Comparison of the Combustion of Pine Species with Two Sizes of Calorimeter: 10 g vs. 100 g

This study aims to analyze the scale effects on the combustion dynamics and smoke emitted during the burning of vegetation species under laboratory conditions. Experiments were carried out at two scales of combustion with two fuels (Pinus pinaster and Pinus laricio needles). Two oxygen consumption calorimetry devices were used: the cone calorimeter with samples in the scale of 10 g, and Large Scale Heat Release rate calorimeter (LSHR) with samples in the scale of 100 g. Fuel loads of 1.2 kg m^?2 and 1.04 kg m^?2 were considered respectively for Pinus pinaster and Pinus laricio needles. The parameters investigated to analyze the combustion dynamics are the heat release rate, combustion efficiency and mass loss rate. Measuring the extinction coefficient allowed us to obtain the soot emission factor. The emission factors of the combustion gases were obtained by using FTIR and NDIR detectors. A carbon mass balance showed that more than 95% of carbon was recovered. This study revealed an effect of scale on the combustion dynamics (peak HRR of 806 kW m^?2 and 651 kW m^?2 respectively at the bench scale and at full scale for Pinus pinaster), total smoke production, soot emission factor (1.32 g kg^?1 and 5.17 g kg^?1 respectively at the bench scale and at full scale for Pinus pinaster) and nitrogen compounds emission factors (2.47 g kg^?1 and 5.25 g kg^?1 for the NO respectively with the cone calorimeter and LSHR for Pinus laricio). Combustion efficiency appeared to be largely independent of the combustion scale (96.89% and 96.61% respectively at the bench scale and at full scale for Pinus pinaster). We also observed differences in the fire behavior for both types of needles.     

Experimental Study on the Combustion Characteristics of Primary Lithium Batteries Fire

The use of lithium batteries requires understanding their fire and explosion hazards. In this paper, a report is given on an experimental study of the combustion characteristics of primary lithium batteries. Burning tests of single and bundles of primary lithium batteries were conducted in a calorimeter to measure their heat release rates when exposed to an irradiance of 20 kW m^?2. Several variables including time to ignition, mass loss, heat release rate and plume temperature were measured to evaluate the ignition and combustion characteristics. The burning batteries were observed to have flame temperatures in excess of 1,200°C and to release corrosive compounds. The experimental results show that the combustion efficiency, carbon dioxide yield and mass loss are proportional to the number of batteries in the bundle. The total heat released by battery bundles was deduced empirically to be proportional to the number of batteries with a power of 1.26. The results provide experimental basis for the development of fire protection measures during the use, storage and distribution of primary lithium batteries.     

Errors in the Compilations of Minimum Explosion Concentration Values for Dust Clouds

Database tabulations of minimum explosion concentration MEC for dust clouds often contain data values that are extremely low, i.e., 30 g m^?3, or lower. Such values invariably represent measurement or analysis errors, often due to inadequate dust uniformity in the test vessel. There are only two organic vapors with MEC values below 30 g m^?3, and it is physically implausible that either stationary or randomly moving dust clouds would be more efficient in combustion than vapors. Combustion of dust clouds will have all of the types of heat losses that occur with burning of vapor clouds, but have additional sources of heat losses, particulate radiation and endothermic pyrolysis, not present for vapors (dusts of unstable chemicals are not considered in this paper). Thus, MEC values for dust clouds necessarily have to be higher than for vapors. Other sources of error for dust cloud MEC values have also been identified. These include incorrect data analysis, unrealistic pressure-rise criteria for what constitutes an explosion, and excessive igniter energies used in some apparatuses. German data based on VDI 2263-1 should be post-corrected for statistical treatment errors. But no specific correction exists for low reported MEC values due to mixture nonuniformity or inappropriate pressure criteria. It is recommended that any reported MEC values below 65 g m^?3 for cellulosic agricultural dusts, below 35 g m^?3 for any other organic dusts, and below 55 g m^?3 for dusts of metals or non-metallic elements be expunged as likely to be incorrect. Even at higher MEC values, there is likely to be a systematic bias in the data and this needs to be considered in longer-range research. ASTM E1515 offers more reliable testing and data analysis procedures than does VDI 2263-1 and is preferred.     

