Laboratory Area Code of Conduct

1. Do not eat, drink, store food, beverages, or other personal items in the laboratory; do not engage in activities unrelated to experiments or research.

2. Smoking is prohibited in the entire laboratory area (including rooms, corridors, elevator lobbies, etc.).

3. Do not bring unauthorized persons into the laboratory without permission from the laboratory management.

4. Be familiar with evacuation routes and emergency procedures. Know the locations of the first aid kit, fire extinguishers, emergency eyewash stations, and safety showers. Memorize emergency numbers: 119/120/110.

5. Keep laboratory doors and aisles clear. Minimize the amount of reagents stored in the laboratory. Storage of highly toxic drugs is strictly prohibited without authorization.

6. Hands must be washed before leaving the laboratory. Do not wear lab coats or gloves into public areas such as cafeterias, libraries, conference rooms, or offices.

7. Keep the laboratory clean and tidy. After experiments, wash, dry, and store experimental utensils and glassware promptly. Avoid excessive accumulation of items on benches and in the lab. Clean the workbench at least once daily.

8. Consult the responsible person for the laboratory or equipment immediately if questions arise during experimental work. Do not operate blindly.

9. Do not leave the experimental area unattended for extended periods during experiments.

10. When performing certain hazardous experiments during evenings, weekends, or holidays, there must be at least two persons present in the laboratory to ensure safety.

Chemical Storage and Custody

1. All chemical containers must have clear, permanent labels indicating contents and potential hazards.

2. All chemicals must have associated Safety Data Sheets (SDS).

3. Be familiar with the properties and potential hazards of the chemicals you use.

4. Chemicals that are unstable during storage or prone to forming peroxides require special labeling.

5. Chemicals should be stored at an appropriate height. Do not store chemicals inside fume hoods.

6. Containers with corrosive liquids should be stored as low as possible, preferably in containment trays to prevent spills and accidents.

7. Store unstable chemicals separately, with purchase dates clearly labeled. Separate chemical reagents that may react to prevent the generation of toxic fumes, fire, or explosion.

8. Volatile and toxic substances require special storage conditions. Storage of highly toxic chemicals in the laboratory is prohibited without authorization.

9. Do not store large quantities of flammable solvents in the laboratory; order only what is needed. Unused full bottles of reagents must be stored away from light and heat sources.

10. When handling hazardous chemicals, wear a lab coat, protective goggles, closed-toe shoes, and tie back long hair.

11. Do not store corrosive chemicals, toxic chemicals, organic peroxides, pyrophoric substances, and radioactive materials together, especially bleach, nitric acid, perchloric acid, and hydrogen peroxide.

Use of Organic Solvents

1. Flammable Organic Solvents
Many organic solvents can cause fires or even explosions if handled improperly. Ignited solvent-air mixtures spread rapidly. The intense heat can instantly ignite flammable materials. Fires are more severe in oxygen-rich environments (e.g., due to gas cylinder leaks), potentially igniting normally non-flammable materials. Explosions can occur when flammable solvent vapors mix with air within certain concentration limits.

Precautions for using flammable organic solvents:
(1) Place containers of flammable liquids on low shelving.
(2) Keep containers tightly closed. Open sealed containers only when pouring.
(3) Use flammable organic solvents in well-ventilated areas (e.g., fume hoods) away from ignition sources. Avoid using large quantities.
(4) Minimize the storage volume of flammable solvents to reduce hazards.
(5) When heating flammable liquids, use a water bath or oil bath. Do not use open flames.
(6) Pay special attention to operating temperatures and conditions. Table 1 shows the flash points, auto-ignition temperatures, and flammable limits of common solvents.
(7) Combustion of chemical gas-air mixtures can cause explosions (e.g., the energy released from burning 3.25g of acetone vapor is equivalent to 10g of TNT). Perform combustion experiments with extreme caution.
(8) Be vigilant of common ignition sources: open flames (Bunsen burners, torches, oil lamps, fireplaces, pilot lights, matches), sparks (electrical switches, friction), heat sources (hot plates, filament lamps, heating mantles, ovens, radiators, space heaters, cigarettes), and static electricity.

2. Toxic Organic Solvents
The toxicity of organic solvents is manifested through local anesthetic effects, irritation, or systemic functional disorders upon contact or absorption. Prolonged, high-concentration exposure to vapors of volatile organic solvents is always toxic.
- Examples: Primary alcohols (except methanol), ethers, aldehydes, ketones, some esters, and benzyl alcohol can damage the nervous system.
- Methyl carboxylate esters and formate esters can cause lung toxicity.
- Benzene and its derivatives, glycols can cause blood poisoning.
- Halogenated hydrocarbons can lead to liver and metabolic toxicity.
- Tetrachloroethane and glycols can cause severe kidney toxicity.

