(Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red CHAPTER 3 GENERAL REGULATIONS 1) (Q) A cooling tower is being erected on the roof of a High Rise building. It is being assembled using parts that are individually listed. Would this installation be allowed under the 2012 code? (A) No. The inspector would not allow the installation to be constructed, however, if the design is sealed by a professional engineer, registered in the State of North Carolina, the inspector must accept the design and construction of the equipment. Ref: 301.4, Exception 2 , 2012 MC 2) (Q) Exhaust Ductwork is installed on the back wall of a garage. It extends out about 4 feet from the wall into the garage area at an elevation of 6 feet above the floor. How should the ductwork be protected from vehicle damage per code? (A) Protection may not be required depending on what types of vehicles are worked on in the garage, however, reflective tape or a bollard would provide adequate protection. Ref: 303.4, 2012 MC 3) (Q) A barbeque grill has been installed on the covered porch of a residence. The owner has constructed the hood himself per NSF requirements. Should the hood be allowed by the Mechanical Inspector? (A) NO. The grill is an appliance that is listed for outdoor use. To allow the grill to be under a covered porch, indoors, per code, the grill would have to have either a type I commercial hood or a hood built by the manufacturer that is approved and compatible with the grill. 304.1, 2012 MC 4) (Q) A tractor trailer has a trailer 11 feet 6 inches high. It is backing into a loading dock inside a public garage. The ceiling of the garage is 20 feet high. What is the minimum height to the bottom of the unit heater from the top of the trailer if the unit heater is installed directly over the trailer? (A) Unless the manufacturers installation instructions specify a greater height the unit heater shall be at least 1 foot 6 inches from the top of the trailer to the bottom of the unit heater. Ref: 304.6, 2012 MC 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red 5) (Q) Can mastic be used in the joints for bonding stacked masonry instead of mortar or surface bonding cement? (A) Mastic is required to protect duct joints by adhering to metal duct which is generally a non porous dry surface when applied. It is not approved for the installation specified above. 304.1, 304.10.3, 2012 MC 6) (Q) If we are changing out a like for like roof top unit and it is over 16' above grade level access does it have to have permanent access? (A) No. 306.5, 2012 MC 7) (Q) I am installing a wood burning stove in my home. When installing the appliance I will always be able to use table 308.6 for unlisted equipment to reduce clearances. Is this a true statement? (A) No. If the solid fuel burning appliance is labeled with clearances those clearances shall be used when installing the solid-fuel burning appliance. Ref: 308.7, 2012 MC 8) (Q) What improvement in sizing mechanical equipment for single family dwellings and duplexes has made it possible in the 2012 code to provide equipment that is properly sized. (So equipment is not under sized nor is it over sized)? (A) The use of Manual S for sizing requirements. Ref: 312.1, 2012 MC CHAPTER 4 VENTILATION 1) (Q) To properly balance air flow and have a constant temperature exchange between all spaces in an occupied building should ventilation be required at a constant value for building occupants? (A) NO. Ventilation shall be provided during the periods that a room or space is occupied. Ref: 401.3, 2012 MC 2) Situation: We are working on a Nail Salon that will be going in a building downtown. From speaking with the owner they will not be doing acrylic nails, and nearly all their 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red products will be organic. In moving forward with the design it has been determined that per 2012 NCMC (table 403.3 footnote b) we are not allowed to reticulate any air, therefore, one would think all the air conditioning in the space must be exhausted. This is not the case per DOI. In conversations with Billy Hinton concerning this section, it is his interpretation that the reference to, “all air supplied to such spaces” means the ventilation air supplied, and does not include the air for conditioning the space, therefore, air for conditioning the space could be returned to the space, but not returned to any other spaces. Due to the occupancy location on a lower floor of a multi-story building the designer would like to utilize one of the existing exhaust shafts near the space. One of the shafts is for toilet exhaust; one shaft is for the pool equipment room. Both exhaust fans are located on the roof; therefore the shafts are negatively pressurized. (Q) From