net occupiable floor area - Mechanical Inspectors of Michigan

Code changes to 2009 Michigan
Mechanical Code
Commercial Installations – Not 1 & 2
family residences – unless not
covered in MRC
Definitions Chapter 2
region within an occupied space
between planes 3 and 72 inches
(76 and 1829 mm) above the
floor and more than 2 feet (610
mm) from the walls of the space
or from fixed air-conditioning
ZONE. One occupiable space or
several occupiable spaces with
similar occupancy classification
(see Table 403.3), occupant
density, zone air distribution
effectiveness and zone primary
airflow rate per unit area.
Formerly known as the
Occupiable zone.
Definitions continued
NET OCCUPIABLE FLOOR AREA. The floor area of an
occupiable space defined by the inside surfaces of its walls but
excluding shafts, column enclosures and other permanently
enclosed, inaccessible and unoccupiable areas. Obstructions in
the space such as furnishings, display or storage racks and
other obstructions, whether temporary or permanent, shall not
be deducted from the space area.
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.
A/C Pads
• 304.10 Clearances from grade.
Equipment and appliances
installed at grade level shall be
supported on a level concrete slab
or other approved material
extending not less than 3 inches
above adjoining grade or shall be
suspended not less than 6 inches
above adjoining grade. Such
support shall be in accordance
with the manufacturer’s
installation instructions.
Condensate Disposal 307.2.1
Why is tool not being
used by certain
• 307.2.1 Condensate disposal.
Condensate from all cooling
coils and evaporators shall be
conveyed from the drain pan
• outlet to an approved place of
disposal. Such piping shall
maintain a minimum
horizontal slope in the
direction of discharge of not
less than one-eighth unit
vertical in 12 units horizontal
(1-percent slope).
• Added for A/C Coils
Good Bye ASHRAE Handbook of
• 312.1 Load calculations. Heating and cooling
system design loads for the purpose of sizing
systems, appliances and equipment shall be
determined in accordance with the procedures
described in the ASHRAE/ACCA Standard 183.
Alternatively, design loads shall be determined by
an approved equivalent computation procedure,
using the design parameters specified in Chapter 3
of the International Energy Conservation Code.
Chapter 4 is been completely
remodeled to a type of ASHRAE 62
• Section 403 & Table
403.3 Minimum
Ventilation rates has been
completely revised.
• Calculations is 3 -4 Step
process depending on
application .
• Time constraints will not
allowed to this to be
Intake opening 401.4
506.3.12.3 Termination location
• 3. Intake openings shall
be located not less than
3 feet below
contaminant sources
where such sources are
• located within 10 feet
of the opening.
• ( Previous 2 feet)
501.2.1 Location of Exhaust outlets
5. For specific systems see the following sections:
Clothes dryer exhaust, Section 504.4.
5.2. Kitchen hoods and other kitchen exhaust
equipment , Sections 506.3.12, 506.4 and 506.5.
5.3. Dust stock and refuse conveying systems,
Section 511.2.
5.4. Subslab soil exhaust systems, Section 512.4
5.5. Smoke control systems, Section 513.10.3
5.6. Refrigerant discharge, Section1105.7
Machinery room discharge, Section 1105.6.1
Revised for to facilitate code usage
Dryer Vent Penetration through ceiling
or wall Fire Caulked.
• 501.2.2 Exhaust opening protection.
Exhaust openings Exhuast openings
was moved to here from chapter 4
504.2 Exhaust penetrations. Where
a clothes dryer exhaust duct
penetrates a wall or ceiling
membrane, the annular space shall
be sealed with noncombustible
material, approved fire caulking or a
noncombustible dryer exhaust duct
wall receptacle.
Make up air required • 505.2 Makeup air required. Exhaust
hood systems capable of exhausting
in excess of 400 cfm (0.19 m3/s)
shall be provided with makeup air at
a rate approximately equal to the
exhaust air rate. Such makeup air
systems shall be equipped with a
means of closure and shall be
automatically controlled to start and
operate simultaneously with the
exhaust system.
Mixed Hoods
• 507.2.4 Extra-heavy-duty.
Type I hoods for use over
• extra-heavy-duty cooking
appliances shall not cover
• heavy-, medium- or lightduty appliances. Such
hoods shall
• discharge to an exhaust
system that is
independent of other
• exhaust systems.
Bath Fans in plenums.
• 601.4 Contamination
• Exception: Exhaust systems
located in ceiling return air
• plenums over spaces that are
permitted to have 10 percent
• recirculation in accordance
with Section 403.2.1, Item
4. The exhaust duct joints,
seams and connections shall
comply with Section 603.9.
Round duct joints
603.4.1 Minimum fasteners.
Round metallic ducts shall be
mechanically fastened by means of
at least three sheet metal screws or
rivets spaced equally around the
• Exception: Where a duct
connection is made that is partially
in accessible, three screws or
rivets shall be equally spaced on
the exposed portion so as to
prevent a hingeeffect.
Ducts in a garage
• 603.7 Rigid duct penetrations.
Ducts in a private garage and
ducts penetrating the
• walls or ceilings separating a
dwelling from a private garage
shall be continuous and
constructed of a minimum 26 gage
• galvanized sheet metal and shall
not have openings into the garage.
Fire and smoke dampers are not
required in such ducts passing
through the wall or ceiling
• separating a dwelling from a
private garage except where
required by Chapter 7 of the
International Building Code .
• 603.9 Joints , seams, and
• Exception: Continuously
welded and locking-type
longitudinal joints and seams
in ducts operating at static
pressures less than 2 inches of
water column pressure
classification shall not require
additional closure systems.
Chapter 7 abducted by Aliens (NFPA)
• 701.1 Scope. Solid fuelburning appliances shall be
provided with combustion air
in accordance with the
appliance manufacturer’s
• installation instructions. Oilfired appliances shall be
provided with combustion air
in accordance with NFPA 31.
Refrigeration Piping
• 1107.2 Piping location. Refrigerant piping that crosses an open
space that affords passageway in any building shall be not less
than 7 feet 3 inches
• 1107.2.1 Piping in concrete floors. Refrigerant piping installed in
concrete floors shall be encased in pipe ducts. The piping shall be
isolated and supported to prevent damaging vibration, stress and
• 1107.2 Piping location.
• Refrigerant penetrations. Refrigerant piping shall not penetrate
floors, ceilings or roofs. With exceptions……
Hydronic System Drain Down
• 1206.2 System drain down.
Hydronic piping systems
shall be designed and
installed to permit the system
to be drained.
• Exception: The buried
portions of systems
embedded underground or
under floors.
Radiant Heating sytems
• 1209.5 Thermal barrier
required. Radiant floor
heating systems shall be
provided with a thermal
barrier in accordance
with Sections 1209.5.1
through 1209.5.4. (R- 5
& Thermal break
required) Bubble wrap
won’t work either.
Other Changes not in the code
• Grease Duct
• 1. For uninsulated air
Enclosures UL
ducts and air connectors,
standard has changed.
disregard references to
• Double wrap required.
insulation and jacket.
• Flexible duct
instructions require
“beaded fittings”
• 2. Use beaded sheet metal
fittings and sleeves when
using nonmetallic clamps.
• 3. Use tapes listed and
labeled in accordance
with Standard UL 181B
and marked “181B-FX”.