(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
Table of Contents Chapter 1 Administration Chapter 2 Definitions Chapter 3 General Regulations Chapter 4 Ventilation. Chapter 5 Exhaust Systems Chapter 6 Duct Systems Chapter 7 Combustion Air Chapter 8 Chimneys & Vents Chapter 9 Specific Appliances Chapter 10 Boilers, Water Htrs Chapter 11 Refrigeration Chapter 12 Hydronic Piping Chapter 13 Fuel Oil Piping Chapter 14 Solar Systems POLICY OTHER (Includes Energy Code) Chapter 1 Administration Chapter 2 Definitions Chapter 3 General Regulations
1) (Q) An Italian MP regulator is installed on an appliance that is specified by the code to meet the reference standard for the 2003 ANSI Z21.80. It meets the 2005 ANSI Z21.80 standard. Should the inspector approve the regulator? (A) The regulator meets the 2005 standard specified by the ICC 2012 Code. We would have no problem approving the regulator with the new ANZI standard. This meets the intent of the code. 101.3, 301.4 NCMC 2012 2) (Q) The inspector has turned down a gas grill installation outside a single family home because the hood is not labeled for use in a damp location. The inspector calls the hood manufacturer to find out if the hood is approved for the location. The manufacturer of the hood informs the inspector the hood is approved for damp locations. What information should be required by the inspector to approve the installation? (A) The inspector should require a letter from the manufacturer defining a damp location and the grills and hood combinations approved for those locations. 301.4 NCMC 2012 3) (Q) I am installing a direct vent fireplace that exhausts onto an open porch. The inspector has turned the job down because the vent is in an enclosed space. The installation exhausts onto a porch and I have a letter from the manufacturers sales representative stating the installation is allowed. I need the installation approved so we can complete the siding installation. Can you approve the installation? 1 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
(A) No. The porch is not fully open on two sides per the manufacturer’s literature. Mecklenburg County would require the porch to be open on two sides and the porch roof should not be over a second floor habitable space such as a bedroom. We would need a sealed letter from an engineer representing the manufacturer with specific installation details outlined in this letter prior to considering approval of the installation of the direct vent as currently installed. 303.1 NCMC 2012 4) (Q) A Mechanical Field inspector has turned down a gas grill installation that is located outside the apartment buildings in a common use area for residents. The grill has a large 20 inch by 20 inch wood beam approximately 9 feet high directly above the grill cooking surface. The manufacturer’s installation instructions do not allow any combustibles above the grill. The manufacturer did not provide any data about the height so it is assumed anything combustible above the grill would violate the installation instructions. The designer wants to provide a flame retardant stain on the beam. Should the inspector approve the stain? Should the Mechanical Inspector ask the Building Inspector to get involved in the approval? (A) The flame retardant stain does not make the beam non‐combustible. The Mechanical Inspector defers to the Building Inspector to make the call on the material. The Building Inspector gives the designer the following options: If you can provide a letter from the manufacturer stating that your installation is acceptable to them based on the height of the combustibles above the grill, we would accept that letter. Otherwise, your options are limited to: (1) placing a hood approved by the manufacturer with exhaust duct above the grills, (2) providing a non‐ combustible covering on the wood above the grills (such as a sheet metal cover), or (3) removing the wood totally from above the grill area. 303.6 NCMC 5) (Q) We are installing a gas grill outdoors under a canopy. The canopy is a non‐ combustible structure and is a standalone structure located 25 feet away from the apartments it serves. The canopy will be 10 feet above the cooking surface. I am including drawings and the manufacturers’ data with the letter you ask for from the manufacturer concerning the location. The data stated the grill could not be located in an enclosed structure such as a breezeway, porch or other enclosure. I have included the letter from the manufacturer you requested via email with a hard copy with original signature to follow. Is it your determination that this is an acceptable installation? (A) Per the drawings you submitted to me via the download attachments in the your email and the manufacturers letter (attached) I am approving the installation of the outdoor gas grill for the project. The installation shall have a 10 foot clearance over the grill surface to the non‐ combustible canopy. The grill installation is shown on the plans as 2 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
being located on the perimeter of the canopy. This will help dissipate the smoke. A hood will not be required per the manufacturer’s instructions and letter provided. As part of this approval you will be required to send a hard copy with original signatures and dates to the Mechanical Code Administrator for Mecklenburg County of the letter from the hood manufacturer. 105.1 NCMC 2012 6) (Q) A contractor has submitted the proper documents requesting a TCO. The inspector finds panels have been attached to the roof top HVAC equipment that are required by the Zoning inspector to screen the units. The screening attached to the units does not allow for the proper clearance around the units per the manufacturer’s instructions for maintenance or air flow. The contractor says it is not part of his contract so it should not hold up the TCO. What should the inspector require to approve the TCO? (A) In the negotiations to approve the project for the TCO the department required a letter from the manufacturer stating the panels as installed would allow enough clearance to satisfy the installation instructions of the units. The manufacturer supplied the letter. The letter was received and signed by the regional sales representative for the manufacturer. Neither the inspector nor the supervisor were comfortable with the letter since the Manufacturer’s literature clearly stated what the clearances had to be for approval. The supervisor told the contractor the letter was unacceptable and requested a letter from the engineering department of the manufacturer. The owner said that would take two weeks and they needed a TCO today because product was on trucks in route to the site. The solution was to remove the panels temporarily with permission from zoning for two weeks so a TCO could be granted and the approval letter from the manufacturers engineering department could be obtained. 304.1, 306.1 NCMC 2012 7) (Q) A roof hatch manufacturer wants me to verify a new requirement in the 2012 Building Code. He says the new code would require all new projects to have a roof hatch for access to equipment that is 16 sq. ft. minimum in size. Does section 1009.13.1 of the building code only apply to buildings 4 stories or more in height? (the exception says a roof hatch has to be 16 sq. ft. min. for access to an unoccupied roof) Are we permitted to use the traditional 3’x3’ roof hatch on a one story buildings? (A) You are correct in the 2012 NC Building Code, 1009.13.1 only applies to buildings four or more stories above grade plane. This is stated in the preceding paragraph 1009.13. If the building is less than four stories above grade plane but the equipment is installed on roofs or elevated structures at a height exceeding 16’, then the 2012 NC Mechanical Code requires that equipment be accessible for inspection, service, and 3 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
repair and replacement with a permanent means of access. A roof hatch would have to be large enough to remove the largest piece of equipment. Note: Each tenant shall have access to the mechanical equipment serving their space. Either common access to all tenants, not access from one tenant space through an adjacent unrelated space, or each tenant shall have separate access to their equipment. 1009.13.1 NCBC & 306.5 NCMC 2012 8) (Q) I am installing a roof top unit that has neither a secondary drain pan or provisions to install a secondary or auxiliary drain pan. Would it be acceptable to install an in line condensate overflow device to shut the unit down so water will not overflow into the ducts? (A) No. It is not acceptable. A water‐level monitoring device is required to shut off the unit in the event the primary drain line becomes restricted. An in‐line detection device is not allowed because blockage inside the pan at the drain hole would not be detected by an in‐line device. Water would overflow from the pan and never reach the device. Ref: 307.2.3.1 NCMC 2012 9) (Q) An up flow furnace and air handler is installed on supports of treated wood located inside the auxiliary drain pan. Is this allowed by the 2012 NCMC? (A) Yes. The code states that supports located inside the pan to support the appliance or equipment shall be water resistant and approved. We have approved treated wood in the past. All portions that are subject to water damage must be installed above the flood level rim of the pan. Examples are electrical components, metal items subject to rust and insulation within the appliance. 307.2.3.2 NCMC 2012 10) (Q) Condensate drainage shall discharge to the sanitary sewer system. Is it acceptable to provide a hub drain in the HVAC closet of each dwelling unit or a riser to collect condensate from multiple dwelling units and provide a hub drain at the lowest level. All condensate drains shall be trapped and provided with either a trap primer or trap guard. (A) Yes. Condensate drains shall be sized properly if directly connected to a primary condensate riser. We would also allow the condensate to go to storm with a backwater valve in the condensate drain line to the storm sewer. See section 307 NCMC 2012 4 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