Predicting the Fire Dynamics of Exposed Timber Surfaces in Compartments Using a Two-Zone Model

There is an increasing desire to use more engineered timber products in buildings, due to the perceived aesthetics of timber and desire for more sustainable architecture. However, there are concerns about fire performance of these products especially in taller buildings. This has led to renewed research to understand the behaviour of timber surfaces in compartments exposed to fire. This paper describes a two-zone calculation model for determining the fire environment within a compartment constructed from timber products where varying amounts of timber are exposed on the walls and ceiling. A set of eight full-scale compartment experiments previously reported in the literature are used to assess the capability of the model. The fire load energy density in the experiments ranged from 92 MJ/m² to 366 MJ/m² comprising either wood cribs or bedroom furniture with the largest compartment having dimensions 4.5?×?3.5?×?2.5 m high with an opening 1.069 m wide?×?2.0 m high. The experiments were ventilation-controlled. It is shown that the model can be used to provide conservative predictions of the fire temperatures for compartments with timber exposed on the walls and/or ceiling as part of an engineering analysis. There are several limitations that are discussed including the need to consider the debonding of layers in the case of cross-laminated timber. It is recommended that further benchmarking of the model be done for different ventilation conditions and with engineered timber products where debonding does not occur. This will test the model under a wider range of conditions than examined in this paper.     

Numerical Simulation of Fire Exposed Façades Using LEPIR II Testing Facility

The fire behavior of external wall insulation system on façades is assessed during LEPIR II testing. This facility involves a 600 kg wood crib fire in a 30 m³ lower compartment of a two levels high concrete structure. External flames develop in front of the façade from the fire compartment through windows with dimensions 1?×?1.5 m (W?×?H). In order to predict the fire exposure of a façade during the test, CFD simulations were carried out with the computational fluid dynamics code Fire Dynamics Simulator (FDS) for two full-scale experiments. The main objective of this study was to evaluate the ability of FDS to reproduce quantitative results in terms of gas temperatures and heat fluxes close to the tested façade. This is an important step before the fire performances of any insulation system can be predicted by numerical tools. A good repeatability was observed in terms of measured gas temperatures for experiments. Maximum heat release rate of the fire, close to 5 MW, was achieved after 5 min of test. When experimental results were compared with numerical calculations, good agreement was found for every quantity. The most critical zone on the facade is located above the fire room and is directly impacted by external flame outgoing from the fire compartment. Temperatures up to 500°C were observed in this zone. For the thermocouples located up to the second level opening, these probes were not located directly in the flames, but rather in the hot gases above the fire plume. The maximum temperature achieved was thus close to 400°C. The proposed model gives correct thermal loads and flames shape near the façade during calibration tests and can be used for further evaluation of combustible material on façade.     

Experimental Study on Downslope Fire Spread over a Pine Needle Fuel Bed

The downslope fire represents a percentage of wildland fireline while the heat transfer mechanism of this process is poorly understood. In this study, the experiments were carried out in a fuel bed of dead pine needles with the slopes of ??30°, ??20°, ??10° and 0° for 0.4 and 0.8 kg/m² fuel loads. Flame length, flame angle, temperatures over the fuel bed, flow speed at the fuel bed surface, radiation heat flux near the end of the fuel bed were measured. The rate of spread shows a parabolic shape which decreases firstly and then increases from 0° to ??30°. The combustion interface, reconstructed from the temperature histories of two vertical thermocouples, was perpendicular to the fuel bed under all slope conditions for two fuel loads. The measured radiation heat flux is higher at ??30° slope than level ground, which is attributed to higher flame emissivity. A quasi-physical model was developed to describe the heat transfer mechanism of downslope fire spread. The calculation results show that the flame radiation dominated the downslope fire spread process and the combustion zone radiation should not be neglected in the near flame region.     

New Approaches to Evaluate the Performance of Firefighter Protective Clothing Materials

This paper presents new proposals in the evaluation and determination of the optimum materials suitable for use in the design and development of firefighter protective clothing by simultaneously addressing the conflicting factors of thermal protection [heat transfer index (HTI), radiant heat transfer index (RHTI) and thermal threshold index (TTI)] and anti-heat stress [water vapor resistance (WVR) and total heat loss (THL)]. To achieve this, this paper proposes new indices for the materials, two types of “total performance” indices, which are defined as the sum and the product of the competing factors of thermal protection and anti-heat stress. The results showed that the candidate materials of firefighter protective clothing were easily rated when the new indices were applied. Of five candidate materials viz. A, B, B₁, B₂ and C, the B sample, with values for HTI₂₄?=?13.2?±?0.2 s, RHTI₂₄?=?18.0?±?0.8 s, TTI?=?1132?±?33 J/m², WVR?=?17.5?±?0.3 m² Pa/W and THL?=?266.2?±?4.1 W/m², was found to exhibit the best total performance. However, the methods proposed to the scientific community in this paper have so far been validated on a limited data set only, and will require further validation by a wider group of researchers and with more samples. Lastly, comments on ISO 11999-3:2015 were also made for the further improvement and development of technical standards.     

