What Does a Spark Arrestor Do, and Why Is It a Must-Have Chimney Part?

Nothing beats gathering around your home’s crackling fireplace on cold winter nights. However, fireplaces and their chimneys are common causes of house fires, so meticulous installation and maintenance are a must. The spark arrestor is a small but significant part of the chimney that’s essential for fire safety. But what does a spark arrestor do, and why is it a legal requirement for most chimneys and many other combustion sources? Read on to learn more. 

What Are Spark Arrestors and How Do They Work? 

Spark arrestors are fire safety devices for emissions systems. They act as physical barriers, preventing stray scorching carbon particles thrown out during the burning process from escaping and igniting on contact with combustible materials. Typically made of appropriately sized, non-flammable steel mesh, spark arrestors allow air to flow while trapping or pulverizing sparks that could be a fire hazard.

Spark Arrestor Uses

Spark arrestors are used on various general-purpose engines to prevent exhaust particles from coming into contact with flammable oil or gas. Examples of the types of engines you can find spark arrestors on include:

• Cars

• Motorcycles

• Boats

• Chainsaws

• Lawn trimmers

• Leaf blowers

• Lawn mowers

• Rototillers

However, the most common residential use for spark arrestors, and the one it’s handiest for homeowners to be aware of, is in fireplaces and chimneys.

Fireplace and Chimney Spark Arrestors

Escaping embers from your wood-burning stove or fireplace are major fire hazards. To reduce the risk, every home with a fireplace must have exterior spark arrestors on the chimney. 

The exterior spark arrestor fits underneath or is integrated into the cap sitting atop your chimney. It prevents burning particles from escaping outside, potentially setting fire to your roof or leaf debris or dry shrubbery in your yard or other nearby landscapes. 

Fireplace hearth screens act as interior spark arrestors for open fireplaces. They provide a protective barrier for people and pets and prevent airborne embers from setting your furniture alight.

How to Install Spark Arrestors

You will need an exterior spark arrestor if you are installing a wood-burning stove or fireplace with a new chimney or replacing an existing one. Chimney spark arrestors are available to buy and DIY install. Pick an arrestor that fits the local regulation guidance regarding mesh width and positioning, and ensure it’s the correct size for your chimney flue. Installation methods vary, so always follow the manufacturer’s instructions. 

While this is a job a handy homeowner can tackle, it involves working at heights and at an awkward angle. Plus, if you get the installation wrong, you could increase the fire hazard risk and invalidate your home insurance. 

While the exact details vary by municipality, there are spark arrestor regulations with specific requirements regarding the size of the spark arrestor mesh and the device position. Hiring a licensed and insured local chimney cap installer ensures the job will be done quickly, safely and correctly. Professional chimney cap installation costs between $75 and $500—expect chimney spark arrestor costs to be similar.

Spark Arrestor Maintenance

Arranging an annual chimney and fireplace inspection and cleaning is a good idea. A local chimney repair company can clean, repair, or replace the spark arrestor if it does not meet current safety standards.