Efficacy Testing of Personal Protective Filters on Biosafety Level 4 Positive Pressure Suits
Bibliographic record
Abstract
Introduction: Positive pressure breathing air-fed protective suits from three vendors are commonly used in biosafety level 4 (BSL-4) laboratories: they are Dover Chemturion suits (ILC Dover, DE), Delta suits (Honeywell Safety, NC), and HVO suits (HVO-ISSI-Deutschland GmbH, Germany). To address the potential risk of infectious agents being introduced through the supplied breathing air stream, some suit manufacturers incorporate protective filters on the suits themselves. However, these integrated filters are not amenable to in situ testing for efficacy verification. We have been using external filters from Matheson USA on the positive pressure suits since our BSL-4 laboratories were commissioned two decades ago. As part of our BSL-4 protective suit management program, we test these filters before them being put into use, and annually thereafter. In the past few years, we have observed these filters failing at a higher rate, as high as two out of three of the new filters tested at one point. Objective: The purpose of this study was to procure personal protective filters from other sources and validate their efficacy long-term. Methods: Filters from Respirex, HVO, and Honeywell were validated for filter integrity and filter loading. Results: Respirex filters performed well during the initial testing and periodic testing thereafter. Regular testing of the Respirex filters has now been ongoing for 30 months with continued successful performance. Conclusion: Filters from Respirex are a suitable option to protect personnel wearing positive pressure suits in BSL-4 laboratories.
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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 | 0.004 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".