2015 SFPE Europe Conference on Fire Safety Engineering

Transcription

1 2015 SFPE Europe Conference on Fire Safety Engineering

2 THE FSE APPROACH FOR A HISTORICAL BUILDING IN LIGHT OF THE ITALIAN STANDARDS. Simonetto Sacco Luciano Nigro HUGHES ASSOCIATES EUROPE, srl FIRE SCIENCE & ENGINEERING

3 Framework of Regulations Any project to build or restructure a substantial building in Italy must be submitted to the Fire Authority for approval prior to commencing any work. The Fire Authority is the Fire Department same as for Fire Fighting This is especially true for Historical buildings that shall also be approved by the conservation authority. Slide 3 of 22

4 The case presented here A Historical Building in Venice, nearby the Rialto Bridge, to be reconstructed. The building is 50x50 m large with 20 m height and 4 stories. Entrance/exit will be from two sides only being the other two siding canals. A luxury shop will be the final destination of the building with assembly as well as restaurant as ancillary spaces. Slide 4 of 22

5 The prescriptive code The shopping areas in Italy are regulated by a decree issued in July 2010 covering all the aspects of construction, fire protection and escape routes in a prescriptive mode. One of the prescriptions is the vertical escape routes to be smoke proof Such a prescription cannot be accomplished for the building under consideration because of heritage constraints. Slide 5 of 22

6 The performance based approach 1/2 Since may 2007 an alternate approach is accepted by the local authorities in Italy, using a performance based analysis of one or more aspects of the project. Indications are given for the technical summary of the project where the scope of the analysis and the fire scenarios considered are declared. The technical summary is the first document to be approved by the AhJ before commencing the quantitative analysis. Slide 6 of 22

7 The performance based approach 2/2 The building under consideration has a major problem for compliance with the prescriptive code requiring the vertical escape routes to be smoke proof for the size and shape of the building The technical summary that was prepared deals with the specific aspect that cannot be complied with and with the proposed technical solution that is based on a mechanical smoke extraction system to be designed following an engineering analysis. Slide 7 of 22

8 The geometry 1/3 Two open stairs; one only protected stair. FDS model Second floor plan view Slide 8 of 22

9 The geometry 2/3 FDS model Section view Slide 9 of 22

10 Slide 10 of 22 The geometry 3/3 A typical «ASET Vs RSET» problem applies Step model Section view

11 The fire scenarios Two basic cases are considered for the fire scenarios. The first one being a fire in a shop protected with sprinklers because in a «covered area» The second one is a fire in the atrium at ground floor not sprinklered because of the ceiling height. A typical Display Kiosk HRR curve has been selected for this case, with two possible peaks. Slide 11 of 22

12 The HRR curves HRR [MW] 2 1,8 1,6 1,4 1,2 1 0,8 0,6 0,4 0,2 0 Curve Kiosk Tempo [s] Kiosk 1 [MW] Kiosk 2 [MW] 600 The fire grow is stopped at 0,65 Mw assuming a manual fire fighting action to be performed Curva FAST The fire grow is stopped at the first sprinkler activation, and kept constant HRR [kw] Tempo [s] Slide 12 of 22

13 The smoke extraction system The different fire scenarios are characterized by a smoke extraction system that is designed to extract smoke from the ceiling of the building with different flows. The activation of the smoke extraction is modeled with delays from 0 to 120 sec. The flow rate is modeled between 100,000 and 200,000 cu.mt. per hour Slide 13 of 22

14 The system schematic Slide 14 of 22

15 Fire Scenarios Summary Scenario HRR Curve Position of the fire Note Base Kiosk 1 measured curve, Max Ground floor yard in the No sprinkler protection; smoke Scenario HRR = 1,8 MW middle of the yard extraction actuated soon. Same as Kiosk 2, HRR limited by Ground floor yard in the No sprinkler protection; limited fire above, but manual intervention; max middle of the yard growth due to emergency intervetion; limited power 0,65 MW smoke extraction acivated soon Fire at Fast curve stopped at 0,5 Mw Third floor shopping area Sprinkler protection; smoke extraction ground floor because of sprinkler activation activated soon. Fire at Fast curve stopped at 0,5 Mw Second floor shopping area Sprinkler protection; smoke extraction second floor because of sprinkler activation activated soon. Fire at third Fast curve stopped at 0,5 Mw Third floor shopping area Sprinkler protection; smoke extraction floor with because of sprinkler activation activated soon. Additional extraction at extraction shop ceiling Slide 15 of 22

16 Results Control point locations The visibility was measured along two basic planes that included the main stairs in their location.

