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Drewsbury, J.; Whiteley, R A

doi:10.1023/a:1015427130420

Cited by 8 publications

(12 citation statements)

References 4 publications

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Section: Deviation Of the Theoretical Equations For The Hold Timementioning

confidence: 99%

“…The theoretical model is derived from the mass conservation equation for the agent inside the enclosure through several assumptions. The assumptions for the hold time of a CEA are as stated below [7,[11][12][13][14][18][19][20][21][22]:  The protected has a constant cross-section according to its height.  The leakage areas through the protected enclosure boundaries occur only at the upper and the lower extremes.…”

Section: Deviation Of the Theoretical Equations For The Hold Timementioning

confidence: 99%

“…Therefore, the time it takes for . H i to descend to the required protected height H p for which the hold time is determined is called the hold time, and H p is usually set as the point of maximum combustibles or 75% of the maximum height of the enclosure [11,18]. The theoretical equation for the outflow volumetric flow .…”

Section: = −mentioning

confidence: 99%

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A Study on a Modified Model for the Hold Time of a Clean Extinguishing Agent

et al. 2021

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When estimating the theoretical hold time of a Clean Extinguishing Agent (CEA), the hold time is predicted using a leakage exponent and leakage characteristics that are measured through an Enclosure Integrity Test (EIT). In particular, the leakage exponent n is conventionally applied as 0.5, but recently, a variable exponent has been applied through measurement (approximately 0.48 to 0.85). When variable n is applied, the hold time varies greatly depending on the size of n. Therefore, in this study, a modified theoretical model for the hold time of a CEA is proposed to improve the accuracy of the hold time depending on the leakage exponent n. The modified theoretical model applies a different analysis of the inflow and outflow volumetric flow, and the results enable a more accurate hold time prediction. The modified theoretical equation shows an improvement of up to 8.6% for outflow volumetric flow V˙o and a maximum improvement of approximately 10.7% for hold time th.

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Section: Deviation Of the Theoretical Equations For The Hold Timementioning

confidence: 99%

Section: Deviation Of the Theoretical Equations For The Hold Timementioning

confidence: 99%

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A Study on a Modified Model for the Hold Time of a Clean Extinguishing Agent

et al. 2021

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“…The most important aspect to consider when using gaseous agents in a fire extinguishing system (FES) is the ability of the system to maintain the concentration of the agents in the enclosure for an extended period of time [1,2]. Therefore, when designing an FES-gaseous system, the structure of the space to be protected, the sealing ability of the agent in the space to be protected, and the design concentration of the agent used, among others, must be considered.…”

Section: Introductionmentioning

confidence: 99%

“…The retention time is defined as the time until the concentration of the FES-gaseous agent drops below the specified threshold at the equivalent specified height for a protected room. At this time, the specified height is usually set as the point of maximum combustibles or 75% to 80% of the maximum height of the enclosure, and the specified threshold is set to approximately 80% of the designed concentration [1][2][3][4]. In particular, the extinguishing ability of the inert agent is the ability of the O 2 concentration in the protected space to maintain a nonflammable concentration that cannot be burned.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Effect of O2 Diffusion on the Retention Time of Inert Agents

et al. 2020

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Gaseous agents are widely used in fire extinguishing systems (FESs) when water extinguishing agents are unavailable. The extinguishing ability of the FES-gaseous agent is determined by the retention time (hold time) at which its concentration is maintained. In particular, the retention time of the inert agent is determined by the O2 inflow from the outside. However, current theoretical models for inert agents do not provide an accurate model for the diffusion of incoming O2. Specifically, because the theoretical equations do not include O2 diffusion or include too large a value, there is a large difference between the measured and theoretical retention times. Therefore, in this study, accurate O2 diffusion was verified through experimental and numerical analyses using three types of deactivators and reflected in the existing theoretical model. O2 diffusion was analyzed through the interface slope α and diffusion velocity vd. As a result, this proposed method can predict the retention time more accurately than existing theoretical models.

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Clean Agent Total Flooding Fire Extinguishing Systems

DiNenno

Forssell

2016

SFPE Handbook of Fire Protection Engineering

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Cited by 8 publications

References 4 publications

A Study on a Modified Model for the Hold Time of a Clean Extinguishing Agent

A Study on a Modified Model for the Hold Time of a Clean Extinguishing Agent

A Study on the Effect of O2 Diffusion on the Retention Time of Inert Agents

Clean Agent Total Flooding Fire Extinguishing Systems

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