After day one
A floor drifts out of range without ever looking different
This is the part that catches facilities out. Resistance moves with wear, with what gets applied to the surface, and with age, and none of it is visible. A floor can look perfect and fail a resistance test. That gap is exactly why STM7.1 and STM97.1 measurement exists instead of a visual check[2].
Keeping a floor in range
Wax and finish are the usual culprit
Anything applied on top of the system sits between the floor and the ground path. A well meant cleaning contract can take a qualified floor out of range in a month, and nobody connects the two until the audit.
Abrasion thins the system
Cart wheels, pallet jacks and pivot points wear the coat down. Thickness affects resistance, so the highest traffic lanes are where a floor goes out of band first.
Humidity moves the reading
Resistance responds to humidity, which is why IEC 61340-5-1:2024 lets a facility qualify at its own lowest annual relative humidity rather than a fixed benchmark[18]. A floor that passed in August can read differently in February.
Reverification is a schedule, not an event
ESD TR53 is the technical report for compliance verification of control items already in service[17]. Your program document sets how often. A floor qualified once and never rechecked is an assumption.
Clean it the way the system expects
Neutral cleaner, no film forming products, no wax unless the system is specified to carry one. Write it into the cleaning contract, because the cleaning crew will not read your ESD program.
Watch the ground connections
The floor can be perfect and the tie to building ground can have been disturbed by other work. Point to ground readings catch this, and point to point readings alone do not.
Questions
How often should an ESD floor be retested?
Our floor failed a retest. Does it need replacing?
Not necessarily. Find out what changed first: a finish applied on top, a disturbed ground connection, or genuine wear are three very different answers with three different costs. Repair and recoat options.
Can we use normal floor cleaner?
Neutral cleaners generally yes, film forming products and wax generally no. Anything that leaves a layer on top is a layer between the floor and ground.
Sources
- ANSI/ESD S20.20-2021, the ESD control program standard for electronics handling
ESD control program requirements (administrative and technical) for any organization that handles ESD-sensitive electrical or electronic parts.
www.esda.org - ANSI/ESD STM7.1-2020, floor resistance test method for static control flooring
Floor systems resistive characterization: the test method for qualifying floor materials before installation and for accepting and monitoring them after installation.
www.esda.org - ANSI/ESD STM97.1-2025, person plus footwear plus floor system resistance test
System resistance measurement of a person, footwear, and floor tested together; this is the test behind S20.20's under-1.0 x 109 ohm system ceiling.
webstore.ansi.org - ESD TR53, compliance verification testing for ESD control items already in service
Technical report for compliance verification testing of ESD control items already in service; the document a facility's periodic floor-resistance recheck follows.
www.esda.org - Does an ESD control program require humidity control, and the 2024 change
Cited here for the IEC 61340-5-1:2024 lets ESD control items, flooring included, be qualified at the facility's own lowest annual relative humidity rather than an arbitrary fixed.
incompliancemag.com
Every number on this page came from one of those documents. Send us the room and we will tell you which of them your floor has to answer to.