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Guants de protecció de mans contra riscos mecànics (part 2)

4.3 Cut Resistance (Straight Blade Test Method)

4.3.1 equipament

The test equipment (see Figure 5) consists of the following parts:

a) Rigid frame: The equipment frame should deform when a force of up to 200N is applied between the blade and the sample.

b) Cutting force application device: During equipment operation, the variation of cutting force between the blade and the sample should be within 5%, and the applied force range should be between 1.0N and 200N.

c) Sample support fixture: The sample support fixture is made of metal, and the sample is mounted on its surface. The mounting area of the sample is a curved surface with a radius of (38 ± 0.5) mm, the length of the mounting area should be greater than 110 mm, the arc length of the curved surface should be greater than or equal to 32 mm, and the sample mounting should allow multiple cuts on a single sample with a minimum interval of 10 mm.

d) Blade: Made of material with a hardness greater than 5, the thickness of the blade should be (1.0 ± 0.5) mm, the width of the cutting edge formed should be (2.5 ± 0.2) mm, the angle formed by the two cutting edges is approximately 22°, the cutting edge length of the blade should be greater than 65 mm, and the width of the blade should be greater than 18 mm.

e) Blade holder: Made of material with a hardness greater than 5, the thickness of the blade should be (1.0 ± 0.5) mm, the width of the cutting edge formed should be (2.5 ± 0.2) mm, the angle formed by the two cutting edges is approximately 22°, the cutting edge length of the blade should be greater than 65 mm, and the width of the blade should be greater than 18 mm.

f) Cutting Motion System: This system moves the sample support fixture and the blade relative to each other, with the plane of the blade making an angle of (90 ± 2)° with the long axis of the sample support fixture, and cuts the sample at a speed of (2.5 ± 0.5) mm/s. The bearings in the system should ensure smooth movement of the blade, restricting any lateral movement of the blade. The blade should make a (90 ± 5)° angle with the long axis, should stop upon contact with the sample, and should apply a force of (5 ± 0.5) N on the side of the blade. The maximum lateral displacement of the blade should be 0.5 mm.

g) Cutting Stroke Length Measurement System: This system is used to measure the distance the blade travels until it completely cuts through the sample, with measurement accuracy to 0.1 mm. The cutting stroke is the distance moved by the blade from its initial contact position with the sample to the point where the blade stops after completely cutting through the sample.

Index of Markings:

1 – Power and drive system; 2 – Blade support and guidance system; 3 – Sensors; 4 – Blade holder;

5 – Blade fixture; 6 – Blade; 7 – Sample holder; 8 – Base of the sample holder;

9 – Counterweight; 10 – Beam; 11 – Weight plate; 12 – Safety handle.

4.3.2 Exemple

The sample requirements are as follows:

a) The sample should be taken from an area that represents the protective performance of the product.

b) For woven, knitted, and other directionally processed materials, the sample cutting angle should be (45 ± 10)° relative to the material processing direction. For non-directionally processed materials (e.g., leather), cutting tests should be conducted in two directions that are mutually at a 45° angle.

c) The sample size should not be less than 25 mm x 100 mm. The minimum sample size for a single cut should not be less than 25 mm x 25 mm.

d) The sample should be conditioned according to the requirements of section 5.2. After removing the sample from the conditioning environment, the test should be conducted within 5 minutes.

4.3.3 Procediment de prova

4.3.3.1 Installing the Sample

Secure the sample to the support device using double-sided tape with a width of (50 ± 2) mm. Place a conductive material with a width of (10 ± 2) mm and a thickness not exceeding 0.03 mm (e.g., aluminum or copper) at the top of the tape and connect it to the sample support device to ensure good conductivity. Secure the sample without tension on the surface of the support device with tape, or paste two longitudinal strips of double-sided tape on the surface of the sample support device, leaving a gap of (10 ± 2) mm in the center for the blade to contact the metal surface. Insulate the conductive sample from the sample support device using a plastic film with a thickness not exceeding 0.03 mm (e.g., low-density polyethylene). Prior to testing, secure the multilayer materials by sewing along the edges or using double-sided tape with an intermediate layer or other suitable techniques. For loosely woven materials, place a layer of filter paper with a mass less than 65 g/m2 between the support device surface and the sample.

4.3.3.2 Blade Sharpness Calibration

Each batch of blades should consist of no less than 200 pieces. Take out one blade from every 20 blades and cut a chloroprene rubber calibration specimen with a cutting force of (5 ± 0.02) N to calibrate the sharpness of the blade. If the cutting stroke length when the blade cuts through the calibration sample is within the range of 20 mm to 30 mm, and the coefficient of variation of 10 test results does not exceed 10%, the batch of blades is considered acceptable. Calculate the blade sharpness calibration coefficient S using the formula S = K / l.

on: S – Calibration coefficient K = 20, l – Cutting stroke length when the blade cuts through the calibration sample, in millimeters (mm).

4.3.3.3 Instrument Equipment Calibration

The steps for instrument equipment calibration are as follows:

a) Level the instrument equipment;

b) Mount the sample on the support;

c) Install a new blade and position the blade holder and sample support device at their starting positions for the cutting stroke. Adjust the blade displacement measurement system to zero position;

d) Adjust the instrument equipment to ensure that the force between the blade and the sample is less than 0.01 N.

4.3.3.4 Procediment de prova

The test procedure is as follows:

a) Conduct the cutting test at a cutting speed of (2.5 ± 0.5) mm/s.

b) Apply the selected cutting force between the blade and the sample. Start the test within 5 seconds of the blade contacting the sample. The cutting stroke when the blade cuts through the sample should be between 5 mm and 50 mm. Perform at least 15 tests at different cutting forces, ensuring that at least 5 readings fall within the ranges of 5 mm to 15 mm, 15 mm to 30 mm, and 30 mm to 50 mm. Each successive cut on the sample should be at least 10 mm apart, and the sample should be insulated with a plastic film with a thickness not exceeding 0.03 mm between cuts.

c) Record the cutting force and cutting length.

d) Multiply each cutting length by the blade sharpness calibration coefficient S to obtain the standardized cutting length. e) Plot the optimal curve of standardized cutting length against cutting force. Based on the curve, determine the cutting force required for a cutting length of 20 mm.

f) Using the calculated cutting force from e), conduct 5 additional tests. If the average cutting length falls within the range of 18.0 mm to 22.0 mm, include these results in the existing data. Recalculate the cutting force based on e). If the average cutting length does not fall within this range, conduct 5 more experiments following the procedure in e), and use all test results to calculate the cutting force.

g) When reporting the cutting force, round the value to the nearest 0.1 N for accuracy.

4.3.4 Informe de prova L'informe de prova ha d'incloure la informació següent:

  • Sample origin, identification, name, or code;

  • Performance level of the required sample (if applicable);

  • Test conditions;

  • Values of all individual cutting test parameters (force, distance, etc.);

  • Blade sharpness calibration coefficient;

  • Corrected cutting stroke lengths;

  • Curve plotted from the initial 15 or more cutting tests;

  • Cutting force determined from the curve;

  • Results of 5 to 10 cutting validation tests;

  • Curve redrawn with all data points integrated;

  • Cutting force obtained from all data points;

  • Any deviations from the methods specified in this document;

  • Date of the test and signature;

  • Information on the blades used and chloroprene rubber calibration specimens.

4.3.5 Dispute Resolution of  Test Results

If the cut resistance performance level of mechanical protective guants is labeled using the straight blade test method, any disputes regarding test results should be resolved according to the cut resistance (straight blade test method) (4.3), and the results of the straight blade test method should be used as the basis for arbitration.

4.4 Tear Resistance

4.4.1 Instrument Equipment

A tensile testing device equipped with a low inertia force measurement system.

4.4.2 Exemple

The dimensions of the sample (see Figure 6) are: (100 ± 10) mm x (50 ± 5) mm. A cut of (50 ± 5) mm should be made along the long edge of the sample at a distance of (25.0 ± 2.5) mm from the edge. The cut should be made with a sharp blade vertically on the surface of the sample. If the palm of the glove contains a reinforcement layer (e.g., padding), the sample should avoid the area of the reinforcement layer. If the sample is composed of several unglued layers, each layer should be tested. The performance level should be determined based on the layer with the highest performance.

4.4.3 Experiment Process

4.4.3.1 Assembling the Sample

Each cut sample strip (see Figure 7) should be securely fixed to the extensometer on the test apparatus with a minimum of 20 mm clamped in the fixtures. The distance between the two fixtures should be at least 10 mm to ensure that the direction of tension is parallel to the long side of the sample.

Llegenda: l – Sample Strip

4.4.3.2 Procediment de prova

The test procedure is as follows:

a) Record the force at which the sample tears using an X-Y recorder, with a pulling speed of (100+-10) mm/min. The sample should be completely torn apart; note: in some cases, the tearing direction may not be along the long side of the sample.

b) If the sample has not torn under a force exceeding 75 N, the test can be stopped, and the maximum force reached should be recorded.

c) Four different gloves from the same glove series are used for testing.

d) Two samples are taken in the direction from the cuff to the fingertips of the glove, and the other two samples are taken in the direction across the palm width (see Figure 8).

e) The tear resistance performance of each sample is determined by the highest value it can achieve, while the tear resistance performance grade of the glove is determined by the lowest value among the 4 sets of test results.

4.4.4 Informe de prova L'informe de prova ha d'incloure la informació següent:

  • Referència al número de clàusula d'aquest document

  • Informació de referència de la mostra

  • Test results according to 4.4.3

  • Qualsevol desviació del mètode de prova

  • Performance grade determined according to Table 1

4.5 Punxar Resistència

4.5.1 equipament The equipment includes:

  • A low inertia compression device capable of testing from 0N to 500N

  • A steel nail mounted on the central axis of the equipment, with dimensions as specified in Figure 9

  • A fixture device for securing the sample on the central axis of the equipment, as shown in Figure 10.

l – The Rockwell hardness of the steel nail is 60 HRC.

l – Fixing knob

4.5.2 Exemple

The sample is circular with a diameter not less than 40 mm. Seams, reinforcements, and thickened areas are outside the clamping and puncture areas. In the presence of unglued layers, the separated layers should be tested together. If the glove palm is designed in an irregular shape, all areas should be tested, and the performance level should be determined based on the lowest value obtained from the tests.

4.5.3 Procediment de prova

The test steps are as follows:

a) Clamp the sample in the center of the fixing device, ensuring that the outer surface faces the steel nail.

b) Move the steel nail downward towards the sample at a speed of 100 mm/min until the nail tip contacts the sample and the displacement relative to the sample reaches 50 mm; record the maximum force during this process even if the sample has not been pierced at this point.

c) Test samples taken from four different gloves of the same series.

d) Each test should confirm that the shape and dimensions of the steel nail comply with the requirements of Figure 9. For most materials, it is recommended to check the steel nail at least every 500 uses, but for materials that can damage the steel nail due to hardness and abrasiveness, more frequent checks are required.

e) The puncture resistance performance level is determined by the lowest recorded value.

4.5.4 Informe de prova L'informe de prova ha d'incloure la informació següent:

  • The clause number of this document being referenced

  • Informació de referència de la mostra

  • Results of the four tests conducted according to 4.5.3

  • Qualsevol desviació del mètode de prova

  • Nivell de rendiment determinat segons la Taula 1

4.6 impacte Resistència

4.6.1 equipament

4.6.1.1 Impact Test Device

An impact hammer that can release with 5J energy falling along a vertically guided path onto the sample placed on the test platform, with the axis of the falling hammer coinciding with the axis of the platform.

4.6.1.2 Martell d'impacte

The mass of the impact hammer should be (2.5 ± 0.01) kg, with a circular impact surface of diameter (80 ± 2) mm, polished surface.

4.6.1.3 Enclusa

The anvil surface should be curved, with a convex curvature radius of (100 ± 1) mm, polished surface.

4.6.1.4 Force Sensor

The requirements for the force sensor are as follows: a) Response Frequency: >=7kHz. b) Accuracy: <0.1kN.

4.6.2 Exemple

The sample requirements are as follows:

a) 4 glove samples, each sample impacted once.

b) Select glove samples of different sizes as much as possible.

c) Each sample from the 4 gloves should test a different back-of-hand joint.

4.6.3 Determining Impact Test Points for Gloves

The method to determine the impact test points for gloves is as follows:

a) No clearly visible impact protection area: The glove sample should be worn by an evaluator with an appropriate hand size, gripping a cylindrical rod with a diameter of (32 ± 5) mm and a length greater than 120 mm. Mark the position where the back-of-hand joint protrudes on the back of the hand. Repeat the same procedure with two other evaluators, and the triangular area formed by the three marked points of the back-of-hand joint should be placed at the center of the test platform.

b) Clearly visible impact protection area: The correct position of the protection area is confirmed according to anthropometric evaluation. Mark the position of the most prominent back-of-hand joint, and place it at the center of the test platform.

4.6.4 Procediment de prova

The test procedure is as follows:

a) The marked glove sample should be laid flat and cut along the junction of the palm and back of the hand.

b) Adjust the sample according to the requirements of 5.2. After removing the sample from the conditioning environment, the test should be conducted within 3 minutes.

c) Place a soft dual-layer leather (thickness of 0.8 mm-1.0 mm, e.g., deer leather) over the curved anvil with a 100 mm radius. Place the marked protective test point of the glove sample at the center of the curved anvil. Raise the 2.5 g impact hammer to the height required for (5 ± 0.1) J of impact energy, release the impact hammer, record the peak force of the impact test, check and record whether the leather is torn or punctured. Repeat the procedure for testing the remaining glove samples, record all test results.

d) Conduct the test as per b) and c), record the following test results in kN, rounded to 0.1 kN:

  1. Record the maximum value of single-conduction force for the 4 samples.

  2. Calculate the average conduction force value for the 4 samples.

4.6.5 Informe de prova L'informe de prova ha d'incloure la informació següent:

  • The clause number of this document being referenced

  • Informació de referència de la mostra

  • Single-conduction force values for each sample tested according to 4.6.4 and the average conduction force value for the 4 samples

  • Qualsevol desviació del mètode de prova

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