The inspection of a chimney is important in order to detect problems within the venting system. Heating appliances and their venting systems can be hazardous when not properly installed, or when damage or deterioration has occurred. Professional chimney sweeps routinely conduct these inspections, and should follow the procedure defined by N.F.P.A. (National Fire Protection Association).
The N.F.P.A. procedure defines three levels of inspection according to the circumstances that "trigger" the need for the inspection. A Level I Inspection is the most basic type of inspection and used to determine if the fireplace is suitable for usage, while Level II and Level III Inspections are progressively more detailed and thorough.
Level 1. A Level I Inspection is generally limited to readily accessible areas of the chimney structure, with additional requirements to insure the flue is clear. Readily accessible areas are those areas that can be reached for inspection or maintenance without the use of tools or ladders. A Level I Inspection will include checking the basic appliance installation and connection, checking readily accessible portions of the chimney structure and flue, and determining that the flue is not obstructed.
Level I Inspections are recommended:
During annual chimney inspections
During routine service of the venting system, including chimney sweeping
Upon direct replacement of a connected appliance with one of similar type. At any other time an inspection is warranted, and conditions of use of the venting system are not changing.
Level 2. A Level II Inspection generally limited to accessible areas of the chimney structure and appliance installation. Accessible areas are those that can be reached without destructive action to the building or building finish. Access may require the movement or opening of doors and panels, and may require the use of common hand tools or ladders.
A Level II Inspection will include all portions of a Level I Inspection as well as accessible areas of the chimney structure, including areas within accessible attics, basements and crawl spaces.
In addition, a Level II Inspection will include an examination of the chimney interior by video scanning or other comparable means of inspection. The inspector should also determine that the flue is properly sized for the connected appliance(s).
Level II Inspections are recommended:
Upon addition or removal of one or more connected appliances, or replacement of an appliance with one of dissimilar type, input rating or efficiency.
Prior to relining or replacement of flue lining.
Upon sale or transfer of the property
After an operating malfunction or external event likely to have caused damage to the chimney.
Level 3. A Level III Inspection includes all portions of a Level I and a Level II Inspection as well as examination of non-accessible areas of the chimney structure that are reasonably suspected of containing hazards.
Non-accessible areas are those areas that cannot be reached without damage or destruction to the chimney, building or building finish, or areas that would require special tools to reach.
Examination of non-accessible areas should be limited to suspect problem areas. In as much as inspection of these non-accessible areas will likely result in damage to the building the inspector and homeowner should discuss these details beforehand.
Level III Inspections are recommended:
Where necessary for the investigation of an incident which has caused damage to the chimney or building.
Where a hazard is detected or suspected during a Level I or II Inspection and that cannot be fully evaluated without access to concealed areas.