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

MICE : Safety July 9, RAL MICE Collaboration Meeting 2 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.

MICE : Safety July 9, RAL MICE Collaboration Meeting 3 Building both walls and the roof - solid (reinforced concrete) no explosion relief panels but the LH 2 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.

MICE : Safety July 9, RAL MICE Collaboration Meeting 4 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

MICE : Safety July 9, RAL MICE Collaboration Meeting 5 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

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

MICE : Safety July 9, RAL MICE Collaboration Meeting 7 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 Operation and maintenance