NAVAL AIR STATION NORTH ISLAND, Calif. –
One of the many “behind-the-scenes” organizations providing crucial support to the fleet is the Navy Primary Standards Laboratory (NPSL) at Fleet Readiness Center Southwest (FRCSW).
Assigned to Buildings 469 and 379, the lab is the Navy’s highest level for metrology calibration (the science of measurements) and provides technical assistance and training to shore metrology and calibration program personnel.
The lab’s calibration program is compliant to the National Institute of Standards and Technology (NIST), an agency of the U.S. Department of Commerce. NIST establishes measurement standards for a variety of devices from atomic clocks to semiconductors.
Of its primary duties, the NPSL tests and calibrates equipment used in the field to detect and monitor laminar (liquid and gas) and devices that generate microwave and radiofrequency (RF) radiation.
According to the Occupational Safety and Health Administration (OSHA), there are “no specific standards for radio frequency and microwave radiation issues.”
Sources that are monitored include radar traffic equipment, wireless communications with cell phones and radio transmission.
Because ships are subject to RF radiation, the NPSL calibrates the probes used to ensure that areas are shielded properly and that equipment is being used only when it’s safe.
The lab will typically generate a known electro-magnetic field that’s traceable through check standards through NIST, and place the probe in the field to verify that it reads the correct stream.
Magnetic probes are tested using transverse electro-magnetic cells that generate a low-frequency magnetic field, while electric probes are tested in an anechoic chamber for high frequency fields.
Six years ago the NPSL moved its liquid, gas and air flow calibration facility to Building 379.
The 2,000 square-foot laboratory includes a closed-circuit wind tunnel used to calibrate anemometers, or air velocity meters, that are found onboard ships for wind speed checks during aircraft operations.
The gas flow calibration tests meters used to measure aircraft cabin pressure, breathing apparatus in oxygen masks, or how much air is going through an oxygen tank, and nitrogen from fuel pumps.
Air is commonly used in testing gas flow meters. Testing flow rates may be as low as one cubic centimeter per minute, to 400 cubic feet per minute.
Liquid flow calibration is used to test turbine flow meters that are found throughout the Navy. In the fleet, they are typically used to transfer jet fuel and water from supply ships to aircraft carriers. Many are high capacity flow meters, with a two-inch diameter.
The shop’s newer test benches can cover a broad range of flow runs and viscosities, providing the lab with greater flexibility to serve its customers.
Over half of the shop’s equipment was upgraded within the past seven years, increasing its capability and automated functions such as generating reports immediately after calibration.
If time permits and parts are on-hand, the laboratory services the instruments it calibrates; otherwise, they are returned to the customer for repair or replacement.
Annually, the shop calibrates about 400 gas meters, 150 liquid flow meters and 80 air velocity meters.
FRCSW is the parent command to two other calibration labs: one in Okinawa and the other in Iwakuni, Japan.