Precautions for use:
(1) Avoid direct skin contact with organic solvents. Always use appropriate personal protective equipment (PPE). Refer to Section III: Personal Protection Knowledge.
(2) Ensure adequate ventilation in the work area.
(3) In case of a spill of a toxic organic solvent, depending on the volume, remove all ignition sources, alert personnel, contain the spill with absorbent material, sweep it up, place it in a sealed bag, and dispose of it as hazardous waste.

Use of Electricity

1. Unauthorized electrical wiring is strictly prohibited in the laboratory.

2. Before using a power outlet, know its rated voltage and power capacity. Do not overload outlets.

3. Do not connect multi-outlet power strips in series. Do not use multiple high-power appliances on the same power strip for extended periods.

4. Large instruments must use dedicated outlets.

5. Do not use temporary extension cords as permanent solutions.

6. Conserve electricity. Turn off air conditioners, lights, computers, and other appliances before leaving the laboratory at the end of the day or before holidays. Turn off these appliances when not needed, even during work hours.

Use of Water

Laboratory water is categorized as tap water, pure water, and ultrapure water. Notes for use:

1. Conserve water. Take only what is needed.

2. Select the appropriate water grade based on experimental requirements. Rinse glassware first with tap water, followed by a final rinse with pure water. Use ultrapure water for chromatography, mass spectrometry, and biological experiments (e.g., buffer preparation, hydroponics, microbial culture media, mobile phases).

3. Do not store ultrapure or pure water; collect it as needed. If the system has been idle, flush the dispenser for several minutes before use.

4. Always turn off the tap firmly after use.

Use of Liquid Nitrogen

Liquid nitrogen is commonly used as a refrigerant. Refrigerants can cause frostbite. Contact with eyes can cause blindness. Rapid evaporation of liquid nitrogen can displace oxygen, causing air hypoxia.

Precautions for handling liquid nitrogen:

1. Wear insulated cryogenic gloves.

2. Wear a long-sleeved lab coat that covers the knees.

3. Wear closed-toe shoes that cover the ankles, protective goggles, and if necessary, a face shield.

4. Ensure adequate ventilation.

Use of Cleaning Solutions

Cleaning solutions include acidic solutions (sodium or potassium dichromate in sulfuric acid), alkaline solutions (sodium hydroxide in ethanol), and neutral solutions (common detergents).

1. Acidic cleaning solutions should be stored in glass containers. Alkaline solutions can be stored in plastic buckets.

2. When using alkaline cleaning solutions, disassemble ground glass joints before placing glassware in the solution to prevent corrosion and fusion. Pre-rinse glassware with acetone and water before placing it in alkaline solution.

Use of Instruments, Facilities, and Apparatus

1. Glassware
Proper use of glassware is crucial for minimizing injury. Do not use damaged glassware in the laboratory. Discard non-repairable glassware as waste. Remove all chemical residues before repairing glassware.

Precautions:
(1) Wear protective gloves when inserting glass tubes into rubber stoppers or tubing. Fire-polish the ends of the glass tube and use water or grease as a lubricant. Do not forcefully pull apart stuck glassware.
(2) Wrap Dewar flasks with tape or other protective layer to contain glass shards if implosion occurs. Glass distillation columns should have similar protection. Perform operations involving non-atmospheric pressure (positive or negative) behind protective shields.
(3) Dispose of broken glass in designated sharps containers. Rinse broken glass before disposal if contaminated.
(4) Use appropriate protective measures (e.g., polycarbonate shields) during vacuum distillation to prevent injury from implosion or explosion.
(5) Ordinary glassware is not suitable for pressure reactions, even at low pressures, and is strictly prohibited for such use.
(6) Do not place hot glassware on cold surfaces to prevent thermal shock and breakage.

2. Rotary Evaporator
Precautions for use:
(1) The typical operating pressure range for rotary evaporators is 10-30 mmHg.
(2) Secure all connections with appropriate clamps.
(3) Do not fill the evaporation flask beyond half its capacity.
(4) Ensure the evaporator rotates at an appropriate speed.

3. Vacuum Pumps
Vacuum pumps are used for filtration, distillation, and vacuum drying. Common types: air pumps, oil pumps, circulating water pumps. Water and oil pumps can achieve 20-100 mmHg; high-vacuum oil pumps can reach 0.001-5 mmHg.

Precautions:
(1) Always use a cold trap before an oil pump.
(2) Change the water in circulating water pumps frequently to prevent solvent residues from igniting due to motor sparks.
(3) Before finishing, cool the distillate, then slowly release the vacuum to atmospheric pressure before turning off the pump.
(4) Change the oil in oil pumps regularly.
(5) Connect the exhaust port of oil pumps to a hose venting into a fume hood.