11) (Q) I am the owner of a home inspection service and a licensed home inspector. Over the last 9 years I have found and reported the absence of a cap on the trap clean out many times. I have a background in HVAC and have also researched the subject of condensate plumbing to insure I was reporting the condition correctly. In the past several weeks I have met with staunch resistance to installing a cap by two different HVAC techs. One tech suggested I contact Code Enforcement for the correct Installation information of the condensate drain. I have attached two pictures of condensate plumbing with venting on the upstream side of the traps. Both HVAC techs insisted that the vent/trap clean out could not be capped due to code. One said he had to put a cap on and then drill a hole in it, this was done to prevent "vapor lock"? Both insisted the vent was required on the upstream side of the trap. Both mentioned that they had just been through a class that addressed this condition. In my training and use of basic logic: #1 vents are on the downstream side of a trap. #2 an open trap clean out disables the trap and I have to report it as "not functioning as intended". Have plumbing fundamentals changed, preventing air from escaping or entering the open hole up stream of a trap? Is there some incorrect continuing education being taught to HVAC techs? Please respond to this as the refusal to cap the clean out is causing my customers to lose faith in my reports. (A) Good morning; the trapped condensate lines in the pictures you sent to me are installed as prescribed by code. The only thing I see is an open pipe on is the secondary drain. One picture shows an electric shutdown switch that appears to be piped somewhere with no trap; secondary overflow drains usually do not require traps. They are for emergency purposes only. Code enforcement requires the contractor to install the condensate drains per NCMC section 307, and the Manufacturer's installation instructions. 307.2.4 NCMC 2012 12) (Q) Condensate traps questions continued from above. In the first picture the primary drain line has a T' installed up stream of the trap which has a moisture detection device installed in it. In the second pictures the primary drain line has a T' installed as a trap clean out. The cap has a 1/2" hole drilled in it. I do understand that a trap is not as necessary in a positive pressure system as it is in negative pressure (heat‐pump) system. The problem is that it is required by code and mfg. installation instructions which means to me it should function as designed. Any opening between the primary drain pan connection and the trap defeats the purpose of the trap by allowing air to freely communicate with ambient air. Please look again at the two pictures. 5 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
(A) From what I understand from some of the contractors, they were having a problem with the high static on positive pressure units pushing the water out of the trap. This was the fix from the manufacturer. Mecklenburg County approved it. 307.2.4 NCMC 2012 13) (Q) Please look at the highlighted paragraph on pg. 7 of the Lennox installation manual I have attached. It appears your office has been misled by an incorrect interpretation by some of the contractors. (A) Your copy of the installation instructions on page 7 quotes the UMC, in North Carolina, we use the International Code (ICC) that gives you a range of options for condensate disposal. If you have an issue with how the Lennox trained dealer is installing their condensate lines, please contact one of their factory engineering staff with your concerns. If he says that their trained staff is doing it incorrectly, have him contact the Mechanical Code Administrator for Mecklenburg County. 307.2.4 NCMC 14) (Q) A hood has been installed over a combustible wall. The inspector told the general contractor that he needed clearance per plans and would need a detail from engineer if it deviated from the plans or show it meets the clearance reduction tables available using the Mech. Code. The installation had 2 layers of Dura rock and 1" air spacer behind hood. The inspector found stainless steel, insulation and chicken wire installed to meet the required clearances. The installation passed the light test for the contractor for the shaft joints only. The inspector told the contractor he would inquire about the use of his hood clearance method. I think I should have told the general contractor that it needed to be installed as stated in Mech. Code or provide an engineered and approved detail. How should we handle this situation? (A) The contractor has been advised he has to meet code minimums either per Manufacturer’s recommendations or the clearance tables in 308.6 of the Mechanical Code. The inspector has done all he can do for the contractors. It is up to the General Contractor and the Mechanical contractor to work out how the change should be made to meet code. Table 308.6 NCMC 2012 Chapter 4 Ventilation 1) (Q) A contractor wants to install an inverted dryer vent to provide make up air for a residential single family dwelling hood that exhausts 300 cfm. Would this be allowed by code? 6 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
(A) Yes. Make up air is not required by the residential code for a hood that exhausts less than 400 cfm. You should check to see whether the designer is requiring natural or mechanical ventilation per chapter 4 on the NCMC kitchen ventilation requirements. 402, 403, table 403.3 NCMC 2012 2) (Q) For the change out on an evaporator coil only would a programmable thermostat be required? (A) No. Not if just an evaporator coil/condensing unit only is changed. 404.1 NCMC 3) (Q) 404.1 of the 2012 Mechanical Code allows an intermittent ventilation calculation to be used when running the ventilation fans continuously in an enclosed parking garage. We have allowed a system which used carbon monoxide detectors to be used when using the intermittent calculation prior to the 2012 Code. The code language in 404.1 allows the intermittent calculation if detection devices are installed that automatically operate upon detection of vehicle operation or presence of occupants. Carbon Monoxide detectors will not perform the functions specified in the new code. What types of systems should the code official accept if the designer wants to use the intermittent ventilation calculation in the design? I am designing a new enclosed parking garage for a high rise up town. The 2012 code is not clear on this issue. Can I still use only the CO detectors to determine the intermittent exhaust air calculation? (A) The ICC code commentary 2009, which is the basic interpretation document for the 2012 NCMC has some specific suggestions for designers that choose the intermittent calculation for garage ventilation. Commentary: “The alternating or modulating operation must be accomplished using approved detection devices that are capable of detecting the operation of vehicles or the presence of occupants in the garage. This section is referenced by footnote “d” to Table 403.3 and is intended to apply to parking garages for vehicles such as auto mobiles, buses and fleet vehicles. The code does not specify the method of detecting vehicles or occupants. It is left to the designer to select the appropriate detectors for the particular application. Note that the detection system cannot rely solely on measuring carbon monoxide (CO) because other gaseous and particulate contaminants can reach harmful concentrations long before CO levels rise to the detection threshold of the CO detectors. The intent is to detect the presence of occupants and/or vehicle operation by some means such as infrared motion detectors.” 404.1, 404.2, tbl. 403.3 2012 NCMC 7 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
DOI comment Dan Dittman; the way 404.1 is written, if the ventilation system is designed to operate intermittently, it must work automatically upon detection of vehicle operation or the presence of occupants. Therefore in either case: A vehicle operating or the presence of occupants the system shall operate. Therefore, a system that only is triggered by CO, would not be satisfying the occupancy‐presence requirement. Section 404.2 also sets a third constraint, in that the system cannot go below 0.05 cfm/SF (many people miss‐read this as 0.5 cfm/SF) And, as we discussed, the code does not specify what technical means of detection are acceptable. 404.1 NCMC 4) (Q) Does an enclosed area that stores and charges electric golf carts come under section 404 of the mechanical code? (A) No this section and section 502.14 of the mechanical code does not cover golf carts or electrically powered vehicles. 404, 502.14, NCMC 2012 5) (Q) One of the items the inspector turned down on a project was the fresh air intake for a gym/multi‐ purpose area. The plans were approved by the department. The designer did show a non‐ motorized louver installed in an outside wall directly into the gym (which is heated with radiant tube heaters) on the plans, however, it was shown on the Architectural plan only and not the Mechanical plan for the project. The inspector turned the item down and required the louver to be motorized. Is the inspector correct? (A) Yes. The louver was not on the Mechanical Plans submitted to the department. While re‐checking the plans the Mechanical Plans Examiner discovered the louver was shown on the Architectural plans but was not shown on the Mechanical Plans. The Mechanical designer will have to resubmit an RTAP to show a motorized air intake damper per Code for fresh intake air for the gym. 405.1, 2012 NCMC Chapter 5 Exhaust Systems 1) (Q) The hood plans on a large mult‐million dollar project were placed on the food service plans. None of the food service plans were sealed. The hood is an engineered system and requires seal. This is a new building and the project plans require seals. Usually someone like captive air will draw the hood plans and the mechanical engineer will place them on their sheets and seal them and then reference the working drawings which are not required to be sealed. The project Architect refuses to have the mechanical design sealed. What is the correct procedure? 8 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
(A) Since the only hood design and information was placed on the hood plans the hood plans shall be sealed by a mechanical engineer licensed in the state of North Carolina. NC Administrative Code, 2012. 2) (Q) Is there a height above a sidewalk where a Type I or II hood exhaust discharge may be allowed? (A) Yes. It can be exhausted over a public walkway but not onto a public walkway. 501.2.1.1 NCMC 2012 DOI Dan Dittman ‐ Yes, refer to 506.3.12.3 for Type I hoods, and 506.4.2 for Type II Ductwork terminations. Do not exhaust onto a walkway, (you could even have an elevated walkway that you would not want to direct it onto, say like at a stadium), but you can exhaust over a walkway provided you have ample vertical clearance. – DED 11/27/12 3) (Q) The mechanical inspector has turned down an existing exhaust duct terminating into an open parking garage while inspecting an existing restaurant renovation. The exhaust system is used to exhaust moisture from a commercial dish washer and is a manufactured system. Should the inspector have turned down the installation? (A) No. If the hood system meets 502.2 exception 2 requirements and is installed per the manufacturer’s instructions the installation should be approved. Under certain circumstances (see DOI comments in italics below) DOI’s current interpretation is that the exhaust discharge from a type I or type II hood may discharge into an open parking garage. The designer will have to supply sufficient information to the Code Official that the dilution of exhaust air will be substantial enough to warrant allowing the exhaust into the open garage. It has been past practice that the Code Administrator has allowed exhaust which terminates in an open parking garage using a water wash hood or an environmental filtering system. This is subject to the discretion of the Code Administrator. 501.2 NCMC 2012 DOI‐Remember to follow the separation requirements and protection requirements. A parking garage will be an S‐2, and there will be a separation requirement from the adjacent building. Section 506.3.12.2 directly prohibits a Type I exhaust from penetrating a plane where protected openings are required, because you cannot put a fire damper in a Type I exhaust duct. Type II exhaust terminations are required to be protected via Section 506.4.2, Item 8.‐DED 11/27/12 9 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
