United States Air and Energy Engineering

Environmental Protection Research Laboratory

Agency Research Triangle Park, NC 27711

Ashley D. Williamson and Joe M. Finkel

E AP Project Summary

Supplement to: Standard

Measurement Protocols, Florida

Radon Research Program

Research and Development EPA/600/SR-94/001 March 1994

The report supplements earlier published standard measurement protocols

for the Florida Radon Research Program (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 measurements; and Indoor Radon Progeny, Radon Entry Rate, and Duct System Leakage are added to the second section,

on building measurements.

This Project Summary was developed

by EPA’s Air and Energy Engineering

Research Laboratory, Research Triangle Park, NC, to announce key findings 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 sections. The first section, soil measurements,

initially contained field sampling protocols

for soil gas permeability and radon concentration, in situ soil density, soil classification, and penetrometer analysis. Laboratory 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 radon diffusion coefficient measurement, and

two radon flux measurements. The second section, building measurements, initially included diagnostic procedures for

radon, sub-slab communications, and differential pressure measurements followed

by building leakage measurements. To the

first section, the supplement adds protocols for measuring radon flux (utilizing

small canisters) and soil water potential.

To the second section, the supplement

adds protocols for: measuring indoor radon decay products, estimating radon entry rates, and measuring heating and airconditioning duct leakage.

Small Canister Radon Flux

A third method for radon flux measurements 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),* except that it reduces the air space between

the soil surface and the charcoal bed to

minimize biases from disturbed radon profiles.

Radon flux is a localized indicator of

radon source strength, and has been used

to define regulatory limits for radon emissions 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 measurements give an indication of radon

source potential at a site. Source potential

in turn is affected by soil radium and radon emanation, whose protocols are in

Section 1.6, and diffusivity, which is related 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 measurements of soil moisture potential. The moisture potential is defined to be the pressure of the tensiometer water necessary

to equilibrate mechanically and hydraulically with the soil solution phase.

This method is specified as a field procedure and measurement to be conducted

in the research house projects of the

Florida Radon Research Program. As presented here, it is a “stand-alone” procedure used for long-term monitoring.

This method may not give a truly representative 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 ambient 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 tensiometer 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 determination of soil moisture as given in Section

1.5, in that the soil moisture and soil water potential for any given soil are monotonically related one to another.

Indoor Radon Progeny

Indoor Radon and Radon Decay Product Measurement Device Protocols.

EPA-402/R-92-004 (NTIS PB92-

206176), U.S. EPA, Office of Radiation Programs, Washington, DC, July

1992.

The referenced document contains indoor radon decay product measurement

protocols utilizing three commonly used

techniques. The method most suitable for

use in FRRP projects is Protocol 3.1 (Continuous Working Level Monitors). Other

radon and decay products methods are

also included which are either already covered in the initial manual (Protocol 2.5 -

Indoor Radon) or less likely to be applicable to the program. The protocol describes 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 concerning 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 radon 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 equilibrium ratios are of interest in any other

of the specialty studies (depressurized conditions, various heating, ventilation, and

air-conditioning (HVAC) conditions, etc.)

of any of the research house groups, then

similar continuous simultaneous measurements may be made. For certain of these

special-purpose measurements, standard

deployment procedures (closed house conditions, etc.) may deliberately be ignored.

Because progeny may be measured under a variety of conditions, care must be

taken to document the actual house conditions 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 communication with the soil or soil gas under

controlled depressurization.

This method is for measuring radon concentrations inside a building after fixed

times of controlled depressurization, during which the indoor-outdoor pressure differential and the exhaust flows are carefully measured to ensure as close to constant levels as possible. The method is

most accurate when small temperature

differentials and low wind-pressure conditions are maintained. This method requires

fairly simple measurements and produces

results that characterize the radon entry

rates at various levels of depressurization. This can be extrapolated down to

normal ranges of building pressure differentials.

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 differentials 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 depressurized, 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 heating and air-conditioning duct leakage protocol for determining: (1) if the air handler

operation has a strong influence on the

house pressure differential, and (2) a quantification 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 pressurization. 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 temperature 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 systems.

This method is an extension of the Standard Test Method for Determining Air Leakage Rate by Fan Pressurization (Section

2.4.1; ASTM E 779-87). Indeed it incorporates and supersedes the last four pages

of Section 2.4.1, Test Method for Determining 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

EPA/600/SR-94/001

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