Determination of material resistance to permeation by chemicals - Part 1: Permeation by potentially hazardous liquid chemicals under conditions of continuous contact
This European Standard specifies a test method for the determination of the resistance of protective clothing, gloves and footwear materials to permeation by potential hazardous liquid chemicals under the condition of continuous contact.
This test method is applicable to the assessment of protection against liquid chemicals that can be collected only by liquid or gaseous collecting media.
This test method is not adapted for the assessment of chemical mixtures, except for aqueous solutions.
This standard shall be used with the specifications given in the products standards (for examples EN 374 1 for gloves) where the following information shall be defined:
- any pre-conditioning;
- precise sampling (place, size, number);
- associated levels of performance.
Bestimmung des Widerstands von Materialien gegen die Permeation von Chemikalien - Teil 1: Permeation durch potentiell gefährliche flüssige Chemikalien unter Dauerkontakt
Diese Europäische Norm legt ein Prüfverfahren für die Bestimmung des Widerstands von Schutzkleidungs-material, Schutzhandschuh- und Fußschutzmaterial gegen die Permeation durch potentiell gefährliche flüssige Chemikalien unter Dauerkontakt fest.
Dieses Prüfverfahren gilt für die Beurteilung des Schutzes gegen flüssige chemische Stoffe, die nur mit flüssigen oder gasförmigen Sammelmedien erfasst werden können.
Dieses Prüfverfahren !ist nicht anwendbar bei der" Beurteilung von chemischen Gemischen, ausgenommen sind wässrige Lösungen.
Diese Norm ist gemeinsam mit den in den Produktnormen angegebenen Festlegungen zu verwenden (z. B. !EN ISO 374-1:2016" für Schutzhandschuhe), wo die folgenden Informationen festgelegt sind:
— jegliche Vorbehandlung;
— genaue Probenahme (Ort, Größe, Anzahl);
— zugeordnete Leistungsstufen.
Détermination de la résistance des matériaux à la perméation par des produits chimiques - Partie 1: Perméation par des produits chimiques liquides potentiellement dangereux dans des conditions de contact continu
La présente Norme européenne spécifie une méthode d'essai pour la détermination de la résistance des
matériaux utilisés dans la confection de vêtements de protection, gants et chaussures à la perméation
par des produits chimiques liquides potentiellement dangereux, dans des conditions de contact continu.
La présente méthode d'essai s'applique à l'évaluation de la protection contre les produits chimiques
liquides qui ne peuvent être collectés qu'au moyen d'un milieu collecteur liquide ou gazeux.
La présente méthode d'essai n'est pas !applicable" à l'évaluation de mélanges de produits
chimiques, à l'exception des solutions aqueuses.
La présente norme est utilisée avec les spécifications fournies dans les normes de produits (par
exemple, l'!EN ISO 374-1:2016" pour les gants), dans lesquelles les informations suivantes sont
tout préconditionnement ;
un échantillonnage précis (endroit, taille, nombre) ;
les niveaux de performance correspondants.
Ugotavljanje odpornosti materiala proti pronicanju kemikalij - 1. del: Pronicanje potencialno nevarnih tekočih kemikalij pri pogojih neprestanega stika
Ta evropski standard določa preskusno metodo za ugotavljanje odpornosti materialov varovalne obleke, rokavic in obutve proti pronicanju potencialno nevarnih tekočih kemikalij v pogojih neprekinjenega stika.
Ta preskusna metoda se uporablja za vrednotenje varovanja pred tekočimi kemikalijami, ki jih je mogoče zbrati samo s tekočimi ali plinskimi mediji za zbiranje.
Te preskusna metoda ni prilagojene za ocenjevanje kemijskih zmesi, razen za vodne raztopine.
Ta standard je treba uporabljati s specifikacijami, podanimi v standardu za izdelke (kot je standard EN 374 1 za rokavice), kjer so opredeljene naslednje informacije:
– morebitni predpogoji;
– natančno vzorčenje (kraj, velikost, število);
– povezane ravni zmogljivosti.
