ASTM F1670-08

This test method is based on Test Method F 903 for measuring resistance of chemical protective clothing materials to penetration by liquids. This test method is normally used to evaluate specimens from individual finished items of protective clothing and individual samples of materials that are candidates for items of protective clothing.

Finished items of protective clothing include gloves, arm shields, aprons, gowns, coveralls, hoods, and boots.

The phrase “specimens from finished items” encompasses seamed and other discontinuous regions as well as the usual continuous regions of protective clothing items.

Medical protective clothing materials are intended to be a barrier to blood, body fluids, and other potentially infectious materials. Many factors can 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. The surface tension range for blood and body fluids (excluding saliva) is approximately 0.042 to 0.060 N/m (1). 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 approximately 0.042 ± 0.002 N/m.

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.

Part of the protocol in Procedure A and B in Table 1 for exposing the protective clothing material specimens with synthetic blood involves pressurization of the test cell to 13.8 kPa (2 psig). This hydrostatic pressure has been documented to discriminate between protective clothing material performance and correlate with visual penetration results that are obtained with a human factors validation (2). Some studies, however, suggest that mechanical pressures exceeding 345 kPa (50 psig) can occur during clinical use (3,4). Therefore, it is important to understand that this test method does not simulate all the physical stresses and pressures that are exerted on protective clothing garments during actual use. This test method is offered to identify those protective clothing materials that warrant further evaluation with a microbiological challenge.

Since this test method uses visual observation rather than analytical measurements for determination of penetration, use this test method as a preliminary evaluation for possible penetration of blood and other body fluids. Perform subsequent testing with a microbiological challenge and analytical technique using Test Method F 1671.

Note 1—No viral resistance claims can be made based on this test method as materials can pass the test method and fail Test Method F 1671.

Testing without considering degradation by physical, chemical, and thermal stresses which could negatively impact the performance 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 barrier can also be compromised during use by such effects as flexing and abrasion (5). It is also possible that prewetting by contaminating materials such as alcohol and perspiration can also compromise the integrity of the protective barrier. If these conditions are of concern, evaluate the performance of protective clothing materials for synthetic blood penetration following an appropriate preconditioning technique representative of the expected conditions of use.

While this test method involves a qualitative determination of the protective clothing material 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.

If this procedure is used for quality control, perform proper statistical design and analysis of the data, when more than three specimens are tested. This type of analysis includes, but is not limited to, the number of individual specimens tested, the average percent passing and/or failing with a standard deviation. Data reported in this way helps to establish confidence limits concerning product performance. Examples of acceptable sampling plans are found in references such as MIL-STD-105, ANSI/ASQC Z1.4, and ISO 2859-1.

TABLE 1 Specimen Exposure Procedures

FIG. 1 Exploded View of the Penetration Test Cell with Retaining Screen

1.1 This test method is used to evaluate the resistance of materials used in protective clothing to penetration by synthetic blood under conditions of continuous liquid contact. Protective clothing pass/fail determinations are based on visual detection of synthetic blood penetration.

1.1.1 This test method is not always effective in testing protective clothing materials having thick, inner liners which readily absorb the synthetic blood.

1.2 This test method is a means for selecting protective clothing materials for subsequent testing with a more sophisticated barrier test as described in Test Method F 1671.

1.3 This test method does not apply to all forms or conditions of blood-borne pathogen exposure. Users of the test method must review modes for work/clothing exposure and assess the appropriateness of this test method for their specific application.

1.4 This test method addresses only the performance of materials or certain material constructions (for example, seams) used in protective clothing. This test method does not address the design, overall construction and components, or interfaces of garments, or other factors which may affect the overall protection offered by the protective clothing.

1.5 The values in SI units or other units shall be regarded separately as standard. The values stated in each system must be used independently of the other, without combining values in any way.

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 appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.