reading through Chapter 5 of the code I cannot find any section that will not allow me to combine the exhaust from the nail salon with either of the existing shafts. Is this allowed? (A) Yes. The ventilation requirement for a nail salon, (as determined by 2012 NC mechanical code and footnote b in table 404.3), would require mechanical exhaust for the entire amount of ventilation air supplied for the space for the nail stations. The code would not require all the conditioned air to be exhausted from the space. The exhaust from the nail stations may be connected to the exhaust for environmental air since the system is negatively pressurized. Ref: 403.2.1, Table 403.3 foot note b, 2012 MC 3) (Q) We traded emails recently regarding the 2012 code requirement for exhaust in residential kitchens, such as apartments and condos. The requirement stems from the footnotes on the ventilation calculation schedule. I was told by another engineer recently that Mecklenburg County will not require the kitchen exhaust if we are utilizing natural ventilation for the apartments. (A) We have not received an interpretation for the table below from DOI at this time. For Natural verses Mechanical Ventilation we have sent a clarification document to list conflicts between the two codes.(See charts below for comparisons) 401.2, 2012 MC vs. R303.4, 2012 Residential Building Code. Date: May 11, 2012 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red To: DOI-David Conner/Dan Dittman Re: Differences in the 2012 NC Mechanical code vs. the 2012 NC Residential Code. 2nd Quarter Land Use and Environmental Service Agency Below is a comparison of the 2 codes (NCRC & NCMC) and the sections related to Natural ventilation. There is some language in multiple sections that seem to conflict along with the available commentary that shows some differences as well. Side by side comparison is listed below to illustrate, question related to application are listed below. NCRC (Residential) NCMC (Mechanical) R303.1 Habitable rooms. All habitable rooms shall have an 401.2 Ventilation required. Every occupied space shall be aggregate glazing area of not less than 8 percent of the floor ventilated by natural means in accordance with Section 402 or area of such rooms. Natural ventilation shall be through windows, doors, louvers or other approved openings to the outdoor air. Such openings shall be provided with ready access or shall otherwise be readily controllable by the building occupants. The minimum open able area to the outdoors shall be 4 percent of the floor area being ventilated. by mechanical means in accordance with Section 403. Exceptions: 1. The glazed areas need not be open able where the opening is not required by Section R310 and an approved mechanical ventilation system capable of producing 0.35 air change per hour in the room is installed or a whole-house mechanical ventilation system is installed capable of supplying outdoor ventilation air of 15 cubic feet per minute (cfm) (78 L/s) per occupant computed on the basis of two occupants for the first bedroom and one occupant for each additional bedroom. HABITABLE SPACE. A space in a building for living, sleeping, eating or cooking. Bathrooms, toilet rooms, closets, halls, storage or utility spaces and similar areas are not considered habitable spaces. OCCUPIABLE SPACE. An enclosed space intended for human activities, excluding those spaces intended primarily for other purposes, such as storage rooms and equipment rooms, that are only intended to be occupied occasionally and for short periods of time. R303.4.1 Intake opening. Mechanical and gravity outdoor air intake openings shall be located a minimum of 10 feet 401.4 Intake opening location. Air intake openings shall (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red (3048 mm) from any hazardous or noxious contaminant, comply with all of the following: such as vents, chimneys, plumbing vents, streets, alleys, parking lots and loading docks, except as otherwise specified in this code. Where a source of contaminant is located within 10 feet (3048 mm) of an intake opening, such opening shall be located a minimum of 2 feet (610 mm) below the contaminant source. For the purpose of this section, the exhaust from dwelling unit toilet rooms, bathrooms and kitchens shall not be considered as hazardous or noxious. 1. Intake openings shall be located a minimum of 10 feet (3048 mm) from lot lines or buildings on the same lot. Where openings front on a street or public way, the distance shall be measured to the centerline of the street or public way. 2. Mechanical and gravity outdoor air intake openings shall be located not less than 10 feet (3048 mm) horizontally from any hazardous or noxious contaminant source, such as vents, streets, alleys, parking lots and loading docks, except as specified in Item 3 or Section 501.2.1. 