# ASTM F2815-10 (Reapproved 2014)

Designation: F2815 − 10 (Reapproved 2014)Standard Practice forChemical Permeation through Protective Clothing Materials:Testing Data Analysis by Use of a Computer Program1This standard is issued under the fixed designation F2815; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (´) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the calculations of all the perme-ation parameters related to Test Method F739, ISO 6529, andPractice D6978 standards by use of a computer program,referred to as “Permeation Calculator” (DHHS (NIOSH) Pub-lication No. 2007 – 143c).2,31.2 The practice is applicable to both open loop and closedloop permeation tests. The closed loop test includes continuoussampling and discrete sampling. The discrete sampling in-cludes tests when sample volume is replaced and also whensample volume is not replaced. For an open loop permeationtest, the computer program also allows permeation data fileswith variable sampling flow rate. Refer to Test Method F739for more details about the different types of the permeationtesting systems.1.3 This practice is applicable to the most typical perme-ation behavior, that is, Type A, where the permeation ratestabilizes at a “steady-state” value. It does not apply to theother types of permeation behaviors. Refer to Test MethodF739 for more details about the various permeation behaviors.1.4 This practice is not applicable to Test Method F1383because the permeation behavior is different under conditionsof intermittent contact than under conditions of continuouscontact.1.5 This practice does not address the procedure of perme-ation testing. Refer to Test Method F739, ISO 6529, or PracticeD6978 for the procedures in detail if needed.2. Referenced Documents2.1 ASTM Standards:4D6978 Practice for Assessment of Resistance of MedicalGloves to Permeation by Chemotherapy DrugsF739 Test Method for Permeation of Liquids and Gasesthrough Protective Clothing Materials under Conditions ofContinuous ContactF1194 Guide for Documenting the Results of ChemicalPermeation Testing of Materials Used in Protective Cloth-ingF1383 Test Method for Permeation of Liquids and Gasesthrough Protective Clothing Materials under Conditions ofIntermittent ContactF1494 Terminology Relating to Protective Clothing2.2 ISO Standards:5ISO 6529 Protective Clothing—Protection againstChemicals—Determination of Resistance of ProtectiveClothing Materials to Permeation by Liquids and Gases3. Terminology3.1 Definitions:3.1.1 analytical technique, n—a procedure whereby theconcentration of a challenge chemical in a collection mediumis quantitatively determined.3.1.1.1 Discussion—The detailed steps for these proceduresare often specific to individual chemical and collection mediumcombinations. Applicable techniques include but are not lim-ited to flame ionization, photo ionization, electro-chemical, andultraviolet and infrared spectrophotometry, gas and liquidchromatography, colorimetry, length-of-stain detector tubes,and radionuclide tagging/detection counting.3.1.2 breakthrough detection time, n—the elapsed time mea-sured from the start of the test to the sampling time thatimmediately precedes the sampling time at which the testchemical is first detected.1This practice is under the jurisdiction of ASTM Committee F23 on PersonalProtective Clothing and Equipment and is the direct responsibility of SubcommitteeF23.30 on Chemicals.Current edition approved May 1, 2014. Published May 2014. Originallyapproved in 2010. Last previous edition approved in 2010 as F2815–10.DOI:10.1520/F2815–10R14.2Gao P, Weise T, and Tomasovic B [2009] Development of a computer programfor permeation testing data analysis. Journal of Occupational solid chemicals move through voids in the materials assolids, liquids as liquids, and gases as gases. Penetration is adistinctly different mechanism from permeation.3.1.12 permeation, n—for chemical protective clothing, themovement of chemicals as molecules through protective cloth-ing materials by the processes of (1) absorption of the chemicalinto the contact surface of the material, (2) diffusion of theabsorbed molecules throughout the material, and (3) desorptionof the chemical from the opposite surface of the material.3.1.12.1 Discussion—Permeation is a distinctly differentmechanism from penetration.3.1.13 protective clothing, n—an item of clothing that isspecifically designed and constructed for the intended purposeof isolating all or part of the body from a potential hazard; orisolating the external environment from contamination by thewearer of the clothing.3.1.14 standardized breakthrough time, n—the first time atwhich the permeation rate reaches 0.1 µg/cm2/min.3.1.15 steady-state permeation rate, n—a constant rate ofpermeation that occurs after breakthrough when all forcesaffecting permeation have reached equilibrium.3.1.16 test chemical, n—solid, liquid, gas or mixturethereof, used to