BLACKFOOT – Following a complaint from a local member of the community regarding the scale at the transfer station, the state’s Bureau of Weights and Measures sent out Mike Howser, the eastern Idaho measurements inspector, to check the scale in question.
Both of the facility’s scales failed, according to the bureau.
The state sends out an inspector every year to register the scales, verifying that they are properly balanced and not over- or under-registering the weight that travels across them. In fact, according to statistics, the Bureau of Weights and Measures inspects over 35,000 scales a year across the state.
The Idaho State Department of Agriculture Bureau of Weights and Measures (ISDA W&M) examines all commercially used weighing and measuring devices used in the state of Idaho on an annual basis. The inspection includes testing the device for accuracy and ensuring the device complies with design, construction and installation requirements. Inspectors also test packaged products for net contents, sample octane, and investigate complaints pertaining to measurements.
Title 71 of the Idaho Code requires any commercially used weighing or measuring device to be tested by ISDA W&M. Devices tested include Retail Motor Fuel Dispensers (RMFD), scales from small grocery store scales to 200,000-pound vehicle scales, propane meters, bulk fuel, and oil meters and any device used to measure or weigh.
After a request was made to the state following an anonymous tip surrounding the validity of the new scales installed at the transfer station, they responded with, “The ISDA received a complaint about the scales at the Bingham County solid waste facility. An ISDA Weights and Measures inspector tested the scales on July 23, 2020. Both of the facility’s scales failed. The facility was notified of the failure as was the complainant. The facility has a set period of time to rectify the problems. These scales are on an annual exam schedule and were last tested in 2019.”
Following the results, the county will need to rectify the problem in a timely manner. The complaint comes on the heels of new policies taking effect as of July 1 that no longer requires a weighmaster to collect state certification to operate a scale. Instead, they are offered education on how to properly operate, balance, and maintain the scales. They are required to operate the scales without prejudice.
According to Quality Scales Unlimited, there are four major factors that can cause inaccuracies in scale systems. The first is an issue with the load cell itself. Load cell inaccuracies are caused by a few different factors and are important for a weighmaster to understand. There are six different factors under load cells that need to be understood — nonlinearity, hysteresis, non-repeatability, creep, temperature effects, and response time. Each of these specific load cell effects can result in improper results.
The second inaccuracy-causing items are load factors. Inaccuracies can be caused by the loads themselves as well as the way the load is applied and supported. All the weight of the load must be supported entirely by the load cell. It should not be resting on check-rods, bumpers or other stabilizing and protective elements.
The load on the load cell is directly channeled through the mounting hardware, so any misalignment can throw the accuracy of the system.
Ensuring the mounting structure or the floor can bear the combined weight of the weighing system, its components and the load without flexing is a factor, as is introducing cross braces on systems with flimsy support legs to reduce side loads when the support legs spread under strain.
The third factor is environmental. Environmental factors include wind loading, shock loading, vibration, pressure differentials, and an unclean scale. Wind loading is caused by air moving over and potentially under the deck of the scale causing inaccurate readings. Shock loading happens when heavy loads are dumped on the deck of a weighing system, causing internal damage to the system.
Vibration from working equipment around the scale may cause issues as well. Pressure differentials occur when the pressure around the working scale is different than the pressure of the calibration. Finally, an unclean scale can affect the weight registration because the load cell may not be receiving the entirety of the load because of unknown buildup.
The last factor is interference. Moisture, temperature, and frequency interference can cause a scale to report inaccurate readings. Frequency interference can cause noise in the signals that may report a false reading while temperatures can cause issues with wire resistance increases or decreases causing voltage drops, resulting in improper readings. Moisture can wick with the wiring, causing readings to double as input or output.
Any of these scenarios can be what caused the scales at the transfer station to present incorrect readings. Until they further investigate the causes of the incorrect weights, they will not know what is the direct cause of the malfunction.
County officials were not able to be reached for comment on the situation Tuesday.