Measuring modified glass bulb sprinkler thermal response in plunge and compartment fire experiments

Frank, Kevin; Spearpoint, Michael; Baker, Greg; Wade, Colleen; Collier, P. C. R.; Fleischmann, Charles

doi:10.1016/j.firesaf.2017.03.017

Cited by 3 publications

(3 citation statements)

References 7 publications

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“…The considered model was experimentally evaluated by Frank et al [24]. Similar but equivalent approaches were presented by other researchers [25,26].…”

Section: Foundations Of Numerical Modeling Of Heat Sensorsmentioning

confidence: 98%

A Study on the Reliability of Modeling of Thermocouple Response and Sprinkler Activation during Compartment Fires

et al. 2022

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Real and numerical fire experiments involve temperature measurements with thermocouples, and thus some considerations on numerical modeling of this process are presented and a new approach to thermocouple modeling is introduced. Using ANSYS Fluent software a well-recognized analytical thermocouple model was implemented in each cell of the computational domain, which allows for determination of thermocouple responses as a continuous field. Similarly, sprinklers are key elements of fire-protection systems. Sprinklers activation is one of the breakthrough moments during the course of a compartment fire. Therefore, assumptions on sprinkler activation time are of crucial importance when designing a fire safety system. Just as for thermocouple modeling, virtual sprinklers based on a commonly admitted response time index (RTI) model were placed in all cells. The proposed approach provides data on sprinklers activation or thermocouple response for the whole domain instead of retrieving data point by point only for predefined locations. In this study, experimental data available in the literature were used for the validation of the proposed approach. In addition, the results were compared with those obtained with the commonly used Fire Dynamic Simulator (FDS) software. The outcomes might be of a significant importance for practitioners, who deal with fire experiments and fire protection. Furthermore, some issues on accurate modeling of fire gases flow are discussed extensively. It was found that commonly applied k-ε and k-ω turbulence models might fail in the case of modeling of fire plumes in confined spaces.

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“…The considered model was experimentally evaluated by Frank et al [24]. Similar but equivalent approaches were presented by other researchers [25,26].…”

Section: Foundations Of Numerical Modeling Of Heat Sensorsmentioning

confidence: 98%

A Study on the Reliability of Modeling of Thermocouple Response and Sprinkler Activation during Compartment Fires

et al. 2022

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“…Alternative but similar approaches were presented by Thorne et al [7] and Melinek [8]. Heskestad and Bill's model was experimentally assessed by Frank et al, who inserted thermocouples into modified sprinkler bulbs to measure the actual bulb temperature when exposed to hot gases as a function of time [9]. They found that the modelled bulb temperature evolution matched the experimental curve closely in the case of the plunge tests, but they detected considerable differences when using ceiling jet temperature and velocity data from compartment fire experiments, especially for fast-growing fires.…”

Section: The Rti Modelmentioning

confidence: 99%

3D Mapping of the Sprinkler Activation Time

et al. 2020

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Sprinkler activation is one of the key events defining the course of a compartment fire. The time when activation occurs is commonly used in the determination of the design fire scenario, which is the cornerstone of the design of building fire safety features. A well-known model of sprinkler activation (response time index (RTI) model) was introduced into the numerical scheme of the ANSYS Fluent computational fluid dynamics (CFD) package. The novel way in which the model is used is the calculation of the time for sprinkler activation within each discrete cell of the domain. The proposed novel approach was used in a case-study to assess the effects of comfort mode natural ventilation on a sprinkler’s activation pattern. It was found that hinged vents in the comfort mode had a significant effect on sprinkler activation, both in terms of delaying it as well as limiting the total number of cells in which the sprinkler would have activated. In some scenarios with a hinged vent, no activation was observed in the central point of the vent, possibly indicating problems with the autonomous triggering of the fire mode of such a device. It was also found that the RTI and C (related to the conductive transport of sprinkler fitting) parameter values had a moderate influence on sprinkler activation time—only for high-temperature sprinklers (≥ 141 °C). This study shows the applicability of the 3D activation time mapping for research focused on the fire safety of sprinkler-protected compartments and for the performance-based approach to sprinkler system design. Even though the RTI model is the industry standard for the determination of sprinkler response, the model implementation in ANSYS Fluent was not validated. This means that sources of uncertainty, mainly connected with the determination of flow velocity and temperature are not known, and the model should be used with caution. An in-depth validation is planned for subsequent studies.

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“…[16][17][18][19] The protective effects of water-related protection systems in contact with glazing assemblies have been studied previously. 17,[20][21][22] Kim and Lougheed 20 outlined numerous approaches for compartment fire protection of glazing assemblies equipped with sprinkler systems and presented an external window protective sprinkler system design guide for application. Wu and Lin 23,24 investigated the heat resistance provided by water films in contact with glass panes and sprinklers in a room fire in a series of fullscale experiments.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on thermal performance of water wall systems exposed to fire

Rathnayake

Karunaratne

Han

et al. 2022

Indoor and Built Environment

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Water wall systems (WWSs) are increasingly being used as glass façades in modern green buildings owing to their enhancement in building energy efficiency. However, little is known about their performance when exposed to fire. In this study, 500 × 1000 mm2 sized water wall systems with 30 mm, 50 mm and 100 mm thick water columns were tested and compared to the thermal performance of a 500 × 1000 mm2 sized single skin glass façade system. These façade systems were heated by a 400 × 600 mm2 isopropanol pool fire. The distance from the pan centre to pane 1 of the façade was 350 mm. Time to first crack and surface temperatures were measured. The experimental results indicate that single skin glass façades are more vulnerable to cracking than water wall systems, but exposed glass pane fallout can easily occur in water wall systems compared to single skin façades. Since the overall performance is dependent on the failure of the fire unexposed glass pane, water wall systems are more fire resistant than single skin glass façades. The water layer thickness significantly affects the WWS thermal performance, where a 50 mm thick water layer would result in a longer time to first crack. The experimental findings of this study are useful for developing practical guidelines for fire-safe glass façade designs.

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Measuring modified glass bulb sprinkler thermal response in plunge and compartment fire experiments

Cited by 3 publications

References 7 publications

A Study on the Reliability of Modeling of Thermocouple Response and Sprinkler Activation during Compartment Fires

A Study on the Reliability of Modeling of Thermocouple Response and Sprinkler Activation during Compartment Fires

3D Mapping of the Sprinkler Activation Time

Experimental investigation on thermal performance of water wall systems exposed to fire

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