EPA/600/R-14/238 | September 2014 | www.epa.gov/nhsrc
United States
Environmental Protection
Agency
Evaluation of the Curing Times
of Strippable Coatings and
Gels as used for Radiological
Decontamination
EVALUATION REPORT
Office of Research and Development
National Homeland Security Research Center
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Evaluation of the Curing Times
of Strippable Coatings and Gels
as used for Radiological Decontamination
Evaluation Report
National Homeland Security Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
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Disclaimer
The United States Environmental Protection Agency through its Office of Research and
Development's National Homeland Security Research Center, funded and managed the research
described here under EPA Contract Number EP-C-09-027, Work Assignment 4-11 with
ARCADIS U.S., Inc. This report has been peer and administratively reviewed and has been
approved for publication as an Environmental Protection Agency report. It does not necessarily
reflect views of the Environmental Protection Agency. No official endorsement should be
inferred. The Environmental Protection Agency does not endorse the purchase or sale of any
commercial products or services.
Questions concerning this document or its application should be addressed to:
Lukas Oudejans, Ph.D.
Decontamination and Consequence Management Division
National Homeland Security Research Center
Office of Research and Development
U.S. Environmental Protection Agency (MD-E343-06)
109 T.W.Alexander Dr.
Research Triangle Park, NC 27711
Phone: 919-541-2973
Fax: 919-541-0496
E-mail: Oudeians.Lukas@epa.gov
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Acknowledgments
Contributions of the following individuals and organizations to the development of this
document are gratefully acknowledged.
United States Environmental Protection Agency (EPA):
John Griggs, Office of Air and Radiation (OAR)/Office of Radiation and Indoor Air (ORIA)
Terry Stilman, Region 4
James Mitchell, Region 5
Ramona Sherman (QA review), Office of Research and Development (ORD)/
National Homeland Security Research Center (NHSRC)
ARCADIS U.S., Inc.
This report builds on published EPA radiological decontamination reports and technical briefs in
which decontamination factors for a select number of decontamination technologies were
measured. The contributions to that work by John Drake (ORD/NHSRC, retired) are greatly
acknowledged.
IV
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Table of Contents
Disclaimer iii
Acknowledgments iv
Table of Contents v
List of Figures vii
List of Tables viii
Acronyms and Abbreviations ix
Executive Summary x
l.OIntroduction 1
1.1.Purpose 1
1.2.Project Objectives 2
2.0Experimental Approach 3
2.1.Experimental Test Chamber 4
2.2.Environmental Controls 5
2.2.1 Temperature Control 6
2.2.2 RH Control 6
2.2.3 Pressure Control 7
2.2.4 Aeration Rate Control 7
2.2.5 Chemical Fume Hood for Decontaminant Preparation 8
2.3.Test Materials 8
2.3.1 Coupon preparations 9
2.4.Selected Decontamination Technologies 10
2.4.1 InstaCote CC Wet/CC Strip 10
2.4.2 CBIDeconGel® 1108 12
2.4.3 Bartlett StripCoat TLC Free™ 13
2.5.Test Matrix 14
2.6. Preparation of Coupons for Testing 15
2.6.1 Wetted coupon preparation 16
2.7. Preparation and Application of the Decontamination Agents 18
2.7.1 Decontamination Coating Amounts 18
2.8.Procedure to Determine Curing Status 20
2.9.Curing Status Definitions 20
3.0Test Results and Discussion 22
3.l.CC Wet/CC Strip 22
3.2.DeconGel® 1108 26
3.3.StripcoatTLCFree™ 30
4.0Quality Assurance and Quality Control 32
4.1.Data Quality Objectives 32
4.2.Data Quality Indicators 32
4.3.Equipment Calibrations 33
4.4.Quantitative Acceptance Criteria 33
4.5.Amendments and deviations from the original QAPP 36
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4.5.1 Formal Amendments 36
4.5.2 QAPP Deviations 37
S.OSummary 38
6.0References 40
Appendix A: Loading volumes versus environmental conditions 41
Appendix B: Critical and non-critical measurements 44
Appendix C: RH profiles during curing of decontamination coatings 51
VI
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List of Figures
Figure 2-1. Decontamination chamber 4
Figure 2-2. Decontamination chamber schematics 5
Figure 2-3. Coupons assembled for testing 16
Figure 2-4. Top- and side-view of concrete coupon soaking up the water after application of the
simulated rainfall 17
Figure 2-5. Scheme of the successive attempts to peel off decontamination coating from coupon
surface 20
Figure 3-1. Appearance of the overly dried-out CC Wet/CC Strip coating (5 °C/20 %RH/1
ACH/dry surface, 4 h post-application of CC Strip coat) 22
Figure 3-2. Several-piece-removal of CC Wet/CC Strip coating (20 °C/80 %RH/1 ACH/dry
surface; 4 h post-application of CC Strip coat) 23
Figure 3-3. One-piece-removal of CC Wet/CC Strip coating from stainless steel (40 °C/20
%RH/1 ACH/dry surface; 4 h post-application of CC Strip coat) 23
Figure 3-4. One-piece-removal of CC Wet/CC Strip coating from concrete (40 °C/20 %RH/1
ACH/dry surface; 4 h post-application of CC Strip coat) 24
Figure 3-5. One-piece-removal of DeconGel® 1108 coating from stainless steel (5 °C/80 %RH/1
ACH/dry surface, 18 h post-application of 2n coat) 26
Figure 3-6. One-piece-removal of DeconGel® 1108 coating from concrete (5 °C/80 %RH/1
ACH/dry surface, 18 h post-application of 2n coat) 26
Figure 3-7. Partial removal of semi-cured DeconGel® 1108 coating (20 °C/80 %RH/1 ACH/dry
surface, 32 h post-application of 2n coat) 27
Figure 3-8. Almost-cured DeconGel® 1108 coating (5 °C/80 %RH/1 ACH/dry surface, 4 h post-
application of 2nd coat) 28
Figure 3-9. One-piece-removal of Stripcoat TLC Free™ coating from concrete (20 °C/20
%RH/1 ACH/dry surface, 4 h post-application of 2nd coat) 30
Figure 3-10. One-piece-removal of Stripcoat TLC Free™ coating from stainless steel (20 °C/20
%RH/1 ACH/dry surface, 4 h post-application of 2nd coat) 30
VII
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List of Tables
Table ES-1. Summary of shortest curing times and major observations for tested strippable
coatings at one air change per hour xi
Table 2-1. Description of building materials for curing time testing 9
Table 2-2. Decontamination agents and technologies used for curing times testing 10
Table 2-3. Test matrix for each decontamination technology 15
Table 2-4. Simulated rainfall parameters 18
Table 2-5. Average loading volumes per surface area for decontamination coatings tested 19
Table 3-1. Assessment of CC Wet/CC Strip curing times with opacity rating of coating under
various environmental conditions with normal ventilation 25
Table 3-2. Assessment of the DeconGel 1108 curing times under various environmental
conditions with normal ventilation 29
Table 3-3. Assessment of the Stripcoat TLC Free™ curing times under various environmental
conditions with normal ventilation 31
Table 4-1. DQIs for critical measurements 33
Table 4-2. Equipment calibration schedule 33
Table 4-3. Acceptance criteria for critical measurements 34
Table 4-4. Summary of critical measurements and completeness of data 35
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Acronyms and Abbreviations
ACH
DI
DQI
DTRL
EPA
ft3
h
L
min
mL
mm
MSDS
NHSRC
NIST
ORD
OSC
PDAQ
PPE
QA
QAPP
QC
RDD
RH
SD
sec
air change(s) per hour
deionized
data quality indicator
Decontamination Technologies Research Laboratory
U.S. Environmental Protection Agency
cubic feet or foot
hour(s)
liter(s)
minute(s)
milliliter(s)
millimeter(s)
Material Safety Data Sheet
National Homeland Security Research Center
National Institute of Standards and Technology
Office of Research and Development
On-Scene Coordinator
portable data acquisition (system)
personal protective equipment
Quality Assurance
Quality Assurance Project Plan
Quality Control
Radiological Dispersal Device
Relative Humidity
Standard Deviation
second(s)
IX
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Executive Summary
In 2010, federal, state, and local authorities participated in a five-day Homeland Security
exercise in Philadelphia, PA. This Liberty RadEx exercise was designed to test the country's
capability to clean up and help communities recover from a radiological dispersal device (RDD)
detonation. As part of this exercise, various decontamination technologies for the removal of
radionuclides from building materials were demonstrated. One of these demonstrations involved
the application of a strippable coating to wall and floor surfaces of the city's subway system.
This method of decontamination had previously been investigated on the laboratory scale as a
potential method for removal of radionuclides from an urban building surface. One of the
observations made during the Liberty RadEx exercise was that the coating did not cure properly
over an extended period of time (more than 24 hours) while the curing time stated by the
manufacturer was (at that time) 4 to 6 hours, depending on environmental conditions. The failure
to cure was postulated as being due to either the high relative humidity (RH) and/or the stagnant
air in the enclosed area as experienced during the demonstration.
This project evaluated the impact that environmental conditions may have on the ability of
strippable coatings to cure properly on a representative building material in the urban
environment. This first report describes the impact of temperature and RH at a fixed single air
change per hour rate. The three decontamination products evaluated in this study were selected
based on their previously observed ability for successful in situ removal of radionuclides from
building materials (EPA 201 la, EPA 201 Ib, EPA 2013a, EPA 2013b). The three strippable
decontamination coatings tested, InstaCote CC Wet/CC Strip, CBI Polymers DeconGel 1108,
and Bartlett Nuclear Inc. StripCoat TLC Free™, were applied to concrete and stainless steel
coupons. The curing process of these coatings was tested under various environmental conditions
ranging from just above the freezing point of the products (5 °C) at low (20 %) and high (80 %)
RH to a summer-like temperature of 40 °C at low and high RH. Up to four attempts were made
to remove a strippable coating from the surfaces, namely 4 hours (h), 18 h, 24 h, and 32 h after
application of the product.
Table ES-1 summarizes the observed curing time for these coatings for all conditions tested.
Curing was defined here as the ability to peel the coating from the stainless steel and concrete
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surfaces as one single piece ("Excellent") or several smaller pieces ("Good") without leaving
areas of uncured coating present on a coupon surface. Partial curing was defined when the
coating could be removed only partially due to the presence of wet spots or if the peeling process
resulted in numerous small dried out pieces of coating. No curing was defined when coatings
were wet and did not peel from the surfaces.
Table ES-1. Summary of manufacturer information and observed shortest curing times for tested
strippable coatings at one air change per hour.