17 Results base Scenario Visibility stair SC3 200 seconds 360 seconds 500 seconds 680 seconds

18 Results base Scenario Visibility stair SC1 200 seconds 360 seconds 500 seconds 680 seconds

19 Results Base scenario limited Visibility stair SC3 200 seconds 360 seconds 500 seconds 680 seconds

20 Results Base scenario limited Visibility stair SC1 200 seconds 360 seconds 500 seconds 680 seconds

21 Results Ground floor scenario Visibility stair SC3 200 seconds 360 seconds 500 seconds 680 seconds

22 Results Ground floor scenario Visibility stair SC1 200 seconds 360 seconds 500 seconds 680 seconds

23 Results Second floor scenario Visibility stair SC3 200 seconds 360 seconds 500 seconds 680 seconds

24 Results Second floor scenario Visibility stair SC1 200 seconds 360 seconds 500 seconds 680 seconds

25 Results Third floor scenario Visibility stair SC3 200 seconds 360 seconds 500 seconds 680 seconds

26 Results Third floor scenario Visibility stair SC1 200 seconds 360 seconds 500 seconds 680 seconds

27 ASET evaluation The fire modeling of the different fire scenarios allow to estimate the available escape time as a consequence of the available time until the visibility is at least 10 m. The values for the different scenarios are always above 12 minutes for the third floor that is the most critical portion of the building to evacuate. The other areas have higher ASETs Slide 27 of 22

28 Same process for escape modeling summary of the configurations used for estimating the RSET Floor Surface( sq.m) Occupant Load Factor (pp/sq.m) Partial Occupant Load Total Occupant Load Commmercial Area 644 0,2 129 Ground Flooor Distribution Area 651 0, Inner Courtyard 339 1,2 407 Office 134 0,1 14 Mezzanine Commmercial Area 122 0, Service Areas about First Commmercial Area ,2 206 Distribution Area 324 0, Second Commmercial Area 993 0,2 199 Distribution Area 323 0, Third Commmercial Area ,2 221 Distribution Area 328 0, Fourth Pavillion 340 1,2 408 Distribution Area 130 0, * Altana (Panoramic Terrace) Panoramic Terrace ** *Number of occupants limited because of the restrictions in the exit width available (see 4.1 of D.M. 27 July 2010 Annex) **these occupants are already include into the Pavillion Occupant Load, for the same limitation mentioned above. According to ISO the following input data are used: Average speed for the persons: 1,25 m/s Minimum reaction time: 60 s for the first person Scenario Scenario A Total number of persons 1817 persons Scenario B 1817 persons 80 persons in the terrace

29 Results Scenario A Dt EVAC [s] Dt EVAC [min] Dt DET [s] Dt A [s] t RESET [s] t RSET [min] Total escape time for scenario A Mean time: ,33 60,00 15, ,58 Partial evacuation time per each floor Average time Ground floor ,33 60,00 15, ,58 Mezzanine floor 204 3,40 60,00 15, ,65 First floor 506 8,43 60,00 15, ,68 Second floor 359 5,98 60,00 15, ,23 Third Floor 247 4,12 60,00 15, ,37 Fourth floor 205 3,42 60,00 15, ,67

30 Results Scenario B Dt EVAC [s] Dt EVAC [min] Dt DET [s] Dt A [s] t RESET [s] t RSET [min] Total escape time for scenario B Mean time: ,37 60,00 15, ,62 Partial evacuation time per each floor Tempo Medio Ground floor ,37 60,00 15, ,62 Mezzanine floor 205 3,42 60,00 15, ,67 First floor 515 8,58 60,00 15, ,83 Second floor 365 6,08 60,00 15, ,33 Third floor 252 4,20 60,00 15, ,45 Fourth floor 211 3,52 60,00 15, ,77 Terrace 186 3,10 60,00 15, ,35

31 RSET evaluation The different scenarios in terms of people distribution in the building, are modeled with a simulation program named STEP The program conduct a series of simulations starting from a series of different distributions of the persons. The average time for the complete evacuation of the building is obtained as well as the time for the first person to evacuate e for the last one. The values are all around 5 minutes << the ASET Slide 31 of 22

32 Conclusions 1/3 It can be observed that, through the performance based approach, it was possible to solve the substantial problem posed by a heritage building that would never comply with the prescriptive measures included in most of the available fire codes. The new approach is now accepted by the authorities in Italy also. Slide 32 of 22

33 Conclusions 2/3 As a general comment, it should be noted that the fire engineering approach moves the burden of responsibility mostly from the authority over the professional engineer. Since the calculation processes are beyond the checking possibilities of most of the fire authorities, they limit the approval to the hypothesis used for the calculations and to the conclusions that the professional engineer is offering them. Slide 33 of 22

