ASTM F1862

Designation: F 1862 – 05 Standard Test Method for Resistance of Medical Face Masks to Penetration by Synthetic Blood (Horizontal Projection of Fixed Volume at a Known Velocity)1 This standard is issued under the fixed designation F 1862; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. INTRODUCTION Workers, primarily those in the health care profession, involved in treating and caring for individuals injured or sick, can be exposed to biological liquids capable of transmitting disease. These diseases, which may be caused by a variety of microorganisms, can pose significant risks to life and health. This is especially true of blood-borne viruses which cause Hepatitis (Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV)) and Acquired Immune Deficiency Syndrome (AIDS) [Human Immunodeficiency Virus (HIV)]. Because engineering controls can not eliminate all possible exposures, attention is placed on reducing the potential of direct skin and mucous membrane contact through the use of protective clothing that resists penetration (29 CFR Part 1910.1030). This test method was developed for ranking the synthetic blood penetration resistance performance of medical ace masks in a manner representing actual use as might occur when the face mask is contacted by a high velocity stream of blood from a punctured wound. 1. Scope 1.1 This test method is used to evaluate the resistance of medical face masks to penetration by the impact of a small volume (~2 mL) of a high velocity stream of synthetic blood. Medical face mask pass/fail determinations are based on visual detection of synthetic blood penetration. 1.2 This test method does not apply to all forms or condi- tions of blood-borne pathogen exposure. Users of the test method must review modes for face exposure and assess the appropriateness of this test method for their specific applica- tion. 1.3 This test method primarily addresses the performance of materials or certain material constructions used in medical face masks. This test method does not address the performance of the medical face mask’s design, construction, or interfaces or other factors with the potential to affect the overall protection offered by the medical face mask and its operation (such as filtration efficiency and pressure drop). Procedures for measur- ing these properties are contained in Test Methods F 2101 and MIL-M-36954C. 1.4 This test method does not address breathability of the medical face mask materials or any other properties affecting the ease of breathing through the medical face mask. This test method evaluates medical face masks as an item of protective clothing. This test method does not evaluate the performance of medical face masks for airborne exposure pathways or in the prevention of the penetration of aerosolized body fluids depos- ited on the medical face mask. 1.5 The values stated in SI units or inch-pound units are to be regarded separately as standard. The pressure values stated in each system are not exact equivalents. However, as the corresponding velocities are within 1 % of each other, (see X1.4.2), reporting of the results in either units is permitted. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. 2. Referenced Documents 2.1 ASTM Standards: 2 D 891 Test Methods for Specific Gravity, Apparent, of Liquid Industrial Chemicals D 1331 Test Methods for Surface and Interfacial Tension in Solutions of Surface-Active Agents 1 This test method is under the jurisdiction of ASTM Committee F23 on Protective Clothing and is the direct responsibility of Subcommittee F23.40 on Biological Hazards. Current edition approved Sept. 15, 2005. Published December 2005. Originally approved in 1998. Last previous edition approved in 2000 as F 1862 - 00a. 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website. 1 Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. E 105 Practice for Probability Sampling of Materials E 171 Specification for Standard Atmospheres for Condi- tioning and Testing Flexible Barrier Materials F 1494 Terminology Relating to Protective Clothing F 1670 Test Method for Resistance of Materials used in Protective Clothing to Penetration by Synthetic Blood F 1671 Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Blood-borne Patho- gens Using Phi-X174 Bacteriophage Penetration as a Test System F 2101 Test Method for Evaluating the Bacterial Filtration Efficiency (BFE) of Medical Face Mask Materials, Using a Biological Aerosol of Staphylococcus aureus 2.2 ANSI/ASQC Standard:3 ANSI/ASQC Z1.4 Sampling Procedures and Tables for In- spection by Attributes 2.3 ISO Standard:4 ISO 2859-1 Sampling Plans for Inspection by Attributes 2.4 Military Standards:5 MIL-M-36954C Military Specification, Mask, Surgical, Disposable 2.5 OSHA Standard6 29 CFR Part 1910.1030 Occupational Exposure to Blood- borne Pathogens: Final Rule, Federal Register, Vol 56, No 235, Dec. 6, 1991, pp. 64175–64182 3. Terminology 3.1 Definitions: 3.1.1 aerosolized body fluids, n—body fluids that have been dispersed into air as very small liquid droplets. 