3. Intake openings shall be located not less than 3 feet (914 mm) below contaminant sources where such sources are located within 10 feet (3048 mm) of the opening. R303.5 Outside opening protection. Air exhaust and intake 401.5 Intake opening protection. Air intake openings that terminate outdoors shall be protected with corrosion-resistant openings that terminate outdoors shall be protected with screens, louvers or grilles. Openings in louvers, grilles and corrosion-resistant screens, louvers or grilles having a minimum opening size of 1/4 inch (6 mm) and a maximum opening size of 1/2 inch (13 mm), in any dimension. Openings shall be protected against local weather conditions. Outdoor air exhaust and intake openings shall meet the provisions for exterior wall opening protectives in accordance with this code. R303.1 Habitable rooms. All habitable rooms shall have an screens shall be sized in accordance with Table 401.5, and shall be protected against local weather conditions. Outdoor air intake openings located in exterior walls shall meet the provisions for exterior wall opening protectives in accordance with the International Building Code. [B] 402.1 Natural ventilation. Natural ventilation of an occupied space shall be through windows, doors, louvers or 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red aggregate glazing area of not less than 8 percent of the floor area of such rooms. Natural ventilation shall be through windows, doors, louvers or other approved openings to the outdoor air. Such openings shall be provided with ready access or shall otherwise be readily controllable by the building occupants. The minimum openable area to the outdoors shall be 4 percent of the floor area being ventilated. other openings to the outdoors. The operating mechanism for such openings shall be provided with ready access so that the openings are readily controllable by the building occupants. R303.1 Habitable rooms. All habitable rooms shall have an [B] 402.2 Ventilation area required. The minimum openable aggregate glazing area of not less than 8 percent of the floor area to the outdoors shall be 4 percent of the floor area being area of such rooms. Natural ventilation shall be through windows, doors, louvers or other approved openings to the outdoor air. Such openings shall be provided with ready access or shall otherwise be readily controllable by the building occupants. The minimum openable area to the outdoors shall be 4 percent of the floor area being ventilated. ventilated. R303.2 Adjoining rooms. For the purpose of determining [B] 402.3 Adjoining spaces. Where rooms and spaces without light and ventilation requirements, any room shall be considered as a portion of an adjoining room when at least one-half of the area of the common wall is open and unobstructed and provides an opening of not less than onetenth of the floor area of the interior room but not less than 25 square feet (2.3 m2). openings to the outdoors are ventilated through an adjoining room, the opening to the adjoining rooms shall be unobstructed and shall have an area not less than 8 percent of the floor area of the interior room or space, but not less than 25 square feet (2.3 m2). The minimum openable area to the outdoors shall be based on the total floor area being ventilated. Exception: Openings required for light and/or ventilation Exception: Exterior openings required for ventilation shall shall be permitted to open into a thermally isolated sunroom or patio cover of not less than one-tenth of the floor area of be permitted to open into a thermally isolated sunroom addition or patio cover, provided that the openable area between the sunroom addition or patio cover and the interior room has an area of not less than 8 percent of the floor area of the interior room or space, but not less than 20 square feet (1.86m2). The minimum openable area to the outdoors shall be the interior room but not less than 20 square feet (2 m2). The based on the total floor area being ventilated. addition or patio cover, provided that there is an openable area between the adjoining room and the sunroom addition minimum openable area to the outdoors shall be based upon the total floor area being ventilated. R303.3 Bathrooms. Bathrooms, water closet compartments and other similar rooms shall be provided with aggregate glazing area in windows of not less than 3 square feet (0.3 m2), one-half of which must be openable. No separate listing for Bathrooms 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red 2nd Quarter Land Use and Environmental Service Agency Exception: The glazed areas shall not be required where artificial light and