Safety

Why is Lab Safety Important?

Laboratory research drives global scientific and engineering advances, making labs hubs for knowledge acquisition and novel materials (Moran & Masciangioli, 2010). A culture of safety, security, responsibility, and education has emerged worldwide. This culture emphasizes individual responsibility and collaboration to ensure the well-being and a safe environment for teaching, learning, and working. It goes beyond institutional regulations to create a healthy, productive atmosphere.

General Guidelines

Things to Do:

1. Always wear:

a) safety goggles when working with substances particularly dangerous for the eyes;

b) a lab coat that is closed in the front;

c) appropriate gloves when using chemicals;

d) firm and closed shoes (no sandals, flip-flops etc.).

2. Always tie up long hair.

3. Always use clean and functional lab equipment.

4. Always wash your hands with soap before and after an experiment.

5. Always label all substances clearly and readably.

6. Always clean the glassware first with acetone, then with water after using them.

Things Not to do:

1. Never eat, drink, or smoke.

2. Never wear:

a) inappropriate clothes (shawls, blouses or shirts with loose sleeves or from easily flammable fabrics);

b) headphones (you could miss the alarms);

c) contact lenses.

3. Never put laboratory equipment in your mouth.

4. Never take out chemical products from the building.

5. Never hook your lab coat on the modules on the media columns, or the dosage valves and gas governors.

6. Never obstruct walkways and safety exits.

7. Never run in the lab.

8. Never put substances into a container in which the label does not match.

9. Never keep food in lab fridges containing chemicals.

10. Never use phones or computers with gloves on your hands.

Heat

1. Turn off heat sources when they are not in use;

2. Always wear thick, protective gloves when handling heated glassware or materials;

3. When heating flasks or beakers over the laboratory burner, use a ring-stand setup with a square of wire gauze;

4. When heating with a laboratory burner, gently move the test tube over the hottest part of the flame;

5. Never pour hot liquids into plastic containers.

6. Always be aware of flammable chemicals (e.g. ether, acetone, ethanol, benzene, sodium metal, etc.), do not leave them in large quantities on a table or near a flame. Pour flammable liquids only when away from the source of ignition, or after the flame has been extinguished.

7. Organic solvents with low boiling points should not be heated directly over a fire, but only heated or distilled in a water bath using a reflux condenser tube.

8. In case of an accidental flame, remove all combustible materials around the area immediately and close the ventilator to prevent the expansion of the combustion. If the area on fire is small, use rags, wet cloths, iron sheets, or sand to cover the fire and isolate it from the air so that it can be extinguished.

9. When flammable solids/gases/liquids are on fire, dry powder extinguishers can be used to stop the fire; When conductors or electrical appliances are on fire, cut off the power of the appliances and use dry powder extinguishers to stop the fire; When someone s clothes are on fire, they can roll them on the ground or the clothes will be removed to extinguish the fire with water.

Gas

1. Handling: When transporting or rotating the gas cylinder, do not move the on/off valve by hand.

2. Use: Select the pressure reducer according to the category of the gas cylinder, and the screw fasteners should be tightened and leak-tested during installation.

a. Open the cylinder: counterclockwise direction is open; first, open the main valve, then open the pressure-reducing valve.

b. Close the cylinder: Clockwise direction is close; first, close the main valve, then close the pressure-reducing valve.

c. Protection of gas nozzle: Use a dead wrench to clamp the gas nozzle before opening the main valve.

Safety: The gas in the cylinder must not be exhausted.

a. Inert gas: Gas with pressure of 0.05MPa or more should be left.

b. Flammable gas: Gas with a pressure of 0.2MPa or more should be left.

c. Hydrogen: Gas with pressure of 2.0MPa or more should be left.

Separate storage

a. The cylinders should be placed upright in a stable position; they should be kept away from heat sources; they should be protected from exposure to sunlight and strong vibration; and the amount of cylinders stored in the laboratory should not exceed two in general.

b.Hydrogen and oxygen cylinders should not be stored in the same place.

Chemicals

1. Many hazardous chemicals are toxic and corrosive, therefore, direct contact should be avoided when using hazardous chemicals, do not use chemical solvents to wash your hands, and do not ingest them;

Hazardous chemicals are divided into eight categories: explosives, compressed and liquefied gases, flammable liquids, flammable solids, self-combustible articles and articles flammable in contact with moisture, oxidizers and organic peroxides, narcotics, radioactive substances, and corrosives, and it is important to familiarize yourself with the hazards of the chemicals before you use them and to be able to skillfully carry out emergency treatment.

Any chemical containers must be labeled with the contents and expiration date.

When using low boiling point organic solvents, be sure to keep them away from sources of fire and heat.

Liquid Waste

1. The waste solution should be categorized according to organic and inorganic, and it is strictly prohibited to mix different categories of liquids in the same bottle.

2.Containers with waste liquids must be clearly labeled with the name of the waste liquid, composition, concentration, date, and name of the person who discarded the solution.

3. Put the containers with waste liquids in the designated place for uniform disposal.

4. It is strictly prohibited to pour toxic, harmful, and strong corrosive reagents and liquids into the sink.

5. Waste washing solution shall not be poured into the sewer, and shall be put into reagent bottles for unified treatment.

Instrument Use

1. Instrument users must carefully read the operating procedures, had training before the operation, and must follow the "instrument operating procedures".

