Table of Contents
Advertisement
INTRODUCTION
This section provides basic information on Indoor Air Quality
(IAQ) and suggested control solutions. The causes and effects
of several contaminants are discussed. These contaminants
provide reason for concern about IAQ. Also included are
recommended or required approaches to IAQ compliance and
general approaches to preventing and controlling IAQ problems.
In addition, typical graphic displays are included illustrating
the usefulness of an operator interface to allow pinpointing and
correcting any problems that might cause degradation of IAQ.
Displays, requiring acknowledgment, can also be provided to
alert the operator that periodic maintenance of IAQ is required.
The issue of indoor air quality (IAQ) has moved from virtual
non-existence to a major concern over the last twenty years.
DEFINITIONS
To control IAQ it is necessary to understand the terms
commonly in use by the various agencies involved in industry
and government which relate to the many disciplines involved.
Aerosol: Liquid droplets or solid particles, suspended in air, that
are fine enough (0.01 to 100 micrometers) to remain
dispersed for a period of time.
Air cleaner: A device that actively removes impurities from the
air. Includes particle filters, gas phase filters and
electronic devices.
Air quality standard: A government-mandated regulation which
specifies the maximum contaminant concentration
beyond which health risks are considered to be
unacceptable.
Allergen: A substance that can trigger immune responses resulting
in an allergic reaction; also known as antigen.
Bacteria: One celled organisms which are members of the protista,
a biological classification.
Bakeout: A technique for reducing emissions of new construction
in which the building temperature is raised (usually to
at least 32 C) for several days to enhance emissions of
volatile compounds from new materials, while running
the ventilation system at full capacity to exhaust the
emissions.
Bioaerosols: Airborne microbial contaminants, including viruses,
bacteria, fungi, algae, and protozoa. The term also refers
to the reproductive units, metabolites, and particulate
material associated with these microorganisms.
ENGINEERING MANUAL OF AUTOMATIC CONTROL
INDOOR AIR QUALITY FUNDAMENTALS
Measures taken to offset increasing energy costs since the 1970s,
increasing use of synthetic materials in building construction
and maintenance, compressed construction schedules, and
reduction in operational maintenance resulting from competitive
pressures have made IAQ a major problem for the building
designer, operator, and owner.
A correctly designed control system properly applied to a
well designed HVAC system can ensure optimal IAQ, which in
turn will ensure occupant comfort and improved employee
productivity. A poorly designed, installed, or maintained control
system can reduce IAQ below acceptable levels, resulting in
reduced productivity, increased employee health costs and
building maintenance costs, and major legal costs.
Biocontaminant: Contaminants which are either life forms
(molds of the genera aspergillis) or are derived from
living things such as rodent droppings.
Building-related illness: A diagnosable illness with identifiable
symptoms whose cause can be directly attributed to
airborne pollutants within the building (e.g.,
Legionnaires disease, hypersensitivity pneumonitis).
Carcinogen: An agent suspected or known to cause cancer.
Commissioning:
• Building: The process of designing, achieving, verifying,
and documenting the performance of a building to meet
the operational needs of the building within the capabilities
of the design and to meet the design documentation and
the owners functional criteria, including training of
operating personnel.
• HV AC System: The process of documenting and verifying
the performance of HVAC systems so that systems operate
in conformity with the design intent.
Contaminant: An unwanted constituent that may or may not be
associated with adverse health or comfort effects. See
Pollutant.
Decay rate: The rate at which the concentration of a compound
diminishes.
Dilution: The reduction of airborne concentration of contaminants
through an increase in outdoor air supplied to the space.
Dioctyl phthalate: An oily liquid used in testing filters.
151
Advertisement
Chapters
Table of Contents
