Nikola Tesla Crossword

Flooring Resistance Test Method 

Using Heel Electrodes

ATP F1000 / May 1999

1. Purpose

1.1 The purpose of this test method is to assess the electrical resistance of flooring using similar weights and pressures to those expected in actual use, and with temperature and humidity conditions in the expected range of actual use. The results of this test can be used to predict static potentials on individuals which are likely to result under various conditions of actual use.

1.2 This test method is also designed to allow rapid auditing of the resistance of installed floors.

1.3 This test method does not include standards of performance. Such specifications are the responsibility of trade or consumer organizations, or the consumer, and may logically vary considerably with the demands

2. Scope

2.1 This test procedure is intended for use with all floor surfaces and floor covering materials.

3. Principle

3.1 The beneficial contribution of electrical resistance (conductivity) to the dissipation of static charges generated by persons walking across flooring materials or of static charges brought onto the floor by persons entering an area has long been recognized. Typically floors with reasonable conductivity across the surface and to ground help keep personnel voltages to a minimum.

3.2 A flooring material brought to equilibrium at controlled conditions is walked on by a test person wearing heel straps with conductive rubber electrodes affixed to the bottom, electri-cally isolated from the test person and connected to a resistance meter.

3.3 Electrical resistance measured with heel attached electrodes is a direct indication of the static dissipation capability of the flooring.

3.4 In this test method the operation is normally carried out under standardized conditions chosen to obtain meaningful results and to permit comparison of test results obtained at dif-ferent times and locations.

3.5 This test method is also specifically designed to allow optimized auditing of installed floors under actual use conditions.

4. Significance

4.1 Static electrification and dissipation is in practice an extremely variable phenomenon. However, a meaningful prediction of personnel voltages due to electrification and dissipa-tion may be obtained by measurement of the electrical resistance of the flooring material both point to point and point to ground under proper selection of test conditions and use of a heel electrode system.

4.2 Tests performed1 show that flooring electrical resistances vary significantly with the weight of the electrodes, particularly at weights below 25 pounds. Therefore the electrical resistance of flooring can and should be measured at or near the weight levels encountered in actual use.

4.3 This test method does not include standards of performance. Such specifications are the responsibility of trade organizations, or the consumer, and may logically vary considerably with the demands of the application.

5. Safety Precautions

5.1 Note: these safety precautions are for information purposes only. The precautions are ancillary to the testing procedures and are not intended to be all inclusive. It is the users re-sponsibility to use safe and proper techniques in handling materials in this test method. Manufacturers MUST be consulted for specific details such as material safety data sheets and other manufacturers recommendations. All OSHA standards and rules must also be con-sulted and followed.

5.2 Where electrical instrumentation is required, all manufacturers' recommendations for safety must be adhered to as well as all applicable electrical codes of practice. If test per-sonnel are not familiar with safety precautions, a competent electrical technician or electri-cian must be consulted.

6. Apparatus and Materials

6.1 Test area: Standard test conditions for this test method require a room or large enclosure which can be maintained at 22 +/- 3 C ( 70 +/- 2 F ) and at a relative humidity of 12 +/- 2% and suitable means for monitoring these conditions. Special requirements of end use may dictate the use of other testing conditions. Audit measurements shall be at the recorded am-bient conditions during the tests of the installed floors..

6.2 Ohmmeter: Electrical resistance measurement instrument capable of reading the ex-pected range of resistances. Typically this range for static protective flooring should be between 1 E4 Ohms and 1 E11 Ohms. The electrical resistance measuring instrument should have a regulated output voltage capability of 100 volts.

6.3 Heel Electrodes: Conductive rubber electrodes attached to heel straps with snaps for connection of leads to the Ohmmeter.

 The conductive electrode pads shall have a resistance of less than 1000 Ohms. The rubber electrode material shall be insulated from the shoe and body of the test person. Note: the person using the heel electrodes shall be wearing non conductive shoe soles and heels.

7. Test Specimens

7.1 The flooring specimens to be tested should be at least 91 cm X 91 cm (3' X 3').

7.2 A minimum of 3 samples should be tested if a statistically valid sampling of specimens is possible..

7.3 Audits of installed flooring require no minimum or maximum size.

8. Conditioning of Specimens

8.1 All test specimens shall be preconditioned at 21 +/- 1 C ( 70 +/- 2 F ) and at a relative humidity of 12 +/- 3% for a period of at least 48 hours.

8.2 Installed floors being audited are of course tested at ambient conditions.

9. Test Procedure ( for Specimens)

9.1 With heel electrodes strapped on the test person's shoes and connected to the ohmmeter,

 

stand with the feet approximately 30 cm (12") apart on an insulative material with a surface resistance of greater than  1E12 Ohms. Record the value. This value must be at least ten (10) times higher than the highest flooring electrical resistance to expected to be measured.

9.2 With heel electrodes strapped on the test person's shoes and connected to the Ohmmeter, stand with the feet approximately 30 cm (12") apart. Record the value. Take at least 3 readings in random locations in the machine direction and cross machine directions for each specimen.

9.3 Report all values.

10. Audit Test Procedures

10.1 With heel electrodes strapped on the test person's shoes and connected to the ohmmeter, stand with the feet approximately 30 cm (12") apart. Record the value. Take at least 2 readings every 3 sq. m (10 sq. ft ) in random locations on the floor being audited . Make sure one of those readings is in each perpendicular direction to determine directionality of the conductivity of the flooring




10.2 Report all values.

11. Precision and Bias

11.1 Precision and bias of this test method are being established.

Cited Documents

1. Fowler, S., and Klein, W., "Static Phenomena and Test Methods for Static Controlled Floors," EOS/ESD Symposium Proceedings, 1992.

2. EOS/ESD Association Standard S7.1, "Floor Materials - Resistive Characterization of Materials," 1994.

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