United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-94/001 March 1994
EPA Project Summary
Supplement to: Standard
Measurement Protocols, Florida
Radon Research Program
Ashley D. Williamson and Joe M. Finkel
The report supplements earlier pub-
lished standard measurement protocols
for the Florida Radon Research Pro-
gram (EPA-600/8-91-212; NTIS PB92-
115294, November 1991). It adds five
new protocols: Small Canister Radon
Flux and Soil Water Potential are added
to the first section, on soil measure-
ments; and Indoor Radon Progeny, Ra-
don Entry Rate, and Duct System Leak-
age are added to the second section,
on building measurements.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory, Research Tri-
angle Park, NC, to announce key find-
ings of the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
This manual is divided into two sec-
tions. The first section, soil measurements,
initially contained field sampling protocols
for soil gas permeability and radon con-
centration, in situso\\ density, soil classifi-
cation, and penetrometer analysis. Labo-
ratory procedures included soil moisture,
radium and radon emanation, particle-size
analysis, specific gravity, the proctor
method for moisture/density relationships,
a laboratory gas permeability test, a ra-
don diffusion coefficient measurement, and
two radon flux measurements. The sec-
ond section, building measurements, ini-
tially included diagnostic procedures for
radon, sub-slab communications, and dif-
ferential pressure measurements followed
by building leakage measurements. To the
first section, the supplement adds proto-
cols for measuring radon flux (utilizing
small canisters) and soil water potential.
To the second section, the supplement
adds protocols for: measuring indoor ra-
don decay products, estimating radon en-
try rates, and measuring heating and air-
conditioning duct leakage.
Small Canister Radon Flux
A third method for radon flux measure-
ments is presented in the first section. It
has been used by Florida Radon Research
Program (FRRP) project members. This
method is similar to the University of
Florida version (see Section 1.12),* ex-
cept that it reduces the air space between
the soil surface and the charcoal bed to
minimize biases from disturbed radon pro-
files.
Radon flux is a localized indicator of
radon source strength, and has been used
to define regulatory limits for radon emis-
sions from uranium mill tailings piles,
phosphogypsum stacks, etc. Radon flux
measurements also may help identify the
potential of building sites to cause elevated
indoor radon levels.
This method is a variant of two similar
methods for radon flux measurements
given in Section 1.12. Radon flux mea-
surements give an indication of radon
source potential at a site. Source potential
in turn is affected by soil radium and ra-
don emanation, whose protocols are in
Section 1.6, and diffusivity, which is re-
lated to Section 1.11.
Referenced Sections 1.1 through 1.12 and 2.1 through
2.5 are in the initially published protocols.
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Soil Water Potential
This method is used for field measure-
ments of soil moisture potential. The mois-
ture potential is defined to be the pres-
sure of the tensiometer water necessary
to equilibrate mechanically and hydrauli-
cally with the soil solution phase.
This method is specified as a field pro-
cedure and measurement to be conducted
in the research house projects of the
Florida Radon Research Program. As pre-
sented here, it is a "stand-alone" proce-
dure used for long-term monitoring.
This method may not give a truly repre-
sentative result if dissolved gases come
out of the solution, if the water in the
tensiometer system is reduced to the level
of the vapor pressure of water at the am-
bient temperature of the system, or if the
difference between the gas pressure and
the pressure in the tensiometer cup water
forces a gas phase through the wetted
porous cup. Any of these phenomena that
introduce a gas phase into the tensiom-
eter system will seriously interfere with its
operation. These conditions are most likely
to occur when the soil is very dry.
This method is related to the determi-
nation of soil moisture as given in Section
1.5, in that the soil moisture and soil wa-
ter potential for any given soil are mono-
tonically related one to another.
Indoor Radon Progeny
Indoor Radon and Radon Decay Prod-
uct Measurement Device Protocols.
EPA-402/R-92-004 (NTIS PB92-
206176), U.S. EPA, Office of Radia-
tion Programs, Washington, DC, July
1992.
The referenced document contains in-
door radon decay product measurement
protocols utilizing three commonly used
techniques. The method most suitable for
use in FRRP projects is Protocol 3.1 (Con-
tinuous Working Level Monitors). Other
radon and decay products methods are
also included which are either already cov-
ered in the initial manual (Protocol 2.5 -
Indoor Radon) or less likely to be appli-
cable to the program. The protocol de-
scribes the method deployment strategies,
operation, documentation, analysis, and
quality assurance considerations.
