|
INDOOR
AIR QUALITY |
| Application |
4.70 |
Sections 4.71
to 4.80 apply to indoor or enclosed areas when occupied
by workers, except |
|
|
(a) a controlled atmosphere enclosure,
|
|
|
(b) a confined space, and
|
|
|
(c) when clearly impracticable, such
as during some construction or renovation projects.
|
| Submitting
plans |
4.71 |
An employer or
the employer’s agent must submit to the board drawings
and specifications for an existing or proposed
ventilation system when requested by the board. |
| Design and
operation |
4.72 |
(1) An employer must ensure that a
ventilation system for the supply and distribution of
air and removal of indoor air contaminants is designed,
constructed and operated in accordance with
|
|
|
(a) established engineering
principles, and
|
|
|
(b) ASHRAE Standard 62-1989,
Ventilation for Acceptable Indoor Air Quality, or
other standard acceptable to the board.
|
|
|
(2) An adequate supply of outdoor air
must be provided to the workplace in accordance with
Table 2 of ASHRAE Standard 62-1989, or other
standard acceptable to the board.
|
|
|
(3) For a building ventilation system
installed prior to 1989, an adequate supply of outdoor
air must be provided in accordance with the ASHRAE
standard in place at the time the ventilation system was
designed, or other standard acceptable to the board.
|
|
|
Note: If workers occupying a
building exhibit signs or report symptoms of illness the
circumstances must be investigated as required by Part 5
(Chemical and Biological Substances). If such signs or
symptoms are attributed to an inadequate supply of
outdoor air, the board will, under subsection (3),
consider a standard other than the ASHRAE standard in
place at the time the ventilation system was designed
where necessary to address the circumstances.
|
| Building
modifications |
4.73 |
The owner of a
building must permit an employer to install a
ventilation system when required by this Part, provided
that all such work is subject to the approval of the
owner, acting reasonably. |
| Distribution |
4.74 |
Outdoor air
must be effectively distributed throughout the
workplace. |
| Balancing |
4.75 |
The ventilation system must be
balanced to
|
|
|
(a) ensure that each space within the
building receives an adequate allotment of outdoor air,
and
|
|
|
(b) accommodate the actual or the
normally anticipated occupancy of each space.
|
| Ventilation
openings |
4.76 |
(1) A ventilation system must not be
obstructed by material or equipment placed in front of
the ventilation air intakes or discharge points.
|
|
|
(2) Outdoor air intakes must be
located so that outdoor air entering the ventilation
system does not contain any contaminant in a
concentration greater than normal outdoor ambient air in
that locality.
|
| Discharged
air |
4.77 |
A ventilation
system that discharges air from the work area must be
designed to minimize the likelihood of exposing any
worker at a workplace, including an adjacent workplace |
|
|
(a) to an air contaminant in a
concentration which exceeds either 10% of its applicable
exposure limit in Part 5 (Chemical and Biological
Substances), or an acceptable ambient air quality
standard established by an authority having jurisdiction
over environmental air standards, whichever is greater,
and
|
|
|
(b) where practicable, to an
objectionable odour.
|
| Preventive
maintenance |
4.78 |
(1) To maintain acceptable air
quality, the employer, or if the employer is not
responsible for maintenance of the ventilation system,
the owner of the ventilation system or the owner's
agent, must establish an effective preventive
maintenance program for the ventilation system.
|
|
|
(2) Preventive maintenance must
include
(a) regular inspections
|
|
|
(i) of all critical components of the
ventilation system, such as dampers, fans, belts,
baffles, ductwork, diffusers and control systems, and
|
|
|
(ii) for conditions which would
promote the growth of micro-organisms, such as water
leaks or stagnant water pools,
|
|
|
(b) correction of any deficiencies
found during the inspections carried out under paragraph
(a),
|
|
|
(c) repair or replacement of
malfunctioning and consumable components, such as
filters and belts, and the cleaning of air distribution
systems, ducts and dampers when necessary to correct an
indoor air quality deficiency,
|
|
|
(d) adequate treatment of open water
systems associated with ventilation equipment such as
cooling towers and humidifiers, to control biological
growth, and
|
|
|
(e) maintenance of combustion sources,
such as furnaces, space heaters and water heaters to
assure proper burning and exhausting of waste gases so
that recirculation of gases to the workplace will not
occur.
|
| Investigation |
4.79 |
(1) The employer must ensure that the
indoor air quality is investigated when
|
|
|
(a) complaints are reported,
|
|
|
(b) occupancy in the space changes
substantially, or
|
|
|
(c) renovations involving significant
changes to the ventilation system occur.
|
|
|
(2) An air quality investigation must
include
|
|
|
(a) assessment of the ventilation
rate, unless the indoor carbon dioxide level is less
than 650 ppm above ambient outdoor levels,
|
|
|
(b) inspection of the ventilation
system as required in section 4.78(2),
|
|
|
(c) sampling for airborne contaminants
suspected to be present in concentrations associated
with the reported complaints, and
|
|
|
(d) a record of the complaint, the
findings of the investigation, and any actions taken.
|
|
|
Note: In subsection (2)(a)
carbon dioxide is considered a marker indicator of
sufficient outdoor air, not as a toxic air contaminant
for which the exposure limit in Table 5-4 would apply.
Normally, ambient levels are approximately 350 ppm, but
may be higher in locations such as urban areas or during
weather conditions such as inversions. Ambient levels
may be assumed to be 350 ppm unless sampling establishes
otherwise.
|
| Temperature
and humidity |
4.80 |
The employer
must ensure that temperature and humidity levels within
the indoor work environment are maintained within
acceptable comfort ranges, as far as is practicable.
Note: Refer
to the ASHRAE publication Handbook of Fundamentals, or
to the WCB standard practice manual on the indoor
environment for information on acceptable temperature
and humidity levels.
|
