The organization sets the periodic retest interval for electrostatic discharge (ESD) flooring in its compliance verification plan. Additional checks may be appropriate after maintenance or required after particular events under the facility’s adopted program. These event-triggered checks are separate from the recurring testing schedule.
Craftsman Concrete helps facilities develop ESD flooring programs that define when testing and retesting are needed, including scheduled checks and checks prompted by maintenance or flooring changes. This support is available for floors installed by Craftsman and other contractors. Contact Craftsman Concrete for help developing or reviewing your facility’s program.
Establish the periodic testing frequency
ANSI/ESD S20.20-2021 requires a compliance verification plan identifying the ESD control items to be tested periodically and their testing frequency (section 7.4). That provision does not prescribe a numerical floor-retest interval.
The informative foreword to ESD TR53-01-22 assigns the interval decision to the organization performing compliance verification and recommends considering how critical each item is to its ESD control program. The foreword is outside the technical report itself.
The explanation of retest intervals under S20.20 and TR53 distinguishes the requirement to establish a frequency from guidance on choosing it.
Account for flooring material and maintenance
Topical finishes may need more frequent monitoring
Topical ESD floor finishes, such as ESD wax, may need more frequent monitoring than ESD vinyl floor covering because they are less permanent. The ESD Association’s Fundamentals of Electrostatic Discharge, Part Four (2020) identifies this consideration without assigning either material a fixed interval.
See how floor finishes affect retest frequency when reviewing a floor whose ESD performance depends on a topical finish.
Maintenance can prompt an additional check
Fundamentals Part Four advises considering a floor test after maintenance. This is a recommendation, not a universal requirement to test after every maintenance activity.
Check whether the facility’s adopted program imposes more specific requirements, such as the cleaning and conductive-wax provisions below.
Meter calibration follows a separate schedule
A resistance meter’s calibration interval does not determine how often the floor must be retested. Consult the equipment’s calibration documentation for the meter and the facility’s compliance verification plan for the floor.
The distinction between meter calibration and floor retesting prevents those two schedules from being confused.
Event-triggered checks in dated agency programs
These dated NASA documents illustrate event-triggered checks within specific programs; they do not establish a universal floor-testing schedule.
The Langley document, LPR 8739.21, was effective April 13, 2011, and prints an expiration date of March 31, 2016. It is included as a historical program example. NASA-HDBK-8739.21, approved June 18, 2010, provides a recommended baseline for developing local ESD program requirements. The Marshall example is MSFC-RQMT-2918 Revision E, effective December 17, 2015.
Checks after cleaning
| Document | Check and timing | Scope and exceptions |
|---|---|---|
| LPR 8739.21, Langley (2011) | The ESD Program Monitor verifies floor resistance and confirms it is recorded after cleaning, at least two hours after cleaning and before room use. | Section 4.8.3 exempts vacuuming and dry sweeping. |
| NASA-HDBK-8739.21 (2010) | Protective-floor resistance is checked and documented at least two hours after cleaning and before room use. | Table 7-1 labels the row a Class 0 requirement and exempts vacuuming. Section 7.8.3 describes post-cleaning checks more generally and also exempts dry sweeping. |
| MSFC-RQMT-2918 Revision E, Marshall (2015) | Floor resistivity of ESD protective floors or mats is verified and recorded after each cleaning. | The protective-flooring footnote exempts vacuuming. |
Confirm which provisions the facility’s ESD program has adopted before applying an example from this table.
Conductive-wax application and new flooring
The historical Langley program requires the ESD Program Monitor to verify floor resistance after conductive-wax application and confirm that the results have been recorded. It also requires conductive waxes to be used in accordance with manufacturer recommendations.
Adding a new conductive floor triggers recertification of the ESD protected area under LPR 8739.21. NASA-HDBK-8739.21 identifies the same trigger in section 5.8.6. This concerns recertification of the protected area, not simply a resistance measurement on the new floor.
Repeating walking body-voltage testing
For a footwear/flooring personnel-grounding system, ANSI/ESD S20.20-2021 recommends periodic body-voltage generation testing to verify that voltage remains below 100 volts (Table 2, footnote 6). Under that provision, periodic testing is recommended, not required, and no repeat interval is specified.
The guide to repeating walking body-voltage tests explains the distinction from initial qualification and the separate JEDEC recommendation.
Put the decisions into the facility’s testing plan
When establishing or reviewing the schedule, document:
- The periodic floor-testing frequency.
- The applicable measurements and acceptance criteria.
- Maintenance activities or other events that prompt additional checks.
- Who arranges the testing and retains the results.
See our ESD floor testing services for assistance carrying out the plan.
Frequently asked questions
Have the person responsible for the facility’s ESD program establish and document the frequency in the compliance verification plan. Review the governing requirements, the floor’s role in the program, and relevant material and maintenance considerations. The cited S20.20 and TR53 provisions do not supply a universal numerical interval.
No. The two-hour provisions discussed here come from specific dated NASA documents. They should be applied within the relevant program scope, including its exceptions. The ESD Association’s general advice to consider testing after maintenance does not impose that timing on every facility.