3.1.2 airborne exposure pathways, n—inhalation routes of exposure to the medical face mask wearer. 3.1.3 blood-borne pathogen, n—an infectious bacterium or virus, or other disease inducing microbe carried in blood or other potentially infectious body fluids. 3.1.4 body fluid, n—any liquid produced, secreted, or ex- creted by the human body. 3.1.4.1 Discussion—In this test method, body fluids include liquids potentially infected with blood-borne pathogens, in- cluding, but not limited to, blood, semen, vaginal secretions, cerebrospinal fluid, synovial fluid and peritoneal fluid, amni- otic fluid, saliva in dental procedures, and any body fluid that is visibly contaminated with blood, and all body fluids in situations where it is difficult or impossible to differentiate between body fluids (see 29 CFR Part 1910.1030). 3.1.5 body fluid simulant, n—a liquid that is used to act as a model for human body fluids. 3.1.6 medical face mask, n—an item of protective clothing designed to protect portions of the wearer’s face including the mucous membrane areas of the wearer’s nose and mouth, from contact with blood and other body fluids during medical procedures. 3.1.7 penetration, n—for biological protective clothing, the flow of a body fluid on a non-molecular level through closures, porous materials, seams, and pinholes, or other imperfections in protective clothing. 3.1.7.1 Discussion—In this test method, the penetration liquid is synthetic blood, a body fluid simulant. 3.1.8 protective clothing, n—any material or combination of materials used in an item of clothing for the purpose of isolating parts of the body from potential hazards. 3.1.8.1 Discussion—In this test method, medical face masks are evaluated. The potential hazard of contact with blood or other body fluids is being simulated. 3.1.9 synthetic blood, n—a mixture of a red dye/surfactant, thickening agent, and distilled water having a surface tension and viscosity representative of blood and some other body fluids, and the color of blood. 3.1.9.1 Discussion—The synthetic blood in this test method does not simulate all of the characteristics of blood or body fluids, for example, polarity (wetting characteristics), coagula- tion, content of cell matter. 3.1.10 spurt, n—a short duration gush or volume of fluid. 3.1.10.1 Discussion—In this test method, a spurt refers to the volume of fluid disbursed from the apparatus at the sample mask. It can also refer to the volume of fluid ejected from a punctured blood vessel. 3.1.11 For definitions of other protective clothing-related terms used in this test method, refer to Terminology F 1494. 4. Summary of Test Method 4.1 A volume of synthetic blood is disbursed at a specimen mask by a pneumatically controlled valve from a set distance to simulate the impact (splatter) of blood or other body fluid onto the specimen. The velocity and volume of fluid are set to simulate a given health care scenario. 4.2 Any evidence of synthetic blood penetration on the inner facing of the medical face mask (side contacting the wearer’s face) constitutes a failure. Results are reported as pass/fail. 4.3 Specimen medical face masks are evaluated at velocities of 450, 500 and 635 cm/s. These correspond to the velocity exiting a small arterial puncture at human blood pressures of 10.7, 16.0, and 21.3 kPa (80, 120, and 160 mmHg). Test results are reported at each velocity, or corresponding pressure, and the medical face mask is rated at the highest corresponding blood pressure for which medical face mask specimens dem- onstrate an acceptable quality limit of 4.0. 5. Significance and Use 5.1 This test method offers a procedure for evaluating medical face mask resistance to synthetic blood penetration that is useful in establishing claims for penetration resistance performance of medical face masks and ranking their perfor- mance. However, this test method does not define acceptable levels of penetration resistance because this determination must be made by each responsible user organization based on its own specific application and conditions. Therefore, when 3 Available from American Society for Quality (ASQ), 600 N. Plankinton Ave., Milwaukee, WI 53203. 4 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036. 5 Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700 Robbins Ave., Philadelphia, PA 19111–5094, Attn: NPODS. 