fatboy
Administrator
Well, the response from ICC backs my initial gut check;
RE: Sections 102.9 and 506.3.11 of the 2009 International Mechanical Code
This staff opinion is in response to your correspondence, dated February 14, 2013, regarding the above referenced code.
Q. Does Section 506.3.11 require grease duct enclosure protection of an exterior grease duct that runs through the exterior wall to the outside and up three stories along an exterior wall to its termination point at the exhaust fan above a roof?
A. The purpose of a grease duct enclosure is to protect the occupants and building from a fire within a grease duct. As most of the figures in the 2009 IMC Commentary illustrate, our opinion is that the grease duct enclosure requirement intends to address grease duct enclosure protection for grease ducts within the building, but assumes the termination point at the exhaust fan discharge is near the penetration of the wall or roof assembly. The verbiage in the text is silent on the requirement for a grease duct enclosure for an exterior grease duct that runs through the exterior wall to the outside and up three stories along an exterior wall to its termination point at an exhaust fan above a roof. In our opinion, an exterior grease duct enclosure is not required since the duct is not connecting floors of a building and is not located within the building. Please note that a grease duct that runs up the outside of a combustible exterior wall must still maintain a clearance to combustibles of 18-inches. The code official needs to determine on a case-by-case basis, whether there is a potential fire and life safety risk to the building and its occupants. The code official might need to consider, but not be limited to, the grease ducts proximity to openings and exits along with the type of exterior wall finish material.
Code opinions issued by ICC staff are based on ICC published codes and do not include local, state or federal codes, policies or amendments. This opinion is based on the information which you have provided. We have made no independent effort to verify the accuracy of this information nor have we conducted a review beyond the scope of your question. This opinion does not imply approval of an equivalency, specific product, specific design, or specific installation and cannot be published in any form implying such approval by the International Code Council. As this opinion is only advisory, the final decision is the responsibility of the designated authority charged with the administration and enforcement of this code.
RE: Sections 102.9 and 506.3.11 of the 2009 International Mechanical Code
This staff opinion is in response to your correspondence, dated February 14, 2013, regarding the above referenced code.
Q. Does Section 506.3.11 require grease duct enclosure protection of an exterior grease duct that runs through the exterior wall to the outside and up three stories along an exterior wall to its termination point at the exhaust fan above a roof?
A. The purpose of a grease duct enclosure is to protect the occupants and building from a fire within a grease duct. As most of the figures in the 2009 IMC Commentary illustrate, our opinion is that the grease duct enclosure requirement intends to address grease duct enclosure protection for grease ducts within the building, but assumes the termination point at the exhaust fan discharge is near the penetration of the wall or roof assembly. The verbiage in the text is silent on the requirement for a grease duct enclosure for an exterior grease duct that runs through the exterior wall to the outside and up three stories along an exterior wall to its termination point at an exhaust fan above a roof. In our opinion, an exterior grease duct enclosure is not required since the duct is not connecting floors of a building and is not located within the building. Please note that a grease duct that runs up the outside of a combustible exterior wall must still maintain a clearance to combustibles of 18-inches. The code official needs to determine on a case-by-case basis, whether there is a potential fire and life safety risk to the building and its occupants. The code official might need to consider, but not be limited to, the grease ducts proximity to openings and exits along with the type of exterior wall finish material.
Code opinions issued by ICC staff are based on ICC published codes and do not include local, state or federal codes, policies or amendments. This opinion is based on the information which you have provided. We have made no independent effort to verify the accuracy of this information nor have we conducted a review beyond the scope of your question. This opinion does not imply approval of an equivalency, specific product, specific design, or specific installation and cannot be published in any form implying such approval by the International Code Council. As this opinion is only advisory, the final decision is the responsibility of the designated authority charged with the administration and enforcement of this code.
