Why should you purchase a scale that is “Legal-for-Trade” when you don’t intend to use the weighing instrument in a commercial weighing setting? Defining a commercial weighing application can sometimes be difficult. Scales can be moved around your facility and get utilized for things that perhaps you didn’t originally intend. Basically, an NTEP approved device is required any time money changes hands based on a scale’s reading. Freight scales, for example, must be NTEP approved. For these situations government requires that a scale must pass tests put forth by the National Type Evaluation Program (NTEP). These regulations are meant to protect the consumer. Click here to see the rest of the story.
The other legal for trade question we wanted to discuss is related to Classes. Often you will see NTEP Legal for Trade Class III. But, what exactly does Class III mean? Handbook 44, the book that spells out rules and regulations for the weighing industry, separates weighing devices into five accuracy classes. Depending on the number and value of scale divisions, equipment can be either class I, II, III, IIIL, or IIII, with Class I having the highest precision. All Legal-for-Trade scales fall under one of these five classes.
Table 7a of Handbook 44 breaks down the description of each class. Class III states: “All commercial weighing not otherwise specified, grain test scales, retail precious metals and semi-precious gem weighing, animal scales, postal scales, vehicle on-board weighing systems with a capacity less than or equal to 30,000 lb, and scales used to determine laundry charges.”
What it’s saying basically is anything that doesn’t fall elsewhere would go here, providing the device meets the criteria for the quantity and size of divisions. Class III covers many different types of scales. It’s a bit of a catch all. Retail price computing scales would be one type of Class III application. While some jewelry scales are Class III if the resolution is appropriate for the application, a more precise jewelry scale could be Class II. It all depends on the number of divisions and capacity. Precision laboratory devices fall under Class I. At the opposite end of the spectrum is Class IIIL which covers heavier capacity on-board applications, truck scales, livestock and railroad scales. Class IIII applies strictly to axle scales and wheel loader devices for highway weight enforcement.
In most cases it’s a good idea to purchase a scale that has earned a certificate of conformance. It’s a good idea for the scale owner, the customer and anyone else involved in the process because the equipment should be a better quality product that will hopefully be accurate and reliable.