CTD 461 Lecture 4: CTD 461 Chapter 4 Notes

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Clothing, Textiles and Interior Design
CTD 461

CTD 461 Chapter 4 Notes Introduction to testing Reasons for Testing • Manufacturers ensure that materials, processes, and products meet requirements • Retailers ensure that products they buy meet expectations for performance, size, fit, and consistency • Companies assess material characteristics and performance and product quality Ways of Testing • Laboratory testing (accelerated testing) quickly assess material and product characteristics and performance • Assumption: material performance predicts product serviceability • Evaluating characteristics or performance of materials using standard procedures in specialized facility Characteristics of Testing • Controlled atmosphere • Trained technicians • Specialized equipment • Specimens from cut or sample fabric piece • Quick • Research, performance testing, and product development • Consumer complaints • Forensic testing Other Types of Testing • Supplier testing • In-house testing • Independent (contract) testing • Most standard test methods work with one material at a time • Many apparel and interior products are made of more than one material and the interactions of the materials are not assessed in these one variable test methods • Some test methods actually test the finished product – mattress for fire retardation Test Method • Definitive procedure for identification, measurement, and evaluation of one or more qualities, characteristics, or properties of material, product, system, or service that produces a test result • Standard test methods: test methods approved by specific organizations Getting Reliable Test Results • Two important concepts • Accuracy: correctness, conformity to reality. ➢ Agreement between true value of property being tested and average of many observations made according to test method by many observers ➢ Synonyms: validity, bias • Precision: consistency in results. ➢ Degree of agreement within a set of observations or test results obtained as directed in a method ➢ Synonyms: reliability, producibility Definitions • Accuracy: agreement between true value of property being tested and average of many observations made according to test method by many observers • Reproducibility: ability to repeat process with same or very similar results • Bias: constant and systematic error in results • Calibration: process of fixing, checking, or correcting gradations of measuring instrument • Verification: done periodically with instrument in its use location Test Method Results • It is possible for at test method to provide results which are: ➢ Neither accurate nor precise ➢ Precise but not accurate ➢ Accurate but not precise ➢ Both accurate and precise Parts and Components of Test Methods • Purpose • Scope or range • Safety • Scientific principle • Procedures for specimens • Conditioning specimens • Apparatus and reagents • Verifying equipment • Summary of procedures • Detailed procedures • Evaluation • Applicable documents • Special notes Pass/Fail Scales • Describe performance level that meets or exceeds acceptable limits for characteristic or condition or performance level that fails requirements • Never included in standard test methods • Included in laws and regulations; usually related to health and safety Standard Conditions for Testing • Standard atmosphere: air maintained at relative humidity of 65 +- 2% and temperature of 21+- 1 C (70+- 2 F); also known as “standard conditions” or “standard environment” • Moisture regain: amount of water in material determined under prescribed conditions • Moisture equilibrium: condition reached by specimen when it no longer takes up moisture form or gives up moisture to surrounding atmosphere Moisture Regain • The amount of water in a material determined under prescribed conditions and expressed as a percentage of the mass of the water-free material • % R = 100 (Wc-Wd)/Wd ➢ R: moisture regain as % ➢ Wc: mass of material in moisture equilibrium ➢ Wd: mass of material dried under specific conditions Moisture Equilibrium • Condition reached by a specimen where it no longer takes up moisture form or gives up moisture to the surrounding atmosphere • Often takes 24 hours to achieve in conditioning room Regain Hysteresis • A property of a material is said to exhibit hysteresis when then measured value of the property depends upon the specimen history AATCC Test Methods • Technical manual in numerical order (1,2, or 3 digit number) • Table of contents, test methods and procedures, alphabetical list, changes from previous volume, and preface • Standard test methods, evaluation procedures, nomenclature for subjective rating processes, and glossary of standard terminology ASTM Test Methods • Vol. 7.01 and 7.02 (textiles); 4.07, 1.03, and 12.02 (furnishings); 12.-2 (general); 15.04 (leather) and 15.07 (sports gear/equipment) • Test method number: three- or four- digit number • Organized alphabetically • Foreword, list of sections, volumes, subjects, table of contents listing standards by numerical designation and subject Other Procedures • National Fire Protection Association (NFPA) • Upholstered Furniture Action Council (UFAC) • Industrial Fabrics Association International (IFAI) • Business and Industrial Furniture Manufacturers Association (BIFMA) • Federal test methods and standards – government agency websites • Consumer Product Safety Commission (CPSC) • Federal Aviation Administration (FAA) • Department of Transportation (DOT) • National Institute of Standards and Technology (NIST) Testing and Product Development • Develop new products, improve current products, modify standards and specs, provide information to buyers, meet label and certification requirements, establish criteria for guarantees, and address complaints • Ensure products or materials conform to requirements • Select most appropriate material or product • Comparative testing: testing two or more products from same plant, different plants owned by same company, or from competitors Materials Testing • Also known as textile testing when only textile materials are evaluated • Evaluate each material in a product to determine its characteristics, quality, and measure its response to performance tests • Identifies individual characteristics • Assesses single performance dimensions in isolation • Focus on laboratory testing Uses of Materials Testing • Identify types of materials • Combine appropriate materials into product • Adjust pattern, spreading, cutting, and construction for materials • Determine manufacturing conditions or settings Understood Nature of Materials • Identify defects and irregularities • Used in advertising • Documentation • Track performance of suppliers • Assess ability to meet target market needs • Compare product performance across time Restrictions on Material Testing • Cannot translate results directly into consumer performance or durability • Only one stress applied to material at a time • Materials tested in their new condition • Most conditions of wear absent Product Testing • Product focus for analysis and evaluation • Product success based materials, design, production, appearance, and material interactions • Wear or service testing: product put to use or worn by consumers • Prototype testing: sample products, prototypes, or several products from a limited production run used or worn by small group of users ASTM D 3181 Practice for Conducting Wear Tests on Textiles • Includes information to design and plan wear testing, conduct wear test, identify evaluation parameters, and evaluate results • Controls or control textiles: textile or textile products with a known history and with previously established performance for end use; comparison standard • I
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