a mechanical ventilation system are provided. The minimum ventilation rates shall be 50 cubic feet per minute (24 L/s) for intermittent ventilation or 20 cubic feet per minute (10 L/s) for continuous ventilation. Ventilation air from the space shall be exhausted directly to the outside. Questions: 1. The definitions between the 2 codes are different NCRC uses habitable rooms and the NCMC uses occupiable spaces. It appears that the NCMC has more requirements than the NCRC in that bathrooms, toilet rooms, laundry rooms, hallways, and possible closets if using natural ventilation would be required openings to the exterior that match floor area, NCRC has natural ventilation minimum opening for bathroom and toilet rooms but NCMC doesn’t. Does the NCMC require hallways, laundry rooms, closets and bathroom/toilet rooms to have windows to the exterior or adjoining room option if using natural ventilation? 2. In reference to both codes is a door or window considered an intake opening? 3. If a door/window is an intake opening is screening required for opening protection. 4. If a door/window is an intake opening, does the lot line or between building requirements apply to NCRC as listed in the mechanical code, would this be the interpretation related to potential contaminants. 5. The IRC and the IMC commentary that support the 2012 codes (2009 version) has conflicting information related to what is a intake opening and when screening is required (Windows) and Lot line issues. The IMC clearly has requirements for lot lines that the IRC doesn’t talk about and the IRC has no reference to “except windows and doors” as listed in the IMC commentary for intake openings. How should this be applied? 6. Should the requirements match in both codes? 4) (Q) Are screens allowed on outside vents? (A) Yes. 401.5 MC and IBC, sizing Table 401.5, 2012 MC (Exception: Dryer Vents) CHAPTER 5 EXHAUSTS SYSTEMS 1) (Q) What would be an adequate amount of make-up air in a residential occupancy if the dryer is exhausting 50 cfm and the Kitchen hood is exhausting through the roof at the same time at 40 cfm. How much make- up air would be required? (A) It depends. Make up air is not required in residential occupancies if natural ventilation is used per 402, however, if 403 is used then make up air would be required. Ref: 501.3 exception. 2012 MC (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red 2) (Q) Would environmental air exhaust ever be considered hazardous or noxious per the Mechanical code? (A) No. 501.2.1 #3, 2012 MC “Such exhaust shall not be considered hazardous of noxious.” 3) (Q) A garage is installing a ventilation system to avoid consideration by the electrical code to be a class 1 division 2 area. Should the fan motors be interlocked with the electrical receptacles and /or equipment/appliances in the garage to shut down the power to the apparatus above if the ventilation fans lose power? (A) Yes. “Electrical equipment and appliances used in operations that generate explosive or flammable vapors, fumes or dusts shall be interlocked with the ventilation system so that the equipment and appliances cannot be operated unless the ventilation fans are in operation.” 503.1 MC 2012 4) (Q) The contractor has the installation instructions for dryer vents for a specific make of Maytag dryer that will be installed in all the apartments in a 40 unit complex. The Manufacturers’ instructions show lengths of duct runs that exceed the minimum code and no equivalent lengths for the fittings used with the dryer duct. Should the inspector approve the installation? (A) NO. The inspector should require the contractor to supply an equivalent length chart for fittings from the manufacturer or re-calculate the runs using the equivalent length chart in the code (table 504.6.4.1) Ref: 504.6.4.2, 2012 MC 5) (Q) A mechanical contractor is insulating the makeup air duct to a type 1 hood with standard fiberglass insulation. He has installed the insulation all the way to the hood. (a) Would this be allowed by the 2012 mechanical code? (b) What should be used as an alternate method if this is not allowed? (A) (a) The standard duct insulation should not be allowed within 18 inches of the hood because of the heat generated by the hood. 506.3.6, 2012 MC (b) A rated fire wrap material could be used to wrap the duct within 18 inches of the hood termination. 506.3.6, exception # 3, 2012 MC 6) (Q) A placard has been provided five feet above the dryer exhaust duct connection on the wall with the dryer manufacturer’s information for duct equivalent length. Does this meet the identification requirements of the 2012 code for length identification? 