evaluate the performance of a protectiveclothing material.4. Summary of Practice4.1 The computer program used in this practice calculatesall the permeation parameters listed in Test Method F739, ISO6529, and Practice D6978, including standardized break-through time, normalized breakthrough detection time, break-through detection time, minimum breakthrough detection time(if applicable), steady-state permeation rate, cumulative per-meation at a given elapsed time, elapsed time at a givencumulative permeation, average permeation rate, and maxi-mum permeation rate if it is an open loop permeation test.4.2 The operation of the computer program involves thefollowing steps:4.2.1 Data Input to the Computer Program—Input a perme-ation testing data file that contains data points in time versusconcentration. The data must be in a spreadsheet software filewith a minimum of seven data points before the breakthroughpoint and the total number of data points can not exceed 5000.The number of significant figures used for the input data willaffect the number of significant figures reported for thepermeation parameters, so appropriate significant figuresshould be used. Refer to Appendix X1 for details in data filerequirements.4.2.2 Analysis—After importing the data file and enteringrequired information, the program determines the permeationparameters based on a series of strategies and approaches.4.2.3 Output—Upon completion, the program displays allthe permeation parameters together with relevant informationand the permeation curve in a spreadsheet software or a textfile-formatted report.5. Significance and Use5.1 Data analysis for chemical protective clothing perme-ation testing involves a number of equations and experimentalfactors. Possible calculation errors are critical issues whendetermining permeation parameters. Because the calculationsof some of the permeation parameters are mathematicallycomplex, this computer program will be useful.5.2 This practice is to help researchers and industrial hy-gienists avoid labor intensive hand calculations of the perme-ation parameters. From a standardization point of view, thispractice prevents variability or inconsistency caused by differ-ent experimenters thus ensuring identical permeation param-eters or results will be obtained from a given permeation testdata file.F2815 − 10 (2014)25.3 Protective clothing manufacturers worldwide will ben-efit since they must inform customers about the permeationparameters of their products in a consistent manner. Thepractice will also help diagnostic laboratories and researchcenters involved in the chemical protective clothing testing.6. Calculation6.1 Symbols—The following symbols are used in thecalculations, where:a = a coefficient for a polynomial equation, Eq 1-3 andEq 15; an arbitrary data point before data point b,Eq 6-10,A = area of the material specimen contacted, cm2, Eq 4,Eq 5, Eq 11, Eq 13, and Eq 14,b = a constant for a polynomial equation, Eq 1-3 and Eq15; an arbitrary data point after data point a, Eq 10,c = a constant for a polynomial equation, Eq 1,C = concentration of test chemical in collectionmedium, µg/L, Eq 11, Eq 13, and Eq 14,C¯= average concentration of test chemical in collectionmedium, µg/L, Eq 5,CP = cumulative permeation beginning with initialchemical contact, µg/cm2, Eq 6-11, Eq 13, and Eq14,F = flow rate of collection medium through the perme-ation cell, L/min, Eq 5,i = data point, Eq 11-14; data point immediately beforedata point a or b, Eq 6-9,m = a collection or a series of data points i, Eq 7 and Eq9,n = total number of data points i, Eq 11, Eq 13, and Eq14,P = permeation rate, µg/cm2/min,P¯= average permeation rate for the time interval TatoTb, µg/cm2/min, Eq 10,R = correlation coefficient of a regression analysis,SSPR = steady-state permeation rate, µg/cm2/min, Eq 4 andEq 5,T = elapsed time, min, Eq 6-10,Vi= remaining medium volume at ti, Eq 12,Vs= volume of discrete sample removed from the col-lection medium, L, Eq 11-Eq 14,Vt= total volume of the collection medium, L, Eq 4, Eq12-Eq 14,x = value of x axis in a permeation curve, min, andy = value of y axis in a permeation curve, µg/L, µg/cm2,or µg/cm2/min.6.2 Breakthrough detection time for open-loop permeationtest and closed-loop permeation test with continuous sampling:6.2.1 Calculate the slope and regression correlation coeffi-cient centered on each data point n starting atn=8,byperforming a linear regression for points n-7 to n+7.6.2.2 Calculate the slope between the data point closest to50 % and the data point closest to 90 % of the maximumconcentration, that is, (y90-y50)/(x90-x50). This is referred to asthe largest slope.6.2.3 Stop when all of the following conditions are met: (1)the slopes calculated in 6.2.1 increase consecutively for seventimes, (2) each of these seven slopes is greater than 2 % of thelargest slope calculated in 6.2.2, and (3) the square of thecorrelation coefficient (R2) for