Ink has been used from at least the 26th century BC for the purposes of writing and drawing. Today, its use remains as pervasive as ever, as it allows us to write letters, print posters, make tattoos, etc.
But have you ever wondered if ink poses a potential fire hazard? In this article, we are going to discuss whether ink is flammable or not. We will begin by looking at the chemical composition of the ink. Then we will discuss the difference between combustible and flammable substances. Finally, we will talk about ink’s relationship to fire.
Table of Contents
What is the Chemical Composition of Ink?
Ink is a complex medium, made up of dyes, surfactants, resins, lubricants, and other materials. But primarily, it is made up of a dye that is mixed with a solvent. The solvent carries the dye, and this solution of ink is pressed onto paper, fabric, or skin. The solvent dries out, leaving the color of the dye on the surface.
The constituents of the ink (such as its colorants, solvent, and other additives) affect the thickness of the ink, its flow, and its dry appearance. Ink is widely used to produce images, texts, and designs.
The worldwide consumption of ink generates revenue of over 20 billion dollars, and while its demand in traditional print media is decreasing, it is now being increasingly used for packaging.
Is Pen Ink Flammable?
Yes and no, depending on the composition of the pen ink. There are mainly two types of inks: water-based and non-water-based. The former use water as its solvent and are not flammable. The latter, however, use hydrocarbons to carry the dye and are usually flammable.
A hydrocarbon is an organic compound consisting of only hydrogen and carbon. These often occur in petroleum, natural gas, coal, etc. Hydrocarbons are highly flammable because the carbon in their structure is in its most reduced form.
This carbon is very easily oxidized by oxygen, making it extremely reactive. Moreover, hydrocarbons are also very volatile, that is, their molecules quickly evaporate and spread. So, the flames during the combustion of a hydrocarbon spread quickly. This is why they are extremely flammable.
A lot of inks use a non-water-based solvent such as alcohols, acetone, benzene, etc. Often these solvents are hydrocarbons, and hence extremely flammable. Now, inks made using these hydrocarbons will be likewise flammable.
But a lot of inks are water-based, that is, they use water as the solvent to carry the pigment. These are not flammable. In most cases, inks are flammable only while wet, and they cannot ignite after the solvent dries out.
Difference Between Flammable and Combustible
The difference between flammable and combustible liquids is based on the temperatures they must be exposed to in order to catch fire. This specific value is known as the flash point. Flammables have a lower flash point (100°F) as compared to combustibles, meaning that they can ignite at lower temperatures.
A flash point is the lowest temperature at which a liquid produces vapors that could ignite in air when close to an ignition source. This is the main descriptive characteristic used to differentiate between flammable and combustible liquids, helping to determine the fire hazard of fuels.
Liquids that have a flash point less than 37.8°C (100 °F) are called flammable. These include petrol, acetone, benzene, etc. Petrol has a flash point of -43°C, which makes it an extremely dangerous liquid. It requires several safety precautions.
Petrol should always be kept in a building away from the main place of residence or business. It should be stored in a chemical storage container so that it can’t be accessed by anyone without awareness of its content. Finally, you should always transfer petrol (say from a container to a vehicle) outdoors so that the vapors can escape into the air.
Liquids that have a flash point above 37.8°C (100 °F) are called combustibles. These include diesel fuel, motor oil, etc. Diesel’s flash point ranges from 52°C to 96°C. It’s non-flammable in most environments, which is why it is used in compression-ignition engines. Still, it needs to be marked properly with a “Combustible Liquid C1” tag and stored properly.
The distinction between flammable and combustible liquids has been set up by the National Fire Protection Association (NFPA) in its Flammable and Combustible Liquids Code, also called NFPA 30.
Is Alcohol Ink Flammable When Dry?
No, after drying out, alcohol ink is not likely to ignite. In itself, alcohol ink is highly flammable and the presence of an ignition source can certainly light up a fire. But the good thing is that alcohol solvent usually evaporates quite quickly after pouring. After this, the chances of a fire are a lot less.