Manufacturer
recommended curing time
CC Wet/CC Strip
24 h at high RH, low
temp, no ventilation
DeconGel 1108
hours for thin coatings to
overnight or longer for
thick coatings and high RH
Stripcoat TLC Free
4-10 h, depending on
coat thickness and RH
Environmental Condition
Observed curing times (h)/observations
5°C/20 %RH/dry surface 4/multiple pieces3
18/one piece
4/one piece
5°C/80 %RH/dry surface
4/several pieces
18/one piece
4/one piece
20°C/20 %RH/dry surface 4/several pieces
4/one piece
4/one piece
20°C/80 %RH/dry surface
4-23/several piecesb
> 32h/semi cured at 32 hc
4/one piece
40°C/20 %RH/dry surface 4/one-several pieces
40°C/80 %RH/dry surface 4/one piece
4/one piece
4/one piece
18/one-several piece(s)
4/one piece
20°C/80 %RH/wet surface
4/one-several pieces
18/one piece
4/one piece
aLoss of elasticity of coating resulted in multiple small pieces being removed; complete removal was achieved.
b One vertical concrete coupon coating wet after 4 h; multiple pieces with low elasticity after 23 h for one concrete
coupon.
0 Complete curing after 48 h.
The curing was found to be very rapid under mild/warm (20 °C/40 °C) temperature and low
humidity (20 % RH) environmental conditions, when all coatings tested were strippable at 4 h
post-application. The surface characteristics (wet or dry) did not cause differences in the curing
process, but high humidity and cold temperatures seemed to be drivers for prolonged curing
times for some strippable coatings (e.g., CC Wet/CC Strip and DeconGel® 1108).
XI
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The observed curing of CC Wet/CC Strip always occurred within 24 h post-application - the time
period recommended by the manufacturer for processing of this coating under worst case
environmental conditions (high humidity, low temperatures, no ventilation). Similarly for
DeconGel® 1108, the observed overnight or longer curing times are in line with the
recommended curing time by the manufacturer. As indicated by the manufacturer, drying times
exceeding 24 h may be required for decontamination scenarios where thicker coatings are
applied in humid environments. StripCoat TLC Free™, which has the shortest manufacturer-
recommended curing times (4-10 h) amongst all strippable coatings tested formed strippable
coatings at 4 h post-applications under all environmental conditions tested.
Results from this study confirm that environmental conditions have an impact on the curing time
of two of the three tested strippable coatings. However, the occasionally observed prolonged
curing time was always less than the manufacturer's provided information. Curing times do
differ across products.
Loading volumes (hence, the thickness) of a coating material per surface test area were
dependent on RH and to a lesser extent temperature. Lower loading volumes were observed
when coatings were applied under high humidity conditions. Temperature-related changes in
loading volumes varied across decontamination products. The impact of the coating thickness on
the curing time was not explicitly determined in this study. However, the impact of the coating
thickness on the curing time appears to be low as all coatings cured within the vendor-
recommended curing times.
All strippable decontamination coatings tested were easy to apply, with no requirement for a pre-
preparation process. None of the products posed major challenges during the application using
the brush-on technique employed in this study.
Xll
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1.0 Introduction
In 2010, federal, state, and local authorities participated in a five-day Homeland Security
exercise in Philadelphia, Pennsylvania. This exercise, called Liberty RadEx, was designed to test
the country's capability to clean up and help communities recover from a radiological dispersal
device (RDD) detonation. As part of this exercise, various decontamination technologies were
demonstrated for the removal of radionuclides from building materials. One of these
demonstrations involved the application of a strippable coating to wall and floor surfaces of the
city's subway system. This method of decontamination had previously been investigated on the
laboratory scale as a potential method for removal of radionuclides from an urban building
surface. One of the observations made during Liberty RadEx was that the coating did not cure
properly over an extended period of time (more than 24 h) while the curing time stated by the
manufacturer was 4 - 6 h, depending on the environmental conditions. The failure to cure was
postulated to be due to the high relative humidity (RH) and the low ventilation environment
experienced during the demonstration in the enclosed area.
Strippable coatings are examples of surface cleaning technologies that most likely would be
employed to decontaminate surfaces for which minimal destruction is desired. These would
include materials that are part of infrastructure of high economic, cultural, or historical
significance. Strippable coatings would also be useful in creating a protective layer on a
contaminated surface as to avoid further penetration of radionuclides into a porous building
material.
1.1 Purpose
The purpose of this work was to evaluate the impact that environmental conditions may have on
the ability of strippable coatings to cure properly on a representative building material in the
urban environment. Curing of these coatings is critical to obtain high contaminant-removal
efficiency as the coating traps the targeted radionuclides. Only removal of the coating leads to
removal of the radionuclides. Uncured coating left on the surface would result in a lower
removal efficacy of the surface. This work did not assess the impact that these environmental
conditions may have on the decontamination efficacy (removal of radionuclides from a surface)
1
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of the technology. Efficacies against various radionuclides were determined previously (EPA
201 la) for these and other decontamination technologies at approximately 20 °C and 20 %RH.
1.2 Project Objectives
The specific project objectives to achieve the overall purpose consisted of:
• a systematical assessment of the curing process as a function of time through measurement of
the ability to peel the strippable coating from a surface under different environmental
conditions, e.g., temperature, RH, and air change conditions; and
• an assessment of whether the orientation of the surface (vertical versus horizontal) affects the
curing time.
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2.0 Experimental Approach
The general technical approach was to use a modified glove box to establish controlled
temperature, RH, and air change conditions that mimic a range of environmental conditions that
may be encountered during the remediation of an industrial or municipal setting following a
release or detonation of an RDD. Building coupons (concrete and stainless steel) were allowed to
equilibrate for a specified period of time within the controlled environmental conditions of the
modified glove box prior to application of the decontamination coating under the set of
conditions. The equilibration period of the materials was at least 48 h long. A decontamination
coating was then applied according to the manufacturer's instructions. After application of the
coating, the curing time was determined through measurement of the ability to successfully
process the coating as per the manufacturer's recommended procedure. For these strippable
decontamination products, the first attempt to peel a decontamination coating was made 4 h post-
application. If not successful, three additional attempts were made at 18, 24 and 32 h post-
application.
The time to cure the strippable decontamination coating on dry, clean surfaces of stainless steel
and concrete coupons was determined for three commercially available decontamination
technologies. This report summarizes results for tests performed at one air change per hour
(ACH) of the experimental chamber (equal to an air flow of 9 cubic feet per hour [ft3/h]) under
six environmental conditions consisting of three temperatures selected within the 5-40 °C range
and two associated humidity values (20-80 %RH range). In addition, for each decontamination
technology, the curing time was also measured for one extra set of coupons that was pre-wetted
and kept at a specific temperature (20 °C), high humidity (80 % RH) condition. This pre-wetting
process was intended to simulate a rain shower prior to the application of the decontamination
product. Including this test point, the total test matrix performed at a normal ventilation rate
consisted of 21 measurements of the curing time.
Each test point consisted of a set of three concrete coupons and one stainless steel coupon as a
smooth surface reference material. For each test set, application and drying/curing of the coating
and the attempted processing was performed for two orientations of concrete coupons (two
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concrete coupons in vertical and one concrete coupon in horizontal position). For stainless steel
reference coupons, curing time assessments were performed for the vertical orientation only as
the anticipated more challenging orientation for curing.
2.1 Experimental Test Chamber
A modified glove box was used as a test chamber to meet the environmental requirements of this
project. The decontamination chamber, shown in Figure 2-1, consisted of a modified glove box
with an internal volume of approximately 255 liters (L) (9.0 ft3). The exterior was insulated
using Va" TUFF-R, a rigid foil-clad polyisocyanurate board. Over an 8-h period, this chamber
was designed to be able to:
• Achieve RH values between 20-80 % and maintain them within ±5 % RH;
• Achieve temperatures between 5-40 °C and maintain them within ± 3 °C;
• Allow for the monitoring of RH and temperature conditions; and
• Allow for the coupons to be introduced and pulled out of the chamber through an airlock.
Figure 2-1. Decontamination chamber.
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2.2 Environmental Controls
The associated schematics of the chamber are shown in Figure 2-2.
VARIABLE
TEMPERATURE
LIQUID RESERVOIR
(VTRL)
Legend-
Description Symbol/Device
Insulated Line l^^^^^^l
Plumbing
Electrical Signal
Vaisala HMD53 Temperature/Humidity Transmitter MT 101
Glove box Ambient Pressure Transmitter PT 101
HF-HBA Gas Humidity Bottle HC 101
Heated injection line Temperature Controller TC 101
Meter Box Flow Controller/Meter FC 101
Solenoid Valve for RH control VI
Solenoid relief valve for Glove box Ambient Pressure V2
Neslab RTE-100 recirculator VTLR
Universal Analyzers Inc. Sample Cooler (M/N-1090PV) Condenser Unit
Figure 2-2. Decontamination chamber schematics.
Temperature and RH in the decontamination chamber were measured using a Vaisala
HUMICAP® temperature and humidity sensor, model HMD53 (Vaisala, Inc.; Helsinki, Finland)
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(MT 101 in Figure 2-2). The humidity sensor was factory preset to measure 0 to 90 % (non-
condensing) RH. The temperature sensor was preset to measure from -20 to 60 °C. This Vaisala
sensor is used for control of temperature and RH inside the glove box. The temperature inside
the glove box was also monitored by a type K thermocouple (OMEGA Engineering, Inc.,
Stamford, CT, USA) that would continuously sense temperatures from 0 to 1100 °C. Output
from the Vaisala RH/T sensor (MT-101 in Figure 2-2) and thermocouple were connected to an
lOTech data acquisition system (lOTech Inc.; Cleveland, OH, USA). Data from this lOTech
were collected by Lab VIEW software (National Instruments Co., Austin, TX, USA). This
software was programmed to control temperature, RH, and glove box pressure.
2.2.1 Temperature Control
A temperature- controlled fluid was flowing through a radiator and returned to a Neslab RTE-
100 recirculator (Neslab Instruments Inc., Portsmouth, NH, USA) which has both heating and
cooling capabilities that span the planned experimental temperature range of 5-40 °C. The
recirculator bath was controlled at a temperature from slightly above or below the target
temperature depending on the need to heat or cool the glove box to reach desired conditions. The
temperature inside the recirculator bath was monitored by a type K thermocouple (Omega
Engineering, Inc., Stamford, CT, USA). The test chamber temperature was controlled by
thermocouple output-controlled fans blowing the glove box atmosphere through a small radiator
mounted inside the glove box. When the temperature was too cold (when heating the glove box)
or too hot (when cooling the glove box), fans on the radiator inside the glove box were activated
by the software using a relay device. The cooling/heating fluid was recirculated at all times
during conditioning.
