For electrostatic discharge (ESD) flooring, resistance to ground (Rtg) is measured between a surface electrode and ground. Resistance point-to-groundable point (Rpgp) is measured between a surface electrode and a groundable point. Resistance point-to-point (Rpp) is measured between two surface electrodes. When selecting an ESD flooring test, the distinction is where each measurement begins and ends.
| Measurement | Measured between |
|---|---|
| Resistance to ground (Rtg) | A single electrode placed on the surface and ground |
| Resistance point-to-groundable point (Rpgp) | A single electrode placed on the surface and a groundable point |
| Resistance point-to-point (Rpp) | Two cylindrical electrodes placed on the surface of the ESD control item |
What a groundable point is
ANSI/ESD STM97.1-2025 is an ESD Association standard test method (STM) approved by the American National Standards Institute (ANSI). ANSI/ESD STM97.1-2025 defines a flooring groundable point as a point on the floor system that accommodates an electrical connection from the floor material to an appropriate ground.
Qualification-sample Rpgp versus installed-floor Rtg
ANSI/ESD STM7.1-2020 states that resistance to groundable point measurements on product qualification samples may differ from resistance to ground measurements performed on installed areas, especially when evaluating materials such as floor finishes.
Frequently Asked Questions
ESD TR53-01-22, the ESD Association’s technical report (TR) on compliance verification, defines resistance to ground (Rtg) as resistance in ohms between a single surface electrode and ground, and resistance point-to-groundable point (Rpgp) as resistance in ohms between a single surface electrode and a groundable point. ANSI/ESD STM97.1-2025 defines a flooring groundable point as a point that accommodates an electrical connection from the floor material to an appropriate ground.
ESD TR53-01-22 defines resistance point-to-point (Rpp) as resistance in ohms between two cylindrical electrodes on the surface of the ESD control item.
No. ANSI/ESD STM7.1-2020 states that resistance to groundable point measurements on product qualification samples may differ from resistance to ground measurements on installed areas, especially for materials such as floor finishes.