Calculating the reliability of a zero-energy state system
Bibliographic record
Abstract
In Canada and other industrialized countries, workers who are required to carry out tasks in the hazardous zone of a machine when performing repairs, maintenance or unjamming activities must follow lockout procedures, unless safe alternative methods exist and can be applied. In Quebec the occupational health and safety regulation has been updated recently and several articles have been added on lockout procedures. That regulation allows for alternative control methods in addition to the traditional lockout/tagout, as long as the risk assessment deems the residual risk level to be acceptable. In Canada the CSA Z460 standard in the control of hazardous energies is viewed as a reference in the area. Lockout procedures have been extended to the construction sector for the control of hazardous energies as well. The lockout procedure consists of the following steps: stopping the equipment, isolating the energies, applying individual locks, dissipating residual energies, and verifying the absence of energies. Lockout procedures require lockout devices as well as training and audits. An important step in the lockout procedure is the verification step. Workers often neglect that step for various reasons. This article focuses on the use of dedicated safety electronic systems as an alternative to achieving a zero-energy state. These systems, rather than eliminating energy, control it to ensure workers’ safety. They are characterized by their reliability and typically involve safeguards such as interlocking devices, safety scanners, light curtains, and other safety mechanisms, during operational tasks. The article also introduces a method for calculating the reliability of these zero-energy-state system, based on the ISO 13849 standard. This method aims to help businesses comply with both the local regulation and the CSA Z460 standard. It builds upon the work of Poisson et al. (2016) [1], who calculated a zero-energy-state system in scenarios involving complex energy return recuperation systems. This innovative approach could potentially replace the need for voltage testing or machine startups following a lockout procedure. This development is particularly relevant given the increased complexity of modern machinery and the challenges in ensuring that no other energy sources that could harm workers are present post-lockout. This approach could significantly change how businesses ensure worker safety and regulatory compliance.
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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 | 0.003 | 0.013 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".