ANSI-ESD STM11.12:2000 pdf download.Volume Resistance Measurements of Static Dissipative Planar Materials.
ANSI-ESD STM11.12 defines a direct current measurement to determine the volume resistance of a static dissipative, planar material, without regard to its conduction mechanism
3.0 Referenced Publications
The following standards contain provisions which, through reference in this text, constitute provisions of this ESD Association Standard. At the time of publication, the editions indicated were valid. All standards are subject to revisions and parties with agreements based on this ESD Association Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. American Society of Testing and Matenals (ASTM) D-257-91: Standard Test Methods for direct current (DC) Resistance or Conductance of Insulating Materials.
ASTM 0-991-89: Standard Test Method for
Rubber Property-Volume Resistance of
Electrically Conductive and Antistatic Products.
ESD Association ADV1 .0: Glossary of Terms
4.0 Definition of Terms
Electrification Period The average of fIve (5) electrification times, plus 5 seconds.
Electrification Time. The time for the resistance measuring instrument to stabilize at the value of the upper resistance range verification fixture (see section 10).
Planar Materia[ An item with a surface sufficiently large and flat to conform to the surface of the electrode(s) used to measure the electrical properties of the material.
Volume Resistance of Static Dissipative Materials The ratio of DC voltage to current passing between two electrodes, of a specified configuration, that contact opposite sides of the material or object under test Volume resistance of static dissipative material is reported in ohms.
5.0 Repeatability
This test has been shown to have a repeatability of approximately one order of magnitude.
General Discussion
This procedure is recommended for measuring the volume resistance of materials that are between 1 x ohms and 1 x 1011 ohms. This test method measures the resistance through a material’s thickness. It has been demonstrated that the relative humidity influences the test results significantty so this test method specifies that samples be conditioned and tested at 12% RH and 72 degrees F (23°C. This test method consists of the following steps:
A) Sample Preparabon.
B) Test instrument including setup and system
venfication tests.
C) A defined electrification period.
0) Test Procedure.
E) Documentation and reporting of data.
7.0 Apparatus
The equipment used for volume resistance measurements of static dissipative material is described below
7.1 Electrode Assembly
The electrode assembly consists of: A top electrode and a bottom electrode. See Figure 1 for system setup
7.1.1 Top Electrode
The top electrode assembty consists of two concentric rings which make contact with the material under test See Figure 2
The contact surface material of the electrode assembty shall be conductive rubber having a hardness of 50 to 70 on the Shore-A Durometer scale and a volume resistivity of less than 10 ohm-cm per ASTM D-991.
The inner electrode shall be flat and make total contact with the test sample.ANSI-ESD STM11.12 pdf download.