Source: Purdue University Chemistry Lab Safety Document
Tags: lab bench, fume hood, snorkel hood, sash, eyewash, safety shower, fire extinguisher, waste disposal, glass disposal, de-ionised water, Purdue chemistry lab
Difficulty: Beginner Prerequisites: None. This is introductory material for your first chemistry lab session.
This covers the physical layout of a Purdue general chemistry lab and the safety equipment you will use all semester. Knowing where things are before you need them is half the battle in a lab emergency. If you are starting CHEM 101 or any entry-level chemistry course at Purdue, this is your orientation material. You should already know what a chemistry lab is in broad terms; everything else is covered here.
Your lab has specific workstations (benches and hoods), waste disposal systems, and emergency equipment (safety showers, eyewash stations, fire extinguishers, and exits). Know where each one is on day one, because in an emergency you will not have time to look around.
Lab bench
The large table where you conduct most experiments in general chemistry. In organic chemistry labs, the bench is contained inside a fume hood.
Fume hood
An enclosed workspace that draws air inward and vents it outside, protecting you from hazardous gases. Think of it as a ventilated box that keeps toxic fumes away from your face and lungs.
Snorkel hood
A smaller, canopy-style hood used in general chemistry labs for specific tasks involving volatile or odorous chemicals. In simple terms, it is a localised suction point above your workspace.
Sash
The sliding glass panel on the front of a fume hood. You raise it to access the interior and lower it while working. The hood works best when the sash is at or below the marked safe working height.
De-ionised water (DI water)
Water that has had its mineral ions removed. Used for final rinsing of glassware and for chemical reactions, because tap water contains dissolved minerals that could interfere with your results.
Safety shower
A ceiling-mounted shower activated by pulling a handle. Used to rinse large chemical spills off skin or clothing, and to extinguish fires on a person.
Eyewash station
A device that produces a gentle stream of water for flushing chemicals out of your eyes. Activated by pulling a handle or pressing a mechanism at the base.
Fire extinguisher
Located in the small room adjacent to each lab (except CHAS B025, where it is in the hallway). Your teaching assistant operates this, not you.
Glass disposal box
Blue and white boxes at the front and back of each lab. All broken, chipped, or cracked glassware goes here. A broom and dustpan sit on top.
Hazardous waste container
Labelled jars in a designated hood for disposing of chemicals that cannot go down the drain. Must be capped at all times except when actively adding or removing waste. Leaving one open is a federal offence.
Safety Data Sheet (SDS)
A standardised document describing the properties, hazards, and handling procedures for a specific chemical. Available online or from your teaching assistant.
General chemistry labs use open lab benches (large tables). Organic chemistry labs contain the bench inside a hood.
You are assigned a specific bench or hood on the first day and use it all semester.
When handling volatile, odorous, or flammable chemicals, work inside a snorkel hood or one of the main fume hoods.
Keep the sash at or below the lowest safe-working-height mark on the side of the hood.
Work at least six inches inside the hood (behind the yellow line). This prevents gases from escaping into the lab.
The hood draws air inward and vents it outside. If your materials are too close to the opening, the airflow cannot capture the fumes.
Each sink has a de-ionised water faucet. Use DI water for the final rinse of glassware and for chemical reactions.
Do not pour leftover chemicals down the drain unless the procedure explicitly says to. When in doubt, ask your TA.
Use the labelled hazardous waste containers in the designated hood.
Always read the label to confirm you are using the correct container.
Cap waste jars immediately after use. An uncapped hazardous waste container is a federal violation.
If you are unsure where something goes, ask your teaching assistant.
Store personal items (bags, coats) in the cubbies near the door, not on the floor. Tripping while carrying glassware causes serious injuries.
Wipe up spilled liquids immediately. If the spill involves hazardous chemicals, get your TA.
Broken glass goes in the glass disposal box (blue and white boxes, front and back of each lab). Use the broom and dustpan on top.
Safety shower/eyewash station: recessed unit in the lab. Pull the handle to activate either one.
Second eyewash: in the support room (small adjacent room). Press the mechanism at the base and hold to your eyes.
Fire extinguisher: in the adjacent small room (hallway for CHAS B025). Only the TA uses this.
Exits: know every exit location. Evacuation route maps are posted at all lab exits.
Fume hoods are standard equipment in every professional chemistry, pharmaceutical, and materials-science laboratory worldwide. Learning to use one correctly now is a skill you will carry into any lab career. The same principle of negative-pressure containment is used in hospital isolation rooms and cleanroom manufacturing.
Students often think any hood will do for any chemical. It will not. Your TA will direct you to the appropriate hood (snorkel, main fume hood, or assigned organic hood) depending on the substance.
Students sometimes assume DI water and tap water are interchangeable. They are not. Tap water contains dissolved ions that can contaminate your reactions and rinses.
Many students believe a fume hood protects them regardless of sash height. It does not. Raising the sash above the marked level breaks the airflow pattern and lets fumes escape.
Some students think they can dispose of all liquids down the sink. Improper disposal is both dangerous and illegal.
⚠️ You will be tested on which safety equipment to use in specific emergency scenarios (chemical spill on skin vs. in eyes vs. fire).
⚠️ Know the six-inch rule for fume hoods and what the sash height mark means.
⚠️ Waste disposal rules (capped containers, labelled jars, federal offence for open containers) are frequently tested.
⚠️ Know the difference between a snorkel hood and a main fume hood.
True or false: You may raise the fume hood sash as high as you like if you are only working briefly.
Fill in the blank: You should always work at least ______ inches inside the fume hood.
True or false: De-ionised water should be used for the final rinse of glassware.
True or false: If you are unsure which waste container to use, just pick the nearest one.
Fill in the blank: Broken glassware goes in the ______ disposal box.
Answers: 1. False (keep at or below the marked height). 2. Six. 3. True. 4. False (ask your TA). 5. Glass.
Q: A classmate leaves a hazardous waste container uncapped after adding waste. Why is this a problem, and what should you do?
A: An uncapped hazardous waste container is a federal offence that can result in large fines. Cap it immediately and remind your classmate of the rule.
Q: You need to heat a volatile compound. Where should you do this?
A: In a snorkel hood, one of the main fume hoods, or your assigned hood, as directed by your teaching assistant.
Q: What is the purpose of de-ionised water in the lab?
A: It is used for the final rinse of glassware and for chemical reactions, because it lacks the dissolved minerals found in tap water that could interfere with results.
Q: You hear the fire alarm. What do you do?
A: Notify your TA, evacuate through the nearest safe exit, follow the posted evacuation route, and pull the fire alarm as you exit the building. If the lab is filled with smoke, crawl on the floor.
Q: Where is the fire extinguisher located?
A: In the small room adjacent to each laboratory, except for CHAS B025 where it is in the hallway. Your TA operates it, not you.
This connects directly to the lab attire and safe lab practices topics, since knowing where safety equipment is only helps if you are dressed properly and following correct procedures. Emergency scenarios (Topic 4 in the source material) will test your ability to combine equipment knowledge with correct emergency responses.
lab bench, fume hood, snorkel hood, hood sash, safe working height, de-ionised water, DI water, deionized water, safety shower, emergency shower, eyewash station, eyewash, drench hose, fire extinguisher, glass disposal, hazardous waste container, waste jar, chemical waste, Purdue chemistry lab, CHEM 101, general chemistry lab safety, lab tour, lab orientation, SDS, safety data sheet, MSDS