2.2.2 RH Control
To assist with low (20 %) RH conditions, air flow in the glove box was supplied by recirculating
the glove box air through a meter box (see Section 2.2.4). This meter box (FC 101 in Figure 2-2)
was pulling glove box air through a cylinder containing desiccant silica gel (Fisher Scientific,
Lane Fair Lawn, NJ, USA) and then Drierite™ (Hammond Drierite Co., Ltd.; Xenia, OH, USA)
to dry the glove box air (Figure 2-2) . This air flow was then pumped back into the glove box
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after passing through a Peltier chiller (Model 1090PV, Universal Analyzer Inc., Carson City,
NV, USA). Recirculation was necessary to maintain cool and dry conditions. The recirculated air
bypasses the silica and Drierite™ when RH is below the set point to reduce the need to exchange
the media. A three-way solenoid valve (Norgren, Littleton, CO, USA) (VI in Figure 2-2)
connected to a relay controls this bypass mechanism. Since water (vapor) is the main constituent
of the strippable coating that is released during the curing process while the humidity is
controlled, the term "air change" can be used to describe this setup despite the recirculating
process of the glove box air.
High (80 %) RH control was accomplished through the use of a high-flow gas humidity bottle,
model HF-HBA with Nafion® tubing (Fuel Cell Technologies, Inc.; Albuquerque, NM, USA)
(HC 101 in Figure 2-2). This device is labeled HC-101 in Figure 2-2. The gas humidity bottle
consisted of a heated vessel containing a length of Nafion® tubing submersed in water. Water
vapor passes through the walls of the Nafion® tubing and is picked up by passing air, which
leaves the gas humidity bottle 90 to 100 % saturated with water vapor.
2.2.3 Pressure Control
The static pressure of the glove box was controlled so that injection of the hot humid air did not
cause a positive pressure to build up in the chamber. This control was accomplished using a
differential pressure transducer (Model 265, Setra Systems, Boxborough, MA, USA) (PT-101 in
Figure 2-2) which compared the static pressure inside the glove box to ambient pressure in the
laboratory. When the differential pressures rose above 0.4 inches H2O, a solenoid connected
directly to the glove box atmosphere was opened by the Lab VIEW software, which allowed the
pressure to equilibrate.
2.2.4 Aeration Rate Control
The aeration rate of the glove box was controlled by an Apex Instruments, Inc. (Fuquay-Varina,
NC, USA) XC-40 meter console (FC 101 in Figure 2-2). This meter box (FC 101 in Figure 2-2)
was equipped with a precision dry gas meter with a mechanical or digital display (model AP25,
0.7/rev. with digital gas volume totalizer, with Quadrature Encoder, 8 digit LCD Display; 1 cc
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resolution) and mechanical orifice flow meter with 50 mm Minihelic® Pressure Gauge (range 0-
2" [0-50 millimeter (mm)] H2O).
2.2.5 Chemical Fume Hood for Decontaminant Preparation
Decontamination agents were prepared in a regular chemical fume hood. Environmental
conditions such as temperature and RH were monitored but not controlled. Environmental
conditions in the chemical fume hood were measured using a temperature and RH data logger
(HOBO U12 T/RH Data Logger, Onset Computer Corporation, Bourne, MA, USA). The
humidity sensor was factory-preset to measure 5 to 95 % RH while the temperature sensor was
preset to measure from -20 to 70 °C.
2.3 Test Materials
The representativeness and uniformity of test materials are essential in achieving defensible
evaluation results. Material representativeness means that the materials are typical of those
currently used in interiors and exteriors of buildings in terms of quality, surface characteristics,
and structural integrity. In this effort, representativeness was assured by selecting test materials
(i.e., concrete and stainless steel) that are typical of those found in industrial and municipal
settings. All materials used in this project met industry standards or specifications for indoor
and/or outdoor use and were obtained from national suppliers.
Material uniformity means that all these material coupons are equivalent for purposes related to
testing. Uniformity was maintained by obtaining and preparing a quantity of test material
sufficient to allow multiple test samples to be prepared with intentionally uniform characteristics
(e.g., test coupons were prepared from the same starting materials, using the same preparation
procedure, as per EPA's Decontamination Technologies Research Laboratory (DTRL) internal
operating procedure. The specifications of materials used for preparation of test coupons are
summarized in Table 2-1.
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Table 2-1. Description of building materials for curing time testing.
Manufacturer/ Coupon Surface Size
Material Material specifications Material Preparation
Supplier Name LxWx H (inches)
Stainless
Steel
Concrete
Multipurpose Stainless
Steel (48"X48") type
McMaster-Carr 304; #2B mill
(unpolished, 0.036"
thick)
Lowe's
hardware
store
Quikrete® Type I & II
Portland Cement;
Quikrete® All Purpose
Sand
6x6x1/8
6x6x1.5
Remove any
lubricant/grease from
shearing with acetone and
wipe dry. Remove
particles and dust by
wiping clean with water
and wipe dry.
Remove particles by
swiping with a soft nylon
brush and Dl* water.
Allow to air dry on a
laboratory bench for at
least five days.
* Deionized
2.3.1 Coupon preparations
Heavy duty power hydraulic shears were used to cut the stainless steel coupons from larger
sheets to the correct length and width.
The concrete coupons were fabricated per internal operating procedure, using the commercially
available Quikrete® Type I & II Portland Cement, Quikrete® All Purpose Sand and DI water.
One batch of fifty (50) 6" x 6" coupons was created by mixing 67.9 Ib Portland cement and
166.5 Ib sand with 19.0 L of DI water. Each batch of concrete coupons was allowed to cure for at
least 30 days in a climate-controlled environment. Environmental conditions for the concrete
coupon storage area were measured using a temperature and RH data logger (HOBO U12 T/RH
Data Logger). The humidity sensor was factory-preset to measure 5 to 95 % RH.
Concrete coupons were labeled with a permanent marker on the side of each coupon. A pre-
printed label was also placed next to each coupon to aid in the identification of coupons and test
conditions on digital photographs.
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2.4 Selected Decontamination Technologies
Specialty decontamination strippable coatings designed for decontamination of radionuclides
were used in this study. Decontamination agents are shown in Table 2-2. Three of the better
performing decontamination technologies for removal of radionuclides from concrete were
selected for this study. This selection was based on technology evaluations performed by EPA
through its National Homeland Security Research Center (NHSRC) (EPA 201 la, EPA 201 Ib,
EPA2013a, EPA2013b).
A description of the technology and its active ingredients as provided by the manufacturer of
each formulation is summarized in Table 2-2. The mechanism of action and other relevant
information regarding each decontamination agent, including special instructions for storage,
handling, as well as the preparation and application instructions and information on
recommended curing times, are described in detail in Sections 2.4.1 through 2.4.3.
1 able 2-2. Decontam
Decon Agent
CC Wet/CC Strip
DeconGel® 1108
StripCoat TLC Free™
mation agents and technologies
Manufacturer/Supplier Name
InstaCote, Inc.; Erie, Ml, USA
CBI Polymers, Inc.; Honolulu,
HI, USA
Bartlett Nuclear, Inc.;
Plymouth, MA, USA
used lor curing times testn
Technology
Contamination control
wetting agent/Strippable
coating applied onto
cured wetting agent
Strippable coating
Strippable coating
ig-
Active Ingredients
Water-Glycerin-non-ionic
surfactants (wetting
agent) and Vinyl-Acrylic-
Latex (coating)
Proprietary
Vinyl-Acrylic-
Polyisobutylene-
Polyisoprene
2.4.1 InstaCote CC Wet/CC Strip
The InstaCote CC Wet/CC Strip product consists of two components. CC Wet is a water-based
wetting agent used to stabilize loose removable contamination on surfaces. This water-based
anti-dusting medium helps prevent airborne areas of contamination from occurring. The
application of wetting agent also aids capturing of contamination in crevices and pores. Here, CC
Wet was used as a pre-coat for the application of the stripcoat (CC Strip). CC Strip is a water-
based vinyl-acrylic-latex coating recommended for removal of loose radiological or other
10
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hazardous contamination. CC Strip is typically applied over CC Wet. CC Strip re-hydrates the
CC Wet coating to encapsulate the contamination captured by the wetting agent. CC Strip is
applied as a liquid and cures to a clear, highly elastic coating which is removed by peeling.
2.4.1.1 Curing information provided by manufacturer for CC Wet/CC Strip
The manufacturer recommends a 24-h curing time for CC Strip to ensure that the product is fully
cured under the worst case environmental conditions (high humidity, low temperatures, no
ventilation). Per the manufacturer, a good indicator of sufficient curing would be a change in the
opacity of the coating - a coating that is ready for removal will become opaque while uncured
coating is translucent.
2.4.1.2 Application information CC Wet/CC Strip
The CC Wet and the CC Strip formulations are sold as ready-to-use products and do not require
any special preparation prior to application. The CC Strip was mixed with a paint stick prior to
use. As per manufacturer recommendation, the CC Wet was allowed to cure for 24 h to account
for the potential for excessive moisture formation on horizontal surfaces. The manufacturer
recommends a spray-on or roll-on/brush-on technique for application of CC Wet and CC Strip
onto contaminated surfaces. In this study, CC Wet was sprayed on using a 240 milliliter (mL)
adjustable spray wash bottle with an adjustable sprayer and allowed to dry for 24 h prior to
application of the CC Strip. The CC Strip was applied to the test coupons using the "brush-on"
technique developed in other research efforts using strippable coating decontamination agents
(EPA 201 la). The application was performed using a standard two-inch (5.0 cm) paint brush.
This paint brush was loaded with wet CC Strip by dipping the brush into the container of the
ready-to-use well mixed CC Strip. The coating was applied evenly over the entire surface of the
coupon. The brush was then used to smooth the applied CC Strip on each test coupon.
11
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2.4.2 CBI DeconGel® 1108
CBI Polymers DeconGel 1108 is a one-component, water-based, broad application, peelable
decontamination hydrogel coating designed for safely removing radioactive contamination or as
a covering to contain contamination. DeconGel® 1108 is recommended for decontamination of
radioisotopes as well as particulates, heavy metals, and water-soluble and insoluble organic
compounds, including tritiated compounds. When dry, the product locks the contaminants into a
polymer matrix. The film containing the encapsulated contamination can then be peeled and
disposed of according to appropriate local, state and federal regulations.
2.4.2.1 Curing information provided by manufacturer for DeconGel 1108
According to the manufacturer, the DeconGel 1108 drying time increases with wet film
thickness and can vary. Drying time depends on a combination of the ambient humidity,
temperature, type of substrate and applied wet film thickness. Curing can take from as little as an
hour for thinner coatings in a dry environment with considerable air flow, to overnight or longer
if thicker coats are applied in humid environments (e.g., thicker coats on porous concrete).
Drying times exceeding 24 h may be required for good peel performance on bare concrete, wood
and other highly porous substrates when thick films are applied in humid environments.