4) (Q) I would like to combine the bathroom exhaust with the kitchen exhaust in an apartment high rise building. The bathroom fans will run continuously at 25 CFM and kick up to 75 cfm when the fan switch is energized. Both exhausts are considered environmental air in a residential unit. Back draft dampers will be installed in the bathroom exhaust so the grease exhaust will not foul the bathroom exhaust duct. Will this installation be allowed by the Code Administrator. (A) No. The Kitchen exhaust and the bathroom exhaust cannot be combined. Moisture from the bathroom should not be combined with grease exhaust. The commercial code specifically prohibits other exhaust from being combined with grease exhaust for a type I hood installation. The 2012 ICC code prohibits combining grease exhaust duct with other environmental air for residential construction. Each exhaust shall separately exit the building. Exhaust clearance per 501.2.1 #3 5) (Q) Regarding outdoor grills under a covered patio. I was told we could have a grill under a covered patio as long as we had an outdoor approved UL listed hood for the grill being used. Both had to be by the same manufacturer. Please let me know what the correct ruling is on this? (A) Cooking under a covered patio would require a grill with a hood approved by the manufacturer for residential use only in a one or two family dwellings. Commercial cooking equipment is not allowed in residential construction. We will approve an outdoor rated residential grill/hood exhaust combination approved by the manufacturer. Make sure you can meet the exhaust clearance requirements and exhaust outside the footprint of the building. The roof or side wall exhaust termination clearance shall meet the code minimums. 304.1, 501.2.1 #3, 2012 NCMC 6) (Q) Are the requirements in the question above a county or state requirement for the Exhaust hood under a covered patio? (A) Generally the manufacturer’s literature on outdoor grills restricts any combustible construction over the hood regardless of the height above the hood unless a hood and exhaust duct system is provided. The requirement is a code requirement and therefore state law. 505.1, 301.4, 301.5 NCMC 2012 7) (Q) The plans examiner on a project has turned a designer down for his design of a “source capture system” per 502.14 in the NC Mechanical Code. The designer says he has put the same system in before and it has been approved in another County as an alternate method. 10 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
The designer is required by code to provide a “source capture system” because the project is a repair garage which means vehicles will be running while under repair. The “source capture” design on the plans has a hose that runs from the exhaust pipe of the vehicle to a hole in the garage door. Should the Plans Examiner approve the installation as submitted? (A) This design would not meet the code for two reasons. The definition of “Source Capture System” says it is a Mechanical Exhaust System. The design does not meet the definition. The code requirement is to design a system to capture contaminants at their source and to exhaust them to outside atmosphere. DOI has allowed a “source capture” system in the example above as an alternate method, however, after a series of emails DOI agreed the system did not meet code and should not be considered as an alternate method. Per Code in areas where motor vehicles operate, mechanical ventilation shall be provided in accordance with Section 403. Additionally, areas in which stationary motor vehicles are operated shall be provided with a source capture system that connects directly to the motor vehicle exhaust systems. Exceptions: 1. This section shall not apply where the motor vehicles being operated or repaired are Electrically powered. 2. This section shall not apply to one‐ and two‐family dwellings. 3. This section shall not apply to motor vehicle service areas where engines are operated inside the building only for the duration necessary to move the motor vehicles in and out of the building. Ref: 502.14 NCMC 2012 Definitions: SOURCE CAPTURE SYSTEM. A mechanical exhaust system designed and constructed to capture air contaminants at their source and to exhaust such contaminants to the outdoor atmosphere. MECHANICAL EXHAUST SYSTEM. A system for removing air from a space by mechanical means. Ref: NCMC 2012 Definitions. 8) (Q) We are working on several multifamily projects with pool equipment rooms. It has come to my attention that the fans for pool equipment rooms are required to be corrosion resistant when storage of chlorine is in the room. In general, this makes sense because the buildup chlorine could eat away at the fan and eventually disable it. The question I have is does this also apply to pools that do not use Chlorine but use Salt and store it in the pool equipment room? (A) Chapter 31, Corrosive Materials, in the Fire Code is the driver for requiring ventilation for indoor use(3105.1.2). 3105.1.2 Refers you to 2705.2.1.1. “Where gases, liquids, or 11 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
solids having a hazard ranking of 3 or 4 in accordance with NFPA 704 are dispensed or used, mechanical exhaust ventilation shall be required.” You would need to ask your fire reviewer about the hazard ranking. If it is not considered corrosive in the quantities you store in the room a non‐ corrosive resistant fan may be used. 503.4 NCMC Note: per the Fire Department a non‐corrosive fan was required. 9) (Q) I am installing a vertical furnace with ductwork located outside an industrial building The temperature in the industrial building area will be maintained below 50 degrees. The inspector wants me to insulate the outside ductwork with R8 insulation. Is this required by code? (A) It depends. The definition of a “conditioned space” in the energy code includes a building or space being heated to 50 degrees. The definition also says for mechanical purposes, an area, room or space, being heated or cooled by any equipment or appliance is considered a conditioned space. 503.2.7 Requires R8 insulation on exterior ductwork unless the designer can meet exception 1 or 2. If you can meet the exceptions with calculations showing the design temperature between the exterior and interior of the duct does not exceed 15 degrees F. Insulation is not required. 503.2.7 & see exceptions 1 and 2, NCECC 2012 (Energy Code) 10)(Q) Can a 4” metal duct of proper gauge be used in a standard stud wall, either wood or metal, which is 3 ½ inches clear? The 4 “metal duct shall be shaped by the contractor in an oval to accomplish this installation. (A) No. If a 4 inch dryer duct goes through a standard stud (3 1/2 inches) the stud shall be cut out and nailing strips shall be installed on both sides of the dryer duct. According to the Plumbing contractors they are getting 6 inch walls installed which eliminates the problem. A dryer box is allowed that would require the contractor to oval the dryer duct to attach it to the box if installed in a 3 ½ inch wall. This would be allowed because the box is approved by the manufacturer and any lint trapped at the box can be readily cleaned. 504.6 NCMC 11)(Q) A contractor has common exhaust duct for dryers and wanted to fire wrap duct to be Considered as a shaft, would it be allowed by code? (A) Yes. 504.8 NCMC‐ Common exhaust systems for clothes dryers located in multistory structures. Where a common multistory duct system is designed and installed to convey exhaust from multiple clothes dryers, the construction of the system shall be in accordance with all of the following: 12 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
1. The shaft in which the duct is installed shall be constructed and fire‐resistance rated as required by the International Building Code. 2. Dampers shall be prohibited in the exhaust duct. Penetrations of the shaft and ductwork shall be protected in accordance with Section 607.5.5, Exception 2. 3. Rigid metal ductwork shall be installed within the shaft to convey the exhaust. The ductwork shall be constructed of sheet steel having a minimum thickness of 0.0187 inch (0.4712 mm) (No. 26 gage) and in accordance with SMACNA Duct Construction Standards. 4. The ductwork within the shaft shall be designed and installed without offsets. 5. The exhaust fan motor design shall be in accordance with Section 503.2. 6. The exhaust fan motor shall be located outside of the airstream. 7. The exhaust fan shall run continuously, and shall be connected to a standby power source. 8. Exhaust fan operation shall be monitored in an approved location and shall initiate an audible or visual signal when the fan is not in operation. 9. Makeup air shall be provided for the exhaust system. 10. A cleanout opening shall be located at the base of the shaft to provide access to the duct to allow for cleaning and inspection. The finished opening shall be not less than 12 inches by 12 inches (305 mm by 305 mm). 11. Screens shall not be installed at the termination 12)(Q) They say Waxhaw, Mecklenburg, and union County inspectors approve dryer duct transitions. I guess this is a transition duct that attaches to the 4” dryer vent and transitions to a 2” x 6” periscope duct then back to a 4” round. Is it true this transition duct fitting is approved in Mecklenburg County? (A) We have never allowed the transition box you are talking about in your question. It is rectangular and can trap lint in the ends of the transition. No one is going to pull the machine out and properly clean the dryer duct annually as is the required maintenance for dryer ducts. It is hard enough to get them to clean the dryer filter. 504.6.3 NCMC 13) (Q) A mechanical contractor wants to install an inverted dryer vent fitting as a makeup air duct for a residential single family hood that exhaust 500 cfm. Would the inverted dryer vent fitting be allowed by the code for makeup air? (A) No. The code would require make up air approximately equivalent to the hood exhaust cfm and the ductwork shall have either a barometric of electrically operated damper 13 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
