Introduction; Definitions - Honeywell AUTOMATIC CONTROL Engineering Manual

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
nonexistence 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 (to at least 90°F) 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.
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.
• HVAC 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.
151 ENGINEERING MANUAL OF AUTOMATION CONTROL