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red (A) Yes. It would be considered permanent identification. Ref: 504.6.5 MC 2012 7) Situation: A restaurant has installed two barbeque cookers under type I hoods which exhaust high-medium- & low heat cooking appliances. The food services inspector discovered the cookers and reported it to the Code Enforcement Department. Answer a. through e. below. a. (Q) The owner says the cookers are safe as installed and they are code compliant. (1) Is the owner correct? (2) What are the obvious code violations related to this installation? (A) (1) The owner is not qualified to determine the safety of the equipment. The restaurant installed the cookers without plans or permits. Require cookers to meet the code. Ref: 106.1, 106.2.1 Administrative Code. (2) Since the cookers use solid fuel and gas for heat for cooking they are classified as extra-heavy-duty cooking appliances and cannot be located under the same type I hood with high-medium & low heat appliances. Ref: 507.3.4 MC b.(Q)Three Type 1 hoods for the cooking equipment are connected to single grease exhaust duct that exits the building into a covered parking garage. (1) Can the separate hoods required for the two Extra-heavy-duty cooking appliances be combined with the existing grease duct exhaust if properly sized? (2) May the grease duct from the extraheavy-duty appliances exhaust into the covered Parking deck? (A) (1) No. Hoods for the two extra-heavy–duty barbeque cookers shall exit the building through a separate exhaust duct system. The two cookers may, however, be under the same Type 1 hood rather than having separate hoods or under a hood or hoods listed for the application by the manufacturer. The exhaust systems may also be combined since both are extra-heavy-duty cooking appliances. Ref: 507.2.4, 506.3.5 exception # 4 (2) No. It is a violation to have the current hood system grease duct exit the building into a parking garage. The new grease duct shall exit the building either vertically or horizontally to the outside. Ref: 506.3.12.2, 506.3.12.3, 506.5.5 c.(Q) Are there more stringent exhaust requirements for hood exhaust CFM and safety devices for a hood over an extra-heavy-duty cooking appliance than over high-mediumlow & heat cooking appliances? 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red (A) Yes, see ventilation tables. Ref: 507.13.1 d.(Q) The manufacturer of the barbeque cookers sends a letter to the Code Administrator with information on the engineering of the cookers. The letter explains how the cookers are engineered/designed to make it virtually impossible for a spark or ember to be exhausted into the duct system. The letter also states the cookers can be located under the same type I hood with high-medium-low heat cooking appliances. Further, the letter states the information will be included in the manufacturer’s literature in the future on the two cookers installed at the restaurant plus 5 other models of cookers with similar exhaust characteristics. Should the Code Administrator accept the manufacturer’s letter and approve the cookers? (note: The manufacturer does not have a registered PE on their staff.) (A) The code official may accept the letter under the conditions stated above if a professional engineer who works directly for the factory provides a letter under his seal that the changes to the literature will be made. The letter must also provide information as to how the engineering/design of the product is such that a spark or ember can never be exhausted from the cookers that may cause a grease fire in the ductwork and ignite fires in heavy-medium or light duty appliances that may also be under the hood. Ref: 105.2 MC e. (Q) Should the Code Administrator require a third party test that confirms the cookers will not emit sparks or embers into the grease duct system before he approves the cookers? (A)This may be one solution the Code Administrator would allow. Ref: 105.3, 105.3.1, 105.3.2 (MC). 8) (Q) a. What is the new clearance requirement in the 2012 Mechanical Code from operable openings for all environmental air ducts? b. Can environmental air ducts ever be considered hazardous or noxious? (A) a. Three feet, Ref: 501.2.1 (MC) b. No. Ref: 501.2.1 (MC) 9) (Q) Is exhausted air ever allowed to discharge into walkways or hallways? 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red (A) No. Ref: 501.2.1.1, 2012 MC 10) (Q) Will the mechanical code allow exhaust outlets to discharge at or below the design flood level (elevation)? (A) No. 501.2.1 # 4 required 2012 MC, interpreted as required by the 2009 code (2009 501.4 ref. Ch 6, [B] 602.4) 11) (Q) (a) Are all occupancies required to provide pressure equalization when the system is exhausting quantities of air? (b) Are there specific occupancy exceptions for appliances and fans and if so what are they? (A) [note: The 2009 code exempted R 3 occupancies only with no mention of specific appliances or exhaust exceptions.] (a) The 2012 code exempts dwelling units in R 2 occupancies. (b) The 2012 code does not require pressure equalization for domestic exhaust systems in residential occupancies and similar uses (domestic clothes dryers, domestic range hoods, domestic bathroom exhaust). 