This method is generally applicable to
the FRRP research house projects, but
may be applicable to any other FRRP
project that requires information concern-
ing radon progeny. Generally continuous
working level monitors will be used in these
projects. They will be deployed at least
once a quarter when baseline indoor ra-
don is being measured continuously. Such
continuous simultaneous radon and radon
progeny measurements will be made for
at least 2 consecutive days each quarter.
If occupant risks, progeny levels, or equi-
librium ratios are of interest in any other
of the specialty studies (depressurized con-
ditions, various heating, ventilation, and
air-conditioning (HVAC) conditions, etc.)
of any of the research house groups, then
similar continuous simultaneous measure-
ments may be made. For certain of these
special-purpose measurements, standard
deployment procedures (closed house con-
ditions, etc.) may deliberately be ignored.
Because progeny may be measured un-
der a variety of conditions, care must be
taken to document the actual house con-
ditions at the time of the measurement.
For instance, the occupancy status, the
HVAC operational mode, the open/closed
conditions of interior as well as exterior
doors and windows, and any pressurized
or depressurized conditions should be
noted.
Radon Entry Rate
The supplement contains a procedure
for estimating radon entry rates through
portions of the building envelope in com-
munication with the soil or soil gas under
controlled depressurization.
This method is for measuring radon con-
centrations inside a building after fixed
times of controlled depressurization, dur-
ing which the indoor-outdoor pressure dif-
ferential and the exhaust flows are care-
fully measured to ensure as close to con-
stant levels as possible. The method is
most accurate when small temperature
differentials and low wind-pressure condi-
tions are maintained. This method requires
fairly simple measurements and produces
results that characterize the radon entry
rates at various levels of depressuriza-
tion. This can be extrapolated down to
normal ranges of building pressure differ-
entials.
This method will be used as a building
diagnostic tool on several Florida Radon
Research Program projects, including the
Research House projects and the New
House Evaluation Program projects. The
test should not be run when strong wind
and large indoor-outdoor temperature dif-
ferentials are likely. Because of differences
between the various conditions under
which a building may be found and the
test conditions on any given day, such
measurements cannot be interpreted as
direct measurements of radon entry rates
that would occur on any given day. If the
building has a very high leakage rate or if
the radon source potential is very low,
then the radon concentrations under de-
pressurized, high exhaust flow conditions
may be near or below detection limits of
the instruments. However, buildings with
these features tend not to have severe
indoor radon concentration problems.
This method uses much of the same
equipment as the Standard Test Method
for Determining Air Leakage Rate by Fan
Pressurization (Section 2.4.1; ASTM E779-
87) and Alpha Scintillation Cell Grab
Samples (Section 2.1) and Indoor Radon
by grab sampling (Section 2.5).
Duct System Leakage
The supplement contains a simple heat-
ing and air-conditioning duct leakage pro-
tocol for determining: (1) if the air handler
operation has a strong influence on the
house pressure differential, and (2) a quan-
tification of gross duct leakage. If either or
both of these simplified protocols produce
measurable results, then a more involved
protocol is introduced for determining the
external air leakage characteristics of the
air distribution systems by fan pressuriza-
tion. This more involved protocol is still
being tested by an ASTM sub committee;
so it cannot be reproduced here. A source
to contact for information concerning the
protocol is given.
These methods will be used as building
diagnostic tools on several Florida Radon
Research Program projects, including
some Research House projects and the
New House Evaluation projects. The tests
should not be run on days with strong
winds or large indoor-outdoor tempera-
ture differentials. Because of the difficulty
in isolating the air handling system or its
components from various zones of the
building structures, it is not possible to
determine precisely the duct leakage by
these protocols. The problems vary as
widely as the differences in individual
houses and their unique air handling sys-
tems.
This method is an extension of the Stan-
dard Test Method for Determining Air Leak-
age Rate by Fan Pressurization (Section
2.4.1; ASTM E 779-87). Indeed it incorpo-
rates and supersedes the last four pages
of Section 2.4.1, Test Method for Deter-
mining the HAC Duct System Leakage. It
is also related to Trace Dilution Methods
(Section 2.4.2; ASTM E 741-83).
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A.D. Williamson and J.M. Finkel are with Southern Research Institute, P.O. Box
55305, Birmingham, AL 35255-5305.
David C. Sanchez is the EPA Project Officer (see below).
The complete report, entitled "Supplement to: Standard Measurement Protocols,
Florida Radon Research Program," (Order No. PB94-144119/AS; Cost: $17.50;
subject to change) 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
Official Business
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