Training chimney sweeps is broken into 3 main types of training programs which was developed from 17th century chimney sweeping. Basically, there are 3 levels of training. These levels include the apprentice, journeyman and the master chimney sweep training. Let’s give an example of the training involved for each level. Here is a question:


What is the minimum net free area of the screen surrounding a spark arrestor on a masonry chimney.

Apprentice level training

Answer: IRC code R1003.9.2 (1) states that the net free area shall not be less than 4 times the area of the flue it serves.

Journeyman level training:

NFPA 211 states (1) The net free area shall not be less then three times the flue it serves. IRC code G2427.5.2 states Masonry chimneys shall be built and installed in accordance with NFPA 211. IRC code R1003.9.2 (1) states it should be 4 times net free area?

Conflict in the codes!

IRC code R102.1 General. Where there is a conflict between a general requirement and a specific requirement, the specific requirement shall be applicable. Where in any specific case, different sections of this code specify different materials, methods of construction or other requirements, the most restrictive shall govern.

The most restrictive is 4 times net free area and thus that is the correct answer.

Master level training:

There is a conflict between NFPA 211 and IRC code regarding net free area of chimney caps. Why did this occur. Inspection of NFPA 211 between 2000 and 2006 reveal they changed the requirement without a vote. This may have been an error because there were many votes regarding changing the requirement of flue liner size verses appliance area to be three times the area.



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