these materials and compare to the deformation of Base Case with stainless steel door, carbon steel in Case B1, carbon structure steel in Case B2 and electro galvanized steel in Case B3, Base Case deformation is much bigger. Such as Case B2, which employed a carbon structure steel door, showed a fire resistance time 20 min higher than a stainless steel. This effectively reduced door deformation at high temperature and increased human escape time. Table 3. Fire resistance comparisons between Case A 、Case B and Base Case Item
Fire resistance time Base case Fire resistance time Difference Remark
Case A1:Decrease elevator door width 154min
Case A2:Increase elevator door width
Case A3:Decrease elevator door height
81min
153min
Case B1: Carbon steel
Case B2:Carbon structure steel
Case B3:Electro galvanized steel
141min
152min
143min
132min
132min
132min
132min
132min
132min
+22min
-49min
+21min
+9min
+20min
+11min
+ : The fire resistance time increase - : The fire resistance time decrease
5. Conclusions and Recommendations The simulation results and recommendations are as follows: A) Within the scope of the regulations, elevator door dimensions should be as small as possible to improve fire resistance time. B) Elevator door material should be a low coefficient thermal expansion material, such as carbon structure steel, to reduce deformation in high temperature situations.
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Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors Te-Chi Chen, Chia-Chun Yu, Cherng-Shing Lin
Through comprehensive consideration, elevator door should be designed to give priority to geometry and material changes.
6. Acknowledgement The authors would like to express their gratitude to the National Science Council of the Republic of China for financially supporting this research under Contract No. NSC 100-2221E-155-076.
7. References [1] Chien-Ming Chen, “Former Congregate Domicile Straight Stair Refuge Safety Improvement Study”,Taiwan Science and Technology University Architecture School, 2006 [2] F.B. Clarke, “Physiological Effects of Smoke Managing Escape”, ASHRAE Transactions, Vol. No. 1103, pp.411~417, 1997 [3] Interior Ministry Architecture School, “Architecture Building Fireproofing Safety Performance Verification Technical Manual”, Taiwan, 2004 [4] Interior Ministry Architecture Office, “Architecture Technology Rules”, Taiwan, 2006. [5] K. Ghazi Wakili, L. Wullschleger, E. Hugi, “Thermal behaviour of a steel door frame subjected to the standard fire of ISO 834: Measurements, numerical simulation and parameter study”, Fire Safety Journal, Vol. No.43, pp.325~333, 2008 [6] Ministry of the Interior, “Former Architecture Fireproofing Equipment and Fire Protection Facilities Management Draft”, Taiwan, 2006 [7] Central Standard Inspection Office, “CNS 10594 Lift”, Taiwan, 2002 [8] EUROCODE 3, “Design of steel structures--Part 1, 2 General Rules --Structural Fire Design”, (DD ENV 1993-1-2: 2001 Corrected and Reprinted September), 2001 [9] Jing Ji, Wenfu Zhang, Wenyan Zhao, Chaoqing Yuan, Yang Yu, "Analysis and Comparison on Dynamic Characteristics of the Bridge Subjected to Moving Load Based on ANSYS”, JCIT: Journal of Convergence Information Technology, Vol. 7, No. 8, pp. 159 ~ 168, 2012 [10] Jing Ji, Wenfu Zhang, Wenyan Zhao, Chaoqing Yuan, Yingchun Liu, “Research of Seismic Testing and Dynamic Character of High-rise Building Structure Based on ANSYS”, JDCTA: International Journal of Digital Content Technology and its Applications, Vol. 6, No. 8, pp. 63 ~ 71, 2012 [11] Xie Liang, “An Improved WM Algorithm for the Firewall”, JDCTA: International Journal of Digital Content Technology and its Applications, Vol. 6, No. 8, pp. 107 ~ 116, 2012 [12] Liou Chu, Shih-Jung Wu, “A Real-time Fire Evacuation System with Cloud Computing”, JCIT: Journal of Convergence Information Technology, Vol. 7, No. 7, pp. 208 ~ 215, 2012 [13] Kongliang Chen, Ronghui Wang, Lurong Cai, “A New Element For Plate-truss Composite Bridge”, JDCTA: International Journal of Digital Content Technology and its Applications, Vol. 6, No. 11, pp. 18 ~ 28, 2012 [14] Kuang Ling, “Building of Forest Fire Early Warning System based on Modular Structure”, JDCTA: International Journal of Digital Content Technology and its Applications, Vol. 5, No. 6, pp. 429 ~ 437, 2011 [15] Fuxian Huang, “The Design of the Gateway Based On ARM and Its Application in the Intelligent Fire Control System”, JDCTA: International Journal of Digital Content Technology and its Applications, Vol. 6, No. 8, pp. 275 ~ 282, 2012 [16] W.K. Chow, Y.Y. Chan, “Computer Simulation of the Thermal Fire Resistance of Building Materials and Structural Element”, Construction and Building Materials, Vol.10 No.2, pp. 131~140, 1996
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Designed Numerical Simulation Calculations of the Fire Protection Capability of Elevator Doors Te-Chi Chen, Chia-Chun Yu, Cherng-Shing Lin
Notation Symbol
Ea Ea,θ θ θa fy fp,θ fy,θ
Description Elastic modulus in ambient temperature The slope of elastic range for steel in θa high temperature Temperature Steel temperature Yield stress of steel in ambient temperature The proportional limit of steel in high temperature The strength of steel before yield stress in high temperature
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