3. Characteristics of liquefied petroleum gas, safety measures, and emergency response principles

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Special warning for highly flammable gases. Its physical and chemical properties are those of a colorless, volatile liquid obtained during the petroleum processing process; its main components are propane, propylene, butane, and butene, with small amounts of pentane and pentenes as well as trace amounts of hydrogen sulfide and other impurities. Insoluble in water. Melting point: -160 to -107°C, boiling point: -12 to 4°C, flash point: -80 to -60°C, relative density (water=1): 0.5 to 0.6, relative vapor density (air=1): 1.5 to 2.0, explosion limit: 5% to 33% (by volume), auto-ignition temperature: 426 to 537°C. Primary uses: It is mainly used as a civilian fuel, engine fuel, raw material for hydrogen production, fuel for heating furnaces, and gas fuel for lighters; it can also be used as a raw material in the petrochemical industry. Hazard Information [Risk of combustion and explosion] Highly flammable; it can form explosive mixtures when mixed with air, and is prone to combustion and explosion in the presence of heat sources or open flames. Heavier than air, it can spread to considerable distances at low altitudes; upon encountering an ignition source, it will ignite and backfire. 【Reactive reaction】 It undergoes violent chemical reactions when in contact with fluorine, chlorine, etc. 【Health hazards】 It primarily affects the central nervous system. Mild acute liquefied gas poisoning is mainly characterized by dizziness, headache, cough, loss of appetite, fatigue, insomnia, etc ； In severe cases, loss of consciousness, urinary incontinence, and shallow or slow breathing occur. Occupational exposure limits: PC-TWA (Time-Weighted Average Allowable Concentration) (mg/m3): 1000; PC-STEL (Short-Term Exposure Allowable Concentration) (mg/m3): 1500. Safety Measures [General Requirements] Operators must receive specialized training, strictly adhere to operating procedures, master operational skills proficiently, and possess knowledge of emergency response. Operate in a sealed environment to prevent leaks, and ensure good natural ventilation at the workplace. Stay away from flames and heat sources; smoking is strictly prohibited in the workplace. Workshops and facilities for the production, storage, and use of liquefied petroleum gas should be equipped with leak detection alarms, use explosion-proof ventilation systems and equipment, and have more than two sets of heavy protective clothing available. Wear anti-static work clothing; when the concentration in the workplace exceeds the allowable level, it is recommended that operators wear filtered gas masks. Frostbite should be prevented when in contact with liquids. Pressure vessels and equipment such as storage tanks should be equipped with safety valves, pressure gauges, level gauges, and thermometers. They must also have safety devices that provide remote monitoring and alarm functions for pressure, level, and temperature. Interlock devices should be installed to connect them to presses, power supplies, pipeline pressures, ventilation systems, or appropriate absorption devices. Emergency shut-off devices shall be installed on storage tanks and similar equipment. Avoid contact with oxidizers and halogens. Safety warning signs should be installed in production and storage areas. During transfer, cylinders and containers must be grounded and bonded to prevent the generation of static electricity. Handle with care during transportation to prevent damage to the cylinders and accessories. The use of electromagnetic cranes, binding with chains, or using the bottle valve as a lifting point is prohibited. Equipped with appropriate types and quantities of fire-fighting equipment and emergency response devices for leaks. 【Special Requirements】 【Operational Safety】 (1) Filling liquefied petroleum gas cylinders must be carried out at a filling station in accordance with the established process. It is prohibited to directly fill liquefied gas from tank trucks, storage tanks, or large bottles into small bottles. Gas cylinders that are defective, such as those with leaks or being overweight, are prohibited from leaving the filling station. (2) When users use liquefied petroleum gas cylinders: it is prohibited to alter the color and markings of the cylinders without permission ； Do not place gas cylinders in direct sunlight, in bedrooms or offices, or near heat sources ； It is prohibited to heat the gas cylinder using heat sources such as open flames, steam, or hot water, or to use an open flame for leak detection ； It is prohibited to use the gas cylinder in a supine or horizontal position ； Do not drop, bump, or roll LPG cylinders ； It is prohibited to transfer liquefied gas between cylinders ； Do not handle liquefied gas residues on your own. (3) Before being put into use for the first time, the oxygen content in the liquefied petroleum gas storage tank is required to be less than 3%. When filling liquefied petroleum gas for the first time, the gas-phase valve should be opened first; once the pressure in both tanks is equalized, the filling can be carried out slowly. (4) During the loading and unloading of liquefied petroleum gas tankers, if any of the following situations occur, the tanker must immediately cease such operations and take appropriate action: —— A fire breaks out in the vicinity ； ——A liquefied gas leak has been detected ； ——Hydraulic abnormality ； ——Other safety hazards. (5) During filling, use a universal joint piping filling system to strictly prevent overfilling. 