Air velocity calibration from 0.1 to 70 m/s
UKAS-accredited calibration for vane, thermal and ultrasonic anemometers and Pitot tubes, carried out in wind tunnels in Lymington by Labcal, the Gill Group's calibration laboratory.
What is air velocity calibration?
Air velocity calibration compares an anemometer or Pitot tube with a reference velocity in a controlled wind tunnel. The result is the instrument's error at each test speed and the uncertainty of that measurement, so readings used for safety checks, commissioning or research can be shown to be traceable.
Labcal uses laser Doppler anemometry and reference meter methods, so the reference velocity is measured without disturbing the airflow. Low-speed work for cleanroom, fume cupboard and HVAC instruments runs in one tunnel; a second accredited facility handles larger instruments and higher speeds, up to 50 m/s.
Accredited from cleanroom airflow to 50 m/s
Every range below sits within Labcal's UKAS accreditation. The second facility also covers ultrasonic anemometers.
| Instrument or quantity | Range | Expanded uncertainty (k=2) |
|---|---|---|
| Thermal anemometers | 0.1 to 5 m/s | Q[0.19 %, 0.030 m/s] |
| Thermal anemometers | 5 to 38 m/s | Q[0.18 %, 0.030 m/s] |
| Vane anemometers, up to 125 mm diameter | 0.3 to 5 m/s | Q[0.24 %, 0.030 m/s] |
| Vane anemometers, up to 125 mm diameter | 5 to 38 m/s | Q[0.22 %, 0.040 m/s] |
| Pitot tubes | 2 to 5 m/s | Q[0.19 %, 0.030 m/s] |
| Pitot tubes | 5 to 38 m/s | Q[0.18 %, 0.030 m/s] |
| Large and ultrasonic anemometers, Pitot tubes | 5 to 50 m/s | Q[1.7 %, 0.16 m/s] to Q[1.7 %, 0.88 m/s] by speed band |
Ranges and best measurement capability from the UKAS schedule of accreditation for laboratory 0625, issue 055, 18 August 2026. Q[a, b] means the two terms are combined in quadrature. The uncertainty on your certificate depends on the instrument under test.
The instruments behind airflow decisions
Vane anemometers
Handheld and fixed vane instruments used for duct, grille and general airflow checks, up to 125 mm diameter in the low-speed tunnel.
Thermal and hot wire anemometers
Low-velocity probes used for cleanroom, laminar flow and fume cupboard face velocity work, accredited from 0.1 m/s.
Pitot tubes
Pitot-static tubes used with a pressure readout for duct traverses and higher-velocity measurements.
Ultrasonic anemometers
Two and three-axis ultrasonic wind sensors from a wide range of manufacturers, calibrated in the larger facility up to 50 m/s.
Instruments with displays
Instruments are calibrated with their own handheld or integrated display, so the certificate reflects the reading the user actually sees.
Legacy instruments
Older instruments still in service can be calibrated. If an instrument is not listed here, ask and the laboratory will confirm suitability.
Typical makes include Airflow, ATP, Fluke, Kestrel, Kimo, RS, Testo and TSI.
From your bench to a certificate and back
Tell us what needs calibrating
Use the form on this page with the instrument, the quantity and the points you need. If you are moving from another laboratory, your current certificate is enough for a like-for-like quote, usually within 24 hours.
Send it to Lymington
Instruments come to the Labcal laboratory at Ampress Park, Lymington. Calibration is laboratory based rather than on site. Courier collection can be arranged for regular and high-volume customers.
Calibration against traceable references
Turnaround averages 8 working days from the day the instrument arrives, with a 3-day fast track available by arrangement. Where an instrument can be adjusted, it is recorded as found, adjusted and recorded again as left.
Certificate and return
A UKAS certificate states the measured values, the expanded uncertainty at k=2 and the traceability to national standards, with as-found and as-left results where adjustment was made.
Request a quote
Tell us what needs calibrating
The instrument, how many and the points you need are enough to start. If you are switching laboratory, mention it and we will ask for your current certificate so the quote matches it like for like.
UKAS accredited. Labcal, laboratory 0625, ISO/IEC 17025:2017.
We aim to respond in one working day. Turnaround averages 8 working days from arrival, with a 3-day fast track by arrangement.
Switching laboratory? Send your current certificate for a like-for-like quote.
Frequently asked questions
Labcal's UKAS accreditation for air velocity runs from 0.1 m/s to 50 m/s. Thermal anemometers are accredited from 0.1 m/s, vane anemometers from 0.3 m/s and Pitot tubes from 2 m/s, all up to 38 m/s in the low-speed tunnel. A second facility covers 5 m/s to 50 m/s, including large and ultrasonic anemometers.
Yes. Ultrasonic anemometers are named on Labcal's UKAS schedule for the facility that covers 5 m/s to 50 m/s. That includes instruments from a wide range of manufacturers. The achievable uncertainty depends on the instrument, its size and how it is mounted in the test section.
Laser Doppler anemometry measures air velocity optically by tracking particles in the flow, so nothing is placed in the airstream to disturb it. Labcal uses it as one of its reference methods, which suits low-uncertainty work such as calibrating reference instruments or research anemometers.
The calibration interval for an anemometer should be set by your quality system, based on how critical the measurement is, the accuracy you need and how stable the instrument has been at previous calibrations. Annual calibration is common for cleanroom and HVAC commissioning instruments, and some users calibrate before critical projects.
Yes. A UKAS air velocity certificate records the measured error at each calibrated velocity together with the expanded measurement uncertainty at k=2. Where an instrument is adjusted, the certificate shows the as-found and as-left results so you can see what changed.
Talk to an engineer
Tell us what you need to measure, where and under what conditions. We’ll help you work out the appropriate approach.