United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S8-91/014 Sept. 1991
xsrEPA Project Summary
Indoor Air Quality Simulator for
Personal Computers
P.A. Lawless and M.K. Owen
The results of this project are the
IAQPC (Indoor air quality simulator for
personal computers), a User's Guide,
and a Technical Manual. The IAQPC
was developed to address the problem
of Indoor air contamination. The pro-
gram requires a large amount of data,
but all values have defaults, many of
which will be applicable to many situa-
tions. The program uses menus for the
data Input and to specify output.
This Project Summary was devel-
oped by EPA's Air and Energy Engi-
neering Research Laboratory, Research
Triangle Park, NC, to announce key find-
Ings of the research project that Is fully
documented In two separate reports and
one computer diskette (see Project Re-
port ordering Information at back).
Computer Requirements
The minimum required computer setup
which will run the IAQPC includes an IBM-
PC or compatible with two floppy disk
drives, DOS Version 2.0 or later,, and 350
K of memory. The recommended hard-
ware configuration includes a PC (or a PC-
compatible) with a hard disk, a math
coprocessor, and a color monitor (e.g., an
Enhanced Graphics Adapter [EGA]). Other
computers or less memory may work but
have not been tested.
Input/Output Options
The IAQPC gives concentration pro-
files to cover up to 62 days based on
information entered on a building layout,
the HVAC (heating, ventilation, and air-
conditioning) system parameters, and
source (machines, cigarettes) and sink
(walls, floors) data.
The general building layout is chosen
from one of six standard configurations.
The building must be single-story and may
have up to 20 rooms. The room volumes
and the cross-sectional areas of the inter-
connections between the rooms (doors,
vents, cracks) may be entered. The HVAC
parameters include the amount of outdoor
air entering the building and the schedule
of the HVAC system. Airflows for the build-
ing are calculated by the program.
The IAQPC can model up to six pollut-
ants. These are selected in one menu.
Note that at this point no pollutant interac-
tions are modeled, so any of the pollutant
slots may be used for any pollutant; how-
ever, it is much simpler to keep track of the
output if the pollutants are referred to by
name. Source production rates are en-
tered, then the locations for the sources
are chosen. Sinks are modeled through
the same process.
The IAQPC provides graphical repre-
sentations of the layout, source/sink loca-
tions, calculated airflows, and source
cycles. The concentrations calculated by
the program may be displayed both as
linear and semilog plots.
Program Design/Menu Setup
The IAQPC uses a series of menus (as
shown in Table 1) to enter data, run the
program, and select output(s). The menu
approach was chosen so that the data can
be entered in an easy, simple to under-
stand way. The menus were prepared so
that related information can be entered in
Printed on Recycled Paper
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the same location. A great deal of data is
needed to describe an indoor environment.
This means that data input could be messy
and difficult. However, the approach used
in IAQPC makes this input as easy as
possible.
The lAQPC's menu system begins with
the Main Menu or the Preliminary Menu,
as chosen in the Reconfigure Program
option. The Main Menu gives access to all
the data input, modeling, output option
menus, and the Preliminary Menu. The
Preliminary Menu contains the master file
options, the exit options, and a program
configuration menu. Data entry begins with
the Main Menu where the user chooses
the type of data to enter. The arrow keys,
pressing the first letter of the choice, or a
mouse may be used to select a choice.
From this step the data entry may be in the
next menu or may be three more menus
deep. The on-screen instructions and the
user's manual will help the user find a way
through the program.
Another part of this approach to make
data entry as simple as possible is the
data file structure. This program saves the
data in a series of files. One of these files,
the Master File, saves the names of the
other data files that were used for the
particular run. In this way, a system of data
files may be built up to operate as a library.
For example, a source strength file with
values that apply to several buildings or
cases could be set up, then used with
several different building design files to
determine the effect of the building layout
on the concentrations. At least one set of
files is included with the program. As the
experimental data base grows and the num-
ber of analyzed test cases increases, more
sample cases will be provided. With these,
a case similar to the user's own building
may be chosen as a base to simplify data
entry.
The User's Guide
The guide introduces the IAQPC and
contains menu instructions, a step-by-step
tutorial, and brief descriptions of the mean-
ings and reasonable inputs for the vari-
ables. It should be extremely helpful for
fist-time users, but will also act as a quick
reference for experienced users.
The Technical Manual
The technical manual provides the theo-
retical background of the program, offers
details on the algorithms, and includes the
program listings. This manual should be
useful to the experienced user and to those
who are interested in the fundamentals of
the program.
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Table 1. Program Flowchart Showing Menus and Functions'
MAIN
-1
(DO f^irrfnni
HVAL> iSystem i
Description i
airflow balancing)
Characteristics '
1
1
1
1
i Sinks \
\
\
1
1
^— In Rnnm _,_.....
Locations \
\
\
\
— Runtime
Configurations
Reconfigure Program
(data input)
... Building Statistics Display
On/Off Times
Pollutant Choices
(choose cleaners)
(choose sink)
(choose sink)
PdssivG Sinks
RuilHinn ^totfc/Jrc
Menus
(data input)
Efficiency Input
Menus
Efficiency Input
Menus
— Reemission Rate
Input Menus
— Continue Simulator
— Graphical Output
I (choices)
Output Results —
(choices)
Output Device Selection
'Menus are in bold print.
" This menu can be reached in two ways.
&U.S. GOVERNMENT PRINTING OFFICE: 1991 - 548-028/40060
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P. Lawless and M. Owen are with Research Triangle Institute, Research Triangle Park,
NC 27709.
Leslie E. Sparks is the EPA Project Officer, (see below).
The complete report consists of two volumes entitled "IAQPC Indoor Air Quality Simula-
tor for Personal Computers:," and one diskette:
"Volume r (Order No. PB91-205153/AS; Cost: $31.00, subject to change) is the
Technical Manual.
"Volume 2" (Order No. PB91-205161/AS; Cost: $17.00, subject to change) is the User's
Guide.
The disk (Order No. PB91-507871/AS; Cost: $130.00, subject to change) contains the
executable files for IAQPC.
Volumes and disk of this report will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati, OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA PERMIT NO. G-35
Official Business
Penalty for Private Use $300
EPA/600/S8-91/014
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