ESD measurement: resistances, body voltage, ionisation
Measure. Assess. Prove. – with calibrated equipment and a complete report.
The effectiveness of your ESD protective measures must be verified with suitable, regularly calibrated measuring equipment – following the conformance-verification methods the 2025 edition references normatively. Without valid records, your readings do not stand up in an audit.
What we measure
- Resistance to ground – work surfaces, flooring, racks and trolleys
- Wrist strap systems – person, cord and strap as a system
- Footwear–flooring system – for standing workstations
- Body voltage (walking test) – charge build-up of the walking person
- Material resistance – point-to-point and to groundable point
- Isolated conductors & fields – potentials and field strength at the ESDS location
- Ionizers – offset voltage and discharge times
- Packaging – resistance and shielding per the referenced test methods
For standing work, resistance and body voltage must both be met. All details on our standard page. DIN EN IEC 61340-5-1:2025
Method
How we measure
Calibrated equipment, standardised methods, results you can defend.
Calibrated equipment
Traceable instruments with valid calibration records – the precondition for defensible readings.
Standardised methods
Measurements follow the test methods of the IEC 61340 series, including the conformance-verification specification referenced by the 2025 edition.
Report per measuring point
Reading, limit, pass/deviation and ambient conditions – documented per point.
Assessment & recommendations
Deviations are prioritised and come with concrete corrective actions.
Klimatická komora
Testing at defined temperature and humidity – e.g. worst-case low humidity.
ESD Manager
On request, results go straight into digital documentation with due-date tracking.
Limits
The limit table of the 2025 edition
These are the values we verify, each measured with its standardised method.
| Requirement | Limit | Test method |
|---|---|---|
| Wrist strap system (person + cord + strap) | < 3,5 × 10⁷ Ω | IEC 61340-4-6 |
| Groundable EPA garment system | < 3,5 × 10⁷ Ω | IEC 61340-4-9 |
| Footwear–flooring system (standing work) | < 1 × 10⁹ Ω | IEC 61340-4-5 |
| Body voltage (mean of the five highest peaks) | < 100 V | IEC 61340-4-5 |
| Isolated conductor before ESDS contact | ± 35 V | Clause 5.3.4.3 |
| Ionizer offset voltage | −35 V … +35 V | IEC 61340-4-7 |
| Insulator (definition) | ≥ 1 × 10¹¹ Ω | Clause 5.3.4.2 |
| Field at the ESDS location | ≤ 5000 V/m | Clause 5.3.4.2 |
| Shielding packaging (energy) | < 20 nJ | IEC 61340-4-8 |
For standing work, the system resistance and the body voltage must both be met. And note for shielding packaging: the rulebooks differ – ANSI/ESD STM11.31 names ≤ 50 nJ, the IEC series requires < 20 nJ. A programme run to DIN EN IEC 61340-5-1 must meet the IEC value – a detail many packaging approvals stumble over. All changes of the 2025 edition are explained on our standard page: DIN EN IEC 61340-5-1:2025 – what changed
Conditions
Why the same measurement turns out differently in January
The leakage resistance of almost all ESD materials depends on humidity. A floor that sits comfortably below the limit in June at 55 % relative humidity can be a full decade above it in February at 20 %. That is why temperature and relative humidity belong in every measurement report – a reading without its climate data is worthless in an audit.
Two things follow. First: recurring verification should take place in the dry season, not in the humid summer. Whoever passes in winter passes all year. Second: for qualifying new materials, measuring under operating conditions is not enough. The standard requires conditioning for 48 hours at 12 ± 3 % relative humidity and 23 ± 2 °C – deliberately unfavourable conditions.
That is exactly what we have our own climate chamber for. Floors, chairs, gloves, garments and packaging can be tested in the worst case before they are purchased and installed – instead of discovering next winter that the decision was wrong. Our climate chamber →
Methods
Measurement methods in detail
There is a standardised method for every quantity – and we measure exclusively by these methods.
