UFGS 09 66 23, Resinous Matrix Terrazzo Flooring (August 2016, Change 1 August 2018), specifies when conductive resinous terrazzo must be tested, the resistance limits it must meet and the documentation required to demonstrate conformance.
This is a guide specification. Its requirements apply when incorporated into the project specification, subject to the project’s adopted wording.
Test timing and governing method
The guide specifies testing 30–45 days after installation is completed and before the floor is put into use (section 3.3). Requirements for other flooring systems and specifications are covered in our guide to when installed-floor acceptance testing should take place.
Section 3.3 directs testing in accordance with NFPA 99 paragraph 12-4.1.3.8(b)(7). However, the guide’s references list identifies NFPA 99 (2024, TIA 24-2), while the testing paragraph retains that older paragraph designation. Confirm the intended NFPA edition and test procedure with the project specifier before testing.
Resistance limits for individual locations and the floor average
The UFGS testing provision sets three acceptance criteria:
| Criterion | Where it applies | Required resistance |
|---|---|---|
| Resistance at any one location | Areas with 110-volt electrical service | More than 5,000 ohms |
| Resistance at any one location | Areas with 220-volt electrical service | More than 10,000 ohms |
| Average resistance | All areas | More than 25,000 ohms and less than 1,000,000 ohms |
The 110- and 220-volt references identify the area’s electrical service, not the voltage to apply with the test instrument.
The individual-location and average limits apply together. An acceptable average does not compensate for a location at or below its applicable minimum. All boundaries are strict: a value equal to a stated limit does not satisfy that criterion.
These are the guide specification’s acceptance values for conductive resinous terrazzo, not general resistance limits for every ESD flooring system.
Required acceptance documentation
Section 3.3 requires certificates indicating conformance with the specified requirements, accompanied by certified test reports demonstrating that the floor was tested and meets those requirements.
Frequently Asked Questions
No. These limits address conductive resinous terrazzo under the cited UFGS provision. Whether they govern a particular installation depends on the project specification.
No. The floor must satisfy both the average-resistance range and the applicable minimum at every tested location. A passing average cannot compensate for an individual reading that fails its minimum.