6 Available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402. F 1862 – 05 2 using this test method to make claims for the performance of medical face masks, the specific conditions under which testing is conducted must be described. 5.2 Medical face masks are intended to resist liquid pen- etration from the splatter or splashing of blood, body fluids, and other potentially infectious materials. Many factors affect the wetting and penetration characteristics of body fluids, such as surface tension, viscosity, and polarity of the fluid, as well as the structure and relative hydrophilicity or hydrophobicity of the materials and the design of the mask itself. The surface tension range for blood and body fluids (excluding saliva) is approximately 0.042 to 0.060 N/m.7 To help simulate the wetting characteristics of blood and body fluids, the surface tension of the synthetic blood is adjusted to approximate the lower end of this surface tension range. The resulting surface tension of the synthetic blood is 0.042 6 0.002 N/m. 5.3 The synthetic blood mixture is prepared with a red dye to aid in visual detection and a thickening agent to simulate the flow characteristics of blood. The synthetic blood will not always duplicate the polarity, and thus the wetting behavior and subsequent penetration, of real blood and other body fluids through protective clothing materials. 5.4 During a medical procedure, a blood vessel is occasion- ally punctured resulting in a high velocity stream of blood impacting a protective medical face mask. The impact velocity depends on several factors, the most important being the blood pressure of the patient. Other factors include the size of the puncture, and distance from the puncture. Because the pres- sure, and thus velocity drops quickly with large punctures, large punctures were not used to model the range of blood splatter velocities considered in this test. Furthermore, this test method is based on the assumption that the medical face mask will be in close proximity (within 300 mm or 12 in.) to the puncture area. The use of this test method is, therefore, based on selecting an appropriate blood pressure, finding the corre- sponding stream or impact velocity, and determining the valve time to create that stream velocity as shown in Appendix X1. 5.4.1 The mean human blood pressure generally varies over a range of about 10.7 to 16.0 kPa (80 to 120 mmHg).8 In this test method, medical face masks are tested at stream velocities corresponding to 10.7 kPa, 16.0 kPa, and 21.3 kPa (80 mmHg, 120 mm Hg, and 160 mm Hg). 5.5 This test method permits the use of other non-standard test pressures, stream velocities, fluid volumes, and specimen orientations for evaluating medical face mask penetration resistance consistent with specific applications. 5.6 This test method differs from Test Method F 1670 by dispensing a stream of 2 mL of synthetic blood against the target area of a complete medical mask specimen whereas Test Method F 1670 involves the continuous contact of a specimen of protective clothing with synthetic blood over the period of an hour. One minute of the exposure in Test Method F 1670 is at hydrostatic pressure of 13.8 kPa [2.0 psig]. Test Method F 1670 is used for preliminary evaluation of protective clothing penetration resistance to synthetic blood in conjunction with Test Method F 1671 that uses a microbiological challenge. Both procedures are intended for assessment of protective clothing which has the potential to contact blood or other body fluids for extended periods of time, and under pressure. 5.7 Users of this test method must realize that certain tradeoffs exist between improved resistance of medical face masks to penetration by synthetic blood and in pressure drop across mask materials as an indicator of medical face mask breathability. In general, increasing synthetic blood penetration resistance for medical face masks results in increasing pressure drop or reduced breathability for medical face masks of the same design and fit of the individual wearer. 5.8 This test method evaluates medical face masks as an item of protective clothing and does not evaluate medical face masks as respirators. If respiratory protection for the wearer is needed, a MSHA/NIOSH-certified respirator must be used. This test method is useful to evaluate the resistance of a respirator to penetration by synthetic blood, if warranted. 