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Record W2562743101

To Standard Hold Time Calculations

2000· article· en· W2562743101 on OpenAlexaboutno aff
R A Whiteley

Bibliographic record

Venuenot available
Typearticle
Languageen
FieldEngineering
TopicFire dynamics and safety research
Canadian institutionsnot available
Fundersnot available
KeywordsEnclosureHVACEnvironmental scienceLeakage (economics)Ignition systemFire hazardMeteorologySimulationMechanicsEngineeringComputer scienceElectrical engineeringMechanical engineeringPhysicsAir conditioning
DOInot available

Abstract

fetched live from OpenAlex

The paper extends existing methods of calculating the hold time for a fire extinguishing gas in an enclosure to cover mechanical HVAC systems and wide descending interfaces, and compares the wide descending interface model’s predictions with some experimental data. A simple approximation to the measured wide descending interface gives conservative hold time predictions, while the sharp descending interface model used in current standards gives optimistic predictions. In the fire protection industry, ‘Fan Integrity Testing’ denotes the tests and leakage modelling carried out to determine the airtightness (or leakage) of an enclosure, and the use of the information to predict the rate of decay of the concentration of a fire suppression gas (‘agent’) at any particular height in the enclosure. Prior to the Montreal Protocol, which brought about the end of Halon 1301 production, serious concerns were being expressed over the number of instances where the required lo-minute hold time was not being achieved. ‘Hold time’ or ‘retention time’ denotes the time taken for the agent concentration at a specified height (usually the highest hazard in the protected enclosure) to fall below a specified concentration (usually 80% of the minimum design concentration). A lo-minute hold time was, and still is, considered important to allow ignition sources to cool and to allow sufficient time for manual intervention to ensure that the danger has passed. Practical enclosures are not perfectly airtight. Pressure differences due to density differences between inside and outside, wind or HVAC systems cause air to flow in and out through leaks in the enclosure. The quantity of agent inside gradually falls as it leaves with the outgoing air. The discharge of the agent into the enclosure generally creates good mixing initially; the uniformity of the later agent distribution in the enclosure depends on the internal airflows during the hold time. Fan integrity testing standards set out methods of measuring enclosure leakage and calculating hold time, using assumptions about the locations of the enclosure

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesInsufficient payload (model declined to judge)
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: Simulation or modeling
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.507
Threshold uncertainty score0.998

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0080.003

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.005
GPT teacher head0.223
Teacher spread0.218 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; both teacher heads agree on what is shown here.

Study designSimulation or modeling
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2000
Admission routes1
Has abstractyes

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