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CHAPTER 2 DEFINITIONS
1) (Q) While inspecting a lab set up for acid waste and vent piping in a medical office
building the inspector finds the acid waste piping system installed without the
minimum required vent sizing requirements for DWV per code. The inspector asks
for and receives the documentation on the engineered system. Should the
Inspector question the seal if a structural engineer seals the design document?
(A) Yes. Current code would require an engineer in his respective design profession to
seal the design. Under the 2012 Code it depends on whether the licensing board
deems them qualified by the state board rules and regulations. 2009 code:
“licensed to practice in his respective design profession” New Code: “registered
and licensed to practice professional architecture or engineering as defined by
statutory requirements…………” Ref: 2012 NCPC. Chapter 2 definitions Registered
Design Professional
CHAPTER 3 GENERAL REGULATIONS
1) (Q) An engineer has designed a gray water waste recycling system including all DWV
located in the basement of a single family dwelling. The system is designed to
allow full flow throughout the system so the engineer has decreased the
minimum pipe sizes of the DWV associated with the gray water system to one
pipe size smaller than the minimum code would allow. Would this
installation be allowed per the 2012 NC Plumbing Code?
(A) No. “All drain, Waste, and Vent piping associated with gray water recycling
systems shall be installed in full compliance with this code. “Ref: 301.3, (2012)
2) (Q) A contractor is installing a rain water recycling system. He explains to the inspector
that he is connecting indirectly to the sanitary drainage system so he does not have
to use the code minimum sizing requirements for the plumbing piping. Should the
inspector pass the rainwater DWV system?
(A) No. 2012 Code requires gray water and rain water recycling systems to meet
minimum code requirements for DWV. The drainage system cannot connect
indirectly to the sanitary sewer. Ref. 301.3 (2012)
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3) (Q) The plumbing contractor has installed a floor drain with a deep seal trap in the slab
at the bottom of an elevator shaft in a multi-story office building. The elevators
are all hydraulic type. Can this installation be approved under the 2012 code? Can
it be approved under the 2009 code?
(A) No. New code requires an oil water separator to be installed in the discharge line
of the floor drain. Ref: 301.6 (2012), 301.6, Exception. 2009 Code would not
require an OWS to be installed. Per research of hydraulic elevator fluid capacities
and spill probabilities an OWS mayl not be required by Mecklenburg County.
See Plumbing interpretations on the web site for current information.
4) (Q) The manufacturer of a new brand of AAV allows a 20 degree deviation from
vertical on the vents installed in an attic. If the plumbing code had a minimum
standard that only allowed an 18 degree deviation, which of the two installations
should be approved by the inspector?
(A) The code minimum shall be met because it is more restrictive. NCPC 2012 Ref:
301.7, Exception
5) (Q) The pump for a domestic hot water recirculation system is located below the
design flood elevation in the garage of a single family dwelling located close to the
ocean. Would this installation be allowed by the 2012 code?
(A) No. A pump for domestic water cannot be installed below the design flood
elevation. The exception allowing the pump in the 2009 code has been deleted
from the 2012 code. Ref: 2012 code see item 2 is deleted from the exceptions.
2012 NCPC [B] 309.2 Exception (deleted)
6) (Q) All permanently installed water closets in buildings are required to be in a separate
room or stall by the 2012 Plumbing Code. What are the two locations exempted by
the 2012 code?
(A) Child Care facilities and facilities where restraint is required per the building codes.
Ref: 2012 NCPC 310.4, exception 3.
7) (Q) An inspector is witnessing the testing of the plumbing system on a single family
dwelling. The dwelling has several shower installations. The inspector has turned
the job down because the plumbing contractor has not provided a shower pan liner
test. Is this a required inspection under the 2009 Plumbing Code? Is it a required
inspection under the 2012 Plumbing Code?
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(A) The 2012 code test procedures require a shower pan test. REF: 2012 NCPC
312.9. The 2009 code did not address shower pan testing.
CHAPTER 4 FIXTURERS, FAUCETS AND FIXTURE FITTINGS
1) (Q) An inspector is called to re-inspect an apartment that has been recently occupied.
The apartment is one in a newly completed complex of over 100 units. While
inspecting a new water connection the inspector notices the water heater
temperature is set at 140 degrees. What should the inspector do per the 2012
code?