34 Conclusions 3/3 Because of this condition, the professional engineer that applies the engineering approach to the development of a fire safety project, has to be competent and responsible to a higher level with respect to the application of the prescriptive codes that can be checked in detail by the authority too. Slide 34 of 22

35 End of Presentation QUESTIONS? Simonetto Sacco: Luciano Nigro: HUGHES ASSOCIATES EUROPE, srl FIRE SCIENCE & ENGINEERING

36 2015 SFPE Europe Conference on Fire Safety Engineering

37 Assessment of Construction Stage External Fire Spread from Timber Buildings Jianqiang Mai, Dr, University of Central Lancashire

38 Introduction: Timber building at construction stage Building example

39 Introduction Fire spread issue with timber building Similar to non-combustible construction at building use stage when fire protection systems are adequately installed High fire load density at construction stage Large unprotected area at construction stage Fire accident: Colindale fire

40 Introduction Principle of external fire spread assessment To avoid pilot ignition of adjacent building Condition for pilot ignition of dry wood: 12.5 kw/m 2 incident thermal radiation Worst case fire scenario: flashover will generate the highest temperature in a compartment, eject flames from openings, and therefore create the highest thermal radiation 84kW/m 2 and 168kW/m 2 radiant sources

41 Introduction External fire spread assessment for finished building Assessment of radiative heat transfer Dependence of separation distance on unprotected area Guidance (e.g. BR 187) and SFPE Handbook Should 84kW/m 2 or 168kW/m 2 radiant source be used?

42 Introduction External fire spread issues at construction stage Fire protection systems could be not installed when the timber structure and walls are completed The whole building could be unprotected Therefore the unprotected area at the construction stage could be significantly larger than the design value

43 Assessment method 1 Radiant panel method Unprotected areas are treated as radiant panels Radiant intensity of the radiant panels can be determined following AD B or BR 187 in UK. Configuration factors are calculated using analytical equations Emissivity can be assumed to be unity Alternative: CFD

44 Case study 1 Radiant panel method Two identical radiant panels of 5m by 5.9m and 11.4m away Radiant intensity of the radiant panel 84kW/m 2. Two parallel surfaces considered Emissivity is assumed to be unity Comparison of analytical and CFD results

45 Case study 1 : Results Analytical model: Two parallel identical rectangular plates CFD model: Same as analytical Analytical result 5.29 kw/m 2 CFD result 5.18 kw/m 2 Difference 2.1%

46 Assessment method 2 CFD radiant panel method (FDS) All building walls, structure elements, and roofs are treated as radiant panels Wall openings are treated radiant panels considering window plume conditions Radiant intensity is of wood fire Combustion model is not required Avoid calculation of configuration factors Suitable for complex geometries

47 Case study 2: Geometry and boundary

48 HRR of wood When consider a radiative fraction of 0.35, a selfsustained fire would give 250kW/m 2 HRR. If 1/2 of the radiative heat is fed back to the fire bed, the incident radiative heat to the fire bed is approximately 44kW/m 2.

49 Case study 2: Results

50 Assessment method 3 Computational fluid dynamics simulation Wood frames and walls are simulated as burning surfaces at constant burning rate Wall openings are modeled 35% of heat released from burning are radiated out of the combustion regions Heat released from the fire are determined from published literatures, at 300kW/m 2 in the simulated example.

51 Case study 3: Results Results

52 Assessment method 4 Computational fluid dynamics simulation Wood frames and walls are simulated as burning wood using a pyrolysis model Burning rate is determined by heat transfer to the burning area 35% of heat released from burning are radiated out of the combustion regions Heat released from the fire are determined by the physical and chemical properties of wood

53 Case study 4 Computational fluid dynamics simulation Yellow pine is used in the case study Physical and chemical properties are taken from SFPE Handbook, 3 rd Ed. All wood surfaces are ignited from the starting of simulation Burning rate is determined by heat feedback to the surface of the combustion area using a pyrolysis model

54 Case study 4: Results Results

55 Comparison of the methods CFD simulation results Method Method 2 Method 3 Method 4 Peak HRR (kw/m 2 ) Methods of reducing thermal radiation Construction procedure control Provide shields

56 Conclusions FDS can provide an effective way of assessing thermal radiation to surrounding buildings 84kW/m 2 radiant panel method is a conservative assessment method Fire models using constant burning rate and complex pyrolysis model give lower thermal radiation levels. Validating these models can improve external fire spread assessment. Construction procedure control or thermal radiation shields are typically needed at construction stage to satisfy the external fire spread requirement.

