We use cookies to give you the best experience possible. By continuing to use the site, you indicate that you accept cookies. See our cookies policy here.
A practical guide for safe setup, lighting, flame control, heating, shutdown and laboratory fire safety.
A Bunsen burner is a laboratory gas burner commonly used in school science, chemistry lessons and practical demonstrations. It provides a controllable open flame for heating suitable non-flammable substances, carrying out flame tests and combustion experiments, and flame-sterilising compatible small tools or vessel mouths as part of an approved aseptic procedure.
Correct use is essential. A Bunsen burner uses a naked flame, so poor setup, the wrong ignition method, damaged gas tubing, loose clothing or unsuitable heating can lead to burns, fires, gas leaks and broken glassware. This guide explains general safe practice; the practical instructions, risk assessment and laboratory rules for the activity always take priority.
This guide was written and reviewed by Better Equipped's technical team, drawing on experience supplying Bunsen burners, heatproof mats, tripods, gauzes, test tube holders, safety goggles and practical science equipment to schools, colleges and laboratories throughout the UK.
Knowing the main parts of a Bunsen burner makes it easier to set up the equipment, control the flame and recognise unsafe flame behaviour.
The vertical metal tube in which fuel gas mixes with primary air before the mixture burns at the top of the burner.
Rotates to open or close the air hole. It controls how much primary air is drawn into the gas stream, changing the flame’s colour, temperature and behaviour.
Allows primary air to enter the burner. With the hole closed the burner produces a yellow safety flame; opening it produces a cleaner, hotter blue or pale-lilac heating flame.
The side connection where approved gas tubing attaches to the burner.
Controls the gas supply. This may be on the bench, on the burner, or both, depending on the installation and burner model.
The heavy lower section that keeps the burner stable and helps prevent tipping during use.
These terms are useful when following school science practical instructions or comparing Bunsen burner equipment.
| Term | Meaning |
|---|---|
| Safety Flame | A visible yellow flame produced with the air hole closed. It is used for lighting and during a brief supervised pause in heating. It is still hot and is unsuitable for heating because it deposits soot. |
| Blue Heating Flame | A hotter, cleaner and less visible flame produced when primary air mixes with the fuel gas before combustion. A gentle or medium blue/pale-lilac flame is used for general heating. |
| Roaring Flame | A recognised very hot heating flame, normally produced with the air hole fully open and sufficient gas flow. A steady roaring sound is not itself a fault; this flame is used only for very strong heating when instructed. |
| Primary Air | Air drawn through the air hole and mixed with the fuel gas inside the burner before combustion. Additional secondary air reaches the flame from the surrounding atmosphere. |
| Air Hole | The opening that allows primary air to enter the burner and mix with the fuel gas. |
| Collar | The rotating part that opens or closes the air hole and regulates the primary-air supply. |
| Gas Inlet | The connection point for the approved gas tubing. |
| Heatproof Mat | A heat-resistant mat placed beneath the burner and hot apparatus to protect the bench. |
| Tripod | A metal stand used to support suitable apparatus above the flame. |
| Gauze | A wire mesh placed on a tripod to support suitable glassware and spread heat. Use only gauzes whose asbestos-free status has been confirmed through the supplier or the laboratory’s assurance procedure. |
| Strikeback | A dangerous fault in which the flame burns inside the barrel. Turn off the gas immediately and do not relight the burner until it has cooled and the cause has been checked. |
The collar controls the amount of primary air drawn into the fuel-gas stream. Changing the gas-to-air mixture changes the colour, temperature, visibility and behaviour of the flame.
| Flame Type | Air Hole Position | Use | Safety Notes |
|---|---|---|---|
| Yellow Safety Flame | Closed | Used for lighting and during a brief supervised pause when the burner remains lit but is not actively heating. | Easy to see but still hot. It produces soot and is not suitable for heating. |
| Gentle or Medium Blue Heating Flame | Partly open, adjusted as instructed | Used for general heating. Start gently and increase the flame only if the procedure requires it. | Hotter, cleaner and less visible than the yellow flame. It can be difficult to see in bright light and may blow out if the settings or draughts are unsuitable. |
| Roaring Blue Flame | Mostly or fully open, with sufficient gas flow | Used for very strong heating when specifically required. | A steady roar is normal. This flame is extremely hot and is not often needed. Do not reduce the gas flow while leaving the air hole fully open, because the flame may go out. |
Use a Bunsen burner only when the practical instructions and risk assessment specify an open flame. The apparatus, flame and heating method must be suitable for the substance and the intended experiment.
