Land Use and Environmental Service Agency (Code Enforcement) Mechanical Q&A 2009

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1 General: 1) (Q) What does a contractor/permit holder have to supply for an inspection? (A) Section of the NC Administrative Code states that it is the duty of the permit holder to provide access to and means for inspection of the work for any inspections that are required by this code. 2) (Q) An existing home with a package unit, installed prior to the requirement for lintels where the duct penetrates the foundation wall is being replaced with equipment and duct of the same size. Would a lintel have to be installed at this time? (A) No, provided there is no increase in size of the foundation opening. 3) (Q) The Mecklenburg County inspection department preaches strongly about how hard it works to combat inconsistency in inspections and interpretations. When are you going to be consistent with other counties? (A) Mecklenburg County Code Enforcement prides itself on achieving a high level of consistency within the confines of Mecklenburg County. We however do not have authority over other counties or the decisions they render. We make interpretation recommendations and/or requests to the NC Department of Insurance from time to time and will continue to do so in and effort to provide consistent code enforcement within Mecklenburg County. 4) (Q) What is the inspection department s policy on wearing hard hats on construction sites? (A) We are to wear hard hats anywhere job sites are posted Hard Hat Area! 5) (Q) Is a permit and inspection required when replacing or installing a free standing appliance? (A) Yes, if the appliance is directly connected to the building utilities and just plugged into an outlet. 6) (Q) How do you calculate the ventilation rate for an upfit that contains multiple types of uses? (A) You split the upfit s square footage into the various uses before applying table ) (Q) Is on demand ventilation design allowed under section of the 2009 NC Mechanical Code? (A) The designer does have prerogative to use on demand as the criteria for their design provided the system has the capacity to achieve the ventilation rate prescribed in table 403.3, the sensors used are correctly placed (plenum, near return, etc.) and the primary 2 nd 1 st

2 General continued: contaminant is carbon dioxide. Occupancies such as a hair solon would not be suitable for on demand ventilation design. (Designs will be evaluated on a case by case basis and it will be the responsibility of the designer to convince the code official that the design meets intent of section 403)

3 Equipment: 1) (Q) Are hinges required on roof mounted exhaust fans ( )? (A) If the exhaust system has code approved cleanouts and removal of the exhaust fan for duct cleaning is not necessary, then a hinge would not be required. 2) (Q) Does equipment installed in an enclosure, accessed by a louvered door, have to be supplied with a high and low combustion air duct? (A) The louvered door can not be used to meet the combustion air requirements (per DOI). Transfer ducts or ducts to the outside are acceptable. 3) (Q) Is a well acceptable to achieve the termination (clearance to grade) requirements on a downdraft exhaust for a domestic range? (A) In cases where there is no possible alternative to achieve the required clearance to grade, a well with positive drain to open air may be provided. 4) (Q) Does the Code require that combustion air openings be screen for pest control? (A) Section , item #5 of the NCFGC prohibits screening of ducts terminating in the attic. 5) (Q) What is the definition of an alcove/closet as it applies to required combustion air openings? (A) An alcove or closet applies to a space typically large enough to accommodate the appliance only. A space containing a sink with standing room would NOT be considered an alcove or closet. 6) (Q) May two water heaters piped together be placed in an alcove, one in front of the other? (A) Yes, provided that both equipment s controls are fully accessible for service or replacement without removing the other water heater. 7) (Q) Would the 16 rule apply to a roof whose slope exceeds the 3 in 12 limitation listed in section 306.5? (A) Actually the Code in section is addressing two different issues. 1. Section When the roof or elevated structure exceeds 16 in height, a permanent means of access (steps/ladder) shall be provided. 2. Section When the slope of the roof exceeds 3 units in 12 units, a platform and railing is required for equipment needing periodic servicing. A catwalk may be required to provide access between the equipment platform and the roof access. 2 nd

4 Equipment continued: 8) (Q) Do decorative appliances such as fire rings, fire bowls, fire pits or fire fountains have to be listed? (A) Yes 9) (Q) Are low voltage electrical permits required for a residential furnace replacement? (A) The mechanical permit covers associated low voltage devices typically installed by the mechanical contractor. Replacement of an HVAC thermostat would be considered service work and no permit would be required. 10) (Q) What is the required scuttle access required for a residential equipment replacement? (A) The access door would have to be large enough to remove the largest component. 11) (Q) May HVAC equipment be turned such that the equipment could be serviced from the steps of a disappearing stair? (A) No. The intent of the Code is to provide the technician a safe area from which to work. The intent of exception 1 of section is to access the appliance through a scuttle opening either standing on the ground, lift, scaffold or ladder. Note: The definition: Disappearing stairs are any configuration for stairs that can be used to move from one floor to another, but is not fixed in place permanently. Some designs for these types of stairs call for retracting sections that fold and can be recessed in the floor between the two levels. Other designs call for stairwells that fold to a more or less flat position against a wall.

