by Jerry Peck - Codeman on Tue May 22, 2012 11:41 pm
That very likely reduces the effectiveness of that exhaust fan and does modify that exhaust fan. which affects the listing of fan - the fan is no longer installed in accordance with it listing and labeling, i.e., its cfm rating is now unknown, as well as any other rating.
I recommend looking up the installation instructions for that and finding the required clearances as stated in those installation instructions, then make sure that the clearances and installation matches that specified in the installation instructions.
Jerry Peck - CodeMan
AskCodeMan.com
Construction Litigation Consultant - Retired
Construction and Code Consultant - Semi Retired