2. Pre-registration should be made before using the instrument, and after completing the measurement of the sample, the time should be registered in the "Use and Maintenance Register" of the instrument.

3. In the process of sample determination, keep the instrument, the experimental table, and the laboratory clean.

4. If the instrument is out of order, report to the management crew immediately, and do not handle it without authorization.

5. There shall be no unauthorized misappropriation of auxiliary equipment and spare parts associated with utility instruments and all utilities in the laboratory.

Pipette

Pipette is a measuring instrument consisting of a graduated glass tube used to measure or transfer precise volumes of a liquid by drawing the liquid up into the tube. It is an instrument used in our experiment to...

Procedures:

1. Set the normal adjustment method for shifting liquid volume from large range to small range, and rotate the scale counterclockwise. When adjusting from small range to large range, it should first be adjusted to exceed the set volume scale, and then back to the set volume.

2. Assemble the pipetting gun head, insert the pipetting gun vertically into the suction head, rotate it half a circle left and right, and tighten it.

3. Suction head tip immersed in liquid level 3mm below.

4. The pipette gun with liquid suction should not be placed flat

5. the pipette gun should be adjusted to the maximum scale after each experiment

6. the liquid must be slowly and smoothly release the thumb

7. in order to obtain higher accuracy, the suction head needs to draw a sample solution in advance, and then the formal pipette.

8. Pipette is strictly prohibited to absorb strong volatile, strong corrosive liquid (such as concentrated acid, concentrated alkali, organic matter, etc.). 9. Do not use a large range pipette to remove a small volume of liquid, so as not to affect the accuracy.

Biological Safety Cabinet

A biosafety cabinet (BSC)—also called a biological safety

cabinet or microbiological safety cabinet—is an enclosed, ventilated laboratory workspace for safely working with materials contaminated with (or potentially contaminated with) pathogens requiring a defined biosafety level.

In this experiment, we used Class I cabinets, which provide personnel and environmental protection but no product protection. In fact, the inward flow of air can contribute to contamination of samples. Inward airflow is maintained at a minimum velocity of 75 ft/min(0.38 m/s). These BSCs are commonly used to enclose specific equipment (e.g. centrifuges) or procedures (e.g. aerating cultures) that potentially generate aerosols.

Biosafety cabinets can provide dual protection for samples and workers. The filtered clean airflow is blown down from the top of the safety cabinet and passes through the work area, where it is captured before reaching the breathing area of the staff. The air stream will be filtered before it is discharged. Normally, the filtered air will be discharged back to the laboratory or out through the exhaust pipe. Follow the typical layout of "clean to dirty" work in the biosafety cabinet. The left side is used to store clean items, which can be operated in the central area, and the right side is used to store contaminated appliances and experimental materials.

Clean Bench

A clean bench provides a highly clean working environment, filtering the air from dust, bacteria, and viruses to protect samples from contamination. It is commonly used in biological experiments, pharmaceuticals, electronics manufacturing, and other fields to ensure a sterile and clean operating environment.

1. Before using the clean bench, clean the surface of the operation table and place the required reagents and items for the experiment (do not place animal, plant, or microbial materials). Turn on the ultraviolet sterilization lamp for 20-40 minutes, then turn it off, start the fan, and switch on the fluorescent lamp. Turn on the ultraviolet sterilization lamp again for 20-40 minutes again after finishing using the clean bench.

2. Unnecessary items are not allowed to be stored on the operation table, ensuring that the clean airflow pattern in the workspace is not disturbed.

3. When handling materials contaminated with fungi, it must be done in a specialized laminar flow cabinet for fungi, and the fan must not be turned on to prevent fungal contamination in the laboratory.

4. The alcohol lamp must have its cover intact, and the alcohol level should not exceed 2/3. Pay attention to safety precautions during the operation.

5. Highly flammable and explosive substances, such as full bottles of alcohol, are prohibited from being placed.

6. Before entering the clean bench, disinfect your hands (wear gloves) with alcohol.

Reference

[1] Angelo, and Angelo Depalma. 2009. Product Focus: Biological Safety Cabinets. October. https://www.labmanager.com/product-focus-biological-safety-cabinets-20141.

[2] Courseware, MIT Open. 2010. General Lab Policies, Do's and Don'ts. https://ocw.mit.edu/courses/20-109-laboratory-fundamentals-in-biological-engineering-spring-2010/pages/labs/general-lab-policies-do2019s-and-don2019ts/.

[3] Fribourg, Department of Chemistry University of. 2016. Safety in the laboratory. Fribourg.

[4] Märder, T., & Gray, N. 2020. Safety and Environmental Manual for the HCI.https://ethz.ch/content/dam/ethz/special-interest/chab/se-management-dam/Hauptseite/EN/Manual.pdf.

[5] Moran, L., & Masciangioli, T. 2010. Chemical Laboratory Safety and Security A Guide to Prudent Chemical Management. Washington, DC.

[6] 2013. Pathogen. https://www.dictionary.com/browse/unabridged.

[7] Services, U.S. Department of Health and Human. 2009. Biosafety in Microbiological and Biomedical Laboratories 5th Edition. Washington, D.C.,

[8] December.2021. Taking a Look at Lab Ssafety. https://www.mcrsafety.com/blog/lab-safety.

[9] University, Tianjin Normal. 2016. 超净工作台操作规范和注意事项. https://swxsy.tjnu.edu.cn/info/1055/1278.htm.