Mecklenburg County Engineering & Building Standards
Plumbing Q & A (2000)
Attention: 4 Denotes a new/revised question!
General:
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August 2000
(Q) When are permits not required to replace a water heater?
(A) The following criteria MUST be met to be exempt from permitting
the replacement of water heaters.
GAS Water Heater Replacement:
1. Must be a Single Family (detached) Residence.
2. NO change in the water heater location.
3. NO change in water heater BTU’s.
4. NO change in gas piping.
5. NO change in flue size or length.
6. NO change in gallon capacity.
7. NO change in energy (elec. to gas, etc.)
ELECTRIC Water Heater Replacement (see note):
1. Must be a Single Family (detached) Residence.
2. NO change in the water heater location.
3. NO change in water heater BTU’s.
4. NO change in element size.
5. NO change in gallon capacity.
6. NO change in energy (gas to elec., etc)
Note: The replacement of an electric water heater will always
require an electrical permit even if the other criteria are met. ALL
commercial, apartments, townhomes and condominiums will
require two (2) permits to replace the water heater (i.e. Plumbing,
+ Mech. or Elec.).
(Q) May courses of block/brick for a water heater support be dry stacked?
(A) NO! All courses of brick or block must be mortared together.
Paruging of brick or block is not acceptable.
(Q) Are installers/contractors allowed to cut wood framing when installing
or replacing Plumbing or systems or equipment?
(A) Yes! Provided that proper heading off of cut members/timbers is
properly completed. The plumbing inspector may require framing to
be inspected (permit) by the building inspector.
(Q) What is the definition of a scullery sink?
(A) A scullery sink is used to wash pots and pan (i.e., pot wash
sink.)
(Q) May a abandoned septic tank be used to house a new sewer lift
pump?
(A) Yes provide that the baffles are removed, the tank
discharge opening capped, access to finish grade to facilitate pump
removal/replacement, and concrete floor (smooth) sloping to the
pump at 1 inch per/foot or more.
Mecklenburg County Engineering & Building Standards
Plumbing Q & A (2000)
Drainage:
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(Q) How close to the p-trap may a fixtures air admittance valve (AAV) be
installed?
(A) No closer than 2 pipe diameters. (ie, 1 ½ “ trap = 3 “ between trap
weir and AAV)
(Q) Do glue type trip waste assemblies (toe tap type) require an access
panel?
(A) No! The only type of trip waste assembly requiring an access
panel is one with slip joints.
(Q) May a “two clean-out” be used in conjunction with a backwater valve?
(A) No! Other clean-out provisions must be made. Damage could
result to backwater valve when piping cleaned out.
Mecklenburg County Engineering & Building Standards
Plumbing Q & A (2000)
Water Distribution
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(Q) How much metallic pipe is required at the water heater inlet and outlet
when a PEX water pipe system is installed?
(A) The Code requires you to install the system per manufacturer’s
installation instructions. These instructions require that 18” of
metallic pipe be installed in the hot and cold sides of gas or electric
water heaters. Contractors may shorten the amount of metallic pipe
after providing proof from published manufacturer’s installation
instructions.
(Q) What type of flux is required by the code?
(A) The code requires flux to meet ASTM B813, which is a water
soluble flux.
(Q) What type of tempering valve is required to control temperature at a
public lavatory?
(A) The device must meet ASSE 1016.
(Q) Where are ASSE 1017 tempering devices allowed?
(A) ASSE 1017 devices are allowed to temper water to equipment or
reduce water temperature to areas or portions of structures, but they
are not allowed to control the end use temperature to lavatories or
showers.
(Q) Are ASSE 1016 tempering devices required on water heaters used for
heating and domestic use in residences?
(A) Yes! The domestic hot water piping would require isolation (asse
1016 device) from the hot water feeding the air handling equipment.
(Q) Are tub or showers required to be installed on the rough?
(A) DOI states that it would be advisable but not required in that
other parts of the distribution system are not tested on the rough
(i.e., water heater, faucets, etc.) Many manufacturers state that their
valves/faucets are rated for less pressure that the distribution test
pressure (example: 60 lbs.) and o-rings or packing may not stand a
100 psi test. The contractor is responsible for any joints where they
opt to install valves after the rough distribution test.
Mecklenburg County Engineering & Building Standards
Plumbing Q & A (2000)
Venting
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(Q) What are the requirements/restrictions on installations where the soil
stack is in close proximity to the water closet and it is advantageous to
utilize an upright wye for venting the group?
(A) The branch of the upright wye shall be within 24” of the floor.
The continuation of the stack to the water closet shall not offset
more than 45° from vertical. Offsetting more than 45° from vertical is
no longer vertical but horizontal and would require re-venting the
horizontal pipe continuing to the water closet.
Mecklenburg County Engineering & Building Standards
Plumbing Q & A (2000)
Misc.
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(Q) What is required for “Future Plumbing” in homes with unfinished
basement areas?
(A) Contractors may install below slab drainage waste piping,
looped water piping and sewage pump tanks (no pump) without
finishing above slab drainage or water piping. A future vent
connection (2” min.) must be provided for the future upfit. Future
sewage pump discharge and water distribution connection is not
necessary provided the building drain and water distribution system
can be accessed later without damaging the building elements. The
installation of the sewage pump will require the completion of ALL
rough plumbing systems (DWV, WD, PUMP & CONTROLS).
Mecklenburg County Engineering & Building Standards
Plumbing Q & A (2000)
Fixtures
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(Q) Is it permissible to offset the trip waste/overflow assembly of a tub?
(A) YES! The trip waste/overflow assembly may be offset to one
side with the use of 1/8 or 1/16 bends (2 max.). The use of bends
exceeding 45° is prohibited.
(Q) Are overflows required on garden tub?(Reprint 1999)
(A) Overflows are required on tubs( Vol. VII, sec. 3215.1)! Whirlpool
type tubs DO NOT require overflows (Vol. VII, sec. 3222.2)
(Q) May “Bottled Water Dispensers” be used to meet the fixture
requirements of table 407?
(A) No! Must be a part of the building amenities, not contractual.
(Q) In structures/occupancies with more than one break room sink, are
ALL sinks required to be handicap accessible?
(A) Yes!
(Q) Are restrooms and drinking fountains for swimming pools required to
handicap accessible?
(A) Yes!
(Q) What parts of a private restroom must be completed to meet the
“adaptable” part of the handicap code?
(A)
1) Clear floor space
2) Water Closet rough dimentions
3) Switches, mechanisms
4) Grab bar rough support
5) Shower curbs
(Q) Are “home offices” required to meet the handicap code?
(A) Yes, if you bring customers/staff (except spouse/children) to
your home/office. No, if you are the only person utilizing the
office.
(Q) May contoured seats be used on handicap designated water closets?
(A) Yes! Provided the meet the 16 ½” minimum requirement
measured at the forward 1/3 rd of the seat.
(Q) What is the definition of a laundry tray?
(A) A laundry tray is a sink used to wash clothes (i.e., laundry tub).
(Q) 11.6.1 (4) of Volume 1-C states that the flush mechanism must be
placed on the “wide” side of a water closet. Does this mean that the
handle must be on the right in restrooms with single water closets?
(A) No! The wide side of the fixture is the front and the narrow side
would be the sides. The handle may be on the right or left as long as
it is on the wide “front” side.
(Q) Does the handicap code apply to drinking fountains where a
owner/tenant chooses to install a drinking fountain in a type of occupancy
not requiring drinking fountains?
(A) Yes! They would have to comply unless they utilize a freestanding bottle water dispenser.