5 Gas Piping: 1) (Q) May a contractor use the merchant coupling provided with each stick of gas pipe, to assemble the permitted gas piping system? (A) The NC Gas Code does not prohibit the use of all thread merchant couplings. 2) (Q) How many gas tests are required for a single gas pipe installation? (A) The Code would require two tests. One before you cover the work and one on final inspection. We require an additional test if you would like temporary heat which would result in a total of three. 3) (Q) Does gas piping have to be steel where the piping terminates at the meter? (A) The Code does not require a steel termination, but many gas utility providers (Piedmont Natural Gas) will refuse to connect to CSST or copper piping. 4) (Q) May the valve for a free standing range be placed behind the range? (A) Yes. The valve is for servicing and does not have to be placed where it can be accessed without moving the appliance. 5) (Q) Does the Code require a cut-off to be placed at the base of decorative gas yard lights? (A) Yes! The light is considered an appliance and would require a cut-off within 6 feet and accessible (box/vault). 6) (Q) What is the minimum length for an appliance drip leg (sediment trap)? (A) Drip legs shall be a minimum of 3 long or per the equipment and/or regulator manufacturer s installation instructions, whichever is greater. 7) (Q) How do you test a new gas line extension or branch, added to an existing gas line within the structure? (A) Section (2009 NC Gas Code) states that only the new branch has to be tested. Section states that you must use two valves in series with a telltale piece, with valve, between the two valves to vent any pressure. 1 st 2 nd

6 Duct: 1) (Q) What does the new 2009 Energy Code require for duct insulation? (A) Section 403. of the NC Energy Code states residential supplies and returns shall be R8 in unconditioned areas. Duct running through the web of floor truss systems may be R6 to limit duct compression. Duct installed between conditioned floors need not be insulated provided there is no condensation. Commercial supplies and returns shall be R5 in unconditioned areas. Commercial outside duct shall be R8. 2) (Q) The new 2009 NC Mechanical Code requires that grease duct be tested with a light. How will this be accomplished? (A) The contractor/installer shall call for an inspection after the job is ready for inspection. The ladders should be in place, the drop cord/light shall be fished through the duct and any obstacles such as fans or grills that might obscure the inspection shall be removed. The light inspection will commence upon arrival. Should the contractor have concerns about open duct or would like the inspector on the job for more time, the contractor may secure an inspection by appointment (Call J. Aidoo (704) ). 3) (Q) What are the new requirements for duct wrap on type I grease exhaust in lieu of shaft requirements? (A) In January 2009 UL, OPL and ICC-ES withdrew the listing and Legacy reports for enclosure materials that used UL1978 as the basis for approval instead of the more appropriate ASTM E2336 standard. Projects with permits issued on or after May 1, 2009 will be required to meet the ASTM E2336 standards. 4) (Q) Is flex duct allowed in a residential garage? (A) HVAC systems whose equipment room is located within the garage shall be constructed of metal (26 gage, Minimum) for all portions located within or penetrating the rated floor or ceiling. Systems that serve the living area shall not supply or return from the garage. Systems dedicated to the garage with not portions penetrating the rated enclosure may be of duct board or flex duct. 5) (Q) What are the requirements for an exhaust fan serving a shaft with 22 inch subducts from the several floors of bath rooms. (A) The fan must be located at the top of the shaft, operate continuously, and be connected to emergency power. 1 st 2 nd

7 Duct continued: 6) (Q) When does an architectural ceiling made of decorative lattice become a smoke or fire contaminant as it pertains to return plenums? (A) When it is placed above the height of the walls in the room it serves which would be classified plenum space. 7) (Q) Is there a minimum R rating for ventilation makeup air duct on a residential structure? (A) No 8) (Q) Would the Code require that this ventilation makeup air duct be filtered? (A) Yes 9) (Q) can a duct from an existing heating system be extended to a sun room addition? (A) Section of the NC Energy Code would allow the extension provided the duct was zoned.

8 Hoods and Exhaust: 1) (Q) What is the definition of light duty as it pertains to equipment exempt from exhaust hood requirements? (A) LIGHT-DUTY COOKING APPLIANCE. Light-duty cooking appliances include gas and electric ovens (including standard, bake, roasting, revolving, retherm, convection, combination convection/steamer, conveyor, deck or deck-style pizza, and pastry),electric and gas steam-jacketed kettles, electric and gas compartment steamers (both pressure and atmospheric) and electric and gas cheese melters. Exception #3 of section would allow a single light duty appliance to be exempt from a type II hood as long as the designer accounts for the load in the HVAC design. Note: We may allow a second Light Duty Appliance provided the total grease laden discharge does not exceed 5 mg/m 3 when tested to EPA ) (Q) How much area is required to be cleared at the termination of a residential dryer exhaust installed below grade? (A) The Code requires 200 square inches be cleared. 3) (Q) May wooden shelves be placed under a type I hood? (A) No