1、 Environmental requirements: Control risks from the source
Ventilation conditions
Core principle: The density of hydrogen is only 1/14 of air, and it is easy to diffuse upwards after leakage. It needs to be quickly diluted through forced ventilation or natural ventilation.
Specific requirements:
The equipment should be installed in a fume hood or an independent ventilation area, with a ventilation rate of ≥ 12 times per hour.
The ventilation opening should be set at the upper part, and priority should be given to using air convection to discharge hydrogen gas.
Avoid using non explosion proof exhaust fans to prevent electric sparks from igniting hydrogen gas.
Case: A pharmaceutical company placed its equipment in a sealed corner, and after a leak, the hydrogen concentration rose to the lower explosive limit (4% Vol) within 3 minutes, causing local combustion.
Temperature and humidity control
Temperature range: The operating environment temperature is strictly controlled between 10-30 ℃ to avoid equipment overheating caused by high temperatures or electrolyte freezing caused by low temperatures.
Humidity limit: Relative humidity ≤ 60% to prevent accelerated corrosion of metal components in humid environments.
Long term disuse: The electrolyte needs to be emptied and sealed with nitrogen gas to prevent oxidation of metal components.
spatial layout
Safe distance: Keep at least 5 meters away from open fire sources and high-temperature heat sources, and stay away from windows with direct sunlight.
Maintenance space: Reserve a maintenance space of ≥ 0.5 meters behind the equipment for easy maintenance of the cooling fan.
Flammable material management: Flammable materials are strictly prohibited from being placed within a 10 meter radius, and no fire signs must be posted in the laboratory.
Electrical safety
Dedicated circuit: powered by an independent circuit, with voltage fluctuations controlled within ± 5%.
Grounding protection: The grounding resistance of equipment and pipelines should be less than 4 Ω to prevent static electricity accumulation.
Explosion proof design: Electrical components such as motors, switches, and junction boxes must comply with explosion-proof standards (such as Ex d Ⅱ CT4).
2、 Emergency response: step-by-step crisis resolution
Initial response to leakage (Level 1 alarm)
Trigger condition: When the hydrogen concentration is ≥ 1.0% Vol, the sound and light alarm will be activated.
Operation steps:
Immediate shutdown: Turn off the equipment power within 30 seconds and cut off the hydrogen supply valve.
Personnel evacuation: Clear personnel within a radius of 10 meters within 1 minute and set up a cordon.
Ventilation dilution: Start the explosion-proof exhaust fan and continue to ventilate for more than 30 minutes.
Case: A semiconductor factory reduced the leakage rate from 200L/min to 0 through rapid response.
Serious leakage disposal (Level 2 alarm)
Trigger condition: When the hydrogen concentration is ≥ 2.0% Vol, the equipment will automatically shut down urgently.
Operation steps:
Cut off power and gas supply: Simply unplug the device's power plug and close the main valve at the output end.
Leakage detection: Use a portable hydrogen gas detector (accuracy ≤ 1ppm) to investigate along the gas path and locate the leakage point.
Temporary blockage:
Small scale leakage: Wrap the leakage point with a damp cotton quilt, spray water to cool down, and apply sealant.
Pipeline rupture: Close the upstream and downstream valves and clamp the rupture with metal clamps.
Valve failure: Replace sealing gasket or integral valve.
Case: A university laboratory used infrared thermography to assist in locating leaks, reducing the search time from 30 minutes to 5 minutes.
Fire and explosion response
Fire extinguishing equipment: dry powder fire extinguisher or carbon dioxide fire extinguisher shall be used, and water or foam is strictly prohibited.
Operation points:
Cut off the gas source: first close the hydrogen supply valve, and then extinguish the fire source.
Prevent reignition: Continuously monitor hydrogen concentration and ensure ventilation to a safe range (<1% Vol).
Alarm and evacuation: If the fire cannot be controlled, evacuate immediately and call 119 for assistance.
Post processing and review
Leakage repair: After confirming that the leakage point has been repaired, use soap water to detect no bubbles before restarting the equipment.
Fault analysis: Read the fault code through the device display screen to locate the root cause of the problem.
Professional maintenance: When it comes to replacing electrolytic cells or repairing circuit boards, contact the manufacturer's technical support.
Record and drill: Record the reasons for leaks (such as loose interfaces and aging components), and conduct emergency drills every quarter.
3、 Key protective measures: Building a safety barrier
Leakage monitoring system
Deploy hydrogen sensors at key locations such as generator outlets and hydrogen storage areas to monitor concentration in real-time and coordinate with ventilation systems.
Set up two levels of alarms: the first level alarm (concentration ≥ 1.0% Vol) indicates risk, and the second level alarm (concentration ≥ 2.0% Vol) triggers emergency shutdown.
Relief safety feature
Install overpressure relief valve (7.5 bar automatic opening) and mechanical pressure switch (electrical isolation protection) to prevent equipment from overpressure explosion.
A certain hydrogen generator cuts off the electrolysis current within 0.1 seconds when overpressure occurs through a pressure interlock device.
Explosion proof electrical design
Use explosion-proof motors, switches, and junction boxes to prevent electric sparks from igniting hydrogen gas.
Regularly inspect the aging status of electrical circuits. A certain enterprise suffered losses of over 500000 yuan due to short circuit sparks caused by failure to replace aging power lines.
Personnel protection and training
Operators are required to wear anti-static work clothes, protective goggles, and gloves, and are prohibited from wearing metal jewelry.
Organize a leak disposal drill every six months to simulate a Level 2 alarm scenario, ensuring that personnel can evacuate, detect, and repair within 5 minutes.