(A) The inspector should inform the tenant, contractor and landlord that an anti- scald
valve is required if the temperature is set above 120 degrees in the dwelling
unit. Ref: 424.3, 102.9
CHAPTER 6 WATER SUPPLY AND DIDTRIBUTION
1) (Q) An underground combined water/fire service line is installed to supply both fire
sprinkler and potable water to a building.
A) Can the FDC (Fire Department Connection) to the building be installed on the
potable water side of the water service piping?
B) Is protection required for Fire Hydrants when FDC branch lines are located
remote from the potable water supply line.
(A) A) No. The potable water shall be protected from the sprinkler water in the
building by a backflow device that meets the code. The combined line shall
meet the requirements of the State Plumbing Code first for protection, material
and testing. Once that has been done the Fire Code requirements shall be met.
Ref: 608.13
B) Yes. When Fire Hydrants or other Fire Apparatus are located on the potable
water supply and the main water line shall be protected from the turbid water
that is located in the water line to the hydrant by a backflow device meeting
minimum code. The backflow device shall be installed on the FDC branch as
close as possible but no more than 10 feet away from the branch connection to
avoid turbid water from entering the domestic water line and contaminating the
potable water. Ref: 608.5, 608.13
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2) (Q) The specifications for a new commercial building call for Polybutylene (PB) water
service and water distribution pipe to be used on a project permitted under the
2012 Plumbing Code. Should the plans examiner approve this material?
(A) No. The 2012 code has removed PB from the list of approved material for water
service piping. Ref: Table 605.3, table 605.4
3) (Q) Sanitary Sewer piping cannot have restrictions to flow because of the waste build
up and eventual clog that results from the restriction either in pipe size reduction
or using a fitting with shoulders that would disrupt flow. Would the 2012 code
require the same restrictions on water pipe fittings?
(A) Yes. “fittings shall not have ledges, shoulders or reductions capable of retarding or
obstructing flow in the piping.” Ref: 605.5
4) (Q) Is cross link aluminum PEX allowed in the 2012 code for water distribution, water
service and fittings?
(A) Yes. See 605.21, 605.21.1, and tables 605.3, 605.4 and 605.5
5) (Q) A Would a stop- and- waste valve be allowed under the 2009 code? B. Would a
stop-and –waste valve be allowed under the 2012 code?
(A) A. No. Not allowed 608.7 2009 NCPC
B. Yes. See 608.7 Exception NCPC Freeze proof yard hydrants that drain the
riser into the ground shall be permitted to be installed, provided that the
potable water supply to such hydrants is protected upstream of the hydrants
in accordance with Section 608 and the hydrants are permanently identified as
no potable outlets by approved signage that reads as follows: “Caution, Non
potable Water. Do Not Drink.”
CHAPTER 7 SANITARY DRAINAGE
1) (Q) An engineering firm has submitted plans to construct a building with a large
meeting room located in a park in Mecklenburg County. The meeting room will be
rented by the parks department for meetings and social occasions. Neither the
parks department nor the health department(food services) will allow food to be
prepared on the site. The prep area contains a 3 compartment sink and a six
burner residential range with a type 2 hood. The waste for the building is drained
into a septic tank. Septic tank installations are required to be approved by the
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Mecklenburg County Groundwater and Wastewater Dept. (GWWD) The
GWWD dept. will not require a grease interceptor on the site. The Code
enforcement department will require a point of use interceptor at the 3
compartment sink. The GWWD rules require the interceptor, if installed, to be
installed outside the building and meet their installation requirements. The
designer is looking for direction to try to comply with the two department
requirements. What should be done to resolve the conflicts between the two
departments?
(A) As with the minimum building codes the most restrictive requirements shall apply.
The grease interceptor is required. It has to meet the minimum standards of both
the GWWD and the Mecklenburg County Code Enforcement Department code
minimums. The sanitary waste and vent system installation is required to be
permitted and inspected by the code enforcement department up to the
connection at the septic tank. Ref: 701.1, 701.2
2) (Q) An AAV is installed on a plumbing vent. The AAV is specified from the
manufacturer for multiple applications. The 1(1/2) inch AAV may be installed
directly to a 1 (1/2) inch pipe (outside) or glued (inside) a 2 inch pipe. Does the
installation meet code and manufacturers recommendations?