2.4.2.2 Application information for DeconGef 1108
The DeconGel® 1108 is sold as a ready-to-use "paint-like" formulation and does not require any
preparation prior to application. For each test, a fresh portion of approximately 200 mL of
DeconGel® 1108 was transferred from the primary container to a test-specific container that was
then moved to the glove box. Per the manufacturer's instructions, the DeconGel® 1108 may be
applied with a paint brush or trowel. For these tests, the DeconGel 1108 was applied to the test
coupons using the "apply-dry-peel" technique developed in other research efforts (EPA 201 la,
EPA 201 Ib). In this method, the application was performed using a standard two-inch paint
brush. The paint brush was loaded with the decon gel by dipping the brush into a plastic
container containing the DeconGel® 1108 coating. Wet coating was applied generously until the
12
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entire surface of the coupon was covered. The paint brush was then used to work the first layer
of wet coating into the surfaces. After the first application, the DeconGel® 1108 was allowed to
dry for 2 h, and a second coat was added on top of the initial coating following the same method.
2.4.3 Bartlett StripCoat TLC Free™
As per Bartlett Nuclear's website (Bartlett 2010), their Stripcoat TLC Free™ is "a non-
hazardous nontoxic strippable coating designed for safely removing and preventing the spread of
radioactive contamination". "While curing, Stripcoat TLC Free™ mechanically and chemically
entraps contamination." The dried coating containing the encapsulated contamination can then be
peeled off the surface and disposed. Stripcoat TLC Free™ can also serve as a barrier to prevent
contamination from attaching to a surface or as a covering to contain contamination. Stripcoat
TLC Free™ should not be exposed to direct sunlight for long periods. Sunlight can damage the
coating, causing it to lose its strippable qualities. Stripcoat TLC Free™ is not a submersible
coating. However, some short-term exposure of the cured coating to water should not adversely
affect the coating's qualities.
2.4.3.1 Curing information provided by manufacturer for Stripcoat TLC Free™
Per manufacturer's information, following the second application, the coating requires 4-10 h to
cure prior to removal. Curing times may depend on the coating thickness and humidity. Stripcoat
TLC Free™ can normally be removed after 4 h at normal room temperature. Thin applications
can cure in as little as one hour.
2.4.3.2 Application information Stripcoat for TLC Free™
The Stripcoat TLC Free™ is sold as a ready-to-use "paint-like" formulation and does not require
any preparation prior to application other than hand mixing prior to and during each use to
ensure homogeneity. Per manufacturer's instructions, the Stripcoat TLC Free™ may be applied
with industrial spray equipment (preferred method), paint rollers or brushes. In this study, the
Stripcoat TLC Free™ was applied to the test coupons using the "apply-allow to dry-reapply"
13
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technique developed in other research efforts (EPA 201 la, EPA 2013a). The application was
performed using a standard two-inch paint brush. The paint brush was loaded with wet Stripcoat
TLC Free™ by dipping the brush into a container containing the ready-to-use, well mixed
Stripcoat TLC Free™. The first coating was applied until the entire surface of the coupon was
covered. The brush was then used to smooth the applied Stripcoat TLC Free™ on each test
coupon. The second coating was applied after 2 h with the thickness of the final coat estimated as
1-2.5 mm, with a visible pattern of brush strokes.
2.5 Test Matrix
The time required for the strippable decontamination coatings to cure on dry surfaces of stainless
steel and concrete coupons was determined for six environmental conditions consisting of three
temperatures (selected within the 5-40 °C range), two RH values (20-80 % range) at 1 ACH.
Since all decontamination products were water based, no efforts were made to include
temperatures below their respective freezing points. Manufacturer-provided freezing points
ranged from 27-28 °F (-3 °C) for the CC Strip and CC Wet products to 32 °F (0 °C) for Stripcoat
TLC Free™. A freezing point for CBI DeconGel® 1108 of 0 °F [sic] was noticed in the material
safety data sheet (MSDS) for this product. Actual freezing points of the decontamination
products were not determined in this study.
The high temperature of 40 °C represents a frequently encountered mid-day high summer
temperature in the continental USA. Although higher temperatures can be observed, it is less
likely that a coating would be applied under such conditions considering the likely need to wear
personal protective equipment (PPE) for extended periods of time during the application of the
coating. Curing time assessments for wet surfaces were performed at 20 °C and 80 %RH at a
normal ventilation rate. The test matrix is shown in Table 2-3.
14
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Table 2-3. Test matrix for each decontamination technology.
Temperature RH Target air flow Surface Concrete Concrete Stainless steel
characteristic vertical horizontal
vertical
5
5
20
20
40
40
20
20
80
20
80
20
80
80
9
9
9
9
9
9
9
Dry
Dry
Dry
Dry
Dry
Dry
Wet
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
*Equivalent of a ventilation rate of 1 ACH.
Up to four attempts, as described in Section 2.8, were made per coupon to peel the
decontamination coating from the surface. A first attempt was made after 4 h followed by
attempts at 18 h, 24 h, and 32 h after application of the coating to the surface. If a peeling
attempt was successful from all four coupons after a specific time, the test for that coating at that
environmental condition was considered to be completed. The overnight drying of these coatings
was in general expected to be sufficient for complete curing based on previous research efforts
for concrete material coupons and environmental conditions with temperatures between 19 and
21 °C and the RH between 20 and 22 % (EPA 201 la).
2.6 Preparation of Coupons for Testing
Prior to the coating application, the surface of each coupon was examined for obvious cracks or
abnormalities and, if none were found, the coupon surfaces (both concrete and stainless steel)
were cleaned with a soft nylon brush and DI water and allowed to air dry on a laboratory bench
for at least five days. Labeled coupons were then moved to the test chamber/glove box that was
set at the specific set of temperature/RH/air change conditions.
15
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After a conditioning period of at least 48 h (up to 72 h if the equilibration phase included a
weekend) to allow equilibration between the coupon material temperature and the glove box
temperature and RH, the decontamination coating was applied to the test coupons. Figure 2-3
shows a set of coupons assembled for testing.
Figure 2-3. Coupons assembled for testing.
2.6.1 Wetted coupon preparation
For the wet surface testing, the sides and bottom of each concrete coupon were sealed with
water-based epoxy resin concrete sealer (StoneLok™ E3, Richard James Specialty Chemicals
Corp., Hastings-On-Hudson, NY, USA) to avoid penetration of water from the sides or bottom.
The sealant was allowed to cure for at least 72 h. Stainless steel coupons were not sealed.
Coupons for wet surface testing underwent a 48-h long equilibration at 20 °C/80 % RH. The
wetting procedure was performed after this equilibration phase in the glove box was finished.
Tap water, used for wetting of coupons was sprayed on the coupon with a 240 mL volume
adjustable spray wash bottle made of high-density polyethylene equipped with an adjustable
polypropylene sprayer. The amount of water needed for complete wetting of the coupon surface
was set to reflect a weather condition corresponding to a very heavy rain fall rate of
approximately 20 mm per hour for half an hour, i.e., approximately 230 mL of water was
sprayed onto each 6" x 6" coupon.
16
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Each of the to-be-wetted coupons was placed in an individual container of known weight with
the unsealed surface facing up. Each coupon was set on four rubber spacers to isolate the
concrete material from any potential run-off water to be collected in the container. After the
water spray/simulated rainfall was applied, coupons were allowed to stay in a horizontal
orientation for 15 minutes (min), to allow absorbing of water by the unsealed top surface of
concrete. Figure 2-4 shows an example of a concrete coupon soaking up the water after
application of the simulated rainfall (top view on the left and side view on the right).
Figure 2-4. Top- and side-view of concrete coupon soaking up the water after application of the
simulated rainfall.
After 15 min, all concrete coupons were turned to vertical orientation and placed on two rubber
spacers of sufficient size to allow the run-off of any excess water. The wet coupons were then
immediately moved to the glove box, and after one hour of equilibration time (at 20 °C/80 %
RH), the decontamination coating was applied to the test coupons. Based on observed changes in
RH in the glove box, these coupons were saturated with water. Containers were weighed to
calculate the amount of simulated rain in mL that ran off from the coupon surface. Table 2-4
summarizes the amounts of water applied onto and absorbed by concrete coupons in the
simulated rainfall procedure.
17
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Table 2-4. Simulated rainfall parameters.
Simulated rainfall parameters
Amount of water applied
Average run-off volume
Average amount of water absorbed by
concrete coupon
Average [ml/coupon] ± SD*; number of coupons
229 ± 2.5; n = 16
188 ± 10; n = 16
41 ± 10; n = 16
* SD: Standard Deviation
2.7 Preparation and Application of the Decontamination Agents
Decontamination products were prepared and applied per manufacturer's instructions, with
emphasis given to realistic application procedures that could be expanded to larger surface areas.
A fresh batch of coating/gel was used for each test. Immediately prior to testing, a small amount
of the coating/gel was prepared in a clean plastic container. The container was weighed and the
weight was recorded in the laboratory notebook. This preparatory work was performed in the
chemical fume hood to satisfy health and safety concerns related to working with the coating (i.e.
appropriate ventilation, respiratory protection). Environmental conditions in the chemical fume
hood were measured using a HOBO U12 T/RH data logger.
The ready-to-use batch of freshly prepared coating material was then transferred from the
chemical fume hood to the glove box using the modified airlock. The coating/gel was applied per
manufacturer's instructions inside the modified glove box under the specified T and RH
conditions maintained in the glove box. The sequence in which the coating/gel was applied to the
test coupons was recorded so that the sequence could be repeated in the coating removal
procedure at the end of the curing period.
2.7.1 Decontamination Coating Amounts
The amount of coating used for each application was assessed gravimetrically by weighing the
test container with coating material before application and then immediately post-application of
the (double) coating to the entire test set of four (one stainless steel and three concrete) coupons.
The loading volume per surface area [liter (L)/m2] for each set was calculated based on the mass
18
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[kg] and specific gravity [kg/L] of each coating applied onto the total test surface area of 4 x 36
r\
square inches (= 144 square inches [0.0929 m ]). Loading volumes were adjusted for the amount
of coating that remained on the brush post application. The remaining amounts on the brush were
calculated from a series of gravimetric measurements of pre- and post-application weights of
brushes [kg] used for coating applications and the specific gravity of each coating.
Test-specific loading volumes for each coating varied across tests and are shown in Figures A-l
through A-3 in Appendix A and Table B-3, B-7, and B-l 1 of Appendix B. The average loading
volumes for each coating/gel are given in Table 2-5.
Table 2-5. Average loading volumes per surface area for decontamination coatings tested.
Decon Agent
CCWet
CC Strip
DeconGel® 1108
StripCoat TLC Free7
Average loading volumes per surface area3
[L/m2, ± SD]; n=number of measurements
0.36±0.10;n = 7
0.48±0.11;n = 7
1.10±0.22;n =
0.35±0.10;n =
a Loading volumes were adjusted for average amount of coating that remained on brush post-application.
b Double coating applied.
The application of these decontamination products by sprayer was not considered as part of this
study. Any potential differences in curing time between application by brush or sprayer due to
differences in the amount applied per surface area would require additional testing.