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.WLNDBestimmung des Widerstands von Materialien gegen die Permeation von Chemikalien - Teil 1: Permeation durch potentiell gefährliche flüssige Chemikalien unter DauerkontaktDétermination de la résistance des matériaux à la perméation par des produits chimiques - Partie 1: Perméation par des produits chimiques liquides potentiellement dangereux dans des conditions de contact continuDetermination of material resistance to permeation by chemicals - Part 1: Permeation by potentially hazardous liquid chemicals under conditions of continuous contact13.340.01Varovalna oprema na splošnoProtective equipment in generalICS:Ta slovenski standard je istoveten z:EN 16523-1:2015+A1:2018SIST EN 16523-1:2015+A1:2018en,fr,de01-december-2018SIST EN 16523-1:2015+A1:2018SLOVENSKI
STANDARDSIST EN 16523-1:20151DGRPHãþD
SIST EN 16523-1:2015+A1:2018
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
t r s z ICS
s uä u v rä r s Supersedes EN
s x w t uæ sã t r s wEnglish Version
Determination of material resistance to permeation by chemicals æ Part
sã Permeation by potentially hazardous liquid chemicals under conditions of continuous contact Détermination de la résistance des matériaux à la perméation par des produits chimiques æ Partie
sã Perméation par des produits chimiques liquides potentiellement dangereux dans des conditions de contact continu
Bestimmung des Widerstands von Materialien gegen die Permeation von Chemikalien æ Teil
sã Permeation durch potentiell gefährliche flüssige Chemikalien unter Dauerkontakt This European Standard was approved by CEN on
t r s v and includes Amendment
s approved by CEN on
t r s zä
egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä
translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä
CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä
EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Rue de la Science 23,
t r s z CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN
s x w t uæ sã t r s w ªA sã t r s z ESIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 2 Contents Page European foreword . 4 Introduction . 5 1 Scope . 6 2 Normative references . 6 3 Terms and definitions . 6 4 Test principle . 9 5 Collecting media . 9 5.1 Gaseous collecting medium . 9 5.2 Liquid collecting medium . 9 6 Apparatus . 10 6.1 Permeation cells . 10 6.1.1 Standard permeation cell . 10 6.1.2 Alternative permeation cells . 12 6.2 Temperature controlled room, cabinet or water bath . 12 6.3 Supply of gas for gaseous collecting medium (dry air or nitrogen) . 12 6.4 Liquid pump and stirrer (in case of a liquid collecting medium) . 12 6.5 Equipment for the quantitative determination of the challenge chemical or its components in the collecting medium . 12 6.6 Time measuring device . 13 7 Test specimens . 13 8 Procedure. 13 8.1 Calibration . 13 8.2 !Assembly of test specimens in the cells" . 13 8.3 Test procedure . 14 8.4 Calculation of results . 15 8.4.1 Open loop system: Permeation rate (PR) . 15 8.4.2 Closed loop system Permeation rate (PR) . 15 8.5 Expression of results . 16 8.6 Uncertainty of measurement . 16 9 Test report . 17 Annex A (informative)
Types of permeation behaviour . 18 Annex B (informative)
Physical assessment of the samples . 20 B.1 General . 20 B.2 Visual appearance . 20 B.3 Thickness . 20 B.4 Mass . 20 B.5 Hardness . 20 Annex C (informative)
Example of appropriate technique for the detection of chemicals . 21 SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 3 Annex D (informative)
!Possible techniques to assess flow and stirring for permeation with liquid collecting medium" . 23 D.1 For the open loop system . 23 D.2 For open and closed loop system . 23 D.3 For open and close loop system . 24 Annex E (informative)
Example of permeation cell . 25 Annex F (informative)
Results of the interlaboratory trials . 27 Bibliography . 29
SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 4 European foreword This document (EN 16523-1:2015+A1:2018) has been prepared by Technical Committee CEN/TC 162 “Protective clothing including hand and arm protection and lifejackets”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2019 and conflicting national standards shall be withdrawn at the latest by April 2019. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights. This document supersedes !EN 16523-1:2015". In comparison with !EN 16523-1:2015", the entire document has been revised. This document includes Amendment 1 approved by CEN on 7 May 2018. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). !Deleted text" EN 16523, Determination of material resistance to permeation by chemicals, is composed with the following parts: — Part 1: Permeation by potentially hazardous liquid chemicals under conditions of continuous contact [the present document]; — Part 2: Permeation by gaseous chemical under conditions of continuous contact. NOTE CEN/TC 162 WG 13 has foreseen to work on other test methods in the future that will spread in several standard parts: — Permeation by solid chemical under conditions of continuous contact; — Permeation by chemical under conditions of intermittent contact; — Permeation by chemical of seams, joins, assemblages and closers; — Permeation by chemical in a form of droplets; — Guide on testing and interpretation. The start and finish of text introduced or altered by amendment is indicated in the text by tags !" According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 5 Introduction Users involved in the production, use, transportation, and emergency response with liquid chemicals can be exposed to numerous compounds capable of causing harm upon contact with the human body. The harmful effects of these chemicals can range from acute trauma such as skin irritation and burn to chronic degenerative disease, such as cancer. Since engineering controls may not eliminate all possible exposures, attention is often placed on reducing the potential for direct skin contact through the use of personal protective equipment (PPE) that resists permeation, penetration and degradation. The test method described in this part of EN 16523 is intended to be used to evaluate the barrier effectiveness of materials used for protective clothing, gloves and footwear materials against permeation by liquid chemicals. This method does not assess the chemical degradation or penetration of the material. Resistance to penetration by liquid chemicals can be determined by using for example ISO 6530  while resistance to penetration by liquid chemicals under pressure can be determined by using for example ISO 13994 . Resistance to chemical degradation can be determined by EN 374-4  for gloves and EN 13832-1:2006, 4.2  for footwear.
