Homeowner Information About Chimney Safety

How the Chimney Works

Your home's air is constantly moving, and airflow typically tries to flow out of the house in the upper floors and into the house in the lower sections. Homes built in the last two decades, and homes that have been renovated, tend to be much more airtight, which can make it difficult for air to enter the home. When warm air rises in your home to the upper sections, this is known as the stack effect. Trapped air becomes pressurized and forces its way out somehow, even if it is through window frames.

Somewhere in the home is the Neutral Pressure Plane (NPP). Above this point, air pressure is slightly positive and trying to escape, while below the plane, air pressure is slightly negative and trying to enter the home.

How a Fireplace Works


When a fireplace is placed below this plane, air will tend to flow into the home through the chimney or vent. The chimney operates on the same pressure that hot air rises because it is lighter than cold air. When the fireplace is in use, the chimney fills with hot gas, which rises outside of the home. The rising hot gas creates a pressure difference known as draft that draws combustion air into the fireplace and expels exhaust gas outside.

Homeowner Information About Chimney Safety Homeowner Information About Chimney Safety


Understanding Chimney Inspections

The National Fire Protection Association adopted levels of inspection of chimneys, fireplaces and vents. Inspections are defined as Level 1, Level 2 or Level 3.

Chimney Information

Level 1 Inspection:

This is the minimum inspection that is recommended if your chimney has been continuously used under the same conditions. This is the most common inspection and it involves a chimney technician examining readily accessible portions of the chimney interior, exterior and parts of the appliance and chimney connection. The technician will be analyzing your chimney for soundness of the flue and chimney structure and basic installation and connections while making sure the chimney is free of obstructions or combustible deposits that pose a fire hazard. This examination includes:

  • The firebox
  • Smoke chamber
  • Damper
  • Chimney cap
  • Chimney crown
  • Structural elements of the chimney
  • Check for blockages or combustible build-up
Fireplace Cleaning

Level 2 Inspection:

This type of inspection is recommended if changes had been made, including changing the flue like relining, or replacing or adding an appliance. A Level 2 inspection is also common upon the sale of a property or if something likely caused damage to the chimney. This inspection is more in-depth and assesses any part of the chimney that can be accessed. This inspection includes the same components as a Level 1 inspection, along with a video inspection to examine internal surfaces and joints.



Chimney Technician

Level 3 Inspection:

This is the most comprehensive inspection and it examines parts of the chimney that are hidden and may need to be removed to be inspected for defects or problems. The chimney technician may need to remove bricks, masonry, chimney crowns endcaps, flue pipes, internal walls or other parts to complete the inspection. This inspection is only required when a previous inspection revealed a problem and opening the chimney is the only way to access the area.

Hiring a Chimney Sweeping Professional

Whether you are hiring a chimney cleaner to perform an inspection or perform repairs on your chimney or fireplace, the Chimney Safety Institute of America (CSIA) recommends taking a few steps to find a trustworthy and experienced technician. While comparing chimney sweeping companies, ask the following questions:

  • How long has the company been in business?
  • Do they offer references?
  • Do they have any unresolved complaints filed with city or state consumer protection agencies?
  • Do they carry valid business liability insurance to protect your property?
  • Do they promise a CSIA Certified Chimney Sweep will be performed?
Chimney Sweeping
Chimney Repairs

No matter what fireplace you have, it is important to get it evaluated annually & cleaned as needed.