57 2015 SFPE Europe Conference on Fire Safety Engineering

58 Managing Fire Risk for Vulnerable People Accessibility of Targeted Fire Preventive Measures Karolina Storesund MSc, Research Scientist SP Fire Research AS

59 Introduction Background and goal Project overview Way forward

60 Prestudy in 2012 Fire fatalities in Norway Who dies in fires and why? Mapping of earlier work Identification of relevant data to collect Recommendations for further research

61 Fatal fires in Norway fatalities every year Most fatalities in dwellings 36 % of victims elderly people 77 % of fatalities in vulnerable groups

62 Studies in Norway, Sweden and Denmark show: Elderly; greater risk of dying in fires Men; greater risk of dying in fires Open fire, smoking the most common causes of fatal fires 62

63 Vulnerable groups Reduced physical and mental health of importance for detecting and escaping from a fire. People with different types if disabilities are overrepresented in death fire statistics.

64 Vulnerable groups People living alone (detecting and escaping) Socioeconomical factor may influence the risk

65 Vulnerable groups Cultural and ethnical background may influence the risk and the way fire safety measures should be communicated

66 Why do people still die in fires?

67 Ongoing project Targeted technical and organisational measures to reduce the number of fire fatalities

68 Project goal Guidance on how to improve interaction and to make the correct technical equipment more available for people in vulnerable groups

69 How to implement measures Understanding structural conditions (formal) Analyse structural conditions in practice

70 Norway 428 municipalities 4 mill in densely populated areas 1 mill in sparsely populated areas

71 Risk Identify risk Decide on measures Implement measures Property management Action Documents Fire service Home care service Interaction Decision Follow-up on measures based on changes in risk Occupant Relatives Action

72 Technical measures Mapping of current access to technical solutions What is working and in which situations? What is still lacking?

73 Organisational measures Examples of cooperation that is working. Authorities, health personel, private How to improve interaction?

74 Technical preventive measures Detectors and alarms Extinguishing systems Fire safe furniture + other good measures

75 Technical preventive measures «Forgiving systems» Daily operation should require No extra costs No extra human resources

76 Stove guards an example SINTEF NBL report 2011 Two main groups involved: Men age at night Elderly women at daytime

77 Stove guards an example Norwegian legislation since July 2011 EN published in March 2015

78 Way forward Interviews Workshops Literature study, information Project to be finalised October 2015

79 Contact us Telephone:

80 2015 SFPE Europe Conference on Fire Safety Engineering

81 Performance-based Analyses of Prescriptive Code Solutions Joe Vaughn, P.E. Associate Manager-Pacific Rim

82 The beginning

83 The project Korea Fire Code International Building Code (IBC) National Fire Protection Association (NFPA) standards November 14, 2013

84 The project team Project/End User Azerbaijan Third Party United Kingdom A/E Firm Seoul, South Korea Fire Engineer Seoul, South Korea Joe Vaughn, P.E. Robert Keough, P.E., SET Macau SAR, China Simon Goodhead, P.E., CEng, MIFireE Atlanta, USA Jim Antell, AIA Kuala Lumpur Stephen Hill, P.E. Washington D.C.

85 Building layout and code issues Tower levels Ground floor

86 ASET vs RSET Shortfalls No performance-based design brief for initial agreement with project stakeholders Small, sprinkler-controlled fires remote from exits No elevator lobby fire scenario Assumptions were not conservative

87 Prescriptive based solutions 2-hour horizontal exits 1-hour corridors

88 Prescriptive based solutions

89 Meeting in Seoul Prescriptive based solutions ASET vs RSET challenges

90 The turning point What is an acceptable level of risk? International Fire Engineering Guidelines (IFEG) Comparative method

91 Initial written procedures Deficiencies and enhancements Goals of analysis Failure criteria Fuel sources Fire scenarios Sensitivity analysis Assumptions

92 Comparative analysis As-built Model Code Compliant Model

93 Elevator lobby analysis

94 Report results Comparative Analysis: Elevator Analysis:

95 Engineering design brief Fires outside lift lobbies equivalent to IBC Design limitations and management approach in lift lobbies Elevator hazard analysis Numerous enhancements

96 Lessons learned Respect your 3 rd party peer reviewer. Get agreement up front. Prescriptive based solutions are easily accepted by third parties, but harder for owners (Letter of the law vs. spirit of the law) Fire protection and life safety is a holistic approach, and the minimum acceptable level of risk varies with the jurisdiction. Prescriptive based solutions don t meet criteria of performance based analyses Comparative method and management approaches are underutilized Paradigm shifts are difficult. Repetition is required for acceptance. You can t expect what you don t inspect. Competent third party review is essential for code compliance.

97 Thank you Contact Joe Vaughn, P.E (671) For More Information Visit 97

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