1, skin contact with liquid nitrogen will cause frostbite.
2. If there is too much nitrogen produced by vaporization under normal pressure, the partial pressure of oxygen in the air will drop, and in extreme cases, it will cause hypoxia and suffocation.
3. In case of high heat, the internal pressure of the container rises, which is in danger of rupture and explosion.
Second, how to prevent the damage of liquid nitrogen
1, engineering control: closed operation and good natural ventilation.
2, respiratory system protection: generally do not need special protection. However, when the oxygen concentration in the air in the workplace is lower than 18%, air respirator, oxygen respirator or long tube mask must be worn.
3. Eye protection: Wear a safety mask.
4, physical protection: wear winter clothes.
5, hand protection: wear cold gloves.
6. Other protection: avoid high concentration inhalation. Prevent frostbite.
7. Precautions for storage: Store in a cool and ventilated warehouse. The reservoir temperature should not exceed 30℃. The storage area should be equipped with emergency treatment equipment for leakage.
Third, the treatment of liquid nitrogen poisoning
1, first aid measures
Skin contact: If frostbite occurs, seek medical attention.
Inhalation: leave the scene quickly and go to a place with fresh air. Keep the respiratory tract unobstructed. If you have difficulty breathing, give oxygen. If breathing stops, give artificial respiration immediately. See a doctor.
2, fire control measures
Hazard characteristics: In case of high heat, the pressure inside the container will increase, which is in danger of rupture and explosion.
Harmful combustion products: This product is nonflammable.
Fire extinguishing method: This product is nonflammable. Use atomized water to keep the container cool in the fire. Spraying atomized water can accelerate the evaporation of liquid nitrogen, but the water gun should not be sprayed on liquid nitrogen.
3, liquid nitrogen leakage treatment method
When the inhaled nitrogen concentration is not too high, the patient initially feels chest tightness, shortness of breath and weakness; Then there are fidgety, extremely excited, running around, shouting, being in a trance, and unsteady gait. This situation is called "nitrogen poisoning" and can enter a lethargic or coma state. Inhalation of high concentrations can lead to rapid coma and death due to respiratory and cardiac arrest.
(1) Evacuate the personnel in the leaked contaminated area to the upwind place quickly, and set up an isolation zone to strictly restrict access.
(2) Notify the fire department and relevant units.
(3) Emergency personnel should wear self-contained positive pressure breathing apparatus, winter clothes and gloves.
(4) Avoid liquid leakage to the basement or other closed occupied workspace. If it is inevitable, the relevant departments should be notified immediately.
(5) Don't touch the leak directly.
(6) Cut off the leakage source as much as possible.
(7) Misty water mist can be used to accelerate the evaporation of liquid, but water gun can't be used to shoot liquid.
(8) In order to prevent gas from accumulating in the depression, an exhaust fan is used to send the leaked gas to the open space.
(9) It is forbidden to stay in low-lying or downwind places.