Hydrogen Lab Safety  

Extracted text

Hydrogen Safety

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorized personnel. © 2019 Peak Scientific Instruments Ltd.

Why a generator is safe

 Low stored gas volume (<300cc) – Cylinders can contain >9000L
 Low pressure operation (up to 100psi) – Cylinders pressurized to
200+Barg
 Real-time leak monitoring both internally and externally – prevents
excessive release of H2 into lab or GC if a leak occurs
 Days of supply following failure would be required to reach LEL
– Cylinders contain sufficient gas volume to reach LEL in seconds

Consecutive failures required for critical build-up of H2
1. Hydrogen vent blockage – causing H2 build-up in generator
2. Oxygen vent blockage – causing O2 build-up in generator
3. Hydrogen exhaust blockage – causing build-up of H2 in PSA dryer
4. Proportional valve failure – preventing delivery of H2 from generator
5.
6.
7.
8.

Pressure sensor failure – 3 sensors would need to fail simultaneously
Valve failure – 4 valves would need to fail simultaneously
Non-return valve failure – 3 non-return valves would need to fail
Separation tank blockage – Hydrogen forced into internal water tank

Ignition source would be required in addition to steps 1-8. System
would also need to be hermetically sealed to reach the 4.1% LEL.

Single Cylinder failures required for Health risk

1.
2.
3.
4.
5.

Internal stress corrosion cracking of the cylinder
Cylinders can fail if over-pressurised or weakened by the application of heat
Cylinders are structurally weakened by the application of any heat source
Cylinders that may ‘rocket’ if the regulator and valve assembly is damaged
Cylinders protected by pressure relief valves, fusible plugs or bursting discs
that may not work correctly in a fire situation, or if damaged
6. Accidental application of a compressed gas or jet into eyes or into an open
wound

8 Consecutive
Failures
+ Combustion +
Sealed Environment

VS

1 Failure

Consequences of a Cylinder Failure
The nature of the failure of a cylinder and its consequences depends on the
combination of cylinder design, age and gas type. Flammable gases present
greater risk but all cylinder failures can have significant safety consequences.
In a fire a cylinder can release its entire combustion energy. A cylinder of up to
1000L or 40kg bursting may result in a combination of the following:






Blast pressure wave
Fireball of up to 25 metres
A Projectile traveling over 100 metres
Flying fragments may travel up to 200 metres with high looping trajectories
Structural damage to buildings in the vicinity

Generator safeguards
 Full internal pressure decay test performed on start-up


Any leak would prevent further production of H2 and internal pressure would be vented.
Audible and visual alarms via HMI

 Forced air ventilation


Fans prevent build-up of H2 and O2 internally if leaks were to occur

 Continuous monitoring of internal gas pressure


Pressure sensor monitoring to prevent under/over pressure

 Mechanical fail-safe in case of high pressure


Automatic isolation and shutdown of the cell

 When generator is in alarm status the following occurs:




current to cell stopped
system depressurized
audible and visual alarms alert user of problem and fault information is displayed via the HMI

Gas generators provide a number of benefits

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorised personnel. © 2020 Peak Scientific Instruments Ltd.

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorised personnel. © 2020 Peak Scientific Instruments Ltd.

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorised personnel. © 2020 Peak Scientific Instruments Ltd.

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorised personnel. © 2020 Peak Scientific Instruments Ltd.

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorised personnel. © 2020 Peak Scientific Instruments Ltd.

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorised personnel. © 2020 Peak Scientific Instruments Ltd.

Kerri Heckrow, NPD Lab Manager, Evergreen Packaging, NC, USA

Certification

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorised personnel. © 2020 Peak Scientific Instruments Ltd.

More on Lab Gas Safety

H2 Safety

Lab Safety Focus

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rom He to H2

Hydrogen Lab Safety
Poster

App note

Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorised personnel. © 2020 Peak Scientific Instruments Ltd.

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Confidential, unpublished property of Peak Scientific Instruments Ltd. Do not duplicate or distribute. Use and distribution limited solely to authorized personnel. © 2019 Peak Scientific Instruments Ltd.