Alcohol inks use alcohol as the solvent to carry the colored pigment. They are waterproof, fast-drying, and highly colored, which makes them look great on a variety of surfaces. They are dye-based (use color substances dissolved in liquid), which allows the creation of unique effects that cannot be achieved through water-based inks.
After the ink is applied to a surface and dried, it can be reactivated by adding alcohol and re-shaped, just like watercolors can be reactivated with water. These inks work best on hard, non-porous surfaces such as glass, metal, plastic sheets, etc.
If you use alcohol-based inks on a regular basis, you should consider buying a chemical fume mask with organic filters. It will keep alcohol vapors away from you. You should also use gloves and glasses to keep yourself safe from exposure. Finally, as the ink is flammable in its liquid state, you should also have some firefighting tools (such as an extinguisher) around.
What Temperature Will Ink Burn?
The flash point (the lowest temperature at which a liquid gives off vapors and can ignite) for ink depends on the composition of the ink. Some inks are water-based and cannot burn, while the non-water-based inks can burn at various temperatures. These are often made up of hydrocarbons which are highly flammable.
For example, Avantik US’s printing ink has a flash point of 76.5°F. They have described this in their Safety Data Sheet, which is a document that lists information about safety and health-related issues that are involved in using a product.
Whenever you are using a chemical, including inks, always make go through the safety data sheet and ensure that you are familiar with the right steps you need to take for using the substance.
What Happens if You Burn Ink?
Inks are either water-based (use water as solvent) or non-water-based (use hydrocarbon as solvents). Nothing will happen if you try to burn the former, as it is not flammable. But the latter, due to the presence of hydrocarbons, are highly flammable. If you bring an ignition source near them, they will light up quickly.
We don’t really recommend trying to burn ink as it can be dangerous. But you can check out YouTube user Make Science Fun’s video showing what happens when you burn a pen. The plastic melts, creating balls of fire.
In the case of alcohol-based ink, the risk of fire hazards is even greater. So, it is advisable to always keep an extinguisher around, especially if you are working with lots of ink in a large painting/printing studio.
Can You Burn Printer Ink?
Yes, if the printer ink is non-water-based (uses hydrocarbons as its solvent), then it can certainly burn. While inside the printer, they are unlikely to get temperatures high enough to ignite. Print cartridges are now available in thicker, heat-resistant casings that prevent fire. But still, if printer ink is brought near an ignition source, it can light up.
Most inkjet printers use a thermal inkjet. In each ink reservoir, there is a heating element with a metal plate or resistor. When signalled by the computer, current flows through the metal, making it warm. The ink in contact with this metal is vaporized into a steam bubble inside the nozzle, which is then forced out in the form of an ink droplet onto paper.
So, the application of heat is part of the functioning of printing. But, this heat is carefully controlled by the computer hardware and software. Otherwise, printer ink, when non-water-based, is quite flammable.
Is Sharpie Ink Flammable?
Yes, the ink inside sharpie pens is usually alcohol-based, so it is flammable. When an ignition source is brought near a sharpie pen, first the plastic body of the pen will burn and then the ink present inside will also catch fire. As such, it is important to use sharpie pens with caution.
Sharpie was originally the name of a permanent writing marker, but it now includes a whole range of writing implements. These include permanent and non-permanent pens as well as markers, having all kinds of tips: ultra fine, extra fine, fine, brush, etc. Sharpie now also has gel and ballpoint pens.
Like all ink that is non-water-based, sharpie ink is also flammable and should be used with caution.
In this article, we have discussed whether ink is flammable or not. We began by looking at the composition of the ink, which usually involves a solvent and a dye. The solvent is usually either water or a hydrocarbon, and this determines whether the ink is flammable or not. We also looked at the difference between flammable and combustible liquids.