5.9 This test method involves the preconditioning of speci- men medical face masks in a relatively high humidity environ- ment (85 6 5 % relative humidity at 21 6 5°C [70 6 10°F]) to simulate the conditions of use when the wearer creates high humidity conditions by breathing through the mask. This preconditioning does not account for saturation of the interior medical face mask layer. However, additional pretreatment techniques in conjunction with this test method as described in 5.10 are permitted. Professional health care providers recom- mend that medical face masks be replaced when saturation occurs from breathing or from contact with other liquids. 5.10 Testing prior to degradation by physical, chemical, and thermal stresses which could negatively impact the perfor- mance of the protective barrier, could lead to a false sense of security. Consider tests which assess the impact of storage conditions and shelf life for disposable products, and the effects of laundering and sterilization for reusable products. The integrity of the protective clothing is occasionally com- promised during use by such effects as flexing and abrasion.9 It is also possible that pre-wetting by contaminants such as alcohol and perspiration also compromises the integrity of the protective clothing. If these conditions are of concern, evaluate the performance of protective clothing for synthetic blood penetration following an appropriate pretreatment technique representative of the expected conditions of use. 5.11 While this test method involves a qualitative determi- nation of the medical face mask resistance to penetration by synthetic blood under specific test conditions, it is possible to use this test method as a material quality control or assurance procedure. 5.12 If this procedure is used for quality control, perform proper statistical design and analysis of larger data sets when more than the required specimens are tested. This type of 7 Lentner, C., ed., Geigy Scientific Tables, Vol 1 - Units of Measurement, Body Fluids, Composition of Blood, Hematology, Somatometric Data, Medical Education Div., Ciba-Geigy Corp., West Caldwell, NJ, 1984. 8 Barach, P. G., Cullen, B.F., and Stoelting, R. K., Handbook on Clinical Anesthesia, Appendix A, J. B. Lippincott Co., Philadelphia, 1994. 9 Telford, G. L. and Quebbeman, E. J., “Assessing the Risk of Blood Exposure in the Operating Room,” American Journal of Infection Control, Vol 21, No. 6, December 1993, pp. 351-356. F 1862 – 05 3 analysis includes, but is not limited to, the number of indi- vidual specimens tested, the average percent passing or failing, or both, with a standard deviation. Data reported in this way help to establish confidence limits concerning product perfor- mance. Examples of acceptable sampling plans are found in references such as ANSI/ASQC Z1.4 and ISO 2859-1. 5.13 In the case of a dispute arising from differences in reported results when using this test method for acceptance testing of commercial shipments, conduct comparative tests between the purchaser and supplier to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for investigation of bias. As a minimum, take a group of test specimens which are as homogeneous as possible and which are from a lot of the product of the type in question. Randomly assign test speci- mens in equal numbers to each laboratory for testing. Compare the average results from the two laboratories using a non- parametric test for unpaired data and an acceptable probability level chosen by the two parties before testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results with consideration to the known bias. 6. Apparatus 6.1 Test Apparatus, to dispense a specified volume of synthetic blood through a small diameter canula over a controlled amount of time at a specimen mask a set distance away. The test apparatus consists of a specimen holding fixture, a targeting plate, a pressurized fluid reservoir, a pneumatically actuated valve with interchangeable canula and a valve con- troller. A permitted optional design for the test apparatus includes a base for more convenient mounting of the compo- nents and a hood or other components to contain or control the splash. A photograph of a typical sample test apparatus is provided in Fig. 1. Other specifications for the specimen holding fixture include as follows: 6.1.1 Specimen Holding Fixture to support the specimen mask during the test. The design and construction of the specimen holding fixture has a significant impact on the outcome of the test. The specimen holder and supporting frame must be sufficiently stiff and rigid that the energy of the impact of the spurt is absorbed solely by the specimen mask. The specimen holder and frame must not deform, flex or bend during a test. The fixture must also generate a consistent tension across the mask, particularly flat masks. The height of the canula on the pneumatic valve is 420 mm [16.5 in.]. This height corresponds to the height of the fluid reservoir.