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* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
STFC QUANTITATIVE RISK ASSESSMENT PRO-FORMA Ref: Description: Danger due to the magnetic fields of the MICE magnets Assessment Date: 14/06/16 Location/Site: MICE Hall and immediate neighbourhood Assessor: Josef Boehm Department: Assessment Team:: Persons Exposed: Any user and visitor of the MICE facility Activity/Task: Analyse the magnetic fields present in the MICE Hall, assess the potential exposure of people and machinery, assess the potential damage to people and machinery, evaluate necessity of removal of magnetic fields Step 1 What are the hazards? Step 2 Who might be harmed What are you already What is the level of risk? and how? doing? H Hazard/Task or Situation L R Harm Likelihood Risk Person being trapped in bore of magnet Anyone accessing the bores of the magnets Bores are blocked by instrumentation and being part of beamline. Access to hall restricted during magnet operation High Very unlikely medi um Person being trapped on outer shell of magnets, possibly only parts of the body Anyone working around the magnets when energised Hall has limited access when magnets are live, access to top of magnet is restricted or forbidden, magnetic fields on surface are low (typically around 1000G, localised hotspots of close to 5000G, these could trap hands between ferromagnetic tools for instance). Fast rampdown buttons solenoids: ~20min, focus coils: ~ 2h mode rate Very unlikely low Step 3: What further necessary? action Step 4: is How will you put the Assessment into action? Action by whom By when Done QRA_r3.1_Nov_14 STFC QUANTITATIVE RISK ASSESSMENT PRO-FORMA Person being exposed to projectiles caused by magnetic attraction Danger to health of person working near surface of magnets Magnetic fields outside PRY too low to allow projectiles, access to top of magnets restricted or forbidden, range of fields that could allow projectiles is short (about 400mm). The magnetic field where detectable forces on ferromagnetic objects appear is approximately 100G. mode rate unlikely medi um Person being exposed to quench gases of superconducting magnets Danger to health of person, possibly even fatal Access to quench ports is blocked during operation, access to top of magnets restricted while magnets are live high Very unlikely medi um Person being injured by cold quench gases Person standing in front of quench port Quench should marked exit ports be clearly high Very unlikely medi um Warning labels to be fitted to quench outlets Anyone working at the top of the magnets Access to top of magnets restricted to experienced staff, banisters are around access platforms, suitable walkways should be installed beyond accessible access areas high Very unlikely medi um Screens to be fitted near walkways at the top of the magnet Person falling between magnet skin and PRY QRA_r3.1_Nov_14 STFC QUANTITATIVE RISK ASSESSMENT PRO-FORMA Danger to people entering areas of high magnetic field (with cardiac pace-makers or brain implants). Unless there is very close proximity to OVC (mainly of the FC) a risk to magnetic media (eg credit cards) is very low. Anyone entering the MICE hall during magnet operation Hall has limited access when magnets are live. The limit of 5G needs to be clearly visible. Warning labels of high magnetic field exposure need to be prominently visible. The 5G line will have to be re-measured each time a new magnet configuration is applied as the stray field from these magnets will change. Distribution List: If the risk is significant, has it been entered into the SHE enterprise database? Step 5 Review Date: high Very unlikely medi um Signed: Yes No Field outlines are clearly outlined, will need to be reconfirmed for alternative magnet arrangements Date: SHE enterprise ref no: Review your assessment to make sure you are still improving, or at least not sliding back. If there is a significant change in your workplace, remember to check your risk assessment and where necessary, amend it. QRA_r3.1_Nov_14 STFC QUANTITATIVE RISK ASSESSMENT PRO-FORMA Description of magnet coils: Focus coils: Properties: Lmax 111H, max ramp-rate: 7V, max I: 220A, normal ramp-down time ~1h Max field in bore: 4T, field at side of OVC: ~0.5T, field at C/H: < 0.2T Bore always enclosed, magnet within iron shield, access to top possible but usually not allowed Biggest stray field in flip mode (220A) Solenoid coils: Properties: Lmax 85H, max ramp rate: 4V, max I: 280A, normal ramp-down time ~ 1.5h Max field in bore: 4T, field on side of OVC: < 