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Comm 64.0401 Ventilation.
(1) VENTILATION REQUIRED.
This is department exception to the requirements of IMC section
401.2: Outdoor air ventilation by natural means or mechanical
shall be permitted to be omitted in large volume spaces containing
5,000 or more cubic feet per occupant.
(2) WHEN REQUIRED. Substitute the following wording for the
requirements of IMC
(a) Except as provided in par. (b), ventilation shall be provided
during the periods that the room or space is occupied.
(b) Mechanical exhaust ventilation shall be provided for natatoriums
even when the space or building is not occupied.
(4) INTAKE OPENINGS. (a) This is a department rule in addition
to the requirements in IMC section 401.4.1: The lowest side of
outside air intake required openings shall be located at least 12
inches vertically from the adjoining grade level, above adjoining
roof surfaces, or above the bottom of an areaway.
(b) These are department exceptions in addition to the requirements
in IMC section 401.4.1 and par. (a):
1. The setback distances as specified in IMC section 401.4.1
and par. (a) shall not apply to the combustion air intake of a direct
2. Where it can be demonstrated that an engineered system
design will prevent the maximum concentration of contaminants
brought in through the outside air intake from exceeding the maximum
contaminant concentration obtainable by providing the separation
distances in accordance with IMC section 401.4.1 and par.
(a), the outdoor air intakes may be located in accordance with such
engineered system design.
Note: See ch. Comm 82 for plumbing ventilator setbacks. That rule requires plumbing
ventilators to be 10 feet from air intakes and 10 feet horizontally from or 2 feet above roof
scuttles, doors or openable windows.
Note: See NFPA standard 45, Fire Protection for Laboratories Using Chemicals,
adopted under s. Comm 62.3500, for chemical fume hood exhaust location. Health
care and related facilities may have additional requirements.
(5) EXHAUST OPENINGS. These are department rules in addition
to the requirements in IMC section 401.4.2:
(a) Gravity ventilation ducts. Gravity ventilation ducts shall
extend not less than 2 feet above the highest portion of the building
within a 10−foot radius of the duct and shall be provided with a
siphon roof ventilator.
(b) Barometric relief ventilators. Where barometric relief ventilators are
installed on the roof, the discharge openings shall be no less than
2 feet above the roof surface where the ventilator pierces the roof.
(6) CONTAMINANT SOURCES. Substitute the following wording
for the requirements in IMC section 401.6: Stationary local
sources producing air−borne particulates, heat, odors, fumes,
spray, vapors, smoke or gases in such quantities as to be injurious
to health shall be provided with an exhaust system in accordance
with IMC chapter 5 or a means of collection and removal of the
contaminants. Such exhaust shall discharge directly to an
approved location at the exterior of the building.
History: CR 00−179: cr. Register December 2001 No. 552, eff. 7−1−02; CR
01−135: r. and recr. (4) (a) (intro.), cr. (4) (a) 4. and (b) 5., CR 01−139: r. and recr.
(4) (a) 3., am. (4) (b) 2. Register June 2002 No. 558, eff. 7−1−02; CR 06−120: r. and
recr. (1), (2) and (4) (a), r. (3), (4) (b) 2. to 4., am. (4) (b) (intro.), 1. and (5) (intro.),
renum. (4) (b) 5. to be (4) (b) 2. and am., cr. (6) Register February 2008 No. 626,
Comm 64.0402 Natural ventilation. This is a department
rule in addition to the requirements in IMC section 402: The
use of natural ventilation shall be permitted as specified in Table
History: CR 00−179: cr. Register December 2001 No. 552, eff. 7−1−02; CR
06−120: am. Register February 2008 No. 626, eff. 3−1−08.
Comm 64.0403 Mechanical ventilation.
AIR REQUIRED. (a) Substitute the following wording for the exception
in IMC section 403.2: Where it can be demonstrated that an
engineered ventilation system design will prevent the maximum
concentration of contaminants from exceeding the maximum
obtainable by providing the rate of outdoor air ventilation determined
in accordance with IMC section 403.3, the minimum
required rate of outdoor air may be reduced in accordance with
such engineered system design.
(b) This is a department rule in addition to the requirements in
IMC section 403.2: The outdoor air shall be free from contamination
of any kind in proportions detrimental to the health and comfort
of the general population exposed to it.
(3) RECIRCULATION PROHIBITED. Substitute the following
wording for exception 3 in IMC section 403.2.1: Where indicated
in Table 64.0403, recirculation of air from such spaces is prohibited.
All air supplied to such spaces shall be exhausted, including
any air in excess of that required by Table 64.0403.
(4) RECIRCULATION OF AIR. This is a department informational
note to be used under IMC section 403.2.1:
Note: The following are examples where the department will accept air transferred
from: corridor to toilet room; corridor to cloak room or janitor closet; dining
room to kitchen; locker room to toilet room; gymnasium to locker room; showroom
to garage; and corridor to school vocational shops.