Application of these water-containing coatings in the glove box resulted in high humidity
spikes/periods for all tests. The recorded RH profiles during post-application of coatings (i.e.,
during the curing phase) are shown in Appendix C, in Figures C-l through C-3. Such RH spikes
may be exaggerated here by the relatively small volume of the glove box. However, it is likely
that increases in RH following application would also occur in smaller interior areas with low air
change rates.
19
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2.8 Procedure to Determine Curing Status
The first attempt to peel off a coating from the coupon surface was made in the lower right
corner of each coupon (Corner 1 in Figure 2-5) at 4 h post-application. Prior to the first peeling
attempt, a slight surface cut at a 45 degree angle was performed with a utility knife to
start/facilitate the removal of the coating. The peel was started at this score line, moving towards
the center of the test coupon. If the first peel-off attempt was unsuccessful, the following
attempts to peel off the coating were performed starting with the upper right corner, then upper
left corner, then lower left corner of each coupon (corners 2, 3 and 4 in Figure 2-5). This curing
assessment process was conducted for all three strippable coatings.
Coupons were allowed to dry for 4 h before the first attempt to peel off the coating was made.
The second attempt (if needed) was performed after an overnight (18 h) curing. A third attempt
was scheduled at 24 h and, if needed, a fourth at 32 h post-application.
1
Figure 2-5. Scheme of the successive attempts to peel off decontamination coating from coupon
surface.
2.9 Curing Status Definitions
Based on the strippable coating/gel design, decontamination of a building material can be
expected to be successful only when a coating can be removed in its entirety from the surface as
the coating would capture the radionuclides. Efforts to remove incompletely cured coatings
20
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would lead to lower decontamination factors. Four definitions of the curing status at a specific
time post application were identified as follows:
1. Excellent curing: Coating was successfully removed from the coupon in one piece,
2. Good curing: Coating was successfully removed from the coupon in several smaller
sections without leaving non-cured coating material on the surface,
3. Partial curing: Coating could only be removed partially as localized wet spots (not cured)
were present or the peeling process resulted in numerous small (dried out) pieces, and
4. No curing: Removal of coating was not possible due to the wet nature of the coating.
21
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3.0 Test Results and Discussion
3.1 CC Wet/CC Strip
The average coating thickness post-application was estimated to be less than 2 mm. The CC
Wet/CC Strip coating cured at 4 h post-application for all environmental conditions, with a
single exception of the stainless steel surface at 20 °C/80 %RH/1 ACH/dry surface test, where
curing occurred after overnight processing (23 h post-application). This resulting coating was
overly dried-out and showed signs of elasticity loss. The coating chipped off during removal (see
Figure 3-1). Similar "brittle" coatings were observed for the 5 °C/20 %RH/1 ACH/dry surface
test. The brittleness may be due to slightly lower loading volumes observed for CC Strip
applications at cold temperatures (Figure A-2, Appendix A). The 5 °C/80 %RH/1 ACH/dry
surface test had the lowest loading volume amongst all tests using the same brush on procedure,
resulting in more inelastic and thinner yet strippable coating, which did come off the coupon
surface in many small pieces as shown in Figure 3-2), suggesting that higher humidity may
protect the lower-loading-volume coatings from over drying over long periods of time and
prevent the consequent brittleness of the resulting coatings. The application of a thicker coating
at low temperature might have improved the ability to remove the coating as one piece. This was
not investigated further in this study.
Figure 3-1. Appearance of the overly dried-out CC Wet/CC Strip coating (5 °C/20 %RH/1
ACH/dry surface, 4 h post-application of CC Strip coat).
22
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Figure 3-2. Several-piece-removal of CC Wet/CC Strip coating (20 °C/80 %RH/1 ACH/dry
surface; 4 h post-application of CC Strip coat).
Figures 3-3 and 3-4 show examples of the CC Wet/CC Strip coating curing that could be removed
completely as one elastic piece from stainless steel and concrete, respectively.
Figure 3-3. One-piece-removal of CC Wet/CC Strip coating from stainless steel (40 °C/20 %RH/1
ACH/dry surface; 4 h post-application of CC Strip coat).
23
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Figure 3-4. One-piece-removal of CC Wet/CC Strip coating from concrete (40 °C/20 %RH/1
ACH/dry surface; 4 h post-application of CC Strip coat).
Table 3-1 summarizes the results of the CC Wet/CC Strip curing time assessment under all
environmental conditions tested for 1 ACH for dry- and wet-surface tests.
24
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Table 3-1. Assessment of CC Wet/CC Strip curing times with opacity rating of coating under
various environmental conditions with normal ventilation.
Test
conditions
5 °C/20 %RH
test/1 ACH/
dry surface
5 °C/80 %RH
test/1 ACH/
dry surface
20 °C/20 %RH
test/1 ACH/
dry surface
20 °C/80 %RH
test/1 ACH/
dry surface
40 °C/20 %RH
test/1 ACH/
dry surface
40 °C/80 %RH
test/1 ACH/
dry surface
20 °C/80 %RH
test/1 ACH/
wet surface
Assessments of
curing process
[h post-
application]
4
18
24
32
4
18
24
32
4
18
24
32
4
23*
24
32
4
18
24
32
4
18
24
32
4
18
24
32
Stainless steel
vertical
OPAQUE
CHIPPED PIECES
SEMI-TRANSLUCENT
SEVERAL PIECES
OPAQUE
SEVERAL PIECES
SEMI-TRANSLUCENT
WET
SEMI-TRANSLUCENT
CHIPPED PIECES
OPAQUE
ONE PIECE
SEMI-TRANSLUCENT
ONE PIECE
SEMI-TRANSLUCENT
SEVERAL PIECES
Concrete
vertical # 1
OPAQUE
CHIPPED PIECES
SEMI-TRANSLUCENT
SEVERAL PIECES
OPAQUE
SEVERAL PIECES
SEMI-TRANSLUCENT
SEVERAL PIECES
OPAQUE
SEVERAL PIECES
SEMI-TRANSLUCENT
ONE PIECE
SEMI-TRANSLUCENT
ONE PIECE
Concrete
vertical # 2
OPAQUE
CHIPPED PIECES
SEMI-TRANSLUCENT
SEVERAL PIECES
OPAQUE
SEVERAL PIECES
SEMI-TRANSLUCENT
SEVERAL PIECES
OPAQUE
ONE PIECE
SEMI-TRANSLUCENT
ONE PIECE
SEMI-TRANSLUCENT
ONE PIECE
Concrete
horizontal # 1
OPAQUE
CHIPPED PIECES
SEMI-TRANSLUCENT
SEVERAL PIECES
OPAQUE
SEVERAL PIECES
SEMI-TRANSLUCENT
SEVERAL PIECES
OPAQUE
ONE PIECE
SEMI-TRANSLUCENT
ONE PIECE
SEMI-TRANSLUCENT
ONE PIECE
* delayed second attempt
LEGEND:
DESCRIPT
DESCRIPTION
DESCRIPTION
excellent curing/complete removal in one piece.
good curing/complete removal in several pieces.
partial curing/partial removal.
no curing/no removal possible.
25
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3.2 DeconGef 1108
Average coating thickness post-application was estimated to be less than 2 mm. For most of the
environmental conditions tested, the DeconGel® 1108 required at least overnight processing (see
Table 3-2), and resulted in easily strippable one-piece coatings, as shown in Figures 3-5 and 3-6.
Figure 3-5. One-piece-removal of DeconGel 1108 coating from stainless steel (5 °C/80 %RH/1
ACH/dry surface, 18 h post-application of 2nd coat).
Figure 3-6. One-piece-removal of DeconGel® 1108 coating from concrete (5 °C/80 %RH/1
ACH/dry surface, 18 h post-application of 2nd coat).
The 20 °C temperature and high humidity (80 %RH) conditions resulted in non-strippable (wet
or semi-cured) coatings at all four time points tested on all surfaces/surface orientations tested
for a dry surface.
26
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The coating was eventually successfully peeled off at 48 h post-application (data not shown). In
contrast, the coating did cure overnight when applied to the wet surface for the 20 °C/80 %RH/1
ACH test condition (Table 3-2). The semi-curing observed for the test on the dry surface may be
attributed to a very high-humidity spike (>90 %) related to a software malfunction and the
consequent deficiencies of environmental controls of the experimental chamber. The extremely
high humidity lasted overnight (as shown in Figure C-2 in Appendix C) and may have prevented
the coating from a complete curing due to condensation inside the chamber. Figure 3-7 shows an
example of the semi-cured DeconGel® 1108 coating, when removal of the coating was possible
only from a portion of the tested surface.
Figure 3-7. Partial removal of semi-cured DeconGer 1108 coating (20 °C/80 %RH/1 ACH/dry
surface, 32 h post-application of 2nd coat).
The 5 °C/80 %RH/1 ACH condition resulted in a wet or almost cured gel at the 4 h post-
application time point (Table 3-2). This "almost cured" coating was defined as a gel that was
starting to cure, but could not be removed, even partially as shown in Figure 3-8.
27
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Figure 3-8. Almost-cured DeconGel® 1108 coating (5 °C/80 %RH/1 ACH/dry surface, 4 h post-
application of 2nd coat).
The DeconGel® 1108 cured at 4 h (Table 3-2) for all humid and hot conditions in line with the
manufacturer's information that heat can reduce the drying times of the DeconGel® 1108,
especially in humid environments.
Table 3-2 summarizes the results of the DeconGel 1108 curing time assessments under all
environmental conditions tested for 1 ACH for dry and wet surface tests.
28
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Table 3-2. Assessment of the DeconGel® 1108 curing times under various environmental conditions
with normal ventilation.
Test
conditions
5 °C/20 %RH
test/1 ACH/
dry surface
5 °C/80 %RH
test/1 ACH/
dry surface
20 °C/20 %RH
test/1 ACH/
dry surface
20 °C/80 %RH
test/1 ACH/
dry surface
40 °C/20 %RH
test/1 ACH/
dry surface
40 °C/80 %RH
test/1 ACH/
dry surface
20 °C/80 %RH
test/1 ACH/
wet surface
Assessments of curing
process
[h post-application]
4
18
24
32
4
18
24
32
4
18
24
32
4
18
24
32
4
18
24
32
4
18
24
32
4
18
24
32
Stainless steel
vertical
WET
ONE PIECE
WET
ONE PIECE
ONE PIECE
WET
WET
SEMI-CURED
SEMI-CURED
ONE PIECE
WET
ONE PIECE
WET
ONE PIECE
Concrete
vertical # 1
WET
ONE PIECE
ALMOST CURED
ONE PIECE
ONE PIECE
WET
SEMI-CURED
SEMI-CURED
SEMI-CURED
ONE PIECE
STICKY
ONE PIECE
ALMOST CURED
ONE PIECE
Concrete
vertical # 2
WET
ONE PIECE
ALMOST CURED
ONE PIECE
ONE PIECE
WET
SEMI-CURED
SEMI-CURED
SEMI-CURED
ONE PIECE
STICKY
ONE PIECE
ALMOST CURED
ONE PIECE
Concrete
horizontal # 1
WET
ONE PIECE
ALMOST CURED
ONE PIECE
ONE PIECE
WET
SEMI-CURED
SEMI-CURED
SEMI-CURED
ONE PIECE
STICKY
SEVERAL PIECES
ALMOST CURED
ONE PIECE
LEGEND:
DESCRIPTION
DESCRIPTION
DESCRIPTION
DESCRIPTI
excellent curing/complete removal in one piece.
good curing/complete removal in several pieces.
partial curing/partial removal.
no curing/no removal possible.
