What is an Ignition Barrier?

We all hope we never have to experience a fire in our homes or offices. They cause damage to property and can be far more devastating if people can’t get out in time. Flames can kill. But there’s another danger associated with structural fires that can harm us. 

Many building materials contain toxic chemicals. When they ignite, those chemicals can become airborne. One such material is spray foam insulation. To prevent toxic building spray foam from igniting, we use ignition barriers and thermal barriers. They are an important aspect of fire safety and are necessary construction components. 

Why We Use Ignition Barriers and Thermal Barriers

As we’ve touched on already, we use ignition barriers and thermal barriers to protect us from fire. Each plays a part in stopping the spread of flames and keeping us safe. When used in conjunction, they give us valuable time to get out before the fire gets out of hand. But what’s the difference, and how do the two work together to provide powerful fire protection? Let’s take a look.

Ignition Barrier vs Thermal Barrier: What’s the Difference?

We know ignition barriers and thermal barriers are both crucial components in constructing fire safe spaces. But the two are not the same, and it’s important to know the difference. We use them in different places, and each serves a different function. In order to get to the meat of the matter, we must first examine what exactly each of these is.

What is an Ignition Barrier?

Some construction materials are particularly combustible. We try to treat these materials with products that prohibit them from fueling the spread of flames. When we believe a material to be toxic or hazardous, it’s especially important to keep them from igniting. We achieve that aim with the help of ignition barriers. 

Very simply, an ignition barrier is something we use to prevent some flammable material from igniting. It creates a barrier to ignition. In home and office construction, we use them extensively with spray foam insulation. 

Ignition barriers aren’t required in all areas, but they are strongly recommended any time spray foam insulation is used. It may be applied to the insulation material as an ignition barrier coating, or it may be built in. Either way, it’s an important part of giving occupants time to get out safely and avoid toxic fumes.

What is a Thermal Barrier?

Thermal barriers, on the other hand, are used to separate one space from the next. Specifically, we use thermal barriers for protecting the area where foam insulation has been used. Thermal barriers protect that insulation from flames originating inside the living and storage areas of a home or office. Barriers must be capable of resisting severe fires for at least 15 minutes. This gives us time to extinguish the flames or get out safely before the fire reaches the insulation.

Most commonly, the drywall we use for building our walls serves this purpose. In fact, the building code defines approved thermal barriers as those equal in fire resistance to half inch gypsum board. Sheetrock or drywall are considered the gold standard.

Most of the time, if the space is finished, it already contains a thermal barrier. Most finished basements, crawlspaces, and attics are finished with half inch drywall. If not, there are other materials that constitute an approved thermal barrier.

If you’d prefer not to finish the space, you can use thermal barrier paint as another option. Thermal barrier paint, also called intumescent paint, rapidly expands when exposed to extreme heat. It’s incredibly light, and provides the 15 minute burn protection expected out of a thermal barrier. Even though it is an expanding foam-like barrier, it doesn’t contain toxic chemicals. That means we aren’t being bombarded with noxious fumes as we make our escape.

When do Ignition Barriers and Thermal Barriers Need to be Used?

The question of whether or not we need to use ignition and thermal barriers can be tricky. Since both barrier materials are used for keeping spray foam insulation from igniting, they are important safety features. We don’t have to use them in every region, but they are required in others. Moreover, if your region does require them, they must be used in some spaces, but not in others. Fortunately, there are some fairly simple ways to decipher when these barriers are or aren’t required. Let’s start with ignition barriers.

Ignition barriers must be used in any indoor space that is accessible to occupants. Even if you don’t really use the space much, the spray foam insulation still requires an ignition barrier. The only instances where it isn’t required are those where you can only access the space by cutting into it. If the space doesn’t connect with any accessible storage or living space in the structure, an ignition barrier is not required. Thermal barriers have a slightly different set of criteria.

Thermal barriers must be used in spaces where we live or store things. These include the interior spaces of homes, as well as attics and crawl spaces. If the attics or crawl spaces can’t realistically be used for storage or living, however, they’re exempt from this rule. Accessibility is how we determine whether storage spaces require thermal barriers or can get by with ignition barriers only. 

If the space is easily accessible, you will most likely need a thermal barrier. The assumption here is that if it’s easily accessible, you’ll likely use it as either a storage or living space. On the other hand, if accessibility is extremely limited, you can likely get by with just the ignition barrier.

Knowing the Difference

Unfortunately, these criteria can cause issues if you aren’t familiar with the specific rules. It can be difficult to know what requirements apply in any given attic, basement, or crawlspace. Luckily, there are some simple ways to determine what you need for your particular spaces. They include:

  • Does the space have flooring? If it does, you’ll likely need a thermal barrier separating it from the spray foam insulation. If not, it’s unlikely that you’ll use that space for storage or as a living space. These types of spaces already have thermal barriers separating them from interior living spaces. You can probably get by without additional barriers. 
  • Does the space have a door or easy access? If it’s so easily accessible that you’re likely to use it for storage, you probably will. These spaces also need a thermal barrier. If it’s got a hatch that’s hard to access, you can likely get by with an ignition barrier only.
  • Is there space to freely move about? If the space is easy to traverse, we tend to store materials there that we don’t use incredibly often. Even if it’s somewhat tricky to put materials into the space, we’ll find a way. If you can stand up and move about, your best bet is to use both an ignition barrier and a thermal barrier.

Make Sure You Build to Code

With all the information out there about ignition barriers and thermal barriers, understanding when they’re required can be tough. Each case is unique, and there is no standard definition of what a storage space is. If you have questions regarding your project, it’s best to reach out to the pros for help. 

We’ve got the products to ensure your home and loved ones have the protection they deserve. Whether you need an ignition barrier, thermal barrier, insulation or any other fire safety product we can help. If you’re unsure what exactly you need, we can help with that too.

Building to code isn’t just a recommendation. It’s an important part of keeping you and your family safe. You just need the knowledge and tools to get it done right. Our fire protection experts have the experience to point you in the right direction.