4. Fume Hoods
Fume hoods protect users from toxic/hazardous gases, but may not capture 100% of contaminants.

Precautions:
(1) Do not place chemicals or equipment blocking the airflow baffle or exhaust outlet.
(2) Do not turn off the ventilation during experiments.

5. Thermometers
Common types: alcohol thermometers (low-temperature: -80°C to +50°C; standard: 0°C to +80°C), mercury thermometers (0°C to +360°C), quartz thermometers (0°C to +500°C). Thermocouples are less common. Select the appropriate thermometer. Do not use thermometers as stirring rods. If a mercury thermometer breaks, use a suction device to collect most of the mercury, place it in a sealed, labeled container for hazardous waste disposal, then cover the residue with sulfur powder for cleanup days later.

6. Gas Cylinders
Cylinders contain materials under high pressure. Tipping, heating, or improper handling can cause explosion. Besides being explosive/propulsive, many gases are flammable, toxic, and/or corrosive.

Precautions:
(1) Characteristics of a safe gas cylinder:
* Clear label indicating gas contents.
* Color-coded according to standard.
* Equipped with a pressure regulator.
(2) Cylinder Storage:
* Compressed gases are hazardous. Minimize the number of cylinders in labs. Storage of hydrogen cylinders inside laboratories is strictly prohibited.
* Cylinders must be secured upright to walls or sturdy stands. Protect from sunlight, heat, corrosive materials, and physical impact. Do not store cylinders in hallways or lobbies.
* Do not store flammable and oxidizing gas cylinders together. Keep flammable gas cylinders at least 10 meters from open flames. Flammable and toxic gas cylinders must be stored outdoors in secure, ventilated gas cylinder cabinets.
(3) Cylinder Use:
* Before connecting the regulator, wipe the cylinder valve outlet clean. After use, close the main valve and release pressure from the regulator. Replace the protective cap (unless designed otherwise). Use caution when removing caps.
* Do not completely empty cylinders (especially acetylene, hydrogen, oxygen); maintain positive pressure.
* Use cylinders with intact regulators and valves in well-ventilated areas. Use local ventilation for toxic gases.
* When using toxic or corrosive gases, wear safety glasses, face shields, gloves, and aprons. Do not strike or collide with cylinders.
* Do not lubricate oxygen cylinder valves, regulators, or associated lines with oil or grease.
* Transport cylinders using a suitable hand truck, secured in an upright position, with the regulator valve closed.

7. Centrifuges
Centrifuges are effective for solid-liquid separation, especially for fine particles.

Precautions:
(1) Balance centrifuge tubes symmetrically. Use water for balancing if necessary.
(2) Close the lid before starting. Start at low speed, then gradually increase to the desired speed.
(3) Wait until the centrifuge comes to a complete stop before opening the lid. Never touch the rotating parts while moving.
(4) Use high-quality glass centrifuge tubes. Avoid using organic solvents or hot solutions in plastic tubes to prevent deformation.
(5) Fill centrifuge tubes only halfway to prevent spillage.

8. Syringes
Prevent needle sticks and breakage. Ensure the needle is tightly attached to the syringe to prevent leakage. Wash used syringes promptly. Destroy disposable syringes before disposal.

9. Refrigerators and Freezers
Laboratory refrigerators/freezers are not explosion-proof and are not suitable for storing flammable, explosive, or volatile solvents.
(1) Storing personal food and drinks is strictly prohibited.
(2) All low-boiling-point reagents stored inside must have proper labels.
(3) All containers must be sealed. Clean refrigerators/freezers regularly and dispose of unneeded samples/reagents.

Major Laboratory Safety Incidents

1. Fire Accidents
Causes: Leaving equipment powered on, leading to overheating; mishandling ignition sources near flammables; aged/overloaded electrical circuits; careless disposal of smoking materials. These can occur in any lab.

2. Explosion Accidents
Causes: Violating procedures, igniting flammable materials; faulty equipment leading to leaks of flammable/explosive materials encountering ignition sources. Common in labs with flammables/explosives and pressure vessels.

3. Biosafety Incidents
Causes: Management oversights or accidents can lead to laboratory-acquired infections, environmental contamination, or large-scale public infection. Biological waste can be more hazardous than chemical waste, containing infectious agents, chemical pollutants, and radionuclides, posing significant risks to health and the environment.