0.2T, field at cold heads < 0.1T Bore always enclosed, magnet within iron shield, access to top possible but usually not allowed Decay magnet (solenoid): Superconducting magnet, bore blocked during operation, magnet is internally shielded, stray field very low Quadrupole and Dipole magnets: Conventional conductors, shielded housing, bore blocked and inaccessible during operation, stray field minimal Extent of 5G line QRA_r3.1_Nov_14 STFC QUANTITATIVE RISK ASSESSMENT PRO-FORMA 0 1000mm ZX plane, horizontal, PRY shown 0mm 1000mm 2000mm Magnetic field profile on skin of magnets (red line) ZY plane, vertical, no PRY at top Plots by H Witte in ZX (through wall of PRY) and ZY planes (towards ceiling). Red line indicates outer skin of OVC (at 700mm). Maximal possible field exposure to 0.5T at section between FC and Solenoid. Lower end is end plate of PRY. Flux densities are shown in Tesla. In other units: 100G, 1000G, 2000G … 10,000G. The red or brown intensities are closer to the centre of the magnet, the dark-blue intensities are away from the magnet. Due to low gradient of the exposed field the magnetic attraction is limited, even at the highest field areas. A hammer would be attracted to the skin of the magnet with a force of approximately 20kg. QRA_r3.1_Nov_14 STFC QUANTITATIVE RISK ASSESSMENT PRO-FORMA LEVEL OF RISK There will be some instances where you may need to assign priorities to actions from an assessment or you may be responsible for managing the actions from a number of assessments. In either case you will need a coherent method for assigning a priority to actions. This Quantitative Risk Assessment pro-forma gives you this option. There are three additional fields available when entering or editing any task in an assessment: Harm, Likelihood and Risk. For each hazard, you choose options for the Harm and Likelihood categories. Use the information contained in Step 2, categorise the harm that might be caused: As a general rule you are looking for ‘the most likely reasonably foreseeable injury’ not just the worst case. Decide How Someone Might be Harmed Major Fatality. High Amputations; multiple serious injuries; major fractures; major burns. Moderate Lacerations; burns; concussion; serious sprains; minor fractures. Slight Superficial injuries; minor cuts and bruises; eye irritation from dust. Below are the phrases that are used in the risk database to describe the likelihood of something happening and how someone might be harmed: How Likely is it to Happen? Very Unlikely The hazard is very rarely experienced and exposure will seldom result in injury. Unlikely The hazard is rarely experienced and exposure will seldom result in injury. Likely The hazard is persistent but exposure may not always result in injury. Very Likely The hazard is persistent and exposure will undoubtedly result in injury. Then use the matrix below to obtain a ‘risk factor’ from the likelihood and harm categories for each hazard (e.g. if you decided the harm category was ‘moderate’ and the likelihood was ‘unlikely’ the risk factor would be ‘medium’). This risk category is then used to determine what priority should be given to reducing the risk factor for that particular hazard. STFC QUANTITATIVE RISK ASSESSMENT PRO-FORMA Risk Factor Harm To manually calculate the risk factors use the table below: Major High High V High V High High Med Med High V High Moderate Low Med Med Med Slight Low Low Low Low Very Unlikely Unlikely Likely Very Likely Likelihood Low Risk - No additional controls are necessary unless they can be implemented at very low cost (in terms of time, money and effort). Actions to further reduce these risks can be assigned low priority. Medium Risk - Consideration should be given as to whether the risks can be lowered, where applicable, to a low risk level, but the costs of additional risk reduction measures should be take into account. The risk reduction measures should be implemented within a defined time period. High Risk – Substantial efforts should be made to reduce the risk. Risk reduction measures should be implemented urgently within a defined time period and it might be necessary to consider suspending or restricting the activity, or to apply interim control measures, until this has been completed. Considerable resources might have to be allocated to additional control measures. V High Risk - These risks are unacceptable. Substantial improvements in risk controls are necessary. The work activity should be halted until risk controls are implemented. If it is not possible to reduce risk the work should remain prohibited.