NullpunktAkkreditiert · D-K-00000-00-00

Institut für Messtechnik / Braunschweig

Zero is a
decision, and
somebody has to
make it.

We calibrate the instruments that other laboratories calibrate against. Six quantities, one uncertainty budget each, published in full.

A fitted case of precision steel gauge blocks opened on a white laboratory bench
Set 04, grade K. Wrung, measured, and put back the same afternoon.

Scope of accreditation

  1. Length0.5 mm to 1 000 mm± (0.05 + L/2000) µmGauge blocks, CMM, interferometer
  2. Mass1 mg to 50 kg± 0.15 mg at 1 kgE1 weights, comparator
  3. Temperature−80 °C to 660 °C± 4 mK at fixed pointsSPRT, fixed-point cells
  4. Time and frequency10 MHz to 10 GHz± 2 × 10⁻¹³ / dayCaesium standard, GNSS link
  5. Pressure1 Pa to 100 MPa± 12 ppmPiston gauges, two ranges
  6. Electrical1 µV to 1 kV± 0.6 ppm at 10 VJosephson standard

Four things we will not negotiate

  1. 1

    A number without an uncertainty is not a measurement

    Every certificate we issue states the uncertainty, the coverage factor and the confidence level. There is no house style that omits them.

  2. 2

    The chain is only as good as its weakest link

    We publish our own traceability chain, upward to the national standard and downward to the instrument on your bench.

  3. 3

    Repeat before you believe

    Every calibration is run at least three times, at least once by a second metrologist, on a different day.

  4. 4

    Report the failures too

    If your instrument is out of tolerance, the certificate says so on the first line and not in an annexe.

A coordinate measuring machine with a probe over a metal part in a clean laboratory
CMM 2, granite table, 20.0 °C ± 0.1.
A polished metal cylinder standing under a glass bell jar on a black granite table
Transfer artefact, checked every ninety days.

Turnaround

  1. Standard15 working daysIncluded
  2. Priority5 working days+ 60 %
  3. Same week3 working days+ 140 %
  4. On siteBy arrangementQuoted

The clock starts when the instrument reaches the laboratory and has reached room temperature, which for a steel artefact from a cold van is not the same morning.

Bundesallee 100

Four measurement rooms held at 20.0 °C, two of them to a tenth. Deliveries to the rear, and please do not open the case in the corridor.

Laboratory
Bundesallee 100
38116 Braunschweig
Goods in
Mon to Thu, 07.30 to 15.00
Certificates
Signed PDF, and paper on request, at no charge
An empty temperature-controlled measurement laboratory with white surfaces
Room 2, empty and at temperature. This is what good looks like.

Three sources of uncertainty

Every certificate states these. The budget is published in full with each result.

01

The reference

How well the standard itself is known, and how long since it was compared upward. This is usually the smallest term and the hardest to improve.

02

The environment

Temperature, and then temperature again. Twenty degrees is a definition, not a room, and holding it to a tenth costs more than the instrument.

03

The operator

Repeatability across three runs and two people. If the operator term dominates, the method is wrong, not the person.

Reference standards held

What sits at the top of our chain, and when each was last compared upward.

  1. Gauge block set, grade KLengthPTBSep 2025
  2. E1 mass set, 1 mg to 20 kgMassPTBJun 2025
  3. SPRT with fixed pointsTemperaturePTBMar 2025
  4. Caesium standardFrequencyPTB via GNSSContinuous
  5. Piston gauge, two rangesPressurePTBNov 2025
  6. Josephson arrayVoltagePTBApr 2025

Before you send an instrument

How should it be packed?
In its own case, in a box, with the case not touching the box. Most damage we see happens in transit and none of it is dramatic.
Will you adjust it as well as calibrate it?
Only if you ask in writing. Calibration and adjustment are different jobs, and an adjusted instrument has no history.
What if it is out of tolerance?
The certificate says so on the first line and we telephone you the same day, because the interesting question is what you measured with it last month.
Can I watch?
Yes. Ask when you book. Most people stay twenty minutes and leave with a better feel for why it takes fifteen days.