29
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3.3 Stripcoat TLC Free™
Assessments of the curing process were performed 4 h post-application of the second coat; no
additional assessments were needed. Stripcoat TLC Free™ produced easily strippable coatings
under all environmental conditions tested at 1 ACH, both on dry and wet surfaces (Table 3-3).
Figures 3-9 and 3-10 show removal of cured Stripcoat TLC Free™ from a concrete and a
stainless steel coupon, respectively. Table 3-3 summarizes the results of the Stripcoat TLC
Free™ curing time assessments under all environmental conditions tested for a normal
ventilation scenario (1 ACH) for dry and wet surface tests.
Figure 3-9. One-piece-removal of Stripcoat TLC Free™ coating from concrete (20 °C/20 %RH/1
ACH/dry surface, 4 h post-application of 2nd coat).
Figure 3-10. One-piece-removal of Stripcoat TLC Free™ coating from stainless steel (20 °C/20
%RH/1 ACH/dry surface, 4 h post-application of 2nd coat).
30
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Table 3-3. Assessment of the Stripcoat TLC Free™ curing times under various environmental
conditions with normal ventilation.
Test conditions
5 °C/20 %RH
test/1 ACH/ dry
surface
5 °C/80 %RH
test/1 ACH/ dry
surface
20 °C/20 %RH
test/1 ACH/ dry
surface
20 °C/80 %RH
test/1 ACH/ dry
surface
40 °C/20 %RH
test/1 ACH/ dry
surface
40 °C/80 %RH
test/1 ACH/ dry
surface
20 °C/80 %RH
test/1 ACH/ wet
surface
Assessments of curing
process
[h post-application]
4
18
24
32
4
18
24
32
4
18
24
32
4
18
24
32
4
18
24
32
4
18
24
32
4
18
24
32
Stainless
steel vertical
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
Concrete
vertical # 1
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
Concrete
vertical # 2
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
Concrete
horizontal # 1
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
ONE PIECE
LEGEND:
DESCRIPTION
DESCRIPTION
DESCRIPTION
excellent curing/complete removal in one piece.
good curing/complete removal in several pieces.
partial curing/partial removal.
no curing/no removal possible.
31
-------
4.0 Quality Assurance and Quality Control
4.1 Data Quality Objectives
The objective of the experiments was to determine curing times for various strippable coatings
used for decontamination of radionuclides on a representative building material in the urban
environment under various environmental conditions (a combination of temperature, RH and air
change rate).
Critical measurements required to fulfill this objective included:
• RH and temperature measurements during the curing process of decontamination
coatings.
• Air change rate of the test chamber.
• Time lapse between application and actual curing of decontamination coating (for up to
four coating removal attempts within 4 - 32 h post-application of the coating).
Non-critical measurements were:
• RH and temperature measurements during curing (aging) process of concrete coupons.
• Concrete coupon curing/aging time (minimum of 30 days under normal laboratory
conditions).
• RH and temperature in fume hood as used during preparation of decontamination
coatings.
4.2 Data Quality Indicators
Data quality indicators (DQIs) for the critical measurements used to determine if the collected
data met the quality assurance (QA) objectives are summarized in Table 4-1.
32
-------
Table 4-1. DQIs for critical measurements.
Measurement Parameter Analysis Method Accuracy Precision/ Repeatability
Differential time
RH
Temperature
Temperature
Air Change Rate
Stop watch
Vaisala probes
Vaisala probes
Thermocouple
Dry Gas Meter
Is
±3%RH*
+0.4 °c**
±1.5 °C***
ImL****
Is
2%RH
0.1 °C
NA
15L/h(6%of 1ACH)
* For 0-90 % RH range; ** For 0-40 °C range; *** For 40-375 °C range; **** For range 0-2 inches Hg (0-50 mm H2O).
4.3 Equipment Calibrations
The equipment used to make the critical measurements was maintained and calibrated prior to
use. The method of calibration as well as the frequency of calibration is listed in Table 4-2.
Table 4-2. Equipment calibration schedule.
Equipment
Stop watch
Frequency
As specified by manufacturer in a Certificate of Calibration (NIST*
traceable re-certification)
Vaisala Probe (T, RH)
Yearly/biweekly checks**
Thermocouple
Yearly
HOBO U12T/RH data logger
Prior to aging of each batch of coupons
Meter Box
Yearly
* National Institute of Standards and Technology.
** Calibration checks every week according to internal operating procedures.
4.4 Quantitative A cceptance Criteria
33
-------
The quantitative acceptance criteria for each critical measurement as established in the Quality
Assurance Project Plan (QAPP) prior to the curing tests are shown in Table 4-3. The percent
completeness of the data set for each test is defined as the ratio of the number of data points
taken that pass the acceptance criteria for the critical measurements to the total number of data
points taken, multiplied by 100 %.
Table 4-3. Acceptance criteria for critical measurements.
Measurement Parameter Target Values Precision p
/o
Curing time/times of strippable
coatings
Chamber Temperature
Chamber RH
Chamber aeration rate
Time points
(4 h, 18 h, 24 h and 32 h)
5, 20, 40 °C
20, 80 %
9ft3/h
± 5 min
±3°C
±5%
±6%
100
90
90
90
Test specific results for all critical and non-critical measurements performed for the curing time
assessments are given in Appendix B (Table B-l through B-12). A summary is given in Table 4-
4 below.
34
-------
Table 4-4. Summary of critical measurements and completeness of data.
Measurement
Parameter
Target Values Average measured Number of tests
for individual below acceptance
tests; n = number criteria out of total
of tests n u m ber of tests
Curing time/times
of strippable
coatings
Chamber
Temperature
Chamber RH
Chamber aeration
rate'
Time point 1
(4 h post -application)
Time point 2
(18 h post-application)
Time point 3
(24 h post-application)
Time point 4
(32 h post-application)
5°C
20 °C
40 °C
20 %RH
80 %RH
9 ft3/h
4 h 00 min 07 sec;
n = 21
18 h 47 min 06 sec;
n = 6
23 h 58 min 49 sec;
n = l
31 h 58 min 04 sec;
n = l
7.4 °C; n = 6
20.6 °C; n = 9
39.7 °C; n = 6
20.6 %RH; n = 9
80.1%RH;n = 12
9.5; n = 21//
9.4; n = 4
0/21
l/6a
0/1
0/1
2/6b
0/9
2/6c
2/9d
2/12e
10/21 //
l/4g
a One 18 h time point was at 4 AM local time and assessment was postponed for this CC Wet/CC Strip test to more
practical time, approximately 23 h post-application (Table B-4).
Two test conditions had average temperatures of 8.3 and 8.5 °C (see Tables B-l and B-9).
0 Two test conditions had average temperature of 37.7 and 39.9 °C (see Tables B-5 and B-9).
d Two test conditions had average RH of 20.0 and 23.8 % RH (see Tables B-6 and B-10).
e One test condition had average RH of 82.9 % RH (see Table B-10).
f Prior to- // post-application of decontamination coating values; air flow measurements calculated for time periods
varying from 0.02 to!20 h; test specific air flows are in Appendix B, Tables B-3, B-7, and B-l 1.
8 Ten test conditions were conducted with flow rates as low as 6.4 and as high as 14.7 ft3/h (0.7 - 1.6 ACH).
The temperature and RH conditions were recorded in real-time using a portable data acquisition
(PDAQ) system and Lab View software. For some tests, sporadic periods without control of
environmental conditions and/or without temperature and RH data acquisitions were observed. A
specific reason for these problems was not identified, but it was attributed to the intermittent
malfunction(s) of the software or hardware (laptop, data acquisition system). The impact of the
periodic lack of environmental controls was typically low, with RH and T holding within their
respective acceptance criteria (as determined after the restart of data acquisition). For some tests,
however, the lack of environmental controls resulted in conditions that were outside the
-------
acceptable T and/or RH range. These periods were assumed to be entirely outside the acceptance
criteria in the completeness of data calculations.
For the air flow measurements, once coupons were placed in the glove box for equilibration, the
meter box was set to a flow rate of 9 ft3/h representative of 1 ACH by adjusting the fine adjust
metering valve on the unit. Initial flow rates were calculated based on the air volume sampled in
2.0 min. Adjustments to the metering valve were made until the flow rate was equal to 0.3
ft3/min (= 9 ft3/h). Once the flow was set, it was recorded only intermittently. For most of the
testing, the flow would not have changed past this point and only minor changes would have
been made to the setup. However, sometimes the flow was increased substantially to "purge" the
glove box environment after the RH fell outside the acceptance criteria, e.g., after a software or
hardware malfunction. Initially, these changes were not completely documented, and they could
have had an effect on the actual flow before testing began, or - if the meter box flow
measurement was not reset after the purge, it could result in the exaggeratedly high average flow
(as calculated prior to curing time assessments). Additional flow measurements were introduced
later on in the project as a standard procedure, with flow being verified and recorded prior to the
equilibration, post-equilibration/prior to the coating application, post-application/during the
curing process, and at the end of the entire test. For tests with multiple flow measurements (n =
4), the air change rates measured before equilibration, after equilibration and during/after curing
varied by less than 20 %, with coefficients of variation of less than 10 % for flow measurements
taken for each individual test. These observations suggest that the average flow values recorded
initially just after equilibration would have reflected the flow rates during the coating curing
process accurately.
4.5 Amendments and deviations from the original QAPP
4.5.1 Formal Amendments
During the course of this study, one amendment was added to the QAPP in response to the
observed experimental difficulties of maintaining some of the environmental conditions at 1
36
-------
ACH. Minor edits were also captured in this amendment. This amendment was submitted to the
EPA QA officer for formal approval.
4.5.2 QAPP Deviations
Deviation 1:
The original test matrix included a fourth decontamination product, a decontamination gel that
does not form a strippable coating against radionuclides. Due to a systematic error in the
preparation of smaller volumes of this product, the product as generated contained approximately
20 % more water than per the manufacturer's instructions. This error was observed during the
quality control (QC) near the end of this study. Since water content is likely to drive observations
on whether a coating or gel cures, the curing results for this decontamination product were
excluded from this report.