(A) No. The manufacturer of the pipe will not allow gluing a fitting on the inside the
pipe. Ref: 702.4
3) (Q) The water service has been completed on a project, however, while installing the
sanitary sewer line the contractor runs into a problem. FYI: (The water service
line is crossing the water line at 90 degree angle.) The water line installation will
not allow the proper slope on the pipe to meet the code per the DFU calculation.
The engineer wants to replace the 4 inch sewer line with an 8 inch line so the
water service will not have to be re-done. With this fix the sewer line will meet
code per the slope requirement and miss the water service line. A. Would this
be allowed by code? B. If no. What are acceptable alternatives that will meet
code?
(A) A. No. 704.1 The “scouring velocity” of the piping cannot be maintained when
using an 8 inch pipe. B. To keep solids suspended a slope with a velocity of 2 feet
per second must be maintained. To use this alternate method the engineer will
have to provide calculations in a sealed letter that show the slope can be reduced
and still maintain the 2fps velocity required to meet minimum code. The 2fps
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allowance is in the code commentary and the NCDNR site utility requirements.
The contractor can re-route the water line as an alternate to providing the
calculations. Ref: 704.1
CHAPTER 8 INDIRECT/SPECIAL WASTE
1) (Q) An indirect waste receptor (hub drain) is installed above a drop ceiling collecting
condensate from an air handler. Should the inspector approve or disapprove the
job under any or all of the following conditions:
a. The hub drain has a deep seal trap.
b. The hub drain has a deep seal trap and is trap primed from the tail piece of a
bathroom lavatory from the floor above.
c. The contractor installs a metered water line directly to the trap as a primer.
d. The hub drain is installed in a return air plenum ceiling.
e. The hub drain is accessible from a pull down stair.
f. The hub drain is in an attic that has a permanent stair.
(A) (a-e disapproved) f. approved. Ref: 2009-802.3, 2012-802.3 “Ready access.”
CHAPTER 10 TRAPS, INTERCEPTORS, AND SEPARATORS
1) (Q) I am the plumbing engineer on the new Ralf and Sons restaurant. Does your
department size the grease interceptor for our restaurant? Can a hand sink be
indirect and go through the interceptor?
(A) Our policy is that the engineer sizes, specifies and seals the Grease interceptor.
We don’t get into interior vs. exterior; we just say that we require any drains such
as flat floor drains in the food prep area, pot sinks/3 compartment/food prep/
sinks/ & dishwashers are required to go thru the Interceptor. We request that any
clear water waste,( i.e.: hand sinks/ice machine condensate in hub drains), go
directly to sanitary, this keeps the size of the Grease Interceptor to a minimum to
assist the utility dept. The engineer should go by the manufacturer’s instructions for
sizing the interceptor and provide cut sheets with the plans. See dept guidelines on
the web site. Ref: 1003.3.1
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APPENDIX REQUIREMENTS
1) (Q) Does the 2012 code regulate swimming pool piping, process piping systems, utility
owned piping systems or rain water recycling systems?
(A) Only rain water recycling systems of the four listed. (Appendix C1 mandatory).
See also page VII.
GENERAL REQUIREMENTS, POLICY, ADMINSTRATIVE CODE
1) (Q) Plumbing permits are currently required for repairs when breaking a trap seal
"Unsafe conditions", does this include all traps?
(A) Yes, permits are required for breaking ALL trap seals. (Admin 102.4)
2) (Q) The new 2012 plumbing code has words italicized in the code text. The 2009 did
not have this feature. A. What does it mean when a word within a paragraph in
the body of the code is italicized? B. It is confusing that some of the same words
that are italicized in one paragraph of the code text are not italicized in other
paragraphs. Did the code writer just miss some words and not others?
(A) Page VI of the new code describes how to understand the italicized words.
A. When a word is italicized in the code text it means it has the exact meaning as
the definition in chapter 2 of the code.
B. If the word is in the definition but not italicized in the code text it does not
have the same exact meaning as the definition.
3) (Q) If the code has a bracket in front of the code text ([B] for Building Code for
instance) does that mean the Building inspector should enforce that section of the
code?
(A) No. The bracket beside the code text means a committee other than the
Plumbing Code change committee is responsible for the change. Enforcement is
still the responsibility of the plumbing plan reviewer or inspector.
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