4. Poisoning Accidents
Causes: Bringing food into toxic chemical labs, leading to accidental ingestion; faulty equipment causing toxic leaks or inadequate fume extraction; poor management leading to dispersal of toxic substances; blocked/modified wastewater lines releasing untreated toxic effluent. Common in chemical labs and labs emitting toxic gases.

5. Equipment Damage Accidents
Causes: Power failure/fluctuation damaging heated apparatus; collisions/crushing of high-speed equipment due to careless operation. Common in labs using electrical heating.

6. Mechanical and Electrical Injury Accidents
Causes: Improper operation or lack of guarding leading to crushing, entanglement, or impact; faulty equipment causing electric shock or arc flashes; mishandling of high-temperature fluids/surfaces. Common in labs with high-speed machinery, electrical work, or high-temperature processes.

7. Theft of Equipment or Technology
Causes: High personnel turnover, difficult management of equipment/technology, low security awareness. These incidents cause property loss, disrupt work, and risk loss of intellectual property.

Preventive Measures

1. Eliminate Human Factors
People are the primary factor in lab safety. Improving personnel safety awareness and literacy through various means is key to minimizing hazards.
* Example: Hong Kong universities mandate safety training and exams for postgraduates before using controlled materials/equipment. Undergraduates in science/engineering also receive compulsory training, including lectures, online courses, and fire/escape drills. Tsinghua University uses an online learning/exam system for lab safety.

2. Build a Safe Environment
A proper safety environment is crucial. This involves both hardware and software.
* Hardware: Equip labs with safety facilities (fire extinguishers, alarms, emergency showers/eyewashes, first aid kits, waste collection). Regularly check emergency exits. Ensure safe water and qualified electrical installations.
* Software: Designate lab safety officers. Post clear warning signs for hazards. Display safety instructions for equipment and chemicals (hazards, emergency measures). Conduct regular safety inspections, training, and competitions. Enforce strict奖惩 policies to foster a safety culture.

3. Improve Systems and Raise Awareness
Establishing and strictly enforcing a comprehensive lab management system is essential for sustainable safety and for implementing safety access control systems.
* Example: Hong Kong universities typically have a university-level Safety and Environment Committee, chaired by a senior administrator, to set policies, rules, and guidelines, improve facilities, and oversee daily management through a dedicated office.

Chemical Laboratory Safety Management System

1. Theft Prevention
Enhance security, conduct regular checks, seal vulnerabilities. Restrict non-personnel access. Close windows/doors when unoccupied. No socializing, overnight stays, or unauthorized visits in labs. Do not store personal valuables in offices. In case of theft, secure the scene and report immediately.

2. Fire and Explosion Prevention
Labs are equipped with fire extinguishers, sand buckets, etc. Open flames for heating are strictly prohibited. Store flammables and explosives separately and properly according to their properties. Follow standard operating procedures strictly to prevent fires/explosions.

3. Water Damage Prevention
Keep water lines and drains clear. Main water valves for buildings and zone valves for labs should be managed by designated personnel. Protect pipes from freezing in winter.

4. Poisoning Prevention
Labs store/handle toxic substances. Store toxics properly. Dispose of toxic waste properly. Establish a dedicated hazardous materials warehouse/store. Store flammables, toxics, oxidizers, corrosives separately in dedicated cabinets. Check and register hazardous chemicals upon receipt and periodically. Implement the "Double Person" rule for management: double custody, double issuance, double receipt, double accounting, double locks. Follow procedures strictly. Prepare toxic gases in fume hoods. Ensure ventilation with exhaust fans. Provide waste containers on student benches and in labs. Utilize designated waste treatment pools.

5. Electrical Safety
Electrical installations should be rational, scientific, and convenient. Main building and floor sub-switches should be installed, with leakage protectors. Main switches controlled by custodial staff; sub-switches by lab managers; checked daily. Student power sources controlled by instructors. Regularly inspect circuits and equipment. Do not use faulty equipment. In case of electrical fire, cut power first, then use sand or CO2 extinguishers. Never use water or foam extinguishers on live electrical fires. For electric shock, cut power immediately, administer first aid, and seek medical help.

Chemical Laboratory Rules

1. Maintain quiet. No loud noise or horseplay.

2. Students must prepare before class. Enter orderly and sit in assigned seats.

3. Instructors must explain the experiment's purpose, requirements, and procedure clearly.

4. Students check equipment and chemicals upon arrival. Do not exchange items randomly. Report discrepancies.

5. Conduct experiments step-by-step, observe carefully, record data, and submit reports promptly.

6. Take care of equipment and conserve materials. Pay for damages/losses due to negligence.

7. After the experiment, clean, dry, and store equipment. Clean the workspace. Leave only after the instructor's dismissal.

8. These rules must be announced to students before the first experiment of each semester.