This method provides tests results in terms of breakthrough time. This parameter is a key measure of the effectiveness of a material to act as a barrier to the challenge chemical. Such information is used in the comparison of the performances of PPE materials during the process of selecting PPE for protection from hazardous chemicals. Long breakthrough times are characteristic of high permeation resistance. Breakthrough time does not provide a correlation between protection and the toxicity of the chemicals tested, only cumulative permeation can provide this information. It has been assumed in the drafting of this part of EN 16523 that the execution of its provisions will be entrusted to appropriately qualified and experienced people with a sound understanding of analytical chemistry. Appropriate precautions should be taken when carrying out this type of testing in order to avoid injury to health and contamination of the environment. A future part of EN 16523 will explain the use of the series of standards EN 16523. SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 6 1 Scope This European Standard specifies a test method for the determination of the resistance of protective clothing, gloves and footwear materials to permeation by potential hazardous liquid chemicals under the condition of continuous contact. This test method is applicable to the assessment of protection against liquid chemicals that can be collected only by liquid or gaseous collecting media. This test method is not !applicable to " the assessment of chemical mixtures, except for aqueous solutions. This standard is used with the specifications given in the products standards (for example !EN ISO 374-1:2016 " for gloves) where the following information is defined: — any pre-conditioning; — precise sampling (place, size, number); — associated levels of performance. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. !EN ISO 374-1:2016, Protective gloves against dangerous chemicals and micro-organisms — Part 1: Terminology and performance requirements for chemical risks (ISO 374-1:2016)"
3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 analytical technique method of identifying and quantifying the amount of permeated chemical in the collection medium Note 1 to entry: Such methods are often specific to individual chemical and collection-medium combinations. EXAMPLE Applicable analytical techniques can include ultraviolet (UV) or infrared (IR) spectrophotometry, mass spectrometry, pH measurement, ion chromatography, conductimetry, colourimetry, atmospheric analytical detector tubes and radionuclide tagging/detection counting. Although liquid and/or gas chromatography are separation techniques rather than detection methods they can be used in conjunction with suitable detectors to quantify the amount of permeated chemical in the collection medium (see Annex C). 3.2 liquid challenge chemical liquid chemical that is used to challenge the protective clothing, gloves and footwear material specimen 3.3 collecting medium liquid or gas on the inner “clean” side of the test sample in which any permeated chemical is collected SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 7 3.4 response time time between the actual arrival of the challenge chemical on the collecting side of the specimen and the time when the analytical instrumentation responds to it 3.5 limit of quantification minimum quantity of a substance which can be measured Note 1 to entry: It is the value where the uncertainty of measurement is equal to 50 % of the determined value. 3.6 loop
3.6.1 closed loop system in which the collecting medium is re-circulated or stirred through the sampling compartments of the test cell Note 1 to entry: Closed loop systems are not commonly used with gaseous collection media. 3.6.2 open loop system where the collecting medium passes through the sampling compartment of the test cell without re-circulation Note 1 to entry: Open loop systems may be used with either liquid or gaseous collection media. 3.7 minimum detectable permeation rate MDPR lowest rate of permeation that is measurable with the complete permeation-test system Note 1 to entry:
This value is not necessarily the intrinsic limit of detection for the analytical instrument. Note 2 to entry: MDPR is usually based upon 3 times the average background noise. Note 3 to entry: Useful information can be found on the following websites: — http://www.measurementuncertainty.org/guide/app_f.thml; — http://www.iupac.org/publications/pac/1997/pdf/6902x0297.pdf. 3.8 normalized breakthrough time NBT time at which the permeation rate reaches the normalization permeation rate