【Storage Safety】 (1) Store in a dedicated, cool, and well-ventilated warehouse for flammable gases. Keep away from flames and heat sources. The warehouse temperature should not exceed 30°C. (2) It should be stored separately from oxidizers and halogens; mixed storage is strictly prohibited. The lighting wiring, switches, and fixtures must comply with explosion-proof standards; the floor should be made of materials that do not generate sparks or anti-static mats should be used, and conductive bonds should be installed between pipe flanges. The pressure gauge must have a valid calibration certificate issued by the technical supervision department. Storage tank stations must strengthen safety management. No smoking or open flames allowed on the premises. Persons entering the site must not wear clothing that generates static electricity or shoes with nails. The exhaust outlet of incoming motor vehicles should be equipped with a fire suppression device, and the speed must not exceed 5 km/h. LPG supply companies and gas supply stations should have dedicated cylinder warehouses that meet fire safety requirements ； Establish an inspection system for the receipt of liquefied petroleum gas cylinders into storage; cylinders that do not meet the standards shall not be stored ； Empty bottles and full bottles should be stored separately, with clear markings in place. The storage area should be equipped with emergency equipment for handling leaks. (3) LPG storage tanks, tank trucks, and cylinders shall be inspected regularly. (4) Pay attention to lightning and static electricity protection; liquefied petroleum gas storage tanks within the factory (workshop) should be equipped with lightning and static electricity protection facilities in accordance with the provisions of the Code for Design of Lightning Protection of Buildings (GB 50057). 【Transportation Safety】 (1) Transport vehicles shall be equipped with signs indicating the transport of hazardous goods, as well as satellite positioning devices with driving record functionality. Without the approval of the public security authorities, transport vehicles shall not enter areas where the passage of hazardous chemical transport vehicles is restricted. (2) Special tank trucks should be used for transport by tank vehicle. The flame arrester (spark extinguisher) installed on the tank truck must be in good condition. Tank trucks and delivery trucks must be equipped with anti-static trailing cables ； The tanker must be equipped with two or more dry chemical or carbon dioxide fire extinguishers and explosion-proof tools. (3) When transporting cylinders by vehicle, the openings of the cylinders must always face to the right, in the direction of travel. The stacking height shall not exceed the vehicle’s protective railing, and the cylinders should be secured with wooden braces to prevent them from rolling. It is prohibited to mix items with conflicting properties in the same vehicle, as well as to allow unrelated persons to ride along. Keep away from sources of fire during transportation; do not park in areas with open flames or in crowded places, and someone should be present to watch over the vehicle when it is parked. In the event of a leak or fire, drive to a safe location to extinguish the fire or seal the leak. (4) Pipelines for transporting liquefied petroleum gas should not be laid near heat sources ； When pipes are laid above ground, protective measures should be taken in areas with high pedestrian traffic and those prone to being struck by vehicles or foreign objects, along with the installation of clear warning signs ； When LPG pipelines are installed overhead, they should be laid on non-combustible supports or trestles. Under the already installed liquefied petroleum gas pipelines, no buildings unrelated to these pipelines shall be constructed, nor shall flammable materials be stored there ； The color and markings on the outer wall of liquefied petroleum gas pipelines shall comply with the provisions of \"Basic Identification Colors, Identification Symbols, and Safety Markings for Industrial Pipelines\" (GB 7231). Principles of first aid 【First aid measures】 Inhalation: Quickly move the affected person to a place with fresh air. Keep the airway clear. If there is difficulty breathing, administer oxygen immediately. If breathing stops, perform artificial respiration immediately and seek medical help. Skin contact: In the event of frostbite, soak the affected area in warm water maintained at 38–42°C to rewarm it. Do not apply or rub. Do not use hot water or radiant heat. Wrap with a clean, dry dressing. Seek medical attention if you feel unwell. 【Fire extinguishing method】 Cut off the gas supply. If the gas supply cannot be cut off, it is not allowed to extinguish the flame at the leak site. Use water spray to cool the container, and move it as far as possible from the fire to an open area. Extinguishing agents: foam, carbon dioxide, water mist. 【Leak Emergency Response】 Eliminate all ignition sources. A safety zone is established based on the affected area caused by the gas, and unrelated personnel are evacuated to a safe area from the side wind and upwind direction ； In the event of a static wind leak, liquefied petroleum gas settles at the bottom and flows toward lower areas; uninvolved persons should evacuate to higher ground. It is recommended that emergency responders wear positive-pressure self-contained breathing apparatus and anti-static, insulated clothing. All equipment used during operations should be grounded. Do not touch or cross the spill. Seal the source of leakage as much as possible. If possible, turn the container upside down to allow the gas to escape rather than the liquid. Sprayed water suppresses vapor or alters the direction of vapor clouds, preventing water flow from coming into contact with the leak. It is prohibited to direct water at the spill or the source of the leak. Prevent the spread of gases through sewers, ventilation systems, and confined spaces. Isolate the leak area until the gas has dissipated. As an emergency preventive measure, the leakage isolation distance should be at least 100 meters. In the case of a large-scale leak, the initial evacuation distance downwind should be at least 800 m.