Iouri Ivaniouchenkov RAL

1. Iouri Ivaniouchenkov RAL Safety considerations at RAL July 9, RAL MICE Collaboration Meeting 1

2. MICE : Safety RAL Safety Code No.1 “Hydrogen and deuterium” specifies the rules and procedures for all work on hydrogen at RAL. • Document structure: • General considerations • Buildings • Mechanical aspects • Electrical aspects • Static electricity • Detectors • Sources of ignition • Irradiation of liquefied gases • Operation and maintenance New systems must not be brought into use without approval by the RAL / ISIS Safety Officer. July 9, RAL MICE Collaboration Meeting 2

3. MICE : Safety Building • both walls and the roof - solid (reinforced concrete) • no explosion relief panels but the LH2 absorbers are contained inside a light-wall igloo construction • windows should be avoided (normal glass must not be used) • mesh or other screens around the area of possible explosion • flooring - anti-static; floor service ducts should be avoided (alternatively use pressurised or flushed trenches) - mesh covered trenches • no lighting inside the igloo - translucent walls • means of escape - 3 exits at present • ventilation - should provide 60 air changes per hour under emergency conditions - inside the igloo • + general ventilation in the hall • ventilation equipment - avoid gas trapping in trunking/piping system; anti-static materials for fan blades; the system is bonded and earthed • lightning protection - a well bonded and earthed steel frame • area control - entry to the building must be controlled and limited to essential personnel. July 9, RAL MICE Collaboration Meeting 3

4. MICE : Safety Mechanical aspects • sealing aspects - double sealing; welded or brazed joints; • pressure and leak tests • hydrogen venting - should be kept to a practical minimum sealed system • purging should be done before and after the use of the apparatus • safety valves and bursting disks - to protect apparatus from over pressurisation buffer volume to collect released hydrogen • protective shields must be used to protect thin metallic and non-metallic membranes double window • materials - avoid materials brittle at cryogenic temperatures • vacuum pumps - carefully selected July 9, RAL MICE Collaboration Meeting 4

5. MICE : Safety Static electricity • bronze or copper plated tools • anti-static clothes for personnel • no personal electronic devices inside hydrogen zone e.g. mobile phones, electronic watches • do not comb the hair in the danger area July 9, RAL MICE Collaboration Meeting 5

6. MICE : Safety Detectors • suitable hydrogen gas detectors initiating a warning system should be provided • regular maintenance and checking of the calibration must be carried out July 9, RAL MICE Collaboration Meeting 6

7. MICE : Safety Operation and maintenance • staffing - adequate staff should be available for the safe operation and necessary maintenance of the equipment • commissioning - • - review all aspects of the installation; • - test the apparatus with the inert gas; • - have personnel present who have been involved in the • design; • - have operating procedures established and explained to the • operators; ensure that all personnel know the emergency • procedures • - when it is intended to introduce hydrogen into the equipment, • notify The Safety Officer, The Fire Officer, The ISIS Duty Officer • operation • - written operating procedures must be provided; • these must be accompanied by flow diagrams and drawings • - clearly written , step-by-step emergency procedures • must be provided • operational and emergency training • - operational staff should be trained in operational and • emergency procedures • - staff should be tested at reasonable intervals • area control • - barriers and fences with warning notices; • - permit-to-work system July 9, RAL MICE Collaboration Meeting 7