Assessing the Sprinkler Activation Predictive Capability of the BRANZFIRE Fire Model

Wade, Colleen; Spearpoint, Michael; Bittern, Adam; Tsai, Kevin

doi:10.1007/s10694-007-0009-5

Cited by 20 publications

(30 citation statements)

References 8 publications

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“…Davis and Cooper included the heat contribution of the upper layer that accumulates in confined ceilings [14], implementing a zone model complemented by a ceiling jet algorithm, that provided more realistic temperatures for the sprinkler link model. The zone model BRANZFIRE implements both Davis' jet model and Alpert's correlations for sprinkler activation, and the relative performance was later assessed by Wade et al [15] by comparing simulated response time to experimental values. They confirmed the expected superior performance of Davis' algorithm over Alpert's correlations.…”

Section: The Rti Modelmentioning

confidence: 99%

“…Both assessed the prediction of sprinkler activation times when compared to experimental values in high rack storage fires, and they reported good agreement. The validation of the sprinkler activation model was revisited by Bittern [20], who compared activation time predictions from FDS version 3 to experimental values reported in [15]. The main conclusion from that study was that the value of the C parameter (Equation (2)) and the position of the fire affect the performance of the model.…”

Section: The Rti Modelmentioning

confidence: 99%

“…The proposed implementation of the RTI model in the commercial code ANSYS Fluent was not validated. The validation of the model in numerical tools exists for simple model DETACT [22], zone models [15], and CFD code FDS [20,21]. Based on the similarities between these tools and ANSYS Energies 2020, 13, 1450…”

Section: Creating a 3d Map Of The Sprinkler Activation Timementioning

confidence: 99%

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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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Section: The Rti Modelmentioning

confidence: 99%

Section: The Rti Modelmentioning

confidence: 99%

Section: Creating a 3d Map Of The Sprinkler Activation Timementioning

confidence: 99%

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3D Mapping of the Sprinkler Activation Time

et al. 2020

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“…BRANZFIRE predicts the ceiling jet temperature and velocity based on either Alpert's correlations [12] or the JET model [13], which includes the effects of the upper layer under a confined ceiling. The JET model is considered here because a previous study has indicated that it provides more accurate results in small rooms when compared with Alpert's correlations [10]. The LAVENT method from NFPA 204 [14] resolves the variation of the ceiling jet temperature and velocity with distance below the ceiling.…”

Section: Deterministic Modelmentioning

confidence: 99%

A Comparison of Sources of Uncertainty for Calculating Sprinkler Activation

Frank¹,

Spearpoint²,

Fleischmann³

et al. 2011

Fire Safety Science - Proceedings of the 10th International Sym

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Treatment of uncertainty is an important consideration when performing a quantitative risk assessment (QRA) for the purpose of performance-based fire safety design. It has been noted in New Zealand that the outcome for fire QRAs is sensitive to uncertainty in the effectiveness of fire safety systems, including sprinkler systems. This paper considers the uncertainty in sprinkler activation time and the heat release rate (HRR) at the time of sprinkler activation for two scenarios; one where a set of sprinkler experiments in a room is modelled and the second which considers a more general design case for the same room. The relative importance of aleatoric (natural) and epistemic (model) uncertainties is shown to depend on the scenario being modelled. Twelve sources of uncertainty were quantified based on literature data and ranked for the scenarios considered. A new probabilistic-deterministic design tool for making risk-informed fire safety decisions is used to calculate output distributions for the two parameters considered and the sources of uncertainty are ranked in terms of sensitivity for output uncertainty. It is found that fire growth rate tends to be more important than the model uncertainty associated with the deterministic zone model engine for the scenarios considered, and uncertainty in the fire location becomes more important than the model uncertainty in design cases where there is greater uncertainty. Uncertainty in sprinkler response parameters and the ambient interior temperature provided the least contribution to the output uncertainties.

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“…Regarding the effect of fire location on the actuation of sprinklers, Wade et al [6] conducted a set of 22 fire/sprinkler experiments to investigate the sprinkler response times and to predictive capability of the BRANZFIRE fire model. Bennetts et al [7] investigated office fires and indicated data relating to the performance of sprinklers, including the times for activation of various types of sprinkler heads (normal and fast response), and the efficacy of the systems as far as extinguishment is concerned, in real office fire situations.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of an Office Fire with a Partially Impaired Sprinkler System

Lai

Ho²,

Chen³

et al. 2009

Fire Technol

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In this work, an actual office fire with a partially impaired automatic sprinkler system was investigated. As per regulations, there were four sprinklers in this model office. In the research conducted here, the first three sprinklers were actuated without water supply, while the last sprinkler was supplied with water at the required operating pressure for a period of 30 min. The fire source, a burning plastic trash can filled with 0.5 kg of paper, burned the adjacent chair, desk, desktop computer, and then reached the interior wooden furniture. The results show that the single remaining sprinkler effectively controlled the fire spread for 30 min. The partially impaired sprinkler system does not completely extinguish the fire, but extends the available time for evacuation. Continuing the discharge from sprinklers is preferable since the heat release from the fire increased after water flow was terminated.

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Assessing the Sprinkler Activation Predictive Capability of the BRANZFIRE Fire Model

Cited by 20 publications

References 8 publications

3D Mapping of the Sprinkler Activation Time

3D Mapping of the Sprinkler Activation Time

A Comparison of Sources of Uncertainty for Calculating Sprinkler Activation

Experimental Investigation of an Office Fire with a Partially Impaired Sprinkler System

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