Sigma-HSE Newsletter - June 2024
FREE On-Demand Webinar: Avoid Over Zoning on Hazardous Area Classification (HAC) - (An Essential Component of DSEAR/ATEX)
A Hazardous Area Classification (HAC) classifies an operational area based primarily on the likelihood of the presence of a flammable atmosphere (the combination of a fuel in oxidant (typically air)). HAC is a necessary starting point for process risk assessments because without it, you cannot identify potential ignition sources within your hazardous zones.
If your zones are hazardous, then equipment in these zones must be ATEX certified so that the probability of the equipment acting as an effective ignition source is reduced. ATEX equipment is more expensive than regular equipment, so it is important that the correct equipment is purchased for a particular zone. This can only occur if you know if/where your hazardous zones are.
What you’ll learn:
• How to identify and classify hazardous zones for dusts and gases in your processing operations.
• How to effectively select equipment via proactive (rather than blanket) zoning to achieve better ROI.
• How to use zonal information i.e., EPL, Ga or Da, Gb or Db and of Gc or Dc to ensure that the equipment you have selected is suitable for your operations.
Speaker: Dr Andy Fowler (Technical & Operations Director)
Where: Online, just register for free HERE.
Quantitative Risk Assessment & Risk Acceptance Criteria
When considering risk acceptance criteria, zero risk should be the only acceptable level, but as we live in the real world, there is no such thing as zero risk.
The Tolerability of Risk (TOR) ‘carrot’ defines the basis on which those in industry should rank risk. The top of the carrot contains the highest risk activities, termed ‘Intolerable’ while the bottom represents those that are ‘Broadly Acceptable’.
After completing calculations via a Quantitative Risk Assessment (QRA) or by a semi-quantitative method, you can use the Tolerability of Risk (TOR) carrot to show that some risks are too great to be acceptable, while others are low enough to be broadly acceptable.
If you discover that the individual risk for worker fatality is greater than 10-3 or 1/1000 event, and are therefore operating in an intolerable region, you must cease the operation and put in place risk reduction measures until the residual risk is reduced.
You must aim to get to the yellow region and then ultimately to the green region (if you can reach it). In the green zone, risk for worker fatalities are 10-6 or a 1/1000000 event. The yellow region, termed ‘Tolerable if ALARP (As Low As Reasonably Practicable), is the region where operators should ask themselves two questions; ‘What more can we do?’ and ‘Why haven’t we done it?’. The second question is the justification and where the operator demonstrates that the risks are ALARP by showing that the cost of any additional risk reduction method is grossly disproportional to the benefit that it delivers.
Ultimately, quantitative risk assessments will always exceed semi-quantitative risk assessments. When doing a semi quantitative risk assessment, you are working in orders of magnitude and in a situation where subjectivity cannot be ruled out. There are three orders of magnitude between ‘Broadly Acceptable’ and ‘Intolerable’, from the TOR carrot and, in a typical Hazard Identification workshop you can find yourself moving between the three classification areas easily, just from a conversation amongst friends.
Completing a quantitative risk assessment, provides far more confidence in your results, providing a more realistic understanding of what the risks are and where you need to act. It certainly requires greater expertise and more resources, but the greater precision of the results and analysis offsets the conservatism associated with less refined techniques.
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Key Stages of Process Scale-Up: Thermal Screening and Adiabatic Calorimetry Testing Methods
During new process and product development, a primary chemical processing concern is the safe and efficient processing of materials and chemicals at large scale. To handle these process safety concerns, thermal stability and adiabatic calorimetry testing methods act as valuable screening steps in the development of new chemical processes.
While these screening test methods do not provide the depth of data that advanced reaction calorimetry methods offer, they are an excellent first step to understanding the fundamental characteristics (reactivity behaviours) of a potentially hazardous material.
The preliminary data collected at the screening stage will guide research and development teams in their process development journey, especially during the product identification and the identification of synthetic route stages. This thermal screening data can then be used to inform and ensure proper plant design (reactor cooling capacity, relief sizing, etc.) for scale-up stages.
The integration of these testing methods alongside proper plant design will ensure that the prevention and control of hazards in your working environment will be adequately controlled.
From the Engineers’ Desk: Leaking explosion vent for a powder hopper
An explosion vent on a powder hopper was leaking dust and the client proposed to remove this vent.
After investigation and discussion with the client we recommended not to remove the existing vent, as the system would not comply with recognised industry standards.
Resources Library Learning from our Process Safety Experts
To access our repository of technical articles and on-demand webinars, providing a wealth of insight into mitigating fire and explosion risk, check out our website resources page.
Professional Bachelor's Degree in Industrial Safety, Health and Environment(HSE )&HSeManeger ,Blood Transfusion Organization ,Mazandaran, Iran,Members Asian Association Of Transfusion Medicine AATM &AABB
6moVery informative