Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code 2011
Attention:  Denotes a new question!
 Denotes a revised/revisited question. March 2011
Chapter 1 Administration
Chapter 3 General Regulations
Chapter 5 Exhaust Systems
Chapter 7 Combustion Air
Chapter 9 Specific Appliances
Chapter 11 Refrigeration
Chapter 13 Fuel Oil Piping
POLICY
Table of Contents
0 Chapter 2 Definitions
3 Chapter 4 Ventilation.
1 Chapter 6 Duct Systems
0 Chapter 8 Chimneys & Vents
0 Chapter 10 Boilers, Water Htrs
0 Chapter 12 Hydronic Piping
0 Chapter 14 Solar Systems
1 OTHER
0
1
0
0
0
0
0
0
1) (Q) What are the requirements for systems installed in a flood plain?
(A) Section 301.13 states:
301.13 Flood hazard. For structures located in flood hazard areas, mechanical
systems, equipment and appliances shall be located at or above the design flood
elevation. Exception: Mechanical systems, equipment and appliances are permitted
to be located below the design flood elevation provided that they are designed and
installed to prevent water from entering or accumulating within the components
and to resist hydrostatic and hydrodynamic loads and stresses, including the
effects of buoyancy, during the occurrence of flooding to the design flood elevation
in compliance with the flood-resistant construction requirements of the
International Building Code.
301.13.1 High-velocity wave action. In flood hazard areas subject to high-velocity
wave action, mechanical systems and equipment shall not be mounted on or
penetrate walls intended to break away under flood loads.
See section 602.4 for similar the requirements covering the duct system.
2) (Q) Would the discharge line of an appliance condensate pump need to be protected
from freezing temperatures?
(A) Chapter 307 does not address the protection of condensate discharge lines
Installed areas subject to freezing temperatures however we would be remiss if
we did not require this protection in areas such as a ventilated attic space. Other
areas of concern would be where the line exits the foundation wall. We would
“recommend” that these installations be sloped downward and increased in pipe
size to limit blockages.

Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code 2011
Attention:  Denotes a new question!
 Denotes a revised/revisited question. March 2011
3) (Q) What type of access would be required on a boiler installation where the device
may be subject to vandalism or component theft?
(A) Chapter 306 covers the typical installation of equipment. Section 105.1
Would allow us the flexibility to allow alternative access on a case by case basis.
1) (Q) What is the minimum ventilation required for toilet rooms?
(A) Toilet rooms are not considered to be habitable space and so their ventilation requirements would be found in table 403.3 which would require mechanical exhaust and not natural ventilation.
Note:
We have allowed natural ventilation in the past and we will begin enforcing the mechanical ventilation requirement on permits obtained after April 1, 2011.
1) (Q) Does Mecklenburg County allow an alternative method for type I hood clearances?
(A) Mecklenburg County allows the use of NFPA 96 , Chapter 4.2.3.2 based on an interpretation by DOI dated 2/2/2004.
2) (Q) In an automotive repair garage with a vehicle exhaust source capture system
per NCMC 502.14, is it permitted to have one (1) –exhaust capture connection
for every two (2) bays or is one connection only allowed per bay?
(A) The Mechanical Code is silent on this question, however the code language
gives the inference that it requires a singular; “a source capture system”
for each vehicle or service bay. One per bay is required. Ref: 502.14
3)

(Q) Even though the code requirements have been met for the installation of the
grease duct the contractor wants to add several more cleanout openings because he
also has the maintenance contract on the grease duct system. The duct is only 10
inches by 10 inches and the code access door manufacturer informs him the
smallest door approved for grease duct installation per code is 12 inches by 12
inches. Can the contractor make his own door to access the grease duct?
(A) Yes. Where the duct is smaller than the 12 by 12 minimum the mechanical
contractor may provide cleanouts approved by the mechanical official at least
equivalent to the minimum requirements of the code for manufactured access
doors. Ref: 506.3.9

Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code 2011
Attention:  Denotes a new question!
 Denotes a revised/revisited question. March 2011
1) (Q) What method can be used to protect the opening in a floor/ceiling or
roof/ceiling assembly where supply duct from the HVAC unit penetrates
the assembly? NOTE: There is not a fire damper currently manufactured that
is approved for this application when the multi-story building is classified as an
R2 occupancy with type V construction.
(A) The current code approval for this application requires a smoke detector to be installed in the same room as the HVAC unit that will shut down the unit
if smoke is detected. The smoke detector shall tie in to the smoke detector circuit provided for the apt/condo unit. A static damper is required at the ceiling penetration of the HVAC duct penetrations from the unit. This method
of protecting the ceiling penetrations is only approved until a Fire Damper is
manufactured that provides adequate protection for the openings.
2)

(Q) What are the minimum requirements for plenum rated materials within an
open air plenum space?
(A) Not required. See plenum definition. Open air returns are typically in
habitable areas and do not have to conform to the material requirements of
enclosed plenums.
Example: Home Depot. Ref: Chapter 2 plenum definition. & 602.2.1
1) (Q) When is a refrigeration permit required?
(A) A refrigeration permit is required for any refrigeration equipment needing
to be assembled (excluding the walk-in cooler box) OR any equipment needing to be hard wired electrically (not plug type).
2)

(Q) Is the outside air make-up air duct located on the non-insulated side of an
attic in a single family dwelling required to be insulated?
(A) No. The temperature difference between the air in the make-up air duct and the air temperature in the attic are not sufficient to cause condensate that would require insulating the duct.
Ref: 503.2.7, Exception #2, North Carolina Energy Conservation Code

Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code 2011
Attention:  Denotes a new question!
 Denotes a revised/revisited question. March 2011
3) (Q) When does a Mechanical Inspector enforce the Carbon Monoxide Alarm
requirements adopted by the NC Department of Insurance in
One-and-Two-Family Dwellings and Townhouses? Effective date:
January 1, 2011
(A ) 2009 NC Residential Code revisions to Section R313 as provided below:
R313.1.1 Carbon Monoxide alarms. In new construction, dwelling units shall be provided with an approved carbon monoxide alarm installed outside of each separate sleeping area in the immediate vicinity of the bedroom(s) as directed by the alarm manufacturer.
R313.1.2 Where required-existing dwellings. In existing dwellings, where interior alterations, repairs, fuel-fired appliance replacements, or additions requiring a permit occurs, or where one or more sleeping rooms are added or created, carbon monoxide alarms shall be provided in accordance with
Section 313.1.1.
R313.1.3 The required carbon monoxide alarms shall be audible in all bedrooms over background noise levels with all intervening doors closed.
Single station carbon monoxide alarms shall be listed as complying with
UL 2034 and shall be installed in accordance with this code and the manufacturer’s installation instructions.
4)

(Q) Can R-4 insulated Flex be used in Icynene insulated attics where a thermal
Barrier is above the ductwork?
(A) Yes. It can be used as long as the attic is now part of the thermal envelope
and properly sealed. Ref: 503.2.7, NC Energy Conservation Code

Land Use and Environmental Service Agency
(Code Enforcement)
NC Mechanical Code 2011
Attention:  Denotes a new question!
 Denotes a revised/revisited question. March 2011
Color code below denotes the calendar year quarter of the question. Colors are left
to right; Brown-first quarter, Blue-Second Quarter, Green-third quarter & Red-forth quarter.