Note 1 to entry: See Figure 1: SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 8
permeation rate in µg cm2 min-1 a normalized permeation rate (NPR) t
b minimum detectable permeation rate (MDPR) 1
steady-state permeation t2 normalized breakthrough time (NBT) Figure 1 — Schematic permeation graph showing actual and normalized breakthrough times 3.9 normalized permeation rate NPR arbitrary fixed figure of 1,0 µg cm2 min1 Note 1 to entry: This optimized figure is a compromise between test method parameters (mixing, flow rate, detection limits, etc.) and the scientific analysis possibilities at the present time, to ensure a better repeatability and reproducibility of the test. Note 2 to entry: In some standards, the NPR is fixed at a lower concentration (for example 0,1 µg cm-2 min1). However, the parameters of the other standards, flow rate, mixing are often less severe than the present test method. The tests are only designed to evaluate protective clothing, gloves and footwear. 3.10 permeation process by which a chemical moves through a PPE (protective clothing, gloves and footwear) material, on a molecular level (see Annex A) and which involves the following: — absorption of molecules of the chemical into the contacted (outside) surface of a material; — diffusion of the absorbed molecules in the material; — desorption of the molecules from the opposite (inside) surface of the material 3.11 permeation rate mass of challenge chemical permeating unit area of the protective clothing, gloves and footwear per unit time Note 1 to entry: The permeation rate is expressed in µg cm 2 min1. SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 9 3.12 steady-state permeation rate SSPR constant rate of permeation that occurs after breakthrough when the chemical contact is continuous and all forces affecting permeation have reached equilibrium
Note 1 to entry: See Figure 1. Note 2 to entry: Steady-state permeation may not be achieved during the period for which permeation testing is conducted. 4 Test principle The resistance of protective clothing, gloves and footwear material to permeation by a liquid chemical is characterized by measuring through the normalized breakthrough time (NBT). In the permeation test apparatus, the protective clothing, gloves or footwear material separates the challenge chemical from the collecting medium. The collecting medium, which can be a gas or a liquid, is analysed quantitatively for its concentration of the chemical as a function of time. 5 Collecting media 5.1 Gaseous collecting medium A gaseous collecting medium is usually used under continuous flow conditions for the collection of permeating molecules that are capable of vaporizing in sufficient quantities for analysis. The gaseous collection medium shall be a gas or gas mixture which does not interfere with the detection of the challenge chemical and does not itself permeate or degrade the material under test. The quality of the gas supply shall be of sufficient consistency over the duration of the test that changes do not interfere with detection of the challenge chemical. NOTE Dry air or nitrogen are often used. 5.2 Liquid collecting medium !A liquid collecting medium is usually used for the collection of permeated challenge chemicals of low volatility that are soluble in the collecting medium under the conditions of the test. The challenge chemical shall be soluble in the collecting medium in sufficient quantities for analysis. The liquid collecting medium shall not influence the resistance of a material to permeation. NOTE 1 Water is generally used (Water grade 3 see EN ISO 3696). In the case of water soluble test specimen (e.g. PVAL-polyvinyl alcohol), an alternative collecting medium shall be used. It shall have no effect on the material. NOTE 2 Limitation due to collecting media: It can be recognized that there are circumstances under which the above criteria are mutually exclusive. For example, when testing a PVC (polyvinyl chloride) fabric for resistance to permeation by involatile isocyanates, it will be found that the challenge chemical is insoluble in aqueous collection media and that the test fabric is readily permeated or degraded by virtually all non-aqueous liquids. Under such circumstances testing is, unfortunately, not possible."
SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 10 6 Apparatus 6.1 Permeation cells 6.1.1 Standard permeation cell Components of the permeation test system that can be in contact with the challenge chemical shall not interact with it. The permeation cell consists of two compartments, separated by the test specimen. The specimen's outer surface is in contact with the challenge chemical, whereas the specimen's inner surface is in contact with a collecting medium. The permeation cell is constructed of two sections with an internal diameter of 51 mm at their open ends (see Figures 2 and 3). The section containing the challenge chemical, Lc is at least 10 mm long; the section containing the collecting medium is 35 mm long. The limit deviation for each dimension shall not be greater than ± 2 mm (see Figures 2 and 3). The cell assembly shall not leak and seals are used (see Figure 4). The material(s) used for the cell shall not interact with the challenge chemical (chemical reaction, adsorption, retention, etc.). NOTE Glass permeation cells are often used. Dimensions in millimetres
!deleted text" compartment for collecting medium 3 outlet collecting medium 2
inlet collecting medium
NOTE Dimensional deviations: ± 2 mm. Figure 2 — Important dimensions for the !deleted text" compartment for collecting medium SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 11 Dimensions in millimetres
Key 1 !deleted text"compartment for challenge chemical 2 fill pipe Figure 3 — Important dimensions for the !deleted text" compartment for challenge chemical Dimensions in millimetres
sample 3 challenge chemical wetting all the sample 2
4 closing system NOTE The cells can be assembled horizontally or vertically. Figure 4 — Cell assembly The open ends of the sections are fitted with connecting joints. The inlet of the section containing the challenge chemical may be closed by a stopper or a valve. SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 12 6.1.2 Alternative permeation cells Alternative permeation cells may also be used, provided the precision, bias and results of the test results are found to be equivalent with the reference cell described in 6.1.1. This should be demonstrated accordingly to the requirement of EN ISO/IEC 17025:2005, 5.4,. If an alternative permeation cell is used it shall be reported in the test report. 6.2 Temperature controlled room, cabinet or water bath Temperature controlled room (cabinet or water bath) at 23 C, able to maintain the temperature of the permeation cell constant to within ± 1 °C over the complete duration of the test. The use of water baths shall be restricted to the testing of PPE (protective clothing, gloves and footwear) material without textile liner, except when adequate measures are taken to prevent the migration of water, e.g. by enclosing the permeation cell in a waterproof bag. 6.3 Supply of gas for gaseous collecting medium (dry air or nitrogen) A gas supply, and a flow meter, shall be connected to the inlet of the collector compartment of the permeation cell. The rate of flow through this compartment shall be (5 ± 0,5) volume changes per minute. The volume of the collector compartment shall be measured accurately. NOTE 1 The volume can be measured by weighing the cell before and after filling the compartment with water. NOTE 2 The required flow rate can be obtained preferably by a flow regulator or at least by a suitable control of the gas pressure at the inlet of the collector compartment or by using a pump at the outlet of the analyser. The choice of configuration is generally determined by the method of collection and/or detection of the challenge chemical. 6.4 Liquid pump and stirrer (in case of a liquid collecting medium) The liquid in the collector compartment shall be stirred to ensure the complete mixing in all parts of the compartment. Annex D provides the possible procedures. The flow rate and stirring speed shall be kept constant to within ± 10 %. !NOTE Annex D provides example of possible procedure."
No part of the pump, stirrer or any other equipment connected to it shall contaminate the liquid passing through the collector compartment of the permeation cell. 6.5 Equipment for the quantitative determination of the challenge chemical or its components in the collecting medium The analytical system shall be sufficiently sensitive for the challenge chemical to measure the defined NPR. The response time of the analytical system shall be measured or calculated. If the response time is greater than 60 s, the breakthrough time shall be corrected by the real response time. The pressure and flow of the collecting medium shall be kept constant regardless of the type of analytical apparatus used. When possible, the analytical technique should permit to identify the analysed chemical (e.g. mass spectrometry instead of FID in the case of chromatography). The analytical equipment can include instruments responding directly to concentration changes in the stream of gas or liquid. Absorbers and sampling equipment associated with specific analytical techniques may also be used. Examples of suitable analytical detection techniques are UV- and IR-spectrophotometry, gas and liquid chromatography, colourimetry and radionuclide tagging detection counting (see Annex C). SIST EN 16523-1:2015+A1:2018
EN 16523-1:2015+A1:2018 (E) 13 6.6 Time measuring device A device capable of measuring elapsed time to the nearest second. 7 Test specimens This European Standard does not define from where to select the test specimens. The selection of the test specimens shall be given in the products specifications standards (for example !EN ISO 374-1:2016" for gloves). !If not otherwise specified in the protective clothing, glove or footwear product standards: — 3 test specimens shall be tested; — they shall be conditioned for at least 16 h at a temperature of (23 ± 2) °C."
For multilayer protective clothing, glove or footwear material, in case of unbonded layers, the internal layers without any effect on the chemical protection can be removed (e.g. thermal insulation layer). The test specimen shall be of a sufficient size and shape so as to completely separate the challenge and collection sides of the test cell (about 68 mm !diameter " in the case of the reference cell). 8 Procedure 8.1 Calibration The response of the collecting and analytical test systems to the challenge chemical shall be calibrated in order to determine the analytical sensitivity (MDPR) and the response time. For open loop system and closed loop system, a calibration curve shall be drawn covering the appropriate concentration range. The calibration may not be linear. Usually the calibration curve includes a blank, the limit of quantification of the analytic