Sheltering in buildings from large-scale outdoor releases
Bibliographic record
Abstract
Air Infiltration and Ventilation Centre Ventilation Information Paper Sheltering in Buildings from Large-Scale Outdoor Releases W.R. Chan, P.N. Price, A.J. Gadgil 1. Introduction Intentional or accidental large-scale airborne toxic release (e.g. terrorist attacks or industrial accidents) can cause severe harm to nearby communities. Under these circumstances, taking shelter in buildings can be an effective emergency response strategy. Some examples where shelter-in-place was successful at preventing injuries and casualties have been documented [1, 2]. As public education and preparedness are vital to ensure the success of an emergency response, many agencies have prepared documents advising the public on what to do during and after sheltering [3, 4, 5]. In this document, we will focus on the role buildings play in providing protection to occupants. 2. How effective is sheltering? The sudden nature of a terrorist or accidental release means that there is often not enough time to safely evacuate the nearby communities. The remaining option is to take shelter until the toxic plume has dispersed. The obvious advantage of staying indoors is that there is a reservoir of clean air contained in buildings. Even though buildings are not airtight, building envelopes restrict the transport of the toxic pollutant to the indoors. The result is that the indoor concentration will increase much slower and remain low relative to the outdoor concentration. 2.1 Outdoor-indoor air exchange When sheltering in buildings, doors and windows should be closed, and ventilation and exhaust fans should be off to minimize air exchange with the outdoors. In such cases, the air change per hour (ACH) is determined by uncontrolled air leakage across the building envelope (Figure 1). Air infiltration is a function of the leakiness of the building, and the differential pressures across the envelope, which are caused by indoor-outdoor temperature difference and the forces exerted by wind. Air infiltration rates can vary from less than 0.1 ACH for a tight house under mild weather conditions to over 1.5 ACH for a leaky house under severe weather conditions (Table 1). These values are derived from air leakage measurements of residential houses in the US [7]. Houses in countries where the climate is more severe, such as Sweden, Norway, and Canada, tend to be more airtight than the values presented here [8].
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.024 | 0.004 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".