Deviation 2:
The original test matrix included test conditions with no air flow present in the modified glove
box to simulate a stagnant air situation. Due to complications in maintaining environmental
conditions with one air change for extended (multiple days) periods of time, this part of the study
was not conducted at this time.
37
-------
5.0 Summary
The decontamination products evaluated in this study are intended for large-area in situ removal
of a wide spectrum of radionuclides, even under challenging environmental conditions. All
strippable decontamination coatings tested (InstaCote CC Wet/CC Strip, CBI Polymers
DeconGel® 1108 and Bartlett Nuclear StripCoat TLC Free™) were easy to apply, with no
requirement for pre-preparation processes. None of the products posed major challenges during
the application using the brush-on technique employed in this study. The loading volumes per
surface test area were dependent on humidity and to a lesser extent on temperature.
The curing process of these coatings was tested under various environmental conditions. The
curing was very rapid under mild/warm (20 °C/40 °C) temperatures and low humidity (20 % RH)
conditions when all coatings tested were strippable at 4 h post-application. The surface
characteristics (wet versus dry) did not cause differences in the curing process, but high humidity
and cold temperatures seemed to be drivers for prolonged curing times for some strippable
coatings (e.g., DeconGel® 1108 and CC Wet/CC Strip). No measurable differences in the curing
times of these coatings were observed when applied to vertical surfaces versus horizontal
surfaces.
The observed curing of CC Wet/CC Strip always occurred within 24 h post-application - the time
period recommended by the manufacturer for processing of this coating at the worst case
environmental conditions (high humidity, low temperatures, no ventilation). The removal of this
coating at 5 °C and 20 % RH was more difficult due to the dried out nature and loss in elasticity
of the coating after 4 h. This observation may be somewhat biased by the lower amount of the
coating material that was applied using the same brush on procedure resulting in a thinner than
recommended coating layer that would be more difficult to remove. An application of a second
layer of CC Strip may facilitate the removal of the coating under those conditions.
For DeconGel® 1108, the observed overnight or longer curing times are in line with the
recommended curing time by the manufacturer for decontamination scenarios where thicker
38
-------
coatings are applied in humid environments when drying times exceeding 24 h may be required
for good peel performance.
StripCoat TLC Free™, which has the shortest manufacturer-recommended curing times (4-10 h)
amongst all strippable coatings tested, formed strippable coatings at 4 h post-application under
all environmental conditions tested.
The information presented in this report should help EPA responders or On-Scene Coordinators
(OSCs) in the field in identifying conditions under which strippable coatings may not cure as fast
as one may expect based on curing times at normal room temperature conditions. The curing
times and identification of more challenging conditions leading to longer curing times by the
manufacturers of these products are consistent with the observations in this report under the
tested environmental conditions.
39
-------
6.0 References
Bartlett (2010). Stripcoat TLC Free™ product information,
http://www.bartlettnuclear.com/producs-technology-contamination-control-coatings-stripcoat-
tic.htm. Last accessed June 2014.
EPA 201 la. Evaluation of Nine Chemical-Based Technologies for Removal of
Radiological Contamination from Concrete Surfaces. EPA Technical Brief. Cincinnati, OH,
USA. National Homeland Security Research Center Office of Research and Development, U.S.
Environmental Protection Agency.
EPA 201 Ib. CBI Polymers DeconGel® 1101 and 1108 for Radiological Decontamination.
Technology Evaluation. Cincinnati, OH, USA, EPA Report 600/R-l 1/084. National Homeland
Security Research Center Office of Research and Development, U.S. Environmental Protection
Agency.
EPA 2013a. Bartlett Services, Inc. Stripcoat TLC Free™ Radiological Decontamination of
Americium. Technology Evaluation. Cincinnati, OH, USA. EPA Report 600/R-13/005. National
Homeland Security Research Center Office of Research and Development, U.S. Environmental
Protection Agency.
EPA 2013b. Development of Standard Test Methods and Evaluation of the Shelf Life and
Weatherability of Fixative Coatings for Control of Radiological Contamination. EPA Report
600/R-l3/233. Research Triangle Park, NC, USA. National Homeland Security Research Center
Office of Research and Development, U.S. Environmental Protection Agency.
40
-------
Appendix A: Loading volumes versus environmental conditions
41
-------
CCWet loading volumes
c
o
Q.
D
u
_l
E
c
O q n .
•<- y'U
ra
u
"5.
Q.
TO
!_ en
£ 6'°
•Q
01
(/l
ep 30
4-1
ra
O
u
n n .
>--
_.
...
...
—
...
...
t
»
^
...
-
..
—
-
«
-
-
••
...
...
—
--
—
..
»
0
10
15
20 25
T[°C]
20% RH dry surf ace tests i 80% RH dry surf ace tests
30
35
40
45
80% RH wet surface test
Figure A-l. Loading volumes for CC Wet applications under different environmental conditions
§.
a.
a.
ea
-o
-------
Decon Gel DG1108 loading volumes
[ml/coupon]
3 t
for application
S Si
Coating usec
5 E
4
•
»
I
...
-
-
....
--
...
—
—
-
-
—
:
-~
—
-
-
-
—
._
-
-
...
-
4
__
>
k
10
»20% RH dry surface tests
15 20 25 30
T[°C]
j RH dry surface tests
i®
35
40
45
i RH test wetsurface
Figure A-3. Loading volumes for Decon Gel DG1108 applications under different environmental
conditions.
StripCoatTLC loading volumes
'E
o
a.
3
£
-90
"a.
"g
TO
O
<->
n n -
^
j
...
»
...
—
<
-
>
^
...
-
...
..
-
—
...
__
—
...
—
..
_t
L
0 5 10 15 20 25 30 35 40 45
T[°C]
*20%RH dry surface tests *80%RH dry surf ace tests
80%RH wetsurface test
Figure A-4. Loading volumes for Stripcoat TLC Free™ applications under different environmental
conditions
43
-------
Appendix B: Critical and non-critical measurements
44
-------
Table B-l. Temperatures prior and post-application of CC Wet/CC Strip.
Test
5 °C/20 %RH test/dry surface
5 °C/80 %RH test/dry surface
20 °C/20 %RH test/dry surface
20 °C/80 %RH test/dry surface
40 °C/20 %RH test/dry surface
40 °C/80 %RH test/dry surface
20 °C/80 %RH test/wet surface
Temperature [°C] measured during equilibration/pre-application
Mean ± SD
7.3±0.10
8.3±0.13
19.9±0.10
19.7±0.14
40.0±0.02
40.0±0.60
21.6±0.10
Range
7.06-7.53
7.5-8.7
19.8-20.0
19.4-20.0
39.9-40.3
35.6-44.1
21.5-21.9
% completeness
100
0.01
100
100
100
98
100
Temperature [°C] measured during curing/post-application
Mean ± SD
7.4±0.18
7.5±0.56
19.2±0.40
18.2±0.54
40.0 ±0.01 6
40.1 ±0.10
21.6±0.12
Range
7.1-12.3
7.1-9.8
18.7-20.0
17.7-20.0
39.8-40.1
40.0-40.3
21.5-22.1
Table B-2. RH conditions prior and post-application of CC Wet/CC Strip.
Test
5 °C/20 %RH test/dry surface
5 °C/80 %RH test/dry surface
20 °C/20 %RH test/dry surface
20 °C/80 %RH test/dry surface
40 °C/20 %RH test/dry surface
40 °C/80 %RH test/dry surface
20 °C/80 %RH test/wet surface
RH [%] measured during equilibration/pre-application
Mean ± SD
19.1±0.29
79.1±0.52
20.7±1 .3
80.1 ±0.20
20.1±0.10
80.4±1 .2
79.0±0.02
Range
18.4-20.0
77.8-84.9
19.6-25.2
78.1-81.3
20.0-21.1
74.1-93.9
79.0-79.1
% completeness
100
100
100
100
100
94
100
RH [%] measured during curing/post-application
Mean ± SD
28.5±7.1
82.2±1 .3
43± 9.8
84± 2.4
25.1±10
80.0±0.50
88.3±9.9
Range
19.1-58.2
75.5-83.2
19.6-73.6
79.5-90.8
19.4-69.5
78.6-82.9
78.9-122=
1 Condensing environment; incorrect reading Vaisala probe at 100% RH
Table B-3. Other parameters for application of CC Wet/CC Strip.
Test
5 °C/20 %RH test/dry surface
5 °C/80 %RH test/dry surface
20 °C/20 %RH test/dry surface
20 °C/80 %RH test/dry surface
40 °C/20 %RH test/dry surface
40 °C/80 %RH test/dry surface
20 °C/80 %RH test/wet surface
Air flow during equilibration
and post-application
[ft3/h/% of target ventilation
rate]
10.0/NA
8.4/NA
10.9/NA
13.4/NA
9.2/NA
8.2 /NA
9/9.4
111/NA
94 /NA
121 /NA
148/NA
102/NA
91 /NA
100/104
Average amount
of CC Wet used
for application
[mL/coupon]
8.1
7.4
11.0
8.4
10.0
5.0
7.9
Average application
rate of CC Wet
[sec per coupon, ± SD
0:00:12
0:00:13
0:00:13
0:00:15
0:00:21
0:00:20
0:00:14
0:00:04
0:00:01
0:00:01
0:00:04
0:00:01
0:00:03
0:00:01
Average amount
of CCStrip used
for application
[mL/coupon]
11.8
9.8
13.8
15.3
16.8
12.5
10.5
Average application rate
of CCStrip
[sec per coupon, ± SD]
0:00:39
0:00:39
0:00:35
0:00:42
0:00:41
0:00:43
0:00:35
0:00:02
0:00:04
0:00:02
0:00:01
0:00:01
0:00:03
0:00:06
Final coating
thickness
[mm]
1.1-2.5
1.1-2.5
1.1-2.5
1.1-2.5
1.1-2.5
1.1-2.5
0.9-1.1
NA — not available
45
-------
Table B-4. Curing time assessments for CC Wet/CC Strip.
Test
Average curing time,
1st attempt to peel off
[h:min:sec post-application, +/- SD]
Average curing time,
2nd attempt to peel off
[h:min:sec post-application, ± SD]
Average curing time,
3rd attempt to peel off
[h:min:sec post-application, ± SD]
Average curing time,
4th attempt to peel off
[h:min:sec post-application, ± SD]
5 °C/20 %RH test/dry surface
4:02:19
0:02:27
5 °C/80 %RH test/dry surface
4:00:21
0:00:27
20 °C/20 %RH test/dry surface
4:00:42
0:00:12
20 °C/80 %RH test/dry surface
4:03:46
0:04:32
22:43:51
40 °C/20 %RH test/dry surface
4:02:05
0:02:31
40 °C/80 %RH test/dry surface
4:03:46
0:04:32
20 °C/80 %RH test/wet surface
3:55:36
0:00:19
46
-------
Table B-5. Temperatures prior and post-application of DeconGel® 1108.
