Tag Archives: calibration test weights

Upcoming Changes to NIST Handbook 105-1 Requirements for Class F Calibration Weights

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Beginning January 1, 2020, Class F calibration weights will no longer be sold for legal metrology use. According to the newly updated NIST Handbook 105-1 (2019), new weights for use as field standards placed into service for weights and measures use after this date must comply with all of the requirements of NIST Handbook 105-1 (2019).

In order to update our Class F inventory to bring it more in line with ASTM and OIML tolerances, all Rice Lake NIST Class F weights will become ASTM Class 5 weights. Part numbers and pricing will remain the same, but the tolerance will be tighter.

nist class f test weight

Note that existing NIST Class F calibration weights in the field are grandfathered in and may continue to be used for legal metrology use, but they must meet NIST Handbook 105-1 (1990) requirements. Although the new revision does supersede the 1990 version, it makes clear that existing Class F weights may continue to be used.

While existing NIST Class F calibration weights may be reclassified to one of the new specifications if all specifications and tolerances fully comply with the alternative standard, the NIST Office of Weights and Measures strongly recommends that you do not reclassify existing Class F weights due to the difficulty of performing compliance evaluation.

This change is taking place to accommodate for the increasing accuracy of weighing devices used for legal metrology. Class F weights are no longer sufficient for the calibration, inspection, or sealing of weighing devices used for the jewelry, marijuana and pharmaceutical industries. Similarly, hydrogen for hydrogen vehicles is being sold by weight, which demands a high level of accuracy.

We are here to help guide customers to select the right calibration weight for each application; however, selection is ultimately based on the customer’s unique needs and requests.

Feel free to contact us with any questions about the NIST Class F legal metrology change in Handbook 105-1 or questions regarding where to buy calibration weights. Call (919) 776-7737 

Truck Scale Calibration Overview

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Since 1980, Central Carolina Scale has been providing outstanding weighing equipment and scale repair service for our customers. Our truck scale calibration and inspection service is what our customers depend on to keep their scales accurate and dependable year round.

Most customers choose to have their truck scales checked and calibrated at several predetermined points during the year. We can customize your service based on your needs and requirements. And, by choosing this method of periodic scheduled service; the customer benefits by receiving priority scheduling, reduced labor rates, and discounted parts.

Before our factory trained, state certified scale technicians hit the road, they perform all mandated DOT vehicle inspections. Safety has always been a top priority.

Once our scale technician reaches the job site, the technician will notify the customer. Then the technician blocks off the scale to keep trucks from entering during the inspection and adjustment period. Keep in mind, Central Carolina Scale works with our customers truck traffic to be as accommodating as possible.

truck scale technician

BUILDUP UNDER THE TRUCK SCALE

The next step in a truck scale inspection is to inspect all critical components. Depending on the scale, the technician checks for buildup of dirt, sand, mud and debris underneath the scale. Dirt buildup under the scale platform is often one of the top reasons for scale inaccuracy.

If the truck scale has bumper bolts, the technician will examine these and adjust if necessary. It’s also a good time to look at any other areas that may need to be addressed periodically such as junction boxes, grounding, rubber t-grip molding, load cell caps, pit cleanliness and more depending on the type of scale. The technician also checks cabling, structural steel, and concrete approach pads.

scale calibration test truck

Next, the scale technician will drive the fully loaded test truck across the scale and check the sections for consistency and accuracy. Weights are recorded and used to assist with adjusting.

certified weight cart

Next, the technician unloads all the certified test weights into a specialized weight cart. This cart is also certified by the state weights and measures department and is traceable to NIST. Then, the technician checks each section of the motor truck scale.

When we mention the word “section” we’re referring to an area of weighbridge which bears on two supporting platform points. Once the section testing of the motor truck scale has been completed, the scale can be adjusted and calibrated if needed.

scale test truck on platform

The technician can once again drive across the sections with the fully loaded test truck which includes the certified weights and certified weight cart. The section weights and the overall weights should be consistent and accurate. The calibration and inspection is now complete.

The technician loads his vehicle and reopens the scale for traffic. Once the technician has moved off the scale and the scale has reopened, the technician completes all the necessary paperwork. The inspection detail report shows both the condition of the scale and components, as well as the as found and as left test results.

Central Carolina Scale has the factory trained technicians, certified test weights, and certified test carts to accurately and thoroughly check your vehicle scales. Give us a call today (919) 776-7737 and we can work with you to customize a service plan that will improve your accuracy and limit downtime.

We Rent Test Weights For Checking Elevators

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If you check elevators for safety and weight capacity limits then you probably need large calibrated test weights to do the test. We have those weights available for rental in the state of North Carolina. If you need 1000 pound weights we can provide those or 2500 pound weights are also available. Call us at 919-776-7737 or fill out our online form for additional information. We are located in the triangle area near Raleigh, Durham, Fayetteville and Sanford, NC area.

Test Weights And Boats

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A customer recently mentioned having an odd question to ask.  His firm does stability testing on boats and ships, and has rented 1000lb NIST Class F Cast Iron Test weights in the past.  He was looking to do a similar test in the U.S. Virgin Islands and having problems finding a local vendor for test weights.

Curious, we asked what exