In various manufacturing and industrial environments where sharp needles, fine wires, or glass components are frequently handled, there is a significant risk of puncture injuries. To mitigate the risk of such occupational injuries, it is crucial to select Personal Protective Equipment (PPE) that has undergone proper validation.
Certain job roles require protective clothing that meets specific minimum standards. To ensure consistency in testing and to provide a standardized rating system for PPE, tests should be conducted in accordance with ASTM F2878, and ratings should be assigned based on the ANSI 105 standard using a universal testing machine that meets these standards.
For needle puncture resistance, the ANSI rating system determines the rating based on the average force needed to puncture 12 PPE samples. Refer to Table 1 below for the ratings.
Table 1. The ANSI needle puncture ratings and the forces required to achieve those ratings. Source: Shimadzu Scientific Instruments
| ANSI Needle Puncture Rating |
Average Force to Puncture |
| 0 |
< 2 N |
| 1 |
≥ 2 N |
| 2 |
≥ 4 N |
| 3 |
≥ 6 N |
| 4 |
≥ 8 N |
| 5 |
≥ 10 N |
Figure 1. Lower support and hypodermic needle used for needle puncture test. Image Credit: Shimadzu Scientific Instruments
Figure 2. Test setup on the EZ-LX showing the lower support and needle holder with hypodermic needle attached. Image Credit: Shimadzu Scientific Instruments
Shimadzu’s EZ-LX testing machine, equipped with the needle puncture jig, surpasses the requirements specified in those standards, facilitating easy and rapid PPE testing according to ASTM F2878. The same frame is used for validation testing of the needle lot, providing flexibility and simplicity when evaluating PPE for needle puncture resistance.
Instrument and Fixtures
The test configuration is detailed in Table 2. Measurements were performed using an EZ-LX table-top universal testing machine featuring a lower support with a six-sample rotating head and a needle holder directly attached to the load cell.
Figures 1 and 2 illustrate the test setup. The 50 N load cell enables direct force measurement on the needle, while the jig setup ensures perpendicular force application to the samples mounted in the lower support. The holes in the lower support had a diameter of 10 mm. For this test, 25G x 1 inch needles from Becton Dickinson (lot no: 2203697) were used.
Table 2. Equipment configuration. Source: Shimadzu Scientific Instruments
| Universal Testing Machine |
EZ-LX |
| Load Cell |
50 N |
| Fixture |
ASTM F2878 needle puncture fixture |
| Software |
Trapezium X (Single) |
Validation Testing
According to the ASTM standard, the specific lot of needles must be validated before they can be used for PPE testing.
The validation material was a sheet of polychloroprene with a Shore A hardness of 50, a thickness of 1/16th of an inch (1.59 mm), and a minimum tensile strength of 1200 psi. Seven samples were cut from the sheet, and the force required to puncture each sample was measured using a new needle for each puncture.
The average peak force recorded was 1.158 N, with a standard deviation of 0.056 N. These results comply with the standard, which requires an average of 1.274 N ± 0.274 N and a maximum standard deviation of 0.137 N. The setup of the rubber samples is illustrated in Figure 3 below.
Figure 3. This shows the polychloroprene samples being loaded into the lower support for the validation testing. Image Credit: Shimadzu Scientific Instruments
Samples and Method
Samples were taken from three different kinds of gloves for the needle puncture test. Glove A was composed of a 10-gauge polyester weave with a natural rubber coating. This glove did not have a needle puncture rating, but it did have an ANSI 105 puncture rating of 4. Glove B was made from a 13-gauge blended weave of polyethylene, steel, and fiberglass coated with polyurethane and had an ANSI 105 puncture rating of 5.
The ANSI puncture ratings refer to a blunt tip puncture and the procedure and testing fixture differ from the testing being performed in this study (for reference, see application note MT-2302). For additional comparison, an ANSI 105 needle puncture rated glove was also used to demonstrate the full capacities of the test frame. This glove was designated as Glove C, a Alycore® multi-layered glove made from leather, cotton, and Kevlar.