that opens automatically when the hood is turned on. The product should be listed and sized for the application by the manufacturer. 505.2 NCMC 2012 14) (Q) The General Contractor on a new tract of homes is installing 600 cfm hoods in Kitchens of new single family homes in a new sub‐division. The General Contractor wants to install a Whirlpool Make up air units with ductwork attached to the return air duct just prior to the connection of the return duct to the unit. The manufacturer’s installation instructions would allow the installation subject to local code requirements. The General Contractor says he has been turned down by the Mechanical field inspector and wants to know if the Mechanical CA can approve the installation? (A) The most efficient method of providing make up air would be to provide the Make Up Air directly into the Kitchen. The Contractor does not want to use this method because of his concern about bringing in unconditioned make up air into the Kitchen. He is worried about getting complaints from the owner. This started a dialogue between the General Contractor, the Mechanical Contractor, The Mechanical Code Administrator and the Department of Insurance. Once all the questions were answered the final determination was discussed with the General and Mechanical Contractors. Based on the information supplied from the Mechanical Contractor and once all the CA and DOI questions were answered the installation was approved by Mecklenburg County pending a makeup air cfm test of the dwelling to see if enough make up air was actually provided. The actual make up air when tested was around 200 CFM. Woefully short of the approximately 600 CFM required by code for the hood Make up air. The Contractor is providing Make Up Air directly to the Kitchen on all other dwellings in the sub‐division. The Contractors Concerns were taken care of by placing the make up air as close to the hood as possible and providing controls such that the MUA would only come on when the hood cfm exceeded 400. By making these changes the Contractor will get approval of the Hood installation. NOTE: Any new or existing installation of Make Up Air equipment and ductwork per 505.2 of the 2012 North Carolina Mechanical Codes for new or relocated, or existing hoods in residential dwelling units, unless all the Make Up Air is provided directly in the Kitchen space, shall be approved by the Mechanical Code Administrator on a case by case basis. The Code Administrator may accept HVAC and ventilation sizing information which shall include Energy Code and Manual D and J calculations from a Mechanical Engineer licensed in the State of North Carolina for single family homes, duplexes, and townhomes land for sale up to three stories. At his discretion the Mechanical Code Administrator may require a performance test of a worst case scenario for makeup air designs that are installed as part of the HVAC duct system. Ref; 505.2 NCMC, NCRC 505.2 14 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
Note: The damper controls mounted above the hood shall be accessible. This may mean a false panel has to be installed within the cabinetry. 15) (Q) A designer has provided a separate 2 hour shaft on the second floor of a two story Building to run the grease duct from a type 1 hood on the first floor of the building. The grease duct from the Type 1 hood will pass through the shaft and then penetrate the roof exhausting through the roof mounted fan. The Type 1 hood is on the first floor in a restaurant. The designer wants to use approved Fire Master duct wrap starting at the hood, penetrating the ceiling of the first floor entering the two hour shaft on the second floor. The plan examiner has turned the plans down the installation stating the reason the Fire Wrap has to be continuous from the hood through the roof penetration. Can the designer terminate the fire wrap at the penetration into the two hour shaft? Does stopping the fire wrap at the penetration comply with the manufacturers installation requirements? (A) Yes to both questions. The designer had to provide a shaft penetration detail approved by manufacturer of the Fire Wrap and the manufacturer had to agree that his product could terminate at the shaft on the second floor. A letter was obtained from the manufacturer with an approved penetration detail. The designer submitted a detail for the Fire Wrap material to the plan examiner and it was approved without a continuous wrap from hood to roof being required. 506.3.10.1, 506.3.10.2 NCMC 2012 16) (Q) Is a light test required on a manufactured Type I grease duct and what should the inspector be looking at on these types of installations? (A) Just because a manufactured grease duct is being installed it does not negate requiring the light test. Code required tests still apply. 506.3.2.5 17) (Q) A large restaurant has been submitted to plan review on the first floor of a high rise building. There are several exhaust systems that terminate into an open parking garage. There are two type 1 hoods that discharge through an environmental air filtering system. They terminate at a louvered exhaust grill in the open parking deck. Another type 1 hood with a separate exhaust duct terminates after exhausting through a water wash hood which also terminates in an exhaust grill in the parking deck. The restaurant also has 4th Type 1 hood that is an approved recirculation type hood. Can the plan reviewer approve these installations? If no, what are the conditions, if any, that these installations may be allowed? 15 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
(A) The Type I recirculation type hood is allowed by current code if the installation meets 507.1 Exception # 2 NCMC. The environmental air system and the water wash hood system may be allowed as an alternate method by the code official. The ductwork is required to be welded both entering and leaving the environmental air filtering system. With Mecklenburg County approval as alternate methods both systems may terminate at a louvered exhaust in the open parking garage. See DOI comment below on design requirements for an engineer who submits exhaust terminations in an open parking garage. DOI‐ Exhaust Terminations in open parking garages. This is not uncommon in heavy urban areas, and to consider it as an alternate means or materials is within your authority. As addressed below, the alternate method must take into account that the exhaust stream leaving the water‐wash system is no longer subject to 506.3.12.2, as you cannot put a fire damper in a Type I exhaust. Since these are open garages, it is little different from exhausting out to the public way, but you would still want to locate the termination in a manner to minimize any potential back drafting or reverse chimney effect. Also when considering any exhaust into any place other than the code‐prescribed locations outside a building, take into account that the exhaust stream many times carries the byproducts of combustion for gas‐fired equipment, and the natural ventilation option that many open parking decks utilize do not take into account any other pollutant source than the cars coming in, stopping, and shutting off. The quantity of combustion byproducts to dilution air in most cases will be very, very, small, but should be addressed in any proposed alternate method. Where the exhaust goes, after it enters the parking deck, should therefore be addressed also since it could have combustion byproducts. Although not real common, in Mecklenburg you could have icing problems also if the exhaust stream carries a high moisture content, so slipping and sliding would occur if not directed to the outside of the parking deck immediately. ‐ DED 11/27/12 (comments by Dan Dittman, Chief Mechanical Engineer) 18) (Q) I want to move a bakery into a space at South Park. I am only cooking bread with light amounts of syrup/chock let or oil used as a base for mixing. South Park will not allow any penetrations thorough the roof or side wall. By not requiring a hood we will be able to put our bakery in the mall. I am requesting a waiver of the hood requirement for our bakery? (A) Your cooking operation does not meet any of the exemptions in the code that would eliminate a Type I hood installation. Therefore a Type I or a Type II hood is required depending on the exhaust criteria of the food prepared. Hoods are generally required to exhaust to the outside. I will need more information on the makeup of the bread 16 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
you are cooking to see if smoke or grease laden vapors may be present, if so a type 1 hood with fire suppression may be required. Exhaust will be required to exhaust through the roof or side wall to the exterior of the building. 507.1, 507.2, 507.2.1, 507.2.1.1, 507.2.2 19) (Q) A hood company has installed a hood in a restaurant and they are requesting the use of the clearance reduction tables for the sides of the hood not rated for zero clearance. The hood itself is listed and complies with UL710, however, this particular hood has not been tested in a zero clearance application. The initial inspection failed because the clearances were not met. The installer argues that by using the reduction tables found in table 308.6 of the NCMC. The installer sees no reason he can install the hood clearance by one of the methods in the table. Should the zero clearance labeled hood be allowed to use the reduction tables in 308.6? (A) The clearance reduction tables may be used but since the hood is labeled for specific clearances the designer may choose his clearance option by using either the tables or the hood design clearances. He may use one method only. He may not mix the table and the label clearances. Ref. Table 308.6, 507.1 #1, 507.9, 507.9 exception (see DOI interpretation below) NC Department of Insurance Office of the State Fire Marshal ‐ Engineering Division 1202 Mail Service Center, Raleigh, NC 27699‐1202 919‐661‐5880 Listed Type I Hood Clearance to Combustibles Code: 2012 North Carolina Mechanical Code Date: September 1, 2011 Section: 308.6, 507.1 and 507.9 Question: Can Table 308.6 be used to reduce the clearance requirement in Section 507.9 for a listed Type I kitchen exhaust hood? Answer: Yes. The clearance reduction methods in Table 308.6 are applicable for equipment and appliances that are not listed for clearance to combustibles. UL710 is the test standard for listing factory built Type I hoods and is referenced in Section 507.1. The UL710 standard does not include testing for clearance to combustibles; therefore the listing does not address clearance to combustibles. The 18 inch clearance required by Section 507.9 may be reduced by application of Table 308.6. 17 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