| Activity | Typical Equipment | Skills Practised |
|---|---|---|
| Heating water or suitable non-flammable solutions | Bunsen burner, tripod, confirmed asbestos-free gauze, beaker, heatproof mat | Controlled heating, flame selection and safe apparatus setup. |
| Heating non-flammable materials in test tubes | Bunsen burner, test tube or boiling tube, suitable test tube holder, goggles | Safe filling, pointing the tube away, gradual heating and continuous agitation where required. |
| Flame tests | Bunsen burner, nichrome wire or splint, chemical samples | Observation, identification and safe use of an appropriate blue flame. |
| Flame-sterilising compatible small tools or vessel mouths | Bunsen burner and suitable laboratory tools | Approved aseptic technique and controlled flame handling. Open flames must not be used inside a biological safety cabinet. |
| Combustion and high-temperature experiments | Bunsen burner, suitable tongs, crucible, heatproof mat | Observation of combustion or oxidation and safe handling of heat-resistant apparatus. |
Using equipment that is suitable for the fuel supply, temperature and practical method helps improve safety and heating control.
Laboratory gas burners for school science heating, flame tests and chemistry practical work. Select a burner designed or correctly configured for the available fuel gas and operating pressure.
View Bunsen BurnersProtect benches from heat and provide a safer working area beneath burners and hot apparatus.
View Heatproof MatsSupport suitable beakers, flasks and other apparatus above the flame during heating.
View TripodsPlaced on tripods to support suitable glassware and spread heat. Use only gauzes whose asbestos-free status has been confirmed through the supplier or the laboratory’s assurance procedure.
View GauzesAllow safer heating of test tubes while keeping hands away from the flame. Check that the holder is in good condition and closes securely before use.
View HoldersEye protection for practical work involving flames, chemicals, heat or splashes, as specified by the risk assessment.
View Goggles| Mistake | Why It Matters | How to Avoid It |
|---|---|---|
| Using the wrong air-hole setting for the ignition method | An unsuitable setting can make ignition less controlled or cause the burner to fail to light. | Close the air hole for a match, lit splint or conventional flint striker. Set it approximately half open for a piezo-electric lighter and follow the device instructions. |
| Continuing to adjust an unlit burner after the flame goes out | Unburned gas can accumulate and create a fire or explosion risk. | Turn off the gas immediately, allow the gas to disperse, correct the cause and restart the lighting procedure. |
| Leaving a blue flame on while not heating | The flame is very hot and can be difficult to see. | For a brief supervised pause, return to the yellow flame. Turn off the gas when the burner is no longer required. |
| Heating a flammable liquid or organic solid directly over the flame | The vapour or material may ignite, and local overheating may break the container. | Use the risk-assessed alternative heating method and extinguish every naked flame before introducing the flammable material. |
| Using a burner intended for a different fuel gas | Natural gas and LPG require different burner configurations and incorrect equipment can produce unsafe or unstable flames. | Use only a burner identified by the manufacturer or supplier as suitable for the available gas and pressure. |
| Leaving the burner unattended | Creates a serious fire and burn risk. | Never leave a lit burner or heated apparatus unattended. |
| Using damaged gas tubing | May cause gas leakage, poor gas flow or unsafe ignition. | Inspect the tubing and connections before use and replace or report damaged equipment immediately. |
| Heating unsuitable, damaged or closed glassware | Can cause thermal shock, cracking, pressure build-up, spitting or boiling over. | Use suitable heat-resistant apparatus, inspect it first, keep containers open and heat gradually. |
| Holding a test tube with crucible tongs | The tube can slip or be gripped unevenly. | Use a suitable test tube holder in good condition. |
| Reaching across or leaning over a flame | Can ignite clothing or hair and cause burns. | Arrange the apparatus before lighting and keep hands, sleeves, hair and equipment clear of the flame path. |
| Problem | Possible Cause | What to Do |
|---|---|---|
| Burner will not light | The gas supply may be off, the ignition source may be incorrectly positioned, the air setting may not suit the ignition method, or the burner or jet may be blocked or unsuitable for the fuel. | Turn off the gas immediately and allow any unburned gas to disperse. Check the approved setup and ignition method. Do not dismantle the burner; report repeated failure or a suspected blockage. |
| Flame goes out or begins to sputter | Gas flow may be too low, the air hole may be too far open for the gas flow, a draught may be disturbing the flame, or the equipment may be faulty. | Turn off the gas immediately. Allow unburned gas to disperse, identify and correct the cause, then repeat the complete lighting procedure. Do not adjust the gas while the burner is unlit. |
| Yellow flame when a heating flame is required | The air hole is closed or not open far enough. | If the practical requires a blue flame, open the collar gradually until the specified stable heating flame is produced. |
| Soot forms on equipment | Combustion is incomplete because too little primary air is mixing with the gas. | When actively heating, open the air hole gradually to produce a stable, cleaner blue or pale-lilac flame. |
| Steady roaring sound | The burner is producing a recognised roaring flame with a large primary-air supply and sufficient gas flow. | This is not automatically a fault. Use it only when very strong heating is required. If a gentler flame is needed, reduce the air setting as instructed while maintaining a stable attached flame. |
| Flame lifts away from the barrel, becomes unstable or repeatedly blows out | The gas/air settings may be unsuitable, the mixture velocity may be too high, or a draught or equipment fault may be present. | If the flame goes out, turn off the gas immediately. Stop using the burner, correct the air and gas settings only as instructed, remove draughts where safe and report persistent instability. |
| Flame burns inside the barrel | Strikeback may occur when the gas flow is too low for the air setting, the burner is overheated, the jet is blocked or unsuitable, or the burner is not configured for the fuel supply. | Turn off the gas immediately. Allow the burner to cool and report it. Do not relight it until the burner, jet, fuel compatibility and gas/air settings have been checked. |
| Smell of gas | There may be a loose connection, damaged tubing, a faulty tap, an extinguished flame or gas left on. | Turn off the gas supply if it is safe to do so. Do not light flames or operate electrical switches. Alert the teacher, technician or supervisor immediately and follow the site gas-emergency procedure. |
Raise the alarm immediately. Stop, drop and roll. A trained adult should use a fire blanket or safety shower where appropriate and in accordance with the laboratory’s emergency procedure.