501.3 and 501.3 exception, 2012 MC 12) (Q) A Mechanical Contractor is installing a 100 cfm bathroom exhaust fan in the kitchen ceiling for a new housing development to meet requirements of table 403.3 footnote b in the 2012 Mechanical Code. He is not installing a kitchen hood over the 4 burner electric range and the manufacturer does not call for a hood. Does this installation meet the code for table 403.3 ft. note b requirements of the 2012 Mechanical Code? (A) Yes. If a mechanical ventilation means is provided per 403.1 MC 2012. [See 401.2. Ventilation shall be required either by using 402 (Natural Ventilation) or 403 (Mechanical Ventilation).] [See 505.1 Exception 1 “where natural or mechanical ventilation is “otherwise provided” listed and labeled ductless range hoods shall not be required to discharge to the outdoors.] Question: If the manufacturer does not require a hood over the cooking equipment would a ductless hood be required? No. 13) (Q) Is a Type I or a Type II hood required over an electric egg cooker that operates under 3000 Watts? (A) No hood is required. Ref: 507.2.2 Exception #4, 2012 MC 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red 14) Project Information: The mechanical design for the a Plant Upgrade consists of the installation of an air cooled chiller and a chilled water pumping system on the roof adjacent to the existing air cooled chillers. The electrical design for this work included an electrical equipment room located within the garage having a UPS system having closed cell batteries. The electrical equipment room design has a 2 hour fire rating and includes an air conditioning unit for heat removal with an exhaust air system, if required, for the removal of hydrogen gas vapors. The closed cell batteries are limited to the UPS equipment and emit very little hydrogen gas. As a result, these batteries do not require an exhaust air system by the mechanical code. However, to be safe, the owner has designed an exhaust air system to protect the electrical equipment room in the event of an emergency. The exhaust air system will be normally off and will be controlled by a hydrogen gas detector installed within the electrical equipment room. When activated, the hydrogen gas detector will start the exhaust air system and provide a local audio and visual alarm at the electrical equipment room and at the building BAS system. The exhaust airflow rate from the electrical equipment room is 150 CFM and it discharges into the garage which is open to atmosphere for its ventilation air requirements. As a result, it is our opinion that the exhaust air system is discharging to the outside and that it will have no impact on the garage environment. The plans examiner has turned the plans down requiring the exhaust to go outside the building. He says garage or loading dock is not considered outside the building per mechanical code. The exhaust duct also has fire dampers in three locations where it penetrates fire rated walls. The plans examiner will not allow fire dampers in a hazardous exhaust system and is requiring the installation to be in shaft from the electrical room to the outside wall penetration. (Q) What can be done to allow the protection as shown on the plans? (A) The plans examiner is correct. If your intent is to protect the electrical room from a possible emergency situation then the installation as described by the plans examiner is in compliance with minimum code. You have two choices. Meet the code minimums described or remove the emergency system. Ref: 510.1, 510.5.7, 510.6.1, 510.6.3 MC 2012 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red CHAPTER 6 DUCT SYSTEMS 1) (Q) DOI, September 1, 2011, 2012 MC If two or more air-handling systems serve a common space and one or more of these systems serve additional spaces and the aggregate capacity of the combined systems exceeds 2,000 cfm, what are the requirements for smoke detectors per Section 606.2.2? (A) Section 606.2.2 requires that when two or more air systems serve common supply or return ducts or plenums with a combined design capacity greater than 2000 cfm, the return system shall be provided with smoked detectors. Section 606.2 states that smoke detectors are not required where the air distribution system is incapable of spreading smoke beyond the closing walls, floors and ceiling of the room or space win which the smoke is generated. If two or more systems serve a common space, but do not share common ducts or plenums, and each system has a design capacity of 2,000 cfm or less, no smoke detector is required. If their combined design capacity is > 2,000 cfm, and no single unit has a design capacity of 2,000 cfm or more, no smoke detector is required because they do not share common ducts or plenums. If multiple systems share common ducts or plenums and the distribution system is incapable of spreading smoke beyond the enclosure of the room or space where the smoke is generated, and then no smoke detector is required. Keywords: smoke detection system control. 