(5) TRANSFER AIR. Substitute the following wording for the
requirements in IMC section 403.2.2: Except where recirculation
from such spaces is prohibited by Table 64.0403, air transferred
from occupied spaces is not prohibited from serving as makeup air
for required exhaust systems in such spaces as kitchens, baths, toilet
rooms, elevators and smoking lounges. The amount of transfer
air and exhaust air shall be sufficient to provide the flow rates as
specified in IMC sections 403.3 and 403.3.1. The required outdoor
air rates specified in Table 64.0403 shall be introduced
directly into such spaces or into the occupied spaces from which
air is transferred or a combination of both.
(6) VENTILATION RATE. Substitute the following wording for
the requirements and exception in IMC section 403.3:
(a) Ventilation rate determination. 1. Except as provided in
sub. (2) (a) and s. Comm 64.0300, a mechanical ventilation system
shall be designed to have the capacity to supply a minimum
outdoor airflow rate of 7.5 cfm per person as determined in accordance
with Table Comm 64.0403 based on the occupancy of the
space and the occupant load or other parameters stated therein. A
mechanical ventilation system shall be designed to have the
capacity to exhaust air as specified in Table Comm 64.0403 except
as provided in par. (c).
2. a. Except as provided in subd. 2. b. to d., the occupant load
utilized for design of the ventilation system shall not be less than
the number determined from the estimated maximum occupant
load rate indicated in Table 64.0403.
b. The estimated maximum occupant load rate may be determined
using other means with justification acceptable to the
department to show that a different number of occupants is reasonable.
c. Where there is no value indicated for the net square feet per
person in Table 64.0403, the actual number of occupants shall be
used to determine the required amount of outside air.
d. Ventilation rates for occupancies not represented in Table
64.0403 shall be determined by an approved engineering analysis,
or by using the most similar occupancy in the table.
(b) Adjacent spaces with differing ventilation requirements.
1. Except as provided in subd. 2., spaces with different ventilation
requirements shall be provided with a complete solid separation,
or the most stringent ventilation requirement shall apply to all
2. The separation as specified in subd. 1. is not required where
an engineered ventilation design system will prevent the concentration
of contaminants from exceeding that obtainable by providing
a physical separation.
(c) Exceptions for certain occupancies. 1.‘Toilet rooms.’ A
toilet room that has only one water closet or urinal and no bathtub
or shower may be provided with either natural ventilation via a
window or louvered opening with at least 2 square feet of area
openable directly to the outside or mechanical exhaust ventilation
as specified in Table 64.0403.
2. ‘Janitor closets.’ A janitor closet that has only one service
sink may be provided with either natural ventilation via a window
or louvered opening with at least 2 square feet of area openable
directly to the outside or mechanical exhaust ventilation as specified
in Table 64.0403.
3. ‘Locker and shower rooms.’ An adjoining locker room,
shower room and toilet room shall be exhausted at the rate specified
in Table 64.0403 based on the largest amount of exhaust
required for any of the three rooms. A negative pressure relationship
shall be maintained in the shower and toilet rooms with
respect to the locker room.
4. ‘Chemical or septic toilets.’ Chemical or septic toilets and
composting privies are prohibited in spaces under negative pressure.
Toilet rooms with chemical or septic toilets shall be provided
with natural ventilation via a window, louver or skylight with at
least 2 square feet of area openable directly to the outside. The
opening shall be provided with a screen to limit the passage of
insects and vermin.
5. ‘Pool ventilation.’ In a natatorium, the volume of supply
air and exhaust air may be reduced to a minimum of 1 cfm per
square foot of pool surface provided automatic humidity controls
perform so as not to create accelerated building material deterioration
from moisture condensation.
(7) SYSTEM OPERATION. Substitute the following wording for
the requirements in IMC section 403.3.1: The minimum flow rate
of outdoor air that the ventilation system must be capable of supplying
during its operation may be based on the rate per person
indicated in Table 64.0403 and the actual number of occupants
(8) COMMON VENTILATION SYSTEM. (a) This is a department
alternative to the requirements in IMC section 403.3.2: Where
multiple spaces having different ventilation rate requirements are
served by a common ventilation system, the minimum amount of
outdoor airflow supplied by the ventilation system shall equal the
total outdoor airflow required for each space if each space is provided
with minimum air changes in accordance with this subsection.
(b) 1. Except as provided in subd. 4., an air change rate of 6
air changes per hour shall be provided in each space.
2. The air change air rate under this subsection shall be determined
upon either the actual height of the space or 10 feet from
the floor level of the space which ever is less.
3. The air movement providing the required minimum air
change shall be that amount that is transferred through the air handling
equipment where the return air is diluted or replaced with
outside air and supplied back to the space.
4. a. Air change rate of less than 6 air changes per hour is permitted
where mechanical cooling is provided to maintain an interior
design temperature of 78oF or lower. The air change rate may
not be less than the minimum air changes rate per hour specified
in Table 64.0403.
b. Air changes are not required to be provided for spaces
required to be mechanically exhausted.