Automatic fire detection in road traffic tunnels

Fire detection experiments in a road traffic tunnel were performed in the Runehamar test tunnel 5th–8th March 2007. The Runehamar test tunnel is a full profile road traffic tunnel, 1.65 km long, located outside Åndalsnes, Norway. The goal was to examinate smoke and heat detection systems to determinate what kind of principle best suited for detecting a fire in an early stage. The systems were tested during small Heptane pool fires, varying between 0.16 m² and 1 m², giving heat release rates from 0.2 MW to 2.4 MW accordingly, and one car fire of about 3–5 MW, and with wind conditions varying from 1.1 m s^?1 to 1.6 m s^?1. The size of the fires, were designed to be in the range from impossible to difficult to detect. The results were conclusive. Earliest detection of a car fire, fire starts inside, was by smoke detection given fixed limits (3000 μg m^?3). With open pool fires, or immediate flames, continues fibre optical heat detection systems was faster given the limits 3 °C/4 min.     

Assessment of Fire Engineering Design Correlations Used to Describe the Geometry and Thermal Characteristics of Externally Venting Flames

Externally venting flames (EVF) may emerge through openings in fully developed under-ventilated compartment fires, significantly increasing the risk of fire spreading to higher floors or adjacent buildings. Several fire engineering correlations have been developed, aiming to describe the main characteristics of EVF that affect the fire safety design aspects of a building, such as EVF geometry, EVF centreline temperature and EVF-induced heat flux to the façade elements. This work is motivated by recent literature reports suggesting that existing correlations, proposed in fire safety design guidelines (e.g. Eurocodes), cannot describe with sufficient accuracy the characteristics of EVF under realistic fire conditions. In this context, a wide range of EVF correlations are comparatively assessed and evaluated. Quantification of their predictive capabilities is achieved by means of comparison with measurements obtained in 30 different large-scale compartment-façade fire experiments, covering a broad range of heat release rates (2.8 MW to 10.3 MW), ventilation factor values (2.6 m^5/2 to 11.53 m^5/2) and ventilation conditions (no forced draught, forced draught). A detailed analysis of the obtained results and the respective errors corroborates the fact that many correlations significantly under-predict critical physical parameters, thus resulting in reduced (non-conservative) fire safety levels. The effect of commonly used assumptions (e.g. EVF envelope shape or model parameters for convective and radiative heat transfer calculations) on the accuracy of the predicted values is determined, aiming to highlight the potential to improve the fire engineering design correlations currently available.     

Smoke Damage Potentials in Industrial Fire Applications

A methodology is presented for the evaluation of smoke damage contours through the coupling of smoke damage functions, deposition profiles and damage thresholds. Previously developed smoke damage functions and deposition velocities are used to illustrate “far-field” smoke damage potentials both for materials representative of semiconductor fabrication facilities as well as large warehouse storage applications. For semiconductor fabrication, smoke damage associated with leakage current (LC) is important, while smoke staining is of primary interest in warehouse storage. Smoke deposition velocities, a key component to quantifying smoke deposition profiles, were determined in a small (1.0 m³) and large (1,200 m³) enclosure. Both enclosures resulted in comparable values. The velocities ranged from 1.2 to 7.3 × 10^?4 m/s. To determine smoke damage potential contours for semiconductor fabrication facilities, electronic circuit board targets were used. Smoke damage was quantified by LC (i.e., shorting). The average normalized LC values for polyvinylchloride, polycarbonate, and nylon ranged from 0.72 to 6.1 × 10^?4 A m²/g. For warehouse storage facilities, filter targets were used. Smoke damage was quantified by brightness change and odor (i.e., volatile organic compounds, VOC) measurements on the targets. Representative materials were liner board, polystyrene, and polymethyl methacrylate. The smoke damage threshold value for brightness change was 0.012 g/m² and for odor was 0.025 g VOC/m². Resulting contours showed strong radial dependency with distance from the fire/smoke source. Smoke damage reached ~28 m for semiconductor fabrication facilities, while for warehouse storage facilities, it was up to 100 m.     

Polyamide 6 and Polyurethane Used as Liner for Hydrogen Composite Cylinder: An Estimation of Fire Behaviours

The most advanced gas storage cylinders are composed of a high molecular weight polymeric liner and fibre reinforced composite. The goal of this paper is to study in ISO 5660 cone calorimeter the thermal behaviours of carbon fibre/epoxy composite covered by a liner made of polyamide 6 (PA6) or polyurethane (PU). Time-to-ignition, amount and rate of mass loss, heat release rate, total heat release rate and effective heat of combustion were measured and calculated at three irradiance levels (20, 40 and 60 kW m^?2). The main exhaust gaseous species evolution as well as oxygen consumption were also quantified during the thermal decomposition process. The transient temperatures were measured at middle-thickness of composite layer and at composite/liner interface by using K-type thermocouples. Indeed, these technical data play a significant role to choose the adequate liner to be used for full-composite cylinder application. Results show that the liner type has no effect on flaming ignition of exposed composite as well as the temperature profiles within materials. Comparing to PA6, the PU liner presents a faster melting and decomposition rate (i.e. with a lower thermal resistance), a lower heat release rate levels and low major gas (i.e. CO, CO₂ and NO) emission yields (i.e. a lower gaseous product toxicity). Based on the comparison of the fire-to-reaction properties, the PU thermoplastics are recommended to be used as liner to cover gas storage composite cylinder.     

Experimental Characterisation of the Fire Behaviour of Thermal Insulation Materials for a Performance-Based Design Methodology

A novel performance-based methodology for the quantitative fire safe design of building assemblies including insulation materials has recently been proposed. This approach is based on the definition of suitable thermal barriers in order to control the fire hazards imposed by the insulation. Under this framework, the concept of “critical temperature” has been used to define an initiating failure criterion for the insulation, so as to ensure there will be no significant contribution to the fire nor generation of hazardous gas effluents. This paper proposes a methodology to evaluate this “critical temperature” using as examples some of the most common insulation materials used for buildings in the EU market, i.e. rigid polyisocyanurate foam, rigid phenolic foam, rigid expanded polystyrene foam and low density flexible stone wool. A characterisation of these materials, based on a series of ad-hoc Cone Calorimeter and thermo-gravimetric experiments, serves to establish the rationale behind the quantification of the critical temperature. The temperature of the main peak of pyrolysis, obtained from differential thermo-gravimetric analysis under a nitrogen atmosphere at low heating rates, is proposed as the “critical temperature” for materials that do not significantly shrink and melt, i.e. charring insulation materials. For materials with shrinking and melting behaviour it is suggested that the melting point could be used as “critical temperature”. Conservative values of “critical temperature” proposed are 300°C for polyisocyanurate, 425°C for phenolic foam and 240°C for expanded polystyrene. The concept of a “critical temperature” for the low density stone wool is examined in the same manner and found to be non-applicable due to the inability to promote a flammable mixture. Additionally, thermal inertia values required for the performance-based methodology are obtained for PIR and PF using a novel approach, providing thermal inertia values within the range 4.5 to 6.5 × 10³ W² s K^?2 m^?4.     

Burning Characteristics of Automotive Tires

The ignition and burning characteristics of individual un-mounted automotive tires are presented including heat release rate and heat flux. The propensity for ignition at various locations on the tire is discussed. The burning characteristics of the tire are discussed for both accelerated and non-accelerated fires along with the effects of tire orientation on burning behavior. Ignition by non-accelerated means was only successful at the tire bead. Ignition location was found to have an effect on time to fire growth and overall burning duration with times ranging from 16.5 min to 47.5 min. Duration of significant burning was 25 min to 30 min for the sidewall orientation and 10 min to 15 min for the on-tread orientation. Tires in the on-tread orientation provide a substantially greater heat release rate (350 kW to 450 kW) and corresponding radiant ignition hazard (20 kW/m² to 35 kW/m²) than the sidewall orientation (200 kW and 10 kW/m² to 13 kW/m²).     

