The Metrology Laboratory offers calibration services for mass, volume and temperature. Customers include service technicians that repair and calibrate scales and meters, as well as industries that use standards in their manufacturing process, such as pharmaceuticals or other laboratories that require such documentation. The lab also tests the standards used by the division's staff to inspect fuel dispensers, meters on delivery trucks and scales of all sizes. Testing can be performed and reported in metric or traditional U.S. units. A certificate of calibration is provided to customers for each artifact.
In order to be consistent with our results, the laboratory operates under specific ranges for temperature , humidity and barometric pressure. If a particular laboratory is not within these specifications, then work must stop immediately, only to resume when the specifications are met, and in some cases, after a period of time that the room has maintained those specifications.
Mass
The majority of the work in the laboratory is mass and much of that is for companies the repair and calibrate scales. In our tolerance laboratory weights from 0.001 - 2500 lbs and 1 mg to 1000 kg at the Echelon III level, which also includes weights carts between 3000-6000 lbs. Echelon II work is also performed in this lab, which means a different method is used and has more detailed results for the customer. Work in Echelon II includes 0.001 - 2500 lbs and 1 mg-250 kg.
Customer weights are compared to the laboratory standards. If they need adjustment because they are not with a given tolerance, lead seals are removed or added to adjust them. Melting and making lead seals takes place in a dedicated room, for both safety and health reasons.
This space is also used to test lottery balls for the NC Education Lottery and the NC Highway Patrol's load cells from their portable wheel load weighers.
In our small mass lab work is performed at the Echelon I level, which are more precise measurements need by some industries. Weights in this area may range from 0.001 lb to 50 lb and 1 mg to 30 kg. Gloves are always worn in this laboratory and handling weights with bare hands leaves skin oils, which collect dust and over time this "dirty" weight would give bad results!
Volume
The volume laboratory performs calibrations by volumetric transfer, transferring water from our known standards into the customers unknown vessel, for vessels of 1-5 gallons. We can also perform volume gravimetric calibrations, using the mass of the water and its density to calculate the volume, for vessels of 50 ml and 1 gill - 5 gallons. Each year we test about four hundred 5 gallon test cans that are used by service technicians, and our inspectors, to check retail fuel dispensers.
Out large volume area performs volume transfer work for 6 - 2000 gallons. Other work in this area includes volume transfer for LPG provers, gravimetric volume and gravimetric SVP (small volume provers).
Our standards for volume transfer are located above the work area and range from 25 -500 gallons, using deionized water to be consistent.
Temperature
Our temperature lab tests both liquid in glass and resistance thermometry. These devices are tested at least at a lower and upper limits, but the customer can choose to include additional temperature within that range that they want calibrated. Services are provided from 30°C to 660°C or -22°F to 1220°F.