602.2, 2012 MC 2) (Q) Is painting exposed galvanized duct allowed by code for weather protection? (A) Weather protection would not be required if the ductwork installation is approved by the manufacturer for outdoor locations. Ref: 303.6, 603.1, MC 2012 3) (Q) Does a filter box have to be manufactured of can it be constructed in the shop of the Mechanical Contractor? (A) The Mechanical Contractor may construct the box to meet the code. 603.1, 2012 MC 4) (Q) What method can be used to protect the openings in a floor/ceiling or roof/ceiling assembly where supply air duct from the HVAC unit penetrates the membrane of the assembly? The type of occupancy is R2 multi-story with type V construction. Note: The Mechanical Code calls for either a shaft, 607.6.2 #1, or a listed ceiling radiation damper installed at the ceiling line, 607.6.2 #2, and a listed ceiling radiation damper installed at the diffuser with no duct attached 607.6.2 #3 (supply plenum). 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red (A) There is an issue that needs to be addressed with 607.6.2 #2. UL 555C and 607.3.1 would require the radiation damper to have dynamic closure because the unit fan will continue to run in a fire or smoke condition. 607.3.1 States; “Only fire dampers listed or labeled for dynamic systems shall be installed in heating, ventilating, an airconditioning systems designed to operated with fans on during a fire.” There is no shut down required by code for the fan of an air handler in an apartment HVAC system for example, therefore, the code and UL 555C require a dynamic type damper for this installation. Per current DOI information a dynamic radiation damper listed for mounting in the membrane ceiling of the penetration shall be used. As an alternate method the air handler must be shut down in case of fire. This can be accomplished by installing a smoke detector in the room adjacent and open to the air handler. You are no longer required to tie it into the smoke detector system of the apartment unit. If you opted for the smoke detector you still are required to protect the penetration with a radiation damper, however, since you have provided a means to shut the air down via the smoke detector you can install a standard radiation damper with static and not dynamic closure. These are the only two methods approved at the present time. Ref: 607.6.2 #2, 607.3.1, UL 555 C, 2012 MC CHAPTER 11 REFRIGERATION 1) (Q) What is the proper procedure to use for changing out the outside condenser only in a mixed system where the old evaporator continues to be used? Current system refrigerant is R22 and the new refrigerant will be R 407 C. (Both are Class A1) (A) Recovered refrigerants shall meet 1102.2.2.2 requirements. 1101.8 notification of code Official of change of refrigerant. 105.5 equipment re use. 304.1 manufacturers data req’d. See also 301.1.1, All references in this answer are from the 2012 MC . GENERAL INFORMATION (Admin. Code/ Mech. Code Admin. Section/ Policy) 1) (Q) Are permits required for B vents when a re-roof permit is pulled for a building with gas flues penetrating the roof? 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red (A) Yes. Alteration of the vent will require a permit. Ref: (102.1/GS 87-21/GS 153-327 Admin. Code), (102.9 2012 MC). A letter is on the Meckpermit.com web site under the Mechanical Section click on “news and updates” there is a link on that page for the reroof permit requirements. 2) (Q) Unitary equipment is being installed in a hotel room. E.g. ptac unit in a hotel. Are permits required for this installation? (A) If this is a like for like change out permits are not required. If it is a new installation it should have permits and inspections if it has a hidden drain/ electrical connection. Ref: 106.1 Administrative codes. 