The Levels of Inspection according to the NFPA (National Fire Protection Association) 211 Standard for Chimneys, Fireplaces, Vents and Solid-Fuel Burning Appliances:

Level I – Inspection is limited to readily accessible portions of the venting system, accessible portions of the connected appliances and the chimney connection. Readily accessible areas are those areas that can be reached for inspection or maintenance without the use of tools or ladders.

Level II – Inspection is more detailed and thorough than a Level I inspection and is the recommended inspection when conditions for use of the appliance or venting system are changing, or when a Level I inspection reveals the need for a more detailed inspection. If we find there has been an operating malfunction, damaged or deteriorated liners or unused opening into the chimney it is appropriate to recommend a Level II inspection. Level II inspection includes all of the requirements of a Level I inspection as well as the following: 1. Inspection of accessible areas of attics, basements and crawlspaces. 2. Accessible areas of the chimney exterior and interior. 3. Accessible portions of the appliance and chimney connection. 4. Video scanning or other thorough inspection of the flue interior. 5. Evaluation of the flue lining to determine that its material and sizing is appropriate for the appliances being served. 6. Proper clearance to combustibles in the accessible areas listed above. 7. Proper construction and condition of the chimney system in the accessible areas listed above.

Level III – Inspection includes concealed areas of the building as well as everything listed in a Level I and Level II inspection and should be limited to areas reasonably suspected of containing hazards that cannot be evaluated otherwise.