Hot Smoke Tests Research Articles

Study on the Smoke Control Performance of Air Curtains in Emergency Stairwells of Multi-Unit Residential Buildings

Recently, in high-rise buildings, pressurization systems have been installed in emergency stairwells to prevent the ingress of smoke. However, in older buildings, these stairwells often lack pressurization systems, while in buildings with fewer stories, such systems are not typically installed. This study conducts simulations and a hot smoke test to evaluate the performance of air curtains in blocking smoke and toxic gases in outdoor emergency stairwells where additional pressurization equipment cannot be installed. The simulation results showed that air curtains installed perpendicular to the floor were useful at preventing smoke ingress, and higher wind speeds increased their effectiveness. It is believed that air curtains can partially reduce smoke ingress in stairwells of older buildings or low-rise structures without pressurization systems, thereby ensuring fire safety.

Study on the Performance of Sandwich Pressurization System

This study aims to outline a verification plan for domestic scenarios using the sandwich pressurization method. We employed four methods: T.A.B, hot smoke test, FDS, and pathfinder. T.A.B and fire and evacuation simulation did not exhibit any issues. However, the smoke flow was observed in both the upper and lower layers during the H.S.T. Evacuation safety was confirmed through simulation, including the adequacy of the procedure. Nonetheless, the introduction of smoke in the hot smoke test highlighted the need for enhancements to the sandwich pressurization method. Consequently, the hot smoke test, alongside T.A.B and fire and evacuation simulations, will enhance verification standards for the sandwich pressurization method.

A new approach to smoke control systems in complex atria

Large occupied spaces such as the atria can have additional internal elements like balconies, stairs, or decorations. Unfortunately, detailed design rules for smoke management systems are lacking in these large contemporary spaces. A series of smoke tests and CFD simulations were conducted to address this shortfall. The project’s first step was realised with full-scale hot smoke tests in Smoke Laboratory, which allowed the observation of a significant influence of the suspended balconies on smoke mass production. CFD simulations confirmed the preliminary observations and were used to evaluate this phenomenon quantitatively. This proved that the wider the balcony, the greater the mass increase. The same fire scenarios were examined with theoretical NFPA 92 correlations dedicated to axisymmetric and balcony spill plumes. They showed that using the standard axisymmetric plume correlation in a complex atrium could lead to a strong underprediction of the required smoke control system parameters. A proposed adapted balcony spill plume correlation can improve the smoke mase calculations. Practical application This study demonstrates that existing standards like NFPA 92 NFPA 204, or BS 7346-4. Do not cover the need for smoke control systems in complex and irregular atria solutions, which often appear in modern buildings. It has been proven that the obstructions in the atrium space significantly influence the smoke mass production. As a consequence, using the original axisymmetric plume correlation in a complex atrium could lead to a strong underprediction of smoke control system requirements. The authors proposed a new correlation for the approach to smoke control systems parameters approach at the design process.

Similarity assessment of using helium to predict smoke movement through buildings with double skin façades during building integrated photovoltaics fires

In comparison to the building attached photovoltaics (BAPVs), Building Integrated Photovoltaics (BIPVs) drive more changes in building envelope. Therefore, tackling the fire safety of building integrated photovoltaic is more complicated due to these changes and the interaction between photovoltaic panels and the building. The photovoltaic fire hazards, including smoke generation of solar glazing, closely affect the fire safety of the building and occupants. This effect is further exemplified in the case of solar double skin façade systems where the stack effect influences smoke spread from ignited integrated photovoltaic panels via the vertical space of plenum in double skin façade. In scientific research field, the sub-scale model or laboratory-scale experiments is often applied to study the building fire smoke spread, which is much less costly, time and effort consuming, compared with full-scale test. However, the major concern of the sub-scale fire tests is providing the efficient but safe ignition source. There are methods such as cold smoke and hot gas (hot smoke test), each of which has their specific limitations on the cost and safety. This paper proposes an alternative method of helium smoke to substitute the real fire test for simulating a real integrated solar façade fire. First the fire dynamic simulator model with helium source is validated by experimental helium test along with particle image velocimetry in terms of helium concentration and flow velocity. The differences between the experiments and simulations are in the acceptable range (23 and 24%). Helium smoke result similarity is then compared to small scale real fire which showed close agreement according to the small coefficient of variation (between 1.6 and 11%).

A study of repeatability of hot smoke test in a subway station

Hot smoke test is a key method for fire studies in metro systems. But most hot smoke test scenarios are conducted only once, which ignores the experiment uncertainties and errors. To quantify the uncertainty and repeatability of hot smoke tests in subway stations, seven experiments are repeated on a station platform. 120 thermistors are deployed among the platform to acquire the temperature curves in the experimental area. The concept of statistical analysis and functional analysis is adopted to study the error and turbulence caused by random effects. The results indicate that: (1) According to the fluctuation properties, the experiment area is divided into fire plume area and ceiling jet area. The data uncertainty of the fire plume area is significantly higher than the ceiling jet area. (2) The repeatability of temperature data in the fire plume area is poor. The difference between single experiment curve and average curve might reach 23%–24%. (3) The repeatability of the data in the ceiling jet area is much better with a deviation smaller than 7.8%. The validated experiment data presented in this work could be used for simulation model verification. The repeatability analysis method presented is applicable for other fire studies.

Visibility analysis by light attenuation ratio recorded with portable camera at the full-scale hot smoke test site

Some countries have enacted the full-scale hot smoke test standards to verify the effectiveness of smoke extraction systems. Unfortunately, the judgment of most performed tests is based on vision and lacks scientific value. It is important to establish a scientific and quantifiable measurement system for visibility judgment in a large space. This paper analyzed the visibility values obtained through the light attenuation in a full-scale hot smoke test site. The quadratic regression relationships between the gray scale values and the attenuation ratios were derived. The visibility of the test site can be also obtained by grayscale analysis of recorded images. A qualified emergency direction light was used as a light source, and a closed-circuit television and a portable camera were adopted for image recording. These images were converted into grayscale pictures to obtain the gray scale values at the center of the bright spot. By comparing with the light attenuation ratio of the quantifiable measurement equipment in front of the light source, the results showed excellent relevance and demonstrated the applicability of the captured images.

Relationship between Designed Fire and Performance of Smoke-Control System in a Living Room

The effects of the size of a designed fire on the ventilation system of an adjacent zone is estimated in this study based on a visibility requirement of 5 m in a non-fire zone at 600 s after ignition. To verify the adequacy of the fire dynamics simulator (FDS) input file, smoke movement and ceiling temperature under the hot smoke test conditions of AS4391-1999 were compared with those from the FDS results. The average temperatures measured at 12 locations were within the range of ± 2σ, with the exception of one point, and predicted smoke movement adequately. The size of the designed fire was analyzed in terms of the air volume conditions of the NFSC 501 for a heat release rate (HRR) of 1650 kW (air supply and exhaust at 45,000 cubic meters per hour (CMH)) as well as air volume conditions for a HRR of 1100 kW (air supply at 35,606 CMH and exhaust at 32,506 CMH). It was determined that one of the major factors influencing the required safety egress time was the mixture of downdraft airflow from the diffusers and smoke layer crossing the ventilation boundary.

Measurement of smoke generation rate using a full-scale hot smoke test for building smoke exhaust systems

In some countries, test standards have been adopted which measure the effectiveness of smoke exhaust systems in clearing out heat and smoke produced separately. However, because these standards provide no quantitative provisions for dealing with the amount of visual smoke, there is an unclear correlation between the amount of smoke generated and the fire load. This paper applied the homogeneity concept of using a smoke collection box to examine the smoke generation rate of a smoke generator using CO2 as the driving gas. To avoid using the previous visual method of judging the rates, this research used measurement equipment to conduct a scientific analysis. Thus, the results were more objective. The equipment used included a Closed-Circuit Television (CCTV) Camera, a thermocouple, a traditional P-type smoke detector, a digital R-type smoke detector, and light attenuation measurement equipment. Under release pressures of 40, 60 and 80 psi, a 15% smoke density required smoke generation at 6.50, 8.42 and 10.46 m3/s, respectively. Achieving a homogeneous distribution of smoke within the space was accomplished. The data obtained in the test could be used not only to judge the efficiency of a smoke exhaust system but also provide adjustment information for a smoke exhaust system.

Performance verification and enhancement of mechanical smoke exhaust system in full-scale hot smoke test for a large space

Full-scale hot smoke test standards have been issued in a number of countries, but the common method of judgment is a visual determination. As Marine Museum K has used a performance-based fire safety design and a numerical simulation during its design stage, this study employs instruments to measure and obtain quantitative comparisons, while enhancing the performance of the smoke exhaust system in different vent-opening modes. The results prove that the measured performance is consistent with the simulation results. The existing model observed that light attenuation is slight at less than 2%, 6% and 10% on the third, fifth and seventh floors, respectively. The effects of the open state of the front and rear vents on the first floor and the vent on the third floor are also discussed. The open mode of the upper and lower vents in Case 2 created a better performance than the other cases due to the excellent flow pattern. In Cases 3 and 4, the fire plumes were significantly disturbed by makeup-air through the vents on the lower floor after all fans were actuated, and the smoke diffused everywhere in the lower floors. This paper also found the disadvantages caused by the makeup air.

Assessment of Smoke Control Performance via. Fire Simulations and Hot Smoke Tests

Assessment of Smoke Control Performance via. Fire Simulations and Hot Smoke Tests

Hot smoke tests for smoke propagation investigations in long rail tunnels

Smoke propagation in an enclosed facility is always a matter of concern whenever the evacuation of people is necessary. The construction of long rail tunnels has made evacuation an even greater challenge. Long rail tunnels are equipped with emergency stop stations so that evacuation may still occur even when trains are on fire and incapable of leaving the tunnel. However, should a train breakdown occur between the portal and the emergency station, passenger evacuation has to be performed via cross passages and into the non-affected (safe) tube. This requires a balanced pressure regime between the two tunnel tubes and/or across the cross passages. The paper describes field tests which were performed in order to investigate smoke propagation in tunnel tubes and over cross passages in the event of severe fires. Fire tests up to 21 MW peak heat release rate were performed, and smoke propagation was monitored, with a strong focus on the situation at cross passages.

Experimental Study on the Characteristics of Fire Smoke Movement in Ultra Thin and Tall Atriums by Hot Smoke Test

The characteristics of smoke natural filling in ultra thin and tall atriums were investigated by hot smoke test method. For the fire located on the atrium ground, the smoke touched the side wall first and then extended both upwards and downwards. The smoke plume rising velocity variation can be divided into four stages, different from the normal law in large spaces. In the very early stage of natural filling, the smoke concentration near the height of wall touching point was highest and maintained at a high level in the whole process. The linear trend of temperature increasing in plume center above the height of touching point was broken, far less than the theoretical predictions, which verified the enhancement effect of boundary heat exchange caused by plume restriction. The variation tendencies of smoke density and temperature were similar during the hot smoke test,and there existed a good linear relation between these two parameters. The height-width ratio was calculated as 3.2 averagely by the test results when smoke plume would likely touch atrium walls, and it was very close to the theoretically derived value. This ratio can be used as the definition condition for ultra thin and tall atriums.

Study on Hot Gases Flow in Case of Fire in a Road Tunnel

This paper presents the results of hot smoke tests, which were conducted in a real road tunnel. The tunnel is located within the expressway S69 in southern Poland between cities Żywiec and Zwardoń. Its common name is Laliki tunnel. It is a bidirectional non-urban tunnel. The length of the tunnel is 678 m and it is inclined by 4%. It is equipped with the longitudinal ventilation system. Two hot smoke tests have been carried out according to Australian Standard AS 4391-1999. Hot smoke tests corresponded to a Heat Release Rate (HRR) equal to respectively 750 kW and 1500 kW. The fire source was located in the middle of the road lane imitating an initial phase of a car fire (respectively 150 m and 265 m from S portal). The temperature distribution was recorded during both tests using a set of fourteen thermocouples that were mounted at two stand poles located at the main axis of the tunnel on windward. The stand poles were placed at distances of 5 m and 10 m. The recorded data were applied to validate a numerical model, which was built and solved using Ansys Fluent. The calculated temperature distribution matched the measured values.

Study on Fire Smoke Control in Super-high Building Atrium

Abstract In this paper, hot smoke test was carried out in the atrium of 60m high in Shanghai Tower, the law of fire smoke movement and smoke control effect has been studied under different fire release rate and different ventilation conditions. In this paper, the Influence of different air supply volume on mechanical smoke exhaust in the atrium of Shanghai Tower has also been studied by numerical simulation. The results showed that: in the tall atrium, smoke rise rapidly with the speed of 2-3 m/s because of “chimney effect”; Because of the “thermal barrier effect”, when the fire power is small, the smoke tends to subside and cannot be effectively discharged; When air supply volume is 50% of smoke exhaust, it is beneficial to exhaust smoke.

Performance-based fire safety engineering assessment of national museum of marine science and technology

Abstract The concept of ocean current and fishery industry is expressed from the architectural design in using crossed exterior corridors to perform ocean current. The contrast between modern and obsolete is represented by the staggered interior design and antiquated building structure of the heritage, which is used to be North Thermal Power Plant. It is therefore partial areas which cannot fulfill the article 79-2 of Building Design and Construction Regulation mandated by Taiwan government that stipulate the requirement of any void space over 3 floors. Requirement of smoke extraction system and smoke curtain is also exempted from article 188 of Standard for Installation of Fire Safety Equipment Based on Use and Occupancy. Performance-based design is adopted by fire engineering approach as an alternative. This project passed the expert panel review of fire engineering strategies and smoke management assessment. At the stage of construction by auditing and reviewing, full-scale hot smoke test was conducted due to the safety consideration raised by local government. The results of tests are significantly different from the simulation modelling and smoke management report approved by National Fire Agency, Ministry of Interior. Visibility in partial areas is around 10 m which is not regarded as a tenable condition. After the improvement of smoke management, the study of full-scale hot smoke tests and computational simulated results are carried out. Acceptance criteria, usually smoke temperature, smoke layer height and visibility in Taiwan, are reached regardless of differences between FDS model and on-site full-scale tested values. This project provided design considerations to designer during design process, including the environmental differences of internal and external building, local weather impact, and grid size used in FDS model. The limitation and discrepancy of chosen software among different versions should be understood so that simulation results would more fit the realistic circumstances.

Study on Fire Evacuation and Smoke Spread of Atrium Metro Station

In recent years, the construction of subway in China is in a period of an rapid development. The passengers are in high density within the subway during the operation time, the problem of safety in emergencies has attracted more and more attentions. The structure of atrium metro station is special, fire partition area in the station is difficult to divide. And there is a hidden danger of fire, which is not easy to realize effective exhaust and smoke control. Once there is a fire the magnitude of injuries will be overwhelmingly disastrous. Therefore, more attention should be paid on pedestrian’s evacuation in subway stations. Therefore, an atrium subway station in Beijing is selected, hot smoke test and STEPS software simulation were carried out. We also analyzed the escape environment and escape routes, reasonable evacuation time is obtained, as well as a reasonable escape strategy.

Performance measurement of a smoke extraction system for buildings in full-scale hot smoke test

Abstract The current inspection method for a smoke extraction system in Taiwan measures whether the air flow of the smoke vent conforms to the design value. However, this method is inapplicable to natural smoke extraction systems. As the plugholing effect is disregarded, adequate air flow cannot ensure that the system will exhaust smoke effectively during a fire. Hence, a full-scale hot smoke test for smoke extraction systems is necessary. Some international test criteria are formulated using visible smoke and alcoholic fuel which is pollution-free after combustion. The effectiveness is judged only by visually observing the smoke’s flow direction, which is indeed unscientific. This study used a string of vertical smoke layer measuring instruments composed of several approved photoelectric smoke detectors, as well as a light attenuation measuring device composed of illuminance meters to conduct tests on the effect of makeup air. The results proved that the former one uses different height induction times to judge the position of the smoke layer effectively, while the latter one uses the light attenuation rate to distinguish the smoke density instantly and accurately. The obtained experimental data were consistent with the onsite smoke distribution. The two sets of equipment designed in this study can be used for full-scale hot smoke tests to obtain performance data for a smoke extraction system.

The Smoke Exhausts Research on Urban Underground Fast Road

The aim of this research is to verify the effectiveness of smoke exhaust system including natural, longitudinal and semi-transverse system in urban underground fast road. For this research, a series of hot smoke tests were accomplished in experimental field in The Ministry of Transportation test site. The temperature distributions were recorded by thermocouples and the smoke flow laws were counted by visibility sensors. Meanwhile, the temperature distributions in the tunnel has been simulated by using the Computational Fluid Dynamics (CFD) software of ANSYS CFX. In terms of the experiments and simulation above, the smoke flow characteristics were demonstrated. Some valuable advices are given finally which can be applied to the design of smoke exhausted system in urban underground fast road.

Using helium smoke as a surrogate of fire smoke for the study of atrium smoke filling

This study developed a method of using pure helium to generate a cold buoyant plume as the surrogate of a fire smoke for the study of the smoke-filling process in an atrium. Aided by the numerical simulations, a series of experiments in a 1:26.5 scale model of the full-size atrium with the fires up to 1.6 MW from the literature were conducted to investigate the similarity between a helium smoke and a hot fire smoke. Helium concentrations, smoke layer heights, and smoke optical densities were compared well between the current experiment and the simulations. The experimental study thus verified the capability of a helium smoke test to reproduce the smoke-filling process of the corresponding hot smoke test in the atrium studied. This study also showed how to model a hot smoke test with a t-squared fire by the corresponding helium smoke test by pre-mixing helium and artificial smoke in a mixing box.

Predicting Spill Plumes with the Fire Risk Zone Model B-RISK

Recent experimental research on spill plume entrainment has developed a range of empirically-based formulae for smoke management design. These formulae form the spill plume entrainment model in B-RISK, a new fire risk zone model. This article describes the performance of B-RISK in predicting spill plume entrainment. Selected experimental data from the series of reduced-scale experiments used to form the new design formulae have been used for model validation, along with other full-scale experimental data from ‘hot smoke tests’ conducted to assess the performance of installed smoke management systems. B-RISK provides predictions of the plume clear-layer height that generally agree with experimental results within the range of experimental error. This gives confidence in its use to predict spill plume entrainment for smoke management design purposes.