The samples from Gloves A & B were taken from the palm while the sample from Glove C was taken from both the palm and the fingers. Their relative thicknesses were measured using a set of Mitutoyo calipers. 12 samples were cut from each type of glove and new needles were used for each puncture.
The test was conducted using the Single module in the Trapezium X software. The needle was positioned 20 mm above the sample, which allows ample room for the needle to reach test speed before puncturing the glove samples. The test speed was calibrated to 500 mm/minute until the total displacement reached 40 mm.
At this stage, the crosshead was returned to the starting position. The software recorded the maximum force during the test. The data was then collected as a batch of 12 samples and from the results and the average and standard deviation of the force for each glove was automatically generated.
Photos of sample loading and positioning in the support and the test setup are displayed in Figures 4 and 5.
Figure 4. Samples (from Glove C in the photo) are loaded into the lower support. Image Credit: Shimadzu Scientific Instruments
Figure 5. Samples (from Glove A in the photo) are fully loaded and are being tested with the hypodermic needle 20 mm above the sample. Image Credit: Shimadzu Scientific Instruments
Test Results
The plots displaying the average force against displacement curve for each of the gloves are exhibited in Figure 6 for Glove A and Figure 7 for Glove B.
While these two gloves did not have a ANSI needle puncture rating, they were considered gloves of interest for needle puncture due to their high values of puncture resistance for the blunt tip. Twelve samples were taken from each glove and during testing the rubber/polyurethane coated side was positioned toward the needle.
The average force required to puncture Glove A was 0.499 N, with a standard deviation of 0.248 N. This would generate an ANSI needle puncture rating of 0. The average force required to puncture Glove B was in the region of 0.729 N, with a standard deviation of 0.596 N. This also means an ANSI needle puncture rating of 0 would be awarded.
The weave used in each of these gloves comes is what contributes to the large deviations. For some punctures, the needle bypassed most of the fibers in the weave, while other punctures were impeded by the fiber weave. The largest puncture force observed for Glove A was 1.040 N and for Glove B it was 2.028 N. This was a result of the needle hitting the thread straight on.
A glove that had already had a puncture rating (Glove C) was also used in this series of tests for comparison. However, due to the fact ratings of the palm and fingers differ for the needle puncture, samples were taken from each section and the average force required to puncture was recorded for each section of the glove.
The plots displaying the average force against displacement curve for the palm section and the finger section of Glove C are exhibited in Figures 8 and 9, respectively.
The average force required to puncture the palm was revealed to be 11.597 N with a standard deviation of 0.674 N. This corresponds with the glove’s ANSI needle puncture rating of 5. The average force needed to puncture the finger was 6.143 N, with a standard deviation of 0.141 N. This means the ANSI needle puncture rating for the fingers would be 3.
Figure 6. Average force versus displacement curve for Glove A. The average force to puncture was 0.499 N. Image Credit: Shimadzu Scientific Instruments
Figure 7. Average force versus displacement curve for Glove B. The average force to puncture was 0.729 N. Image Credit: Shimadzu Scientific Instruments
Figure 8. Average force versus displacement curve for Glove C with samples taken from the palm. The average force to puncture was 11.597 N. Image Credit: Shimadzu Scientific Instruments
Figure 9. Average force versus displacement curve for Glove C with samples taken from the finger. The average force to puncture was 6.143 N. Image Credit: Shimadzu Scientific Instruments
Summary
The Shimadzu EZ-LX was used for conducting the needle puncture tests as described in ASTM F2878.
Trapezium-X has the capacity to set 12 samples per batch, run each sample within the same method, calculate averages and standard deviations automatically, and allow the user to generate a curve showing the average result. From this method of testing, the ANSI ratings for these gloves can be determined with relative ease.
This information has been sourced, reviewed and adapted from materials provided by Shimadzu Scientific Instruments.
For more information on this source, please visit Shimadzu Scientific Instruments.