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 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.

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