Keywords: Unlisted, reduced, reduction 20) (Q) Under what conditions could the Mechanical Code Administrator approve a hood other than Type I in a commercial application where there may be smoke or grease laden vapors present? (A) Per DOI the 2012 ICC code has a provision to allow a cooking appliance to operated with a type II hood if the appliance has been tested to meet UL 710 B requirements. The owner must provide a menu. Food shall be prepackaged and precooked to meet the EPA 202 requirements of less than 5mg/m3 for smoke and grease laden vapor quantities. The approval would be an alternate method per 105.2 for that particular project and with a defined use. DOI comment‐If the designer can demonstrate the HVAC system has the capacity to handle the heat and moisture the AHJ may approve the installation without a hood. DED 507.2, 507.2.1 NCMC 2012 21) (Q) A contractor has installed a Type 1 hood over a Stove with Charcoal finishing added integral to the appliance for flavor and in addition several gas fryers are under the same hood. The test report is per plans but the job is failed by the inspector. The Contractor tells the inspector he has installed these all over North Carolina without any problems. Can the inspector allow this installation per current code? (A) No. 2012 N.C. Mechanical Code Chapter 2 definition of Extra‐ Heavy‐ Duty Appliance includes appliances utilizing solid fuel such as wood, charcoal, briquettes, and mesquite to provide all or part of a heat source of cooking. The Mechanical Code relating to Extra‐Heavy‐Duty appliances states that a hood shall not also cover heavy, medium or light duty appliances. Such hoods shall discharge to an exhaust system that is independent of other exhaust systems. Section 507.2.4 of 2012 N.C. 22) (Q) A ventilation contractor is installing a zero clearance hood listed per 710 of the mechanical code. Exceptions under 507 do not include 507.9 which requires 18" minimum to combustibles. Is this the correct way to install the hood or do we go by equipment label even though it is contrary to code? (A) You have to make sure how the zero hood is listed and that the clearance reduction is correct. The zero clearance designation may not be allowed if the fan unit and the panel do not match the hood listing. You cannot just slap a zero clearance hood on the wall and say just look at the clearance label and it is good to go. The installation shall meet all of the manufacturers/listing parameters before you can use the less 18 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
restrictive hood label clearances. 507.9, 507.9 exception, 507.9, Table 308.6 23) (Q) The 2012 NCMC section 507.2.3 requires that residential appliances utilized for commercial purposes be provided with a Type I or Type II hood, based on the type of appliance(s) and cooking process. This section has an exemption which allows a maximum of two domestic ranges installed in dwelling units, churches, schools, day care centers, break areas, and similar installations. It is Mecklenburg County’s interpretation that a domestic range in the clubhouse of an apartment building would fall under “similar installations,” but that this only lowers the requirement from a Type I hood to a Type II hood and does not eliminate the requirement for a hood altogether. Per the 2012 NCMC section 507.13, a wall‐ mounted canopy Type II hood located over an electric range would be required to exhaust 200 cfm per linear foot of hood. A similar hood located over a gas‐fired range would exhaust 400 cfm per linear foot of hood. Providing a Type II hood over a 36” wide gas‐fired domestic range results in 1,200 cfm of exhaust, increasing the amount of outside air required for the clubhouse to provide sufficient makeup air. Attached is a cut‐sheet and installation manual for a proposed solution. This hood exhausts less air than is required per the 2012 NCMC section 507.13, but has an integral fire suppression system. The proposed hood will engage the fan in stages based on the temperature under the hood, shut off the power/gas to the appliance at extreme temps, sound alarms locally and remotely (i.e. in the manager’s office) when the suppression is activated, etc. Is it acceptable to use the attached Denlar hood, or comparable system, in lieu of a Type II hood designed in accordance with the 2012 NCMC section 507.13? (A) The Denlar Hood specified in the cut‐sheets provided as an alternate to a Type II hood for the club house is acceptable. The range is a 4 burner residential electric range per the information provided. The approval is ONLY for the Denlar hood per the cut sheets. Any alternate hood would have to have a separate approval from this office prior to installation. All of the safety equipment specified for the hood shall be installed as part of this approval. 507.13 NCMC 24) (Q) A Mechanical Field inspector is inspecting a new restaurant. The plans for the project show a specific hood manufacturer with the CFM and Makeup Air calculated per that manufacturer’s hood. How should the Mechanical Field Inspector proceed with the inspection if the hood installed on the project is a hood from a different manufacturer than is shown on the plans? Should the inspector use the values shown on the plans or require the contractor to have the engineer recalculate the hood CFM 19 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
and MUA per the new hood specifications? (A) Even though hood manufacturer data is different from specified, they would need to show data to justify change. 507.13 & 508.1 NCMC 2012 25) (Q) Upon inspecting a new automobile body shop the inspector finds a fire damper has been installed in the exhaust duct separating the flammable paint storage room from the body shop. The installation is shown on the approved plans. The inspector failed the inspection citing the fire damper in exhaust duct as not allowed by code. The mechanical contractor says the installation is on the approved plans. The project engineer calls the inspector and tells the inspector that he thinks the design meets code and should be approved. Is the contractor correct? Is the engineer correct? (A) No. The contractor is correct that the installation is on the approved plans, however, the inspector has to turn down a code violation he sees in the field. He has the discretion of requiring the plans to be corrected or to approve the installation per the engineer per a bulletin drawing with the plan area noted and changed to meet code. The contractor is also responsible per the North Carolina Administrative code to install a code compliant installation. The contractor is ultimately responsible per state law. The engineer is incorrect because the installation is a direct code violation. A shaft enclosure rated for the penetration is required. Per 2012 N.C. Mechanical Code 510.6.1 Fire and smoke dampers are prohibited in hazardous exhaust ducts. 26) (Q) A Hood performance test for type 1 hood is performed and the wrong form is used by contractor using self‐certification Engineer’s test report. The report was refused as tester was not an Engineer. What would contractor need to get job tested, certified and finaled? (A) The inspector can witness a tester performing a capture and containment test for a type 1 hood. If the inspector does not witness the test the form per new code on line shall be used which shall be used to test the system and the form shall be sealed by a NC professional Engineer who shall give the original to the code official. 507.16, 507.16.1, 507.16.2 NCMC 2012 27) (Q) A Hood performance test for type 1 hood is performed and the wrong form is used by contractor using self‐certification Engineer’s test report. The report was refused as tester was not an Engineer. What would contractor need to get job tested, certified and finaled? 20 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
(A) The inspector can witness a tester performing a capture and containment test for a type 1 hood. If the inspector does not witness the test the form per new code on line shall be used which shall be used to test the system and the form shall be sealed by a NC professional Engineer who shall give the original to the code official. 507.16, 507.16.1, 507.16.2 NCMC 2012 Chapter 6 Duct Systems 1) (Q) Have field inspectors been requiring any extra protection added to exterior galvanized exhaust duct, un‐lined and un‐insulated, running on top of a roof? The project contractor ask this question about ductwork on the rood used as part of an engineered dust collection system and is installed after the filters so the exhaust is non‐hazardous. Examples: Painting, insulation. (A) Some inspectors are and some are not depending on the installation. Some inspectors require contractors to paint or cool seal fresh air intakes and non‐kitchen hood exhaust. For exposed grease duct inspectors will ask the designer prescribe protection. Most designers use high temp paint others designers have used fire wrap with a protective cover. For a dust system like the one in the example in the question we leave it up to the system designer to require protection. If the ductwork is HVAC then galvanized ductwork is an adequate protection without adding paint or wrap. If it is black metal ductwork unprotected it will need protection and either paint or a wrap approved for outside use will be acceptable. (603.12 2012 NCMC) 2) (Q) Is access required to a volume dampers located in a hard (sheetrock) ceiling? We are starting to see more enclosed ceilings (sheetrock, not lay in tile) because of the new energy code requirements. When volume dampers are installed above the ceiling access is required per 603.17 I believe the access is to adjust the damper not to the damper itself unless that is the only means of adjustment. I am not requiring direct access for adjustment of volume dampers as long as remote access is provided. Access doors at each volume damper really make for a very ugly ceiling. The Architect would like to avoid this if possible. (A) No. The remote access controls will meet the intent of the code. DOI actually recommend people use these where they have very tall ceilings or remote diffuser locations that would be difficult to access via a ceiling tile or access panel. Plus they have the added benefit of being so user‐friendly there is a better chance of the system actually getting balanced correctly. They are more likely to actually stay put once the balancing is done. The McKinnon center at NC State, where the Building Code Council 21 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
