FAQ 1.  Can duct coverings penetrate a wall or floor required to be fire blocked if the covering and all materials are non-flammable or combustible?
                Answer - Section 604.6 of the International Mechanical Code addresses 
                                 penetrating a wall required to be fire blocked.  It states that "Duct
                                 coverings shall not penetrate a wall or floor required to have a fire
                                 resistance rating or required to be fire blocked."  Be sure to check with 
                                 your local AHJ (Authority Having Jurisdiction) about your community
                                 application of this rule.

FAQ 2. Refrigerants must be classified as to high and low probability systems.  What factors are considered  in making these determinations?
                Answer - Section 1103 covers Refrigerant Classification and says that High
                                  or Low will be based upon the potential hazard resulting from 
                                  leakage or refrigerant into an occupancy classified area other
                                  than the machinery room.  Examples of this consideration would be 
                                  direct, indirect open spray indirect closed etc.... being Low.
                                  If you are not familiar with these systems post a question with our
                                  discussion group.    

FAQ 3.  I do not have enough room on the roof to get the ten-foot separation between a source of contaminants and a fresh air inlet opening.  What are my options for compliance?
                Answer - Section 401.5 governs opening locations and it essentially says that
                                  all contaminant sources shall be at least ten (10) feet away,
                                  horizontally, or they must terminate at a point not less than two (2) feet
                                  above the Outside air inlet.  I initially said be raised to but the inlet
                                  opening could also be lowered, the critical issue is a two (2) foot 
                                  vertical separation.

FAQ 4.  What is the function of a duct smoke detector with respect to controls?
              Answer - Section 606.4 states that "upon activation the smoke detectors shall
                                shut down the air distribution system.  One of the common
                                misconceptions is that a time delay is acceptable in shutting the air
                                system down, the code states "upon activation".  This is a life safety
                                provision of the code to prevent the distribution of smoke
                                contaminated air.

FAQ 5. Do I need a smoke detector if a unit on a commercial application has 2000 cfm
             maximum supply?
            Answer - Section 606.2.1 requires that a smoke detect be installed in return air 
                              systems if the DESIGN capacity is greater than 2000 CFM.  In your
                              instance the critical question is the design of the return air system not
                              the capacity of the equipment.  With an eye to the fact that the building
                              will probably outlast the equipment and a replacement unit will have to 
                              be installed, it is the capacity of the duct system that is a concern.  
                              Please check with the AHJ in your location.

FAQ 6. Can removal of flex duct from a fire damper  be permitted as access to the
             damper?  What type of marking if any is needed?
            Answer - Section 607.4 does not specifically address flex duct however, the
                              methods of attachment for flex duct does not provide an  effective
                              means to routinely and regularly remove and reattach the duct.  If a
                              system is a flexible duct system and contains a fire damper, a rigid
                              permanently attached duct connector with an access door would be 
                              required between the flex duct and the fire damper.  The connector 
                              would have to be large enough to permit inspection and maintenance
                              access to the damper and its operating parts.  This same section 
                              required a label with the marking not less than 1/2 inch in height that
                              reads SMOKE DAMPER or FIRE DAMPER

FAQ 7.  Where do I install the smoke detectors, in the supply or return air?
            Answer - Section 606.2.1 says smoke detectors shall be installed in the return
                              air system when required.  This does not restrict additional smoke 
                              detectors being added in addition to the required detectors.

FAQ 8.  Does the ceiling of my furnace closet need to be sealed or can I use
              combustion air from the attic with an open ceiling?
              Answer - Chapter 7 governs the rules for combustion air and combustion
                                air continues to be an area that generated many questions.  Section
                                701.4 tells us that the attic air can be considered outside air if the 
                                attic is ventilated to provide air equal to that required for ventilation and
                                combustion.  Again better check with the AHJ