3) (Q) What types of installations do not apply to a refrigeration trade or business and are not required to be installed by a refrigeration contractor? (A) House Bill 1105 was recently passed by the General Assembly and signed into law by Governor Perdue. Changes to the law are summarized as follows: Section 1 provides that “refrigeration trade or business” does not apply to the following: (1) The installation of self-contained commercial refrigeration units equipped with an original equipment manufacturer (OEM) molded plug that does not require the opening of service valves; (2) the replacement of lamps, fuses and door gaskets; and (3) the installation and servicing of domestic house-hold self-contained refrigeration appliances equipped with an OEM molded plug connected to suitable receptacles which have been permanently installed and do not require the opening of service valves. 4) Situation per Designer: A couple of weeks ago we discussed an old (approx. 35 years) building (approx. 15,000 sq. ft.) utilizing the original hallway for the return. The ceiling is extremely tight and there is no real room or access or practical method for adding a return duct. It is served now by a couple of self-contained single zone units utilizing boiler hot water and condenser water. We want to replace the ancient units with split systems with the AHU installed in the same mechanical rooms, with condensing units on the roof and utilizing the same single zones – no changes to ductwork. There is really no other practical/efficient/cost effective way to replace the ancient units and get rid of the ancient boilers and cooling towers. We know we need to submit the mechanical, electrical, and structural but really need to know about the hallway return before we spend a lot of effort and money. When we 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red talked before you indicated that this hallway return could be grandfathered since it is very close to being like-for-like and there is no work other than replacing the central unit. (Q) Can we still utilize the hallways for returns? (A) Yes. Since you are doing away with an ancient cooling tower and boiler you we will need a split system with a condenser on the roof. There will be no changes outside of the mechanical room and roof. The installation will be allowed per the conditions specified. 105.3, 2012 MC 5) (Q) What are the current requirements for installing Carbon Monoxide detectors in residential single family dwellings, duplexes and townhomes? Is the requirement the same for commercial construction? (A) In general, a change out of fossil fuel equipment in a residence will require the addition of a Carbon Monoxide Detector per GS. CO2 detectors are currently required adjacent to each sleeping area per BCC rules. An all electric residence is exempt unless they currently have an existing attached garage or are adding a new attached garage or have or are adding a fireplace. If these conditions are present Carbon Monoxide Detectors are required even if they do not have fossil fuel equipment. Fossil fuel fired equipment such as a hot water heaters in a hut attached to the house are exempt from the CO2 detector requirements, however, a gas pack or other appliance that is communicating with the inside of the house is not exempt. The “special exemptions” only apply to single family dwellings, duplexes and townhomes. Not required for commercial occupancies. If a “plug in type or table model” Carbon Monoxide detector will be used the inspector shall have ready access to the detector on the premises. It must be in the box and readily accessible for the inspector. Having an empty box for the inspector or taping a box to the inside of a window is not acceptable. 6) (Q) What are the plan review requirements for compliance with the new energy code when a plan is submitted for an addition to a single family home to RTAC? The contractor is submitting plans for an addition. The plans show extending the existing duct and using the existing HVAC system. (A) RTAC will not be checking the plans for energy code requirements. 2nd Quarter Land Use and Environmental Service Agency (Code Enforcement) NC Mechanical Code 2012 st 1 Quarter Q&A in Brown, 3rd Quarter Q&A in blue nd th 2 Quarter Q&A in green, 4 Quarter Q& A in red 7) (Q) What tools are currently available to help inspectors with Energy Code field compliance? (Ref. Dept. of Energy information below, will discuss DOI information under training information later on the agenda) (A) Per the meeting on energy code on Friday May 18th at the Dept of energy site has both a residential and commercial checklist for the IECC codes. See the link below. http://www.energycodes.gov/arra/compliance_checklists.stm 8) (Q) (1) Would the 2012 Energy Code require the inspector to witness a duct leakage test for a single family dwelling? (2) Is a whole house or partial blower door test required to be witnessed by the inspector? (A) (1) No. 402.4.2 EC (2) Yes. 4032.2 EC 2nd Quarter Land Use and Environmental Service Agency