meets, has these units. 603.17 NCMC 2012 3) (Q) A Hood performance test for type 1 hood is performed and the wrong form is used by contractor using self‐certification Engineer’s test report. The report was refused as tester was not an Engineer. What would contractor need to get job tested, certified and finaled? (A) The inspector can witness a tester performing a capture and containment test for a type 1 hood. If the inspector does not witness the test the form per new code on line shall be used which shall be used to test the system and the form shall be sealed by a NC professional Engineer who shall give the original to the code official. 507.16, 507.16.1, 507.16.2 NCMC 2012 4) (Q) The plan reviewer has turned down a 5 story type R2 occupancy. He is requiring smoke dampers or a code approved alternate where individual bathroom exhaust ducts terminate in an exhaust shaft. The engineer is using the exception for sub ducts in lieu of fire dampers at the shaft penetration per 606.5.5 Exception #1 (1.1). The reviewer is asking, in addition to the sub ducts, either smoke dampers at the penetration of each bathroom exhaust duct terminating through the two hour shaft or to supply emergency power for the roof mounted exhaust fan. The fan on the roof is pulling exhaust air from all the bathrooms and runs continuously. The designer does not believe he needs to supply the protection the plan reviewer requires and sites 909.1 of the NC Building Code as a reference. (1)Does section 909 of the building code apply? (2) Should the reviewer turn the job down, if yes, why? (3) Can the designer use an alternate power source as an approved method? (A) (1) Section 909 of the building code does not apply. Section 909 states that “Mechanical smoke control systems shall not be considered exhaust systems under chapter 5 of the North Carolina Mechanical Code”. The requirements the plan examiner is turning the system down for are in Chapter 6 not chapter 5 of the Mechanical Code. (2) Yes. The designer has to either install smoke dampers as referenced above or comply with 909.11.1 of the NC Building Code. (3) Yes. 909.11.1 allows the designer to use an alternate power source that will allow the roof mounted exhaust fan to run for a sufficient duration to span a 15 minute primary power interruption. A separate one hour room is required for the alternate power source per 909.11. Ref: 606.5.5 Exception # 2 22 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
5) (Q) We had a fire master product seminar last week and there product is not tested to be wrapped say 18 inches on both sides of the wall to be a substitute for a fire damper. They say there is no approved test for that installation. The only approved test is a wrap or shaft from the hood to the penetration of the rated wall. Is the altered duct wrap method described allowed by code? (A) No. There is currently no manufacturers’ data allowing an alternate method to a fire damper or an approved shaft or shaft wrap from the hood to the penetration. A fire damper is not prohibited for ductwork serving a Type II appliance. This exhaust stream should only see heat and/or moisture. The damper shall be approved for moisture when the type II exhaust duct is over dishwashers and similar appliances. 607.1.1 NCMC 2012 6) (Q) I have an exhaust duct located in a 2 hr. shaft. The shaft extends vertically and extends through the bottom of the membrane of a roof/ceiling assembly into an attic space in the hotel. This is located on the top story of the hotel. Plans on the job showed no smoke/fire damper. The general contractor said the duct was not required to have a fire/smoke damper because the shaft penetrated the roof/ceiling assembly and therefore the duct was above the ceiling rating which is one hour. Would a fire/smoke damper be required when duct comes from shaft, through attic space and into the rated ceiling of the motel top floor ceiling? (A) Because the shaft has fire/smoke dampers on the first two floors there is no reason the top floor membrane penetration should not also be protected with a fire/smoke damper. 607.5.1, 607.5.3, 607.6 NCMC 2012 7) (Q) Is there a reference in the code that specifically disallows a fire damper to be installed in a Type II hood exhaust duct that penetrates a rated wall? (A) No. A fire damper will be allowed by the commercial code. An issue with residential is there may not be a fire damper that will work for the given situation. Even with the commercial code, it is not necessarily the best solution, but in our code, addresses fire dampers that are not required if installed in accordance with the code. Of course, what that is saying is there is usually a shaft or other means of protecting the kitchen exhaust ductwork that penetrates a rated assembly. The fire damper still has to be suited for the exhaust stream it is going to be located in. Residential ranges are typically going into a rated floor/ceiling assembly and would require a radiation damper. 607.5.5 Exception# 5, NCMC 2012 23 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
8) (Q) The 2012 North Carolina Mechanical Code (2012 NCMC) section 607.6.2 requires membrane penetrations to be protected by a ceiling radiation damper or a shaft enclosure in accordance with the 2012 North Carolina Building Code (2012 NCBC) section 708. Per the 2012 NCMC section 607.6.2.1 exemption 2, where exhaust duct penetrations protected in accordance with the 2012 NCBC section 713.4.1.2 are located within the cavity of a wall and do not pass through another dwelling unit or tenant space, ceiling radiation dampers are not required. Per the 2012 NCBC section 708.2 exemption 2, a shaft enclosure is not required for pipe, tube, conduit, wire, cable, and vent penetrations protected in accordance with the 2012 NCBC section 713.4. In summary, all exhaust ducts routed within a wall cavity into a floor/ceiling or roof/ceiling assembly do not require ceiling radiation dampers or shaft enclosures, but must be installed in accordance with the 2012 NCBC section 713.4, which requires that the penetration be protected by an approved through‐penetration fire stop system with an F‐rating not less than 1 hour but not less than the required rating of the floor penetrated. (A) Correct. This will only apply to the wall cavity installation with penetrations through the top plate into the floor/ceiling or roof/ ceiling assembly. Your question was specifically related to the dryer exhaust duct. A membrane penetration shall require a shaft or an approved one hour fire wrap for dryer exhaust duct. 607.6.2.1 NCMC 2012, 713.4.1.2 NCBC 2012 9) (Q) The 2012 North Carolina Mechanical Code (2012 NCMC) section 607.6.2 requires membrane penetrations to be protected by a ceiling radiation damper or a shaft enclosure in accordance with the 2012 North Carolina Building Code (2012 NCBC) section 708. Per the 2012 NCMC section 607.6.2.1 exemption 2, ceiling radiation dampers are not required “Where exhaust duct penetrations protected in accordance with Section 713.4.1.2 of the [201 NCBC], are located within the cavity of a wall and do not pass through another dwelling unit or tenant space.” Per the 2012 NCBC section 708.2 exemption 2, a shaft enclosure is not required for pipe, tube, conduit, wire, cable, and vent penetrations protected in accordance with the 2012 NCBC section 713.4. The 2012 NCBC section 713.4.1.2 Membrane Penetrations states “Penetrations of membranes that are part of a horizontal assembly shall comply with Section 713.4.1.1.1 or 713.4.1.1.2.” The 2012 NCBC section 713.4.1.1.2 Through‐penetration Fire stop System states “Through penetrations shall be protected by an approved through‐penetration fire 24 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
stop system installed and tested in accordance with ASTM E 814 or UL 1479, with a minimum positive pressure differential of 0.01 inch of water (2.49 Pa). The system shall have an F rating/T rating of not less than 1 hour but not less than the required rating of the floor penetrated. EXCEPTION: Floor penetrations contained and located within the cavity of a wall above the floor or below the floor do not require a T rating.” In short, membrane penetrations are required to comply with the same requirements as through penetrations. In summary, all exhaust ducts routed within a wall cavity into a floor/ceiling assembly do not require ceiling radiation dampers or shaft enclosures, but must be installed in accordance with the 2012 NCBC section 713.4. Per the architectural plans, the wall assembly used is UL U341, and the floor assembly is UL L579. A UL‐listed penetration detail for a duct penetrating an L500 series floor assembly has been included and has been added to the plans. Using this logic we should be able to simply fire stop at the top plate for the dryer and bathroom exhaust fans which will comply with current code. Do you agree? (A) No. Per Mr. Lon McSwain, the Building Code Administrator for Mecklenburg County, the dryer exhaust duct will be required to have a shaft enclosure when it exits the top plate of the wall into the floor/ceiling or roof/ceiling assembly (approved rated fire wrap is acceptable). This would not be considered a through penetration to the floor above since each dryer duct is terminated within the rated assembly. If the dryer duct has only been fire stopped at the top plate penetration there is still a potential fire problem because dryer duct fires are usually concentrated in the dryer duct itself. A dryer duct fire will burn through the 90 degree elbow of the dryer duct and spread fire and smoke into the rated assembly between tenants. This will neutralize the rating of the floor/ceiling assembly. 607.3.1, 607.6.2 #2 NCMC 2012 10)(Q) Per the interpretation from the Building CA the designer agreed to wrap the dryer duct within the rated membrane floor/ceiling assembly. He did not have a clear understanding of the requirements because he ask the following question. Am I correct in understanding that it is still acceptable to fire caulk the bath exhaust duct at the top plate per the detail sent previously? (A) No. It is the determination of this department that we accept a ceiling mounted fan with a radiation damper or if a side wall fan is used it must be wrapped with fire wrap from the top plate to the exterior. If the duct is just calked at the top plate the fire can enter the fan, burn out the duct and spread through the floor system. 607.3.1, 607.6.2 #2 NCMC 2012 25 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