Test
5 °C/20% RH test/dry surface
5 °C/80% RH test/dry surface
20 °C/20% RH test/dry surface
20 °C/80% RH test/dry surface
40 °C/20% RH test/dry surface
40 °C/80% RH test/dry surface
20 °C/80% RH test/wet surface
Temperature [°C] measured during equilibration/pre-application
Mean ± SD
7.3±0.0.13
7.2±0.0.10
19.1±0.74
19.7±0.10
40.1±0.09
37.7±1.3
22.2±0.10
Range
7.0-7.8
6.8-7.4
18.3-20.0
19.2-20.0
40.0-40.5
30.0-38.1
22.0-22.4
% completeness
100
100
100
100
100
74
100
Temperature [°C] measured during curing/post-application
Mean ± SD
7.4±0.0.18
7.5±0.0.19
20.0±0.10
19.6±0.50
40.1 ±0.07
35.0±0.32
21.7±0.17
Range
7.1-9.0
7.2-8.6
19.9-20.5
18.2-20.0
40.0-40.4
33.4-35.3
21.3-22.3
Table B-6. RH conditions prior and post-application of DeconGel® 1108.
Test
5 °C/20% RH test/dry surface
5 °C/80% RH test/dry surface
20 °C/20% RH test/dry surface
20 °C/80% RH test/dry surface
40 °C/20% RH test/dry surface
40 °C/80% RH test/dry surface
20 °C/80% RH test/wet surface
RH [%] measured during equilibration/pre-application
Mean ± SD
19.2±0.30
82.9±0.13
20.1±1.50
80.1±0.50
20.5±1 .00
80.5±1.10
79.1±0.02
Range
18.4-20.9
82.5-83.3
4.23-30.7*
76.3-86.9
19.7-24.9
74.6-81 .6
78.4-79.1
% completeness
100
100
84
100
100
99.5
100
RH [%] measured during curing/post-application
Mean ± SD
41.0±6.00
82.3±0.56
81 .6±6.8
82.4±3.4
60.2±9.3
77.1 ±0.61
87.5±6.1
Range
19.7-63.9
79.2-83.4
23.1-84.7
79.4-90.4
19.7-71.5
74.7-79.1
79.0-94.6
Table B-7. Other parameters for application of DeconGel® 1108.
Test
5 °C/20% RH test/dry surface
5 °C/80% RH test/dry surface
20 °C/20% RH test/dry surface
20 °C/80% RH test/dry surface
40 °C/20% RH test/dry surface
40 °C/80% RH test/dry surface
20 °C/80% RH test/wet surface
Air flow during equilibration/post-
application
[ft3/h/% of target ventilation rate]
9.7 /NA
9.0 /NA
8.8/8.9
10.3/NA
14.7/NA
6.4 /NA
9.0/9.9
107 /NA
99 /NA
97/99
114/NA
163 /NA
72 /NA
100/110
Average amount
of coating used
for 1st application
[mL/coupon]
18.8
10.7
12.9
13.4
16.5
17.0
13.4
Average amount
of coating used for
2nd application
[mL/coupon]
12.9
9.1
10.9
9.6
16.5
8.1
12.2
Average application rate
[sec per coupon, ± SD]
0:01:01
0:00:53
0:00:55
0:00:58
0:01:06
0:00:54
0:00:54
0:00:06
0:00:02
0:00:05
0:00:05
0:00:10
0:00:05
0:00:12
Final coating thickness
[mm]
1.1-2.5
1.1-2.5
1.1-2.5
1.1-2.5
1.1-2.5
1.1-2.5
1.1-1.4
NA — not available
47
-------
Table B-8. Curing time assessments for DeconGel® 1108.
Test
Average curing time,
1st attempt to peel off
[h:min:sec post-application, ± SD]
Average curing time,
2nd attempt to peel off
[h:min:sec post-application, ± SD]
Average curing time,
3rd attempt to peel off
[h:min:sec post-application, ± SD]
Average curing time,
4th attempt to peel off
[h:min:sec post-application, ± SD]
5 °C/20% RH test/dry surface
3:58:50
0:00:45
17:59:51
0:00:14
5 °C/80% RH test/dry surface
3:59:10
0:00:45
18:00:14
0:00:36
20 °C/20% RH test/dry surface
3:59:53
0:00:10
20 °C/80% RH test/dry surface
3:58:44
0:00:46
17:58:51
0:00:56
23:58:49
0:00:38
31:58:04
0:00:27
40 °C/20% RH test/dry surface
4:00:48
0:00:32
40 °C/80% RH test/dry surface
3:57:12
0:00:43
18:00:39
0:02:34
20 °C/80% RH test/wet surface
3:58:14
0:00:51
17:59:11
0:00:17
48
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Table B-9. Temperatures prior and post-application of Stripcoat TLC Free™.
Test
5 °C/20% RH test/dry surface
5 °C/80% RH test/dry surface
20 °C/20% RH test/dry surface
20 °C/80% RH test/dry surface
40 °C/20% RH test/dry surface
40 °C/80% RH test/dry surface
20 °C/80% RH test/wet surface
Temperature [°C] measured during equilibration/pre-application
Mean ± SD
5.98±0.25
8.5±0.16
20.0±0.06
21.4±1.2
40.1±0.06
40.0±0.22
21 .9±0.09
Range
5.56-6.52
8.24-8.78
20.0-20.7
17.3-27.2
39.9-40.3
25.9-40.0
21.6-22.1
% completeness
100
0
100
100
100
61
100
Temperature [°C] measured during curing/post-application
Mean ± SD
6.33±0.10
8.5±0.17
20.0±0.09
20.7±0.20
40.1 ±0.06
36.8±3.8
21.3±0.10
Range
6.02-6.53
8.3-9.4
19.9-20.5
20.6-21.6
40.0-40.4
25.9-40.0
21.2-21.7
Table B-10. RH conditions prior and post-application of Stripcoat TLC Free™.
Test
5 °C/20% RH test/dry surface
5 °C/80% RH test/dry surface
20 °C/20% RH test/dry surface
20 °C/80% RH test/dry surface
40 °C/20% RH test/dry surface
40 °C/80% RH test/dry surface
20 °C/80% RH test/wet surface
RH [%] measured during equilibration/pre-application
Mean ± SD
23.8±3.0
78.6±1.2
21.7±1.4
78.8±3.5
20.2±0.15
82.3±0.62
80.0±0.017
Range
20.00-30.3
75.7-80.1
20.0-24.1
62.7-92.9
18.9-21.1
71 .5-92.0
80.0-80.1
% completeness
66
100
100
92
100
61
100
RH [%] measured during curing/post-application
Mean ± SD
37.1±3.0
78.8±0.30
44.0±11.9
80.4±0.30
24.1±5.9
82.1±3.4
87.5±5.5
Range
22.4-44.0
77.4-79.6
20.0-73.4
79.2-82.6
18.46-44.7
82.1-93.8
78.9-94.4
Table B-ll. Other parameters for application of Stripcoat TLC Free™.
Test
5 °C/20% RH test/dry surface
5 °C/80% RH test/dry surface
20 °C/20% RH test/dry surface
20 °C/80% RH test/dry surface
40 °C/20% RH test/dry surface
40 °C/80% RH test/dry surface
20 °C/80% RH test/wet surface
Air flow during equilibration/post-
application
[ft3/h/% of target ventilation rate]
9.5 /NA
8.7 /NA
9.1 /NA
9.0 /NA
8.8 /NA
8.0 /NA
9.1/9.2
106/NA
97 /NA
101 /NA
100/NA
98 /NA
88 /NA
101/102
Average amount
of coating used for
1st application
[ml_ ./coupon]
5.7
5.7
6.4
4.8
5.7
5.7
5.7
Average amount
of coating used for
2nd application
[mL/coupon]
5.5
4.8
7.1
3.1
4.3
3.6
4.7
Average application rate
[sec per coupon, ± SD]
00:29
00:25
00:27
00:25
00:30
00:22
00:24
00:05
00:02
00:03
00:01
00:03
00:03
00:03
Final coating thickness
[mm]
<2
<2
<2
<2
<2
<2
<2
NA — not available
49
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Table B-12. Curing time assessments for Stripcoat TLC Free™.
Test
Average curing time,
1st attempt to peel off
[h:min:sec post-application, ± SD]
Average curing time,
2nd attempt to peel off
[h:min:sec post-application, ± SD]
Average curing time,
3rd attempt to peel off
[h:min:sec post-application, ± SD]
Average curing time,
4th attempt to peel off
[h:min:sec post-application, ± SD]
5 °C/20 %RH test/dry surface
4:00:52
0:00:23
5 °C/80 %RH test/dry surface
4:00:49
0:00:44
20 °C/20 %RH test/dry surface
3:59:34
0:00:29
20 °C/80 %RH test/dry surface
4:00:06
0:00:37
40 °C/20 %RH test/dry surface
4:00:08
0:00:36
40 °C/80 %RH test/dry surface
4:00:48
0:00:37
20 °C/80 %RH test/wet surface
3:58:34
0:00:34
50
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Appendix C: RH profiles during curing of decontamination coatings
51
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CCWet/CC Strip RH Profiles
-•-RHTest S-40T.SORH
-*-RHTest 7-40T.20RH
-K-RHTest 11-5T.20RH
-*-RHTest 12b-20T, 20RH
-•-RHTest 14-20T. SORH
-t- RHTest 19-ST.BQRH
-•-RHTest 2S 20T.BQRH WET
Figure C-l. RH profiles during curing of CC Wet/CC Strip.
52
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Decon Gel DG1108 RH Profiles
100
-•-RH Test 6- 40T, 20RH
-*-RH Test 10- 5T, 20RH
-*-RH Test 15- 20T, 80RH
-*-RH Test 20- 5T, 80RH
-•-RH Test 22- 40T, 80RH
-I-RH Test 24- 20T, 20RH
-•-RH Test 27 20T, 80RH WET
Figure C-2. RH profiles during curing of DeconGel® DG1108.
53
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StripCoat RH Profiles
100
-•-RH Test 1 - 20T, 20RH
-«-RH Test 8- 5T, 20RH
-A-RH Test 2 - 40T, 20RH
-*-RH Test 3 - 20T, 80RH
-*-RH Test 4- 40T, 80RH
-•-RH Test 17- 5T, 80RH
-I-RH Test 25 20T, 80RH WET
Figure C-3. RH profiles during curing of Stripcoat TLC Free™. The double spikes in RH are
associated with the application of two coatings.
54
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United States
Environmental Protection
Agency
PRESORTED STANDARD
POSTAGE & FEES PAID
EPA
PERMIT NO. G-35
Office of Research and Development (8101R)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
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