Flammable Liquids and Ignition Sources

It’s vital that you know how to identify and eliminate ignition sources if your business is carrying Class 3 Flammable Liquids. Ignition sources aren’t always easy to spot — or control — in a busy workplace. However, the safety of your people and property depends on how successfully you control ignition sources in areas that carry flammable chemicals.  

If your staff aren’t sure how to identify a source of ignition — or they’re unaware of the potential dangers that they pose — your workplace could be at real risk of a fire or explosion. To help you reduce your chemical risk, this blog explains the various types of ignition sources that may be present in your business. We’ll also offer some advice on how to control the risk of fire and explosion when you’re handling and storing Class 3 Flammable Liquids. 

What is an Ignition Source?

So, what exactly is an ignition source and how can they create risk in your workplace?  

An ignition source in a workplace is something that can produce enough heat to ignite flammable substances or materials. When flammable liquids come within 3 metres of an ignition source, the flammable particles are provided with enough energy to ignite. This then results in the spontaneous burning of the flammable substance.  

Identifying ignition sources is key in reducing the risk of fire or explosion in areas that carry Class 3 Flammable Liquids.

For businesses that rely on flammable liquids, there is a real risk of fire, explosion and human harm if ignition sources are not prohibited from work areas which handle or store Class 3 Flammable Liquids. 

In the workplace, some ignition sources can be very easy to identify such as a naked flame. However, others are not so easy to identify — such as a spark produced from static electricity. There are many sources of ignition in the average workplace. Even a small spark can cause flammable liquids to ignite.

The best way to identify an ignition source is to determine whether the object will contain enough heat to cause a flammable substance to ignite. The object might be very small, such as a spark or an ember, however these small particles can be very hot (100 C0+) and contain enough energy to ignite flammable substances. 

Types of Ignition Sources in the Workplace 

There are 4 main categories of ignition sources: thermal, electrical, mechanical and chemical.  

To give you a better understanding of the range of ignition sources that may be present in your business, we’ll explain each category of ignition source in further detail below. 

To control the risk associated with carrying flammable liquids, you must first identify any potential ignition sources in your workplace.

Thermal Ignition Sources

Therman ignition sources are those objects which produce heat. These may be commonly found objects such as a cigarette butt or essential tools like welding equipment. 

Some examples of thermal ignition sources include: 

Flames

• Blow torch 
• Welding Flame 
• Cigarette lighter 
• Stove 
• Pilot Light 

Hot Surfaces 

• Soldering Iron 
• Electric Lamp 
• Cigarette butt 
• Hot slag 
• Glowing ember

Electrical Ignition Sources  

Electrical ignition sources are perhaps some of the most misunderstood ignition sources in the workplace. Items such as power points can produce sparks which may cause flammable liquids on your premises to ignite. 

Some examples of electrical ignition sources: 

Electrical Current 

• Electric motor 
• Electric Switches 
• Cable Break 
• Spark produced under short circuit or other fault conditions 

Electrostatic Charge 

• Pneumatic Conveying of Solid Flow of liquid in pipeline 
• Rubbing of plastic or rubber 
• Liquid spray generator 
• Powder flow 

Lightning 

• Direct strike 
• Induced Voltage 

Stray current 

• Arc Weld 

Even outdoor stores of flammable liquids may be vulnerable to ignitious sources such as lightning strikes

Mechanical Ignition Sources

Mechanical equipment in the workplace can present a significant ignition hazard. Frictional heat, sparks and the fracturing of materials all pose a serious risk to businesses that handle or store flammable liquids. 

Some examples of mechanical ignition sources 

Friction Heat 

• Abrasive wheel 
• Bearing 
• Jamming of material 
• Piston movement 

Materials Fracture 

• Cracking of metal 

Chemical Ignition Sources 

For fires to occur, there must be a mixture of heat, oxygen and fuel. This is known as ‘the fire triangle’. However, there is also another element that you must consider — and that is chemical ignition caused by exothermic reactions. 

Some examples of chemical ignition sources that you may find in the workplace include: 

Exothermic Reactions 

• Vigorous oxidising reactions 
• Exothermic Polymerisation 
• Exposing pyrophoric Substances (sodium metal) to air 

Controlling Ignition Sources 

Flammable liquids must never be handled or stored within 3 metres of an ignition source. 

The Australian Standard AS 1940 – The storage and handling of flammable and combustible liquids states in Section 4.9.7: 

Exclusion of ignition sources  

There shall be no ignition sources within the cabinet. Where flammable liquids are stored, ignition sources shall be excluded from the area outside the cabinet to a distance of 3 m measured laterally, and from floor level to a height of 1 m above any opening in the cabinet, including the door, or a distance determined in accordance with AS/NZS 60079.10.1. 

Once you have clearly identified and eliminated any ignition sources from those work areas, you must then alert personnel to the presence of this hazardous chemical with flammable cabinet signage. 

Flammable cabinets should clearly display safety signage that alerts staff to the chemical dangers that are present in that area.

It’s vital your business displays clear hazard identification signage in all areas where Class 3 Flammable Liquids are stored.  

In the Australian Standard AS 1940, you will find the requirements for cabinet markings. The standard explains that each flammable cabinet shall be marked with:  

4.9.4 Cabinet marking 

(d) a sign bearing the words 'NO SMOKING, NO IGNITION SOURCES WITHIN 3m' in lettering at least 50 mm high. 

All signs and markings shall be clearly visible when the cabinet doors are closed. 

In addition to these safety signage measures, you must also ensure that all staff, supervisors and contractors are trained to correctly identify and eliminate possible ignition sources from these work areas. Training your staff to correctly handle and store flammable liquids is key to maintaining safety and compliance for your business. 

Your staff must be trained in the safe handling and storage of flammable liquids, so they can identify and eliminate any potential ignition sources from areas which carry flammable liquids.

How are you Storing Flammable Liquids?  

As we’ve explained in this blog, ignition sources can come in many shapes and forms. To make sure that your workplace is protected against the risk of fire or explosion, we strongly recommend that you identify every ignition source in the workplace. You can then take preventive measures to ensure that all flammable substances are stored in a safe and compliant way.  

If you’d like to learn how to conduct a risk assessment for your workplace, please click on the image below to access our helpful Chemical Risk Assessment Template Pack. This will walk you through the chemical risk assessment process, so you can take the steps towards chemical compliance in your business. Get your copy of our eBook for free today.