11)(Q) We have been getting complains about the alternate design requirements allowed in multi‐family dwelling. We allow a smoke detector mounted either in the return at the unit, a separate line powered thermostat with battery backup, or a smoke detector tied to the apartment unit smoke detector system in lieu of a dynamic one hour radiation damper which is required at the penetration of the floor/ceiling or roof/ ceiling assembly. The engineer ask if the smoke detectors could be on a delay of 3 minutes to allow a cool down period for the unit because of unit warranty issues? (A) No. The fan shall shut down immediately upon detection of smoke. If the designer can not comply with that requirement as part of the alternate method allowed then the designer should provide a dynamic radiation damper required by code. We understand a 3 hour dynamic radiation is manufactured, however, a one hour is allowed for the floor/ceiling membrane penetration. The designer may use the 3 hour or find a one hour dynamic radiation damper that is approved for the penetration. Ref: 607.6.2 #2, 607.6.2.1.1 NCMC 2012 12)(Q) A Contractor called with a question about an inspector who required a duct mounted smoke detector to be installed to shut the system down for a corridor and required the unit to be wired into the house fire alarm system. The Contractor has motorized fire/smoke dampers at the penetrations in the return duct into the corridor and feels this is adequate protection for code compliance. Upon talking with contractor, the inspector finds out the supply plenum penetrates the membrane between the rated floor/ceiling assembly and there is a radiation Fire Damper installed at the unit. Is the inspector correct in requiring the duct mounted smoke detector to be installed? (A) Yes. A duct mounted smoke detector is an installation required if a static radiation damper is installed in a duct that will have air flowing from the unit against the damper when the damper closes in a fire situation. The installation of a dynamic radiation damper is required by code. If an “approved” dynamic radiation damper is per installed per UL 555C then the smoke detector would not be required, however, until a dynamic radiation damper is produced (one hour rated typically) to meet the UL 555C requirement a static radiation damper with the added protection of a smoke detector to shut down the unit is the only approved alternate method approved in Mecklenburg County. 607.6.2.1, 607.3.1, 105.2 NCMC 2012 Chapter 7 Combustion Air Chapter 8 Chimneys & Vents 26 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
Chapter 9 Specific Appliances Chapter 10 Boilers, Water Htrs 1) (Q) A contractor that we work closely with is asking if “mushroom type” emergency burner/boiler push‐button shutoff switches are required at each exit door from the mechanical room (per ASME CSD‐1) where a large boiler has been installed. The Fuel Gas Code only references manual valves at each piece of equipment. Does Mecklenburg county code enforcement require such devices? (A) I need more information before I can answer your question.  There is no definition of a mechanical room in the gas code. I assume you have a gas fired boiler?  Boiler Room and Machinery Room requirements are discussed in the 2012 North Carolina Building Code: 1015.3 Boiler, incinerator and furnace rooms. This section has a square foot/ BTU limitation in determining the number of exits. 1015.4 Refrigeration Machinery Rooms. (Note: Square footage of the room determines number of exits.) Which of these requirements apply to your project?  What sections of the Boiler Code apply to your project. Does 13 NCAC 13.0420 (c) apply to your Boiler? If so a shut off at each exit is required by the Boiler Code.  North Carolina Fuel Gas Code Section 631 has standards specified for “listed” Boilers. The requirements of ASME‐CSD‐1 apply if applicable.  If the manufacturers installation instructions for the Boiler require the “mushroom type” shut off devices then they shall be installed per code. (See 631.2 NCFGC). 631.2 NCFGC also references the North Carolina Mechanical Code. You need to analyze chapter 10 requirements to see what information applies to your installation. Providing the information above should help in determining if the “mushroom type” kill switches are required. I do not have the ASME‐CSD‐1 reference. Please provide a copy of the reference information. Chapter 11 Refrigeration 1) (Q) How and when should you apply chapter 11 Refrigeration of the 2012 NC mechanical code to the following situation: When a change in refrigerant type is proposed, would we require the entire system to come into compliance with the current code? 27 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
(A) If the only change is the refrigerant type and not the equipment itself we would allow the change out of refrigerant, with prior notification to the code official and compliance of all applicable code provisions for the new refrigerant. 1101.8 NCMC 2012 Chapter 12 Hydronic Piping Chapter 13 Fuel Oil Piping Chapter 14 Solar Systems POLICY OTHER: Includes: General Policy, NC Energy Code 2012, NC Building Code 1) (Q) We received the attached email from one of our clients yesterday regarding the NC Energy Code compliance path. It is my understanding from Mr. Billy Hinton’s email that we can use either NCECC‐ 2012 or ASHRAE 90.1‐2010 for compliance. Is Mecklenburg County allowing the use of ASHRAE 90.1‐2010 as it appears that it is approved per the attached letter from Billy Hinton? (A) Yes. We will allow the designer to use the ASHRAE 90.1‐2010 standard as an alternate method of compliance with the 2012 NCECC. Per the letter the standard must be used in its entirety and no portions of the 2012 NCEEC shall be substituted for ASHRAE 90.1‐ 2010 requirements. A Com Check program may be used to calculate the Building Energy and that program shall be used with the ASHRAE 90.1‐2010 program not the 2007 ASHRAE 90.1 2007 Com Check software. (Ref: see DOI web site letter) 2) (Q) The Energy Code in Section 503.2.4.4 exception 2 allows gravity dampers for exhaust airflows of 300 cfm or less. Is the exhaust airflow based on what an individual fan is providing or do you add the aggregate amount of exhaust as in the case of when multiple fans are manifold together? (A) If multiple fans are manifold together such that the resultant air flow exceeds 300 cfm, the shutoff dampers would be required, unless exempted elsewhere. The code cites “airflows”, so I am going with air flow of the outlet and not the individual fan capacity. – DED—503.2.4.4, exception 2, NC Energy Code 2012 3) (Q) Same situation as above. How is this code section applied to the case of kitchen 28 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
exhaust ducts? (A) A type I exhaust system is not required to have a fire damper, per NCMC 607.5.5 Exception 4, and in fact anything that restricts the air flow would be prohibited, including motorized backdraft dampers.‐DED 607.5.5 Exception 4, NCMC 2012 4) (Q) Same situation as in # 3 above... how could a motorized damper be located in the exhaust air stream of a type 1 hood exhaust? (I don’t think that even a gravity damper has ever been used in a type 1 or type 2 hood exhaust) (A) A Type II hood would not be exempt, but be careful if it is serving appliances that require exhaust of byproducts of combustion, such as a water heater installed under a kitchen dishwasher Type II hood. – DED‐‐607.5.5 Exception 4, NCMC 2012 5) (Q) When is a programmable thermostat required by 403.1 of the 2012 NC Energy Code? (A) Per the North Carolina Energy Conservation Code, section 403.1.1, where the primary heating system is a forced‐air furnace, (not a Heat Pump) at least one programmable thermostat per dwelling unit shall be capable of controlling the heating and cooling system on a daily schedule to maintain different temperature set points at different times of the day. This thermostat shall include the capacity to set back or temporarily operate the system to maintain zone temperatures down to 55 degrees (F) or up to 85 degrees (F). North Carolina Department of Insurance Comments: This requirement (programmable thermostat) only applies to the installation of gas, oil, solid fuel and electric furnaces. Heat pump installations do not require programmable thermostats, but, (strip lock out controls) are required to be installed per the North Carolina Energy Conservation Code, section 403.1.2 Heat pumps having supplementary electric‐resistance heat shall have controls that, except during defrost, prevent supplemental heat operation when the heat pump compressor can meet the heating load. A hear strip outdoor temperatures lockout shall be provided to prevent supplemental heat operation in response to the thermostat being changed to a warmer setting. The lockout shall be set no lower than 35 degrees (F) and no higher than 40 degrees (F). 403.1.1, 403.1.2 NCEC 2012 6) (Q) Are Nest@ programmable thermostats allowed to be installed for HVAC system controls in Mecklenburg County? (A) Yes, We had a call from a contractor who said another County was questioning the use of the thermostats. A Nest@ Thermostat system is a smart stat with an IP connection that can be 29 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
controlled through the internet. It reads outdoor temperature via the location of the property zip code. The other County was concerned about what would happen if you lost the internet connection. The thermostat has a very strong battery back up system that should easily keep the dwelling temperature stable until the homeowner returns or the internet connection is restored. As long as the thermostat is installed per manufacturer’s installation instructions Mecklenburg County will have no problem approving the installation of Nest@ Programmable thermostats. Ref: 403.1.1 NC Energy Conversation Code (Chapter 4 residential) DOI information: From: Dittman, Daniel E [dan.dittman@ncdoi.gov] Sent: Monday, February 25, 2013 9:18 AM To: Paul D. Roper Subject: Excerpt from Prior outdoor T’ stat Proposal Mr. Roper. A proposal that allowed essentially a small DDC system to be used has already been approved by the BCC. It is in rules review now, and there is no indication it will not pass. The proposed method does not monitor outdoor air temperature at all; please refer to the wording below my signature. If combined with the requirements of sizing the heat pump according to Manual S, the heat pump compressor should be capable of meeting the loads when air temp is above 34 – 40F. Therefore, although there is no direct measurement of outdoor air temperature, the added time delays that the DDC system has in the software will likely limit the amount of time that the heat strips are energized when they do not need to be. I view the NEST t’ stat along the same lines. It has the capability to work and meet the intent of the code, but it is difficult as an inspections department to know it is working when you leave a building. The requirement to get and maintain an internet connection is also something that would need to be communicated to the owner of the house. As any Alternate Materials proposal, these issues would need to be addressed. Based on the previous proposal to the BCC, I think the NEST would be well‐received, as it does not impact the affordability of a code‐minimum house, but is intended to be an upgrade to minimum. The following is a link to the code‐change form; the provider may want to submit this. http://www.ncdoi.com/OSFM/Engineering_and_Codes/Documents/BCC_Documents/CodeChangeForm.