Flame Heights and Heat Transfer in Façade System Ventilation Cavities

The design of buildings using multilayer constructions poses a challenge for fire safety and needs to be understood. Narrow air gaps and cavities are common in many constructions, e.g. ventilated façade systems. In these construction systems flames can enter the cavities and fire can spread on the interior surfaces of the cavities. An experimental program was performed to investigate the influence of the cavity width on the flame heights, the fire driven upward flow and the incident heat fluxes to the inner surfaces of the cavity. The experimental setup consisted of two parallel facing non-combustible plates (0.8 × 1.8 m) and a propane gas burner placed at one of the inner surfaces. The cavity width between the plates ranged from 0.02 m to 0.1 m and the burner heat release rate was varied from 16.5 kW to 40.4 kW per m of the burner length. At least three repeated tests were performed for each scenario. In addition, tests with a single plate were performed. The flame heights did not significantly change for Q′/W < 300 kW/m² (where Q′ is the heat release rate per unit length of the burner and W is the cavity width). For higher Q′/W ratios flame extensions up to 2.2 times were observed. When the distance between the plates was reduced or the heat release rate was increased, the incident heat fluxes to the inner surface increased along the entire height of the test setup. The results can be used for analysing methodologies for predicting heat transfer and fire spread in narrow air cavities.     

The effect of fuel area size on behavior of fires in a reduced-scale single-track railway tunnel

A set of experiments was carried out in a 1/9 reduced-scale single-track railway tunnel to investigate the effect of fuel area size on the temperature distribution and behavior of fires in a tunnel with natural ventilation. Methanol pool fires with four different fuel areas 0.6 × 0.3 m² (1 pan), 1.2 × 0.3 m² (2 pans), 2.4 × 0.3 m² (4 pans) and 3.6 × 0.3 m² (6 pans), were used in these experiments. Data were collected on temperatures, radiative heat flux and mass loss rates. The temperature distribution and smoke layer in the tunnel, along with overflow dimensions and radiant heat at the tunnel entrance were analyzed. The results show that as the fuel area enlarges, the fire gradually becomes ventilation-controlled and the ceiling temperature over the center of fire source declines. Burning at the central region of fire source is depressed due to lack of oxygen. This makes the temperature distribution along the tunnel ceiling change from a typical inverted V-shape to an M-shape. As observed in the experiments, a jet flame appeared at tunnel entrances and both the size and temperature of the flame increased with the enlargement of fuel area leading to a great threat to firefighters and evacuees in actual tunnel fires.     

Toward predictive simulations of pool fires in mechanically ventilated compartments

The objective of this work is to propose an effective modeling to perform predictive simulations of pool fires in mechanically ventilated compartments, representative of a nuclear installation. These predictive simulations have been conducted using original boundary conditions (BCs) for the fuel mass loss rate and the ventilation mass flow rate, which depend on the surrounding environment. To validate the proposed modeling, the specific BCs were implemented in the ISIS computational fluid dynamics (CFD) tool, developed at IRSN, and three fire tests of the PRISME-Door experimental campaign were simulated. They involved a hydrogenated tetrapropylene (HTP) pool fire in a confined room linked to another one by a doorway; the two rooms being connected to a mechanical ventilation system. The three fire scenarios offer different pool fire areas (0.4 and 1 m²) and air change rates (1.5 and 4.7 h⁻¹). For the one square meter pool fire test, the study presents, in detail, the effects of the boundary conditions modeling. The influence of the ventilation and fuel BCs is analyzed using either fixed value, or variable, function of the surrounding environment, determined by a Bernoulli formulation for the ventilation mass flow rate and by the Peatross and Beyler correlation for the fuel mass loss rate. The results indicate that a full coupling between these two BCs is crucial to correctly predict the main parameters of a fire scenario as fire duration, temperature and oxygen fields, over- and under-pressure peaks in the fire compartment. Variable BCs for ventilation and fuel rates were afterward both used to predictively simulate the fire tests with a pool surface area of 0.4 m². The predicted results are in good agreement with measurements signifying that the model allows to catch the main patterns characteristic of an under-ventilated fire.     

A Quantitative Infrared Imaging System for In Situ Characterization of Composite Materials in Fire Tests

A novel non-intrusive measurement system based on quantitative infrared imaging has been designed and developed specifically for the study of composite plates submitted to fire. The system consists of two synchronized infrared cameras that image both sides of the sample during a fire test, providing surface temperature maps spatially corregistered. Flame effects on measured temperature are minimized through selection of a spectral band with near negligible infrared absorption-emission (wavelength centre 9585 nm, full width at half maximum 135 nm), as well as software post-processing. An ad hoc experiment has shown that this procedure retrieves surface temperatures with an uncertainty of \(\pm 5\) K, compared to a systematic error larger than 60 K for a classic thermographic measurement. Surface emissivities of both sides of the sample are measured and included in the retrieval procedure. By adding a flash lamp, the system implements an adaptation of the classical Parker’s flash method to thermally thick samples, providing also a map of thermal diffusivities along the sample both before and after the burning. In the region most degraded by fire, the effective thermal diffusivity is reduced approximately one order of magnitude as compared to the pre-test value (from 5.9 × 10^?7 m² s^?1 to 0.5 × 10^?7 m² s^?1). Several composite samples have been analysed while exposed to fire in different conditions, showing that thermal diffusivity after the burning shows a strong correlation with the local maximum temperature reached during the test. More precisely, in the temperature range between \(\sim \)325 and 350\(^{\circ }\)C a drastic change in diffusivity seems to takes place, in a way that suggest a phase change.     

Isolation,identification and development of culture medium in the production of Chlorella vulgaris

Microalgae have gained importance as a potential component of conventional food. The aim of the present study was to study the behaviour of the microalga Chlorella vulgaris in relation to the different carbon and nitrogen sources and to improve a culture medium in terms of glucose, urea, manganese chloride and sodium nitrate concentrations. In the investigation of the best source of carbon and nitrogen, it was observed that 1.14 mg L^?1 of glucose and 8.32 mg L^?1 of urea stood out with the production of 0.823 g L^?1 of dry biomass and yield of 52 mg L^?1 day^?1. The best growth rate and specific yield were achieved at the central points for all salts.     

Radioactive element contents of some granites used as building materials: insights into the radiological hazards

This study was conducted to investigate the radioactive potential hazard of granite, which is widely used as building material in Turkey. Natural radiation levels of 18 various, globally-distributed industrial granite samples imported by Turkey, were analyzed using gamma-ray spectrometer. The results are compared with the formerly published findings of granite samples from Turkey. Radioactivity levels of ²³⁸U, ²³²Th, and ⁴⁰K natural radioactive series elements of the selected 18 specimens were measured, which were from 2.4 ± 0.5 to 88.8 ± 3.6 Bq kg^?1 for ²³⁸U, from 2.4 ± 0.7 to 273 ± 0.9 Bq kg^?1 for ²³²Th, and from 169 ± 24 to 1,479 ± 94 Bq kg^?1 for ⁴⁰K. Radium equivalent activities (Ra_eq) were calculated for the granite samples to assess their radiation hazards in the construction of dwellings. The Ra_eq values of granite samples varied in the range of 39.05–570 Bq kg^?1, only one sample exceeded the safe limit value of 370 Bq kg^?1 set by the OECD-NEA (Nuclear Energy Agency. Exposure to radiation from natural radioactivity in building materials. Report by NEA Group of Experts 1979). Absorbed dose rates in air were found between 18.74 and 261 nGy h^?1 and radiogenic heat production values were calculated in the range of 0.45–6.53 μW m^?3. All rock samples used in this study were also analysed mineralogically and defined their compositions.     

The Impact of a Change on the Size of the Smoke Compartment in the Evacuation of Health Care Facilities

Evacuation in health-care facilities is complex due to the physical impairment of the patients. This kind of evacuation usually requires the assistance of the workforce members. A proposed change of NFPA 101, Life Safety Code, would increase the maximum allowable size of a smoke compartment (a space within the building enclosed by smoke barriers on all sides that restricts the movement of smoke) in health-care occupancies from 2090 m² to 3700 m², almost double the size. This study aims to analyse the impact of this change in the required time for evacuating patients during a fire in order to understand the consequences of that potential change. This paper is focused on the area where the patient’s rooms are located. The evacuation scenario is a floor plan comprised of four smoke compartments. To analyse the proposed change, the smoke barriers between two adjacent compartments were removed in a floor plan and three ratios of number of patients per one staff member were considered (4:1, 3:1 and 2:1). A computational methodology was conducted to calibrate the model STEPS for simulating assisted evacuation processes. In addition, Fire Dynamic Simulator (FDS) was used to simulate the fire and smoke spread in a table and a PC to compare fire and evacuation results The evacuation results show that the change of the smoke compartment size increases the mean evacuation time by 23%; however, the fire results show that the available safe egress time is 16 min for both smaller and large smoke compartment. The ratio of the number of patients per staff member is also a strong factor that increases the evacuation up to 82% when comparing the ratios of 2 patients per staff member and 4 patients per staff member.