Laboratory Safety and Apparatus
Senior 1 · Chemistry
Laboratory Safety and Apparatus
Lesson 1 of 5
22 min
Walk from your classroom into the chemistry laboratory and look around. The benches have hard, smooth tops instead of wooden desks. There are sinks with taps in the middle of the room, a cupboard with a glass front and a fan, a red cylinder by the door, and often two doors instead of one. Every one of these features is there for a reason: a laboratory is a room where fires, spills and poisonous fumes are possible, so it is built to stop small accidents becoming big ones.
Definition
Laboratory: a room or building equipped for scientific experiments, tests and investigations. Example: your school's chemistry laboratory, or the water-testing laboratory at a treatment plant.
With your teacher, walk slowly around your school laboratory. Draw a rough plan of the room and mark on it: the exits, the gas taps, the main gas shut-off valve, the sinks, the fire extinguisher, the fire blanket, the first-aid kit and the eye-wash station. Then compare your plan with Figure 1.1. Which items are missing from your laboratory, and what does your school use instead?
Figure 1.1: Plan of a school chemistry laboratory, seen from above. Green arrows show the two ways out.
Warning
Before your first experiment, know where the two exits, the fire blanket, the extinguisher, the eye-wash station and the main gas valve are. In an emergency there is no time to look for them. Never block an exit with bags or stools.
Table 1.1: Safety features of a laboratory
| Feature | What it is for |
|---|---|
| Two exits | if a fire blocks one door, everyone can still get out through the other |
| Fume cupboard | a glass-fronted cabinet with a fan that pulls poisonous or smelly gases out of the room, away from your face |
| Fire blanket | a fire-resistant sheet pulled from its case to smother a small fire or a person whose clothes are burning |
| Fire extinguisher | puts out larger fires; the right type must be used for each kind of fire |
| Eye-wash station | gives a gentle stream of clean water to rinse chemicals out of the eyes |
| First-aid kit | plasters, bandages and burn dressings for small injuries |
| Main gas shut-off valve | the teacher closes it to cut off gas to every bench at once |
| Sinks with running water | for washing apparatus, and for cooling burns and washing chemicals off skin |
| Locked chemical store | keeps dangerous substances away from people who have not been trained to use them |
| Hard, smooth benches | do not burn easily, are not damaged by most chemicals, and are easy to wipe clean |
Definition
Fume cupboard: a cabinet with a sliding glass front and an extractor fan that removes harmful gases and vapours. Example: experiments that give off chlorine or ammonia are done in the fume cupboard.
Definition
Fire blanket: a sheet of fire-resistant material kept in a quick-release case. It puts out a fire by cutting off the oxygen the fire needs.
Definition
Eye-wash station: a fitting, often at a sink, that sprays clean water gently into both eyes to wash out a chemical.
A fire needs three things: fuel (something that burns), oxygen (from the air) and heat. Take away any one of the three and the fire goes out. A fire blanket and a carbon dioxide extinguisher both work by cutting off the oxygen. Water works by taking away heat, but it is dangerous on some fires.
Table 1.2: Choosing how to put out a fire
| Kind of fire | What to use | Never use |
|---|---|---|
| Paper, wood, cloth | water, or a fire blanket for a small fire | nothing forbidden |
| Small amount of burning liquid in a beaker (for example ethanol) | cover it with a heat-proof mat or damp cloth; carbon dioxide extinguisher | water, which spreads the burning liquid |
| Electrical equipment | switch off at the socket, then a carbon dioxide extinguisher | water, which conducts electricity |
| A person's clothes | stop, drop to the floor and roll; wrap in a fire blanket | running, which fans the flames |
Warning
Common mistake: throwing water on burning oil or ethanol. The liquid floats on the water and spreads, carrying the flames with it. Smother the fire instead.
Worked example
Problem. Look at Figure 1.1. A small fire starts at the left-hand end of the bench nearest the main door (3). Which exit should the class use, and what should the teacher do on the way out?
Solution.
Answer: use the emergency exit (2); close the main gas valve (11) on the way.
Worked example
Problem. During an experiment, a little ethanol in a beaker catches fire. Keza reaches for the tap to pour water on it. Explain what she should do instead.
Solution. Ethanol is a burning liquid, so water would spread it. The fire needs oxygen, so Keza should turn off any gas, then slide a heat-proof mat over the top of the beaker. With no oxygen reaching the flames, the fire goes out in seconds. If it spreads, the teacher uses the carbon dioxide extinguisher.
Important
Report every accident to your teacher at once, however small: a spill, a cut, a burn or broken glass. Many serious injuries start as small accidents that nobody reported.
Tip
Remember the fire triangle: fuel, oxygen, heat. To put out a fire, take one side of the triangle away.
CrashCourse: Lab Techniques & Safety, Crash Course Chemistry #21 (9 min). Pay attention to the eye-wash, the fume hood and the rules for handling glassware.
Practice
Sources and credits
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