Turn off the gas supply only if it is safe to do so. Do not light flames or operate electrical switches. Alert the teacher, technician or supervisor and follow the site gas-emergency and evacuation procedure.
Cool the burn under cool or lukewarm running water for at least 20 minutes. Remove nearby jewellery or clothing only if it is not stuck to the skin, and obtain first aid. Do not use ice or creams.
Raise the alarm, alert others and turn off the gas only if safe. Follow the laboratory fire procedure and evacuate as directed. Attempt to fight the fire only if trained, authorised and it is safe to do so.
Do not touch it. Keep others away, allow it to cool and have it cleared using the laboratory’s broken-glass procedure.
Turn off the gas immediately, stop using the burner and report it so that the burner, tubing, jet, gas supply and fuel compatibility can be checked.
A Bunsen burner is used for approved open-flame heating of suitable non-flammable materials, flame tests, combustion experiments and, in some approved aseptic procedures, flame-sterilising compatible small tools or vessel mouths.
With a match, lit splint or conventional flint striker, closing the air hole produces a visible yellow flame and makes ignition easier to observe. A piezo-electric lighter is an important exception: the air hole should normally be approximately half open, following the device and laboratory instructions.
The yellow flame is easier to see and is used for lighting or a brief supervised pause, but it is still hot and deposits soot. A blue or pale-lilac flame is hotter, cleaner and used for heating, but it is less visible.
No. A steady roaring flame is a recognised very-hot flame used for strong heating when instructed. A flame that lifts off the barrel, becomes unstable, burns inside the barrel or repeatedly goes out is unsafe and must be dealt with promptly.
In a roaring blue flame, the hottest region is usually just above the tip of the inner blue cone.
They must not be heated directly over a naked flame. Use the risk-assessed alternative method, such as a hot-water bath, and extinguish all naked flames before the flammable material is introduced.
Turn off the gas immediately. Allow any unburned gas to disperse, identify and correct the cause, and then repeat the full lighting procedure. Do not continue adjusting an unlit burner.
No. A lit Bunsen burner and any apparatus being heated must remain under continuous supervision.
Turn off the gas supply if it is safe, do not light flames or operate electrical switches, and report the issue immediately to a teacher, technician or supervisor. Follow the site gas-emergency procedure.
Soot is produced by incomplete combustion when too little primary air mixes with the fuel gas. When heating, open the air hole gradually until a stable cleaner flame is produced.
Not unless the manufacturer or supplier confirms that it is designed or correctly converted for both. Natural gas and LPG require different burner configurations, so the burner must match the available fuel and pressure.
Depending on the practical, equipment may include a heatproof mat, tripod, confirmed asbestos-free gauze, suitable test tube holder, safety goggles, beakers, test tubes, boiling tubes, crucibles, suitable tongs and heat-resistant glassware or ceramics.
Choosing heating equipment that is suitable for the fuel gas, operating pressure and practical method helps improve science safety, lesson efficiency and experimental results. Better Equipped supplies Bunsen burners, heatproof mats, tripods, gauzes, safety goggles and laboratory heating accessories for schools, colleges and laboratories throughout the UK.
View Bunsen Burners View Bunsen Burner Buying Guide Contact Us for AdviceThis guide was written and reviewed by Better Equipped's technical team, drawing on experience supplying Bunsen burners, laboratory heating equipment, safety products and practical science resources to schools, colleges, universities and laboratories throughout the UK.
Our aim is to help users understand safe Bunsen burner technique, improve practical science confidence and reduce avoidable laboratory accidents. This page provides general guidance and does not replace the activity-specific risk assessment, practical instructions, manufacturer information or current laboratory safety guidance.
Last reviewed and updated: July 2026
Call us: 
Email us: 