pdf Sincerely, Daniel Dittman, PE, CMVP
919-661-5880 x237
NC DOI
Chief Mechanical Code Consultant
30 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
7) (Q) I have attached a form for review given to me by the Mechanical Contractor. My mechanical Contractor insists he needs this to receive a CO. I think he may need something, but he says he pays $125 for the certificate and Mecklenburg County requires it to be filled out by a HERS Rater. I have attached what the contractor thinks is a HERS rater Energy Certificate. Is a HERS rater required to fill out and approve a form prior to a CO in Mecklenburg County? (A) The 2012 North Carolina Energy Code, Chapter 4, has the information you are looking for on The Energy form and the Tests required. I have included the energy code sections that apply below. 401.3 Requires a permanent Certificate to be posted on or in the electrical distribution panel, in the attic next to the insulation card or inside the kitchen cabinet or other approved location by the inspector. As you stated this is required to be posted prior to final building approval and getting a CO. The builder, permit holder, or registered design professional shall be responsible for completing the certificate. The rest of 401.3 lists the items that shall appear on the certificate. The two code test requirements that are listed on the form that specifically require a HERS rater as ONLY ONE of the testers that can conduct the test and provide report information on the tests are: 402.4 Air leakage control test (Blower Door Test) –“Testing shall be reported by the permit holder, a NC licensed general contractor, a NC licensed HVAC contractor, a NC licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater. “The air leakage information, building air leakage results, tester name, date, and contact information, shall be included on the certificate described in 401.3” (see above for reference) As you can see directly from the code a HERS rater is only one of many choices for a tester. 403.2 Ducts 403.2.2 Sealing required (Duct Blast Test) –“Testing shall be reported by the permit holder, a NC licensed general contractor, a NC licensed HVAC contractor, a NC licensed Home Inspector, a registered design professional, a certified BPI Envelope Professional or a certified HERS rater. “The duct leakage information, including duct leakage result, tester name, date, and contact information shall be included on the certificate described in Section 401.3” (see above for reference) Exceptions to 403.2.2 testing for Duct Leakage: 1. Duct systems or portions thereof inside the building thermal envelope shall not be required to be leak tested. 31 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
2. Installation of a partial system as part of replacement, renovation or addition does not require a duct leakage test. A copy of the Builders Certificate required to be posted for a CO and be found on the Meckpermit.com website in the forms section. 8) (Q) The 2012 North Carolina Energy Conservation Code (2012 NCECC) Table 503.2.8 requires refrigerant piping to have 1‐1/2” thick insulation. Since multifamily buildings 4‐stories or greater are classified as commercial, apartment DX split system refrigerant piping would be required to comply with Table 503.2.8. A typical suction line for a 1.5‐ton to 3.0‐ton system is 5/8” – 7/8” diameter, depending on line length. The overall diameter of the insulated pipe is up to 3‐7/8”, which does not fit within a 3‐1/2” stud cavity. Fire caulk manufacturers have expressed concern that this creates a large, non‐rigid penetration which could result in cracks and broken seals at these penetrations. I have attached to this letter the pipe insulation requirements of the 2012 International Energy Conservation Code (2012 IECC) Table C403.2.8. A typical split system would fall under the category of <1” pipe with a fluid operating temperature of 40‐60°F, so the insulation is required to be at least ½” thick. (A) The table you reference is not in the current 2012 North Carolina Energy Code. Will the installation of the piping not fall into any of the exceptions in 503.2.8 of the 2012 North Carolina Energy Code? It was my understanding from our phone conversation table 503.2.8 was changed in the 2012 ICC Energy Code. You are referencing a table in chapter 4 of the residential energy code requirements. I do not have a copy of that code for reference. The only deviation I would consider would be the use of ASHRAE 90.1 section 6.8.3B which would allow a reduction. ASHRAE 90.1 2012 may be used as an alternate means of compliance. There are other materials that could be used that could mean a further reduction but they would be very difficult to install. Table 503.2.8 NCECC 2012. 9) (Q) The 2009 IECC had residential requirements in chapter 4 and commercial requirements in chapter 5. The 2012 IECC has been restructured, so sections with a C prefix apply to commercial buildings and sections with an R prefix apply to residential buildings. Unfortunately, I do not believe any of the exemptions listed under the 2012 North Carolina Mechanical Code Section 503.2.8 would apply. I have evaluated various insulation products using the formula for adjusted insulation thickness, but only the most expensive insulation available typically used on large chilled water systems offers the thermal conductivity needed to allow 1” insulation. As you said, it would also be very difficult to install. 32 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
All the split systems in the multifamily projects I am working on have suction lines 5/8” to 7/8”, so they would require 1/2” thick insulation per ASHRAE 90.1‐2010 Table 6.8.3B. Would you accept refrigerant line insulation to comply with ASHRAE 90.1‐2010 Table 6.8.3B, but the rest of the building complies with the 2012 North Carolina Energy Conservation Code? We would actually specify 3/4” thick insulation as it is a very common size. (A) We will accept the ASHRAE 90.1‐2010 Table 6.8.3B alternative for the insulation thickness of suction lines on your project. This acceptance is job specific per 105.1 [“individual cases”] of the North Carolina Mechanical Code 2012 edition. This interpretation will not apply to future installations required to meet the 2012 North Carolina Energy Code. You will be required to submit this document information with the plans for your project. I have also discussed your suction line insulation problem with Dan Dittman, Chief Mechanical Engineer for the Department of Insurance in Raleigh North Carolina. To quote Mr. Dittman in an email sent to me today, April 26th 2013 concerning the suction line insulation; “I think it is acceptable to use the insulation requirements from the ASHRAE 90.1‐2010 standard, on a job‐by‐job basis.” 10) (Q) It is my understanding the new 2012 North Carolina Energy Code provides a 30 % savings in energy over the 2009 NCECC. Does the newly adopted IgCC provide a further Energy Savings if you use if it for sustainable design projects? (A) Answer per Billy Hinton sustainability Energy Code Engineer for DOI. The 2012 NC Energy Conservation Code (2012 NCECC) was targeted to be 30% more efficient than the 2006 IECC, not the 2009 IECC. Reports from the project team indicate the targeted 30% improvement was achieved. The 2012 IgCC requires a minimum zEPI of 51 which corresponds to a 30% improvement over the 2006 IECC. (This is explained in the 2012 IgCC Commentary section 602.1.1.) The 2012 IgCC does contain provisions to allow for jurisdictions to require increased performance under section 302.1 item 2, but this would exceed the minimum requirements otherwise in effect. So, at this time, it appears that the performance required by the 2012 NCECC and the 2012 IgCC are basically equivalent as both look to achieve a 30% improvement over the 2006 IECC. 2012 NCECC, 2012 IgCC 11) (Q) The Mechanical Inspector on a 10 story building finds supply and return duct penetrating the wall of the elevator machinery room. The ductwork is part of the same system supplying air conditioned air to the floor. The machinery room also has a separate unit in the room that heats and cools only that room. The elevator machinery room contains solid state equipment for controlling the elevator operation. 33 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
Should the Mechanical inspector approve this installation? (A) The inspector cannot allow ductwork from other spaces/rooms on the same or adjacent floors to penetrate the elevator machinery room. A separate unit supplying heat and air to the room installed within the room would meet code. Ref: 3006.2 NCBC 2012 12) (Q) Are CO detectors required in apartment units that have electric HVAC units only. I am doing a change out of electric HVAC equipment only in an existing apartment? (A) Carbon Monoxide detectors may not be required unless you have a gas appliance such as a water heater, a fire place or an attached garage. Local ordinances in Mecklenburg County still require CO detectors in apartments and condominiums. There are also provisions in the General Statutes for installation of CO detectors for landlords. The adoption of the 2012 NC Residential Building Code put the requirements for CO detectors in one and two family residences and townhomes up to 3 stories in height in the residential code. No law or code has been passed to circumvent the Mecklenburg County Ordinance for CO detectors in apartments and condominiums so those ordinances are still being enforced. Ref; Mecklenburg County Local Ordinance, NC Residential Building Code R 315.1, 315.2, & 315.3 13) (Q) What is the responsibility of the Mechanical Inspector when checking Fire Dampers? How do Mechanical and Building inspectors coordinate Fire Damper inspections? Comment CEM: It seems that we have a lot of these hitting us and there are differences of opinions and confusion on who is responsible for what as well. This is the fourth major complex with issues we have had to deal with after the fact and I just need a way to prevent this for us and our customers? (A) Building inspectors often will turn a contractor down for the flange thickness around the fire damper opening. The collar thickness is a minimum requirement not a maximum as is sometimes misinterpreted. The fire damper needs space to move in the opening. 14) (Q) The inspector finds an assisted living home with mini‐split system. The facility has a separate AHU in each living area (about the size of hotel room) with an energy recovery system which handlings several rooms. Is a Shut Off switch required in each room for the Energy Recovery Control? (A) No. A switch in a controlled area such as behind the counter in an accessible location for use by the assisted living personnel would meet the disconnecting requirement for 34 4th Quarter
Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code & NC Energy Code (Mech. Only)
1st Quarter 2013 (Jan-Mar) Answers in Brown, 3rd Quarter (Jul-Sep) 2013 Answers in Blue
2nd Quarter 2013 (Apr-Jun) Answers in Green, 4th Quarter 2013 (Oct-Dec) Answers in Red
the Energy Recovery Control? 15) (Q) A contractor has boots in unconditioned attic space of apartment. The boots are wrapped with foil insulation. The contractor tells the inspector it was R‐12, 3” insulation. Insulation was ½”, pulled tight to keep appearance neat. Inspector failed job citing inadequate insulation on boots. No label, marking or info left on job for verification. Is contractor correct, that R‐12 is insulation value? (A) No. Manville info for 3” foil wrapped insulation has exceeded compression value allowed on installed product. When Manufacturer website was checked, R‐3 was installed R value as installed. Manufactures data is checked to 25% allowable compression, which is based on Section 604.7 Identification, N.C. 2012 Mechanical Code. External duct insulation, except spray polyurethane foam, and factory‐insulated flexible duct shall be legibly printed or identified at intervals not greater than 36 inches (914 mm) with the name of the manufacturer, the thermal resistance R‐value at the specified installed thickness and the flame spread and smoke‐developed indexes of the composite materials. All duct insulation product R‐values shall be based on insulation only, excluding air films, vapor retarders or other duct components, and shall be based on tested C‐values at 75ºF (24ºC) mean temperature at the installed thickness, in accordance with recognized industry procedures. The installed thickness of duct insulation used to determine its R‐value shall be determined as follows: 1. For duct board, duct liner and factory‐made rigid ducts not normally subjected to compression, the nominal insulation thickness shall be used. 2. For duct wrap, the installed thickness shall be assumed to be 75 percent (25 percent compression) of nominal thickness. 3. For factory‐made flexible air ducts, the installed thickness shall be determined by dividing the difference between the actual outside diameter and nominal inside diameter. 35 4th Quarter
Land Use and Environmental Service Agency