the last slope is greater than 0.9.NOTE 1—Conditions (1) and (3)in6.2.3 are to filter out the backgroundnoise and Condition (2) is to avoid determining the breakthrough detectiontime in a flat region before the real breakthrough. The values specified forthese three conditions were optimized using hundreds of permeation datafiles. Refer to Section 9 on the precision and bias. In addition, adequatelypredicting the real tendency of the data for determining the breakthroughdetection time could not be ensured when using fewer data points for thelinear regression analysis.6.2.4 When the last slope is determined in 6.2.3, select thefirst data point used in that slope’s calculation as the break-through point (BP).6.2.5 Using the data points from BP to the point closest to15 % of the maximum concentration, perform a regressionanalysis to obtain a polynomial equation (yBP=ax2+bx+c) asillustrated in Fig. 1(a).NOTE 2—Calculating breakthrough detection time by taking the regres-sion analysis and then solving the polynomial equation is to avoidreporting the standardized breakthrough time only at the times (Ti) that areshown in the data file but not really at a time within a data collection timeinterval (same purpose for the calculations of standardized breakthroughtime and normalized breakthrough detection time as to be describedbelow).6.2.6 Calculate the breakthrough detection time by solvingthe polynomial equation for x. Take the root x1 or x2,whichever is closest to xBP.6.3 Standardized breakthrough time:6.3.1 Closed-loop permeation test with continuous sam-pling:6.3.1.1 As shown in Fig. 1(b), for a permeation curve of y(µg/cm2) against x (min), the program performs a regressionanalysis using a range of data points to obtain a polynomialequation, that is, Eq 1. The first data point is the one with anelapsed time closest to 75 % of the time value for the BP, asdetermined previously for calculation of the breakthroughdetection time, and the last data point is the one with a CPclosest to 15 % of the maximum CP.y 5 ax21bx1c (1)6.3.1.2 Take the derivative to obtain the permeation rate inµg/cm2/min:dydx5 2ax1b (2)6.3.1.3 Based on the ASTM definition stated above, let2ax1b 5 0.1 (3)6.3.1.4 Solve Eq 3 for the standardized breakthrough time(x). If the calculated x value is outside the time range for thedata points used for the regression, repeat the above proce-dures. The data for the next regression analysis uses the samenumber of data points but the starting point is incremented byone.6.3.1.5 Report the value of x determined in 6.3.1.4 asstandardized breakthrough time for a closed-loop permeationtest once the conditions are satisfied.6.3.2 Open-loop permeation test:F2815 − 10 (2014)36.3.2.1 Find two consecutive points where the permeationrate at point i 0.1 µg/(cm2*min) and point i+1 ≥ 0.1µg/(cm2*min). Select the point with a permeation rate closestto 0.1 µg/(cm2*min).6.3.2.2 Perform a regression analysis using 11 data pointscentered on the selected point from Step 6.3.2.1 to obtain apolynomial equation (0.1 = ax2+bx+c) as illustrated in Fig.1(c).6.3.2.3 Calculate the standardized breakthrough time bysolving the polynomial equation. Take the root x1 or x2,whichever is closest to the time of the point determined in6.3.2.1.6.4 Normalized breakthrough detection time:6.4.1 Closed-loop permeation test with continuous sam-pling:6.4.1.1 Find two consecutive points where the cumulativepermeation at point i 2.5 µg/cm2and point i+1 ≥ 2.5 µg/cm2.Select the point with a cumulative permeation closest to 2.5µg/cm2.6.4.1.2 Perform a regression analysis using eleven datapoints centered on the selected point from Step 6.4.1.1 toobtain a polynomial equation (2.5 = ax2+bx+c) as illustrated inFig. 1(b).6.4.1.3 Calculate normalized breakthrough detection timeby solving the polynomial equation. Take the root x1 or x2,whichever is closest to the time of the point determined in6.4.1.1.6.4.2 Open-loop permeation test:6.4.2.1 Find two consecutive points where the permeationrate at point i 1.0 µg/(cm2*min) and point i+1 ≥ 1.0µg/(cm2*min). Select the point with a permeation rate closestto 1.0 µg/(cm2*min).6.4.2.2 Perform a regression analysis using eleven datapoints centered on the selected point from Step 6.4.2.1 toobtain a polynomial equation (1.0 = ax2+bx+c) as shown inFig. 1(c).6.4.2.3 Calculate normalized breakthrough detection timeby solving the polynomial equation. Take the root x1 or x2,whichever is closest to the time of the point determined in6.4.2.1.6.5 Steady-state permeation rate (SSPR):6.5.1 Closed-loop permeation test with continuous sam-pling:6.5.1.1 For a permeation curve of y (µg/L) against x (min),determine the slope of the steady-state region by taking a linearregression of the data points between 65 % and 85 % of theFIG. 1 Determination for Various Breakthrough TimesF2815 − 10 (2014)4maximum concentration point to obtain the slope. Calculate theSSPR based on Eq 4:SSP