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2 - Testing and Calibration Initial testing and calibration typically is the responsibility of the manufacturer or distributor. The procedure is rather simple. The test team adds incremental weights until they reach the capacity of the scale, taking readings after the addition and the removal of each weight. The readings must fall within a pre-established tolerance. If they do not, the scale is recalibrated and the test is performed again. The calibration/test cycles continue until the scale performs within specifications. Most legal-for-trade applications require the scale to gain certification of compliance from local Weights and Measures authorities at certain intervals (annually, semi-annually, etc.). They may witness or play a role in the initial calibration. As the scale owner, you should ensure that this initial test is coordinated with any required inspection visits from regulatory agencies. That way, you avoid repeating the test if someone who needed to witness the test wasn’t notified. This same type of test/calibration procedure is used throughout the life of the scale for regular scale calibrations and recertifications. Those procedures may be performed by the company that provided the scale or by a third party. Most companies that provide standard testing services are qualified to work on any type of vehicle scale. However, the level of service they provide for maintenance and repairs can vary. 3 - Approval and Certification Any truck scale used in public or private commercial transactions must be inspected and certified by your regional and/or local Weights and Measures department. Local laws typically require you and/or the scale supplier to notify the W&M department when a new scale is installed. That prompts an inspection by a department official to check the installation and test scale accuracy. Typically, that must be done before the scale can be used. Many manufacturers have their scale designs certified by NTEP, OIML, or other metrology organizations. In some cases, buying a certified scale can simplify your approval process. But some state and local authori- ties have their own, more stringent, certification processes. You may also have to satisfy the scale require- ments of other regulatory agencies depending on your location and the business you operate. Examples in- clude state and local building code enforcement; the Federal Grain Inspection Service; and state and federal departments of agriculture, customs, departments of transportation and others. An experienced scale suppli- er knows which agencies are applicable to your project. Also keep in mind that the scale may need to be recertified after performing repairs or replacing failed com- ponents. For example, replacing a single load cell can require you to pay for your local Weights and Mea- sures department to test and recertify your scale. That is just one of the many reasons to properly maintain your scale and become familiar with scale service and warranties.
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