- IEC 61340-4-1 – floor coverings
Resistance to ground and point-to-point at measuring points distributed over the area – the basis for assessing ESD floors. - IEC 61340-2-3 – material resistance
Surface and volume resistance of work surfaces, containers and materials, measured at defined test voltages. - IEC 61340-4-3 – footwear
Testing of ESD footwear – every shoe–floor combination in use has to comply. - IEC 61340-4-5 – person + footwear + flooring
The system test on the person: system resistance and body voltage of the walking person (walking test). - IEC 61340-4-6 – wrist strap systems
Person, cord and strap tested as a complete system at the workstation. - IEC 61340-4-7 – ionizers
Offset voltage and discharge times – decisive wherever insulators are process-essential. - IEC 61340-4-8 – shielding packaging
Energy penetration of shielding bags – the IEC value applies in European audits. - IEC TS 61340-5-4 – conformance verification
The technical specification the 2025 edition references normatively: it defines how recurring verification is performed.
Evidence
A measurement report that holds up in an audit
For every measuring point we document: unique designation and location, measurement method with its reference to the standard, the instrument used including serial number and calibration date, test voltage, temperature and relative humidity, the reading, the applicable limit and the assessment – passed or deviation. One example row:
| Measuring point | Quantity | Limit | Reading | Climate | Result |
|---|---|---|---|---|---|
| Station 4, footwear–flooring | System resistance | < 1 × 10⁹ Ω | 3,2 × 10⁸ Ω | 23 °C / 25 % RH | passed ✓ |
This completeness is no end in itself. In a customer or certification audit, a report without calibration evidence, climate data or a named test method is open to challenge – the reading may be right, but the evidence does not hold. On request the results flow directly into the ESD Manager, which also tracks the next due verification and makes the trend per measuring point visible over the years. Exactly that trend line shows a floor slowly drying out long before it breaks the limit.
Instruments
Without a valid calibration certificate, no reading counts
The standard requires suitable and regularly calibrated measuring equipment. In practice this is one of the most frequent audit findings of all: measurements are done properly, but the instrument has not seen a calibration certificate for four years – which strips every report from that period of its evidential value.
We calibrate ESD measuring instruments in-house, with traceable references and a documented calibration certificate: high-resistance meters, surface resistance meters, field meters, body-voltage measuring stations and walking-test systems. You can send your instruments in or combine the calibration with an on-site measurement appointment – then the equipment is back at the line, ready for use, the same day.
Costs
Price & effort
The effort is driven by the number of measuring points: workstations, floor areas, racks and trolleys, persons and ionizers. Based on your key data we scope individual measurements, a complete EPA verification or a recurring measurement schedule.
You receive a fixed-price quote in advance – usually within 24 hours on business days. Combined with an ESD audit you save travel and set-up time.
Occasions
When measurements are due
Individual measurements, complete EPA verification or a recurring measurement schedule – scoped to your site.
Related
Frequently asked questions
How often do ESD measurements have to be carried out?
The standard names no fixed interval; it requires the frequency to be defined in the control programme plan and then kept. Proven practice: wrist straps daily by the employee, workstations and floor areas annually, ionizers every six months, plus a complete measurement after every structural change. What matters is less the interval than the gapless documentation.
How much does an ESD measurement cost?
The price depends on the number of measuring points and the travel, not on the floor area. A single workstation measurement is considerably cheaper than a complete EPA survey with a floor grid. For recurring verification a fixed measurement plan pays off: the points are already defined and the on-site effort drops with every round.
Can we measure ourselves?
For the daily wrist strap check and simple control measurements: yes, that is even the normal case. For the conformance verification of the EPA you need calibrated instruments, the standardised methods and someone who can also assess the values. We provide both – the instruments through our sales, the measurement as a service.
Which instruments do you use?
High-resistance meters for surface, volume and ground-leakage resistance, field meters for insulators and ionizers, body-voltage measuring stations and walking-test systems for personnel grounding. All instruments are traceably calibrated; the calibration date appears in every report.
Why do our readings fluctuate in winter?
Because the leakage resistance of most ESD materials rises as humidity falls. At 20 % relative humidity the same floor can be a full decade above its summer value. That is why temperature and humidity belong in every report, and why the dry season is the more honest time to test.
What is a walking test?
The measurement of the body voltage of a walking person on the real floor with the real shoes. It shows how strongly a person actually charges up while walking normally. Assessed is the mean of the five highest peaks, which must stay below 100 V. For standing work it is the second mandatory test besides the system resistance – both must be met.
Is it enough if floor and shoes each meet the limit on their own?
No – and that is one of the most common misconceptions. What is tested is the system of shoe, floor and person. Every shoe–floor combination in use must be qualified, and both shoes must meet the requirement – a single conductive shoe is not enough.