Gas safety
High-pressure gases
Usage of gases after pressurization to over 1 MPa, or usage of high-pressure gases over 1 MPa in their pressurized state
Approval from Ibaraki Prefecture is required in accordance with the High-Pressure Gas Safety Act. Currently at MLF, the Hydrogen Absorption / Desorption Measurement System at the J-PARC BL21 NOVA instrument has been approved; however, this is not approved for use elsewhere. Please discuss beforehand with the staff.
Decompression usage of high-pressure cylinder gases
Decompressing high-pressure (1 MPa+) cylinder gases to pressures below 1 MPa before use is considered "consumption of high-pressure gas" and does not fit the above criteria, Gases of this category are regularly used at MLF. We outline some key points below.
(1) When consuming specified high-pressure gases:
The notification of the prefectural governor, the assignment of a chief operator, the implementation of safety training to the employee, the observance and maintenance of technical standards, the implementation and recording of regular self-inspection procedures, etc., must all be conducted. Furthermore, please observe the standard criteria below (see Article 24-2 through 4 of the High-Pressure Gas Safety Act and Articles 53-58 of the Regulation on Safety of General High-Pressure Gas for reference).
(2) When using high-pressure gases other than the specified high-pressure gases, as regulated by ministerial order (flammable gases, toxic gases, oxygen, air):
Technical standards must be observed and maintained. Additionally, please observe the standard criteria below (see Article 24-5 of the High-Pressure Gas Safety Act and Articles 59-60 of the Regulation on Safety of General High-Pressure Gas for reference).
(3) When using high-pressure gases besides those listed above:
Please observe the standard criteria below, referencing the technical standards listed above.
Standard criteria
① Cylinder storage
- The cylinder is to be stored with a fixed stand in a vertical position at a storage location.
- Flammable and oxygen gas cylinders are not to be kept in the same location.
- Ensure that the cylinders that must be placed horizontally cannot roll away.
- Acetylene cylinders are not to be placed horizontally.
- Ensure that the gas cylinder valve is firmly closed, and that the storage cap is in place.
- Chains are to be used to ensure that cylinders do not topple over (cylinder cabinet use is recommended for flammable gases).
- Flames and heat sources are not to be used near gas cylinders.
- Other electrical equipment, wiring, ground wires, etc., should not be used in the proximity of flammable gas cylinders.
- Do not expose cylinders to direct sunlight, to avoid pressure increases.
- Avoid container corrosion by preventing excessive humidity and salt damage. Corroded containers are not to be used.
- Keep the containers free of oil products.
- Manage the cylinders with prescribed recording the necessary criteria.
- Return cylinders that are empty, no longer to use, or whose use-by date is expired.
② Cylinder use
- Carefully open and close the valve, and ensure that the valve is closed after use.
- Ensure sufficient ventilation to avoid the risk of suffocation.
- Return to the storage location after use.
- Use suitable equipment depending on the type of gas.
- Ensure that there are no flames or flammable materials in the vicinity of flammable or oxygen gases (see Article 60 of the Regulation on Safety of General High-Pressure Gas for reference).
- Sufficiently understand the attributes, characteristics, features, etc., of the gas prior to use.
- Stop using of the cylinder and immediately contact the supplier if there are any abnormalities.
③ Handling of liquefied gases
- Pay attention to the following points.
- Pressure increases due to liquid vaporization
- Blocks due to the freezing of moisture, etc.
- Oxygen concentration increase due to condensation of atmospheric oxygen
- Freezing, frostbite
- Hypoxic / anoxic conditions, injuries due to cold gas inhalation
- Cryogenic pressurized cylinders are to have suitable measuring instruments—e.g. a pressure gauge, liquid level meter, safety valve, etc.—and must be regularly inspected to ensure that they are under normal operating conditions ・Use protective gear such as gloves, etc.
- Similar to other cylinders, handle the cryogenic cylinders quietly and carefully, and place them in a horizontal and well-ventilated area with no direct sunlight. ・Take sufficient precautions so as not to topple over or strongly impact the cryogenic cylinders during transport.
④ Emergency responses
During an emergency, promptly contact the appropriate facility staff, and follow their instructions.
Follow the instructions of the appropriate facility staff during an incident.
For example,
(a) When there is a gas leak:
- Stop using the gas and close the cylinder valve.
- Open doors, windows, etc., and allow for sufficient ventilation.
- Contact the experimental equipment managers and shift leader.
(b) When a valve is damaged:,
- Stop using the gas, and contact the experimental equipment managers and shift leader.
(c) When a gas has ignited:
- Contact the fire department promptly.
- Try to extinguish the fire as much as possible early on, by cutting the gas supply and closing the cylinder valve.
(d) When a fire has broken out in the vicinity:
- Contact the fire department promptly.
- Try to extinguish the fire as much and as soon as possible; furthermore, try to move the container from its location so as to prevent it from being heated.
(e) When a cylinder has been lost or stolen:
- Please file a police report and promptly contact the appropriate facility staff.
Attention to high-pressure gas generation during the work process
Gases that are not initially under high pressure can be come pressurized under the scenarios listed below, causing dangers such as explosions, etc. Please ensure that the necessary precautions are taken beforehand to avoid the following situations:
- Generation of high-pressure gases in cryogenic experiments due to liquid containment and heating processes.
- Generation of high-pressure gases in gas flow experiments due to blocked air outlets (in cases where the cylinder does not have a pressure-proofed structure)
Flammable, toxic gases
Leakage prevention measures
- Airtight / pressure-proof inspections, He leak inspections
- Welded structure
- Multilayer structure
- Checks (pre-experiment, during experiment), etc.
Countermeasures against leakage scenarios
- Leakage detector
- Interlock (connected with leakage detector) (escalation prevention)
- Explosion prevention measures (electrical equipment, antistatic sheets, antistatic work clothing / shoes)
- Gastight protective gear
Disposal
Ensure that the gas can be safely released below the permittable concentration limit (e.g., below the lower explosive limit for flammable gases, or below the allowable concentration (threshold limit value) for toxic gases, etc.).
Miscellaneous
In case that there are no experiment-related issues, use gases at concentration levels lower than the allowable concentration limit to reduce risk.
Gases that can become radio-activated
If gases that could become radioactive under neutron beam exposure—such as Xe, 3He, and Ar—are used in experiments that involve neutron beam exposure, then MLF facility personnel will confirm if appropriate measures have been taken to ensure that the radio-activated gas are not dispersed externally.
When importing gases
Please submit the experimental equipment carry-in / use form from the user support system(https://jus.j-parc.jp/usjparc/ui/index_E.jsp)in cases where the user will bring in their own gas due to its lack of availability within the MLF facility. Please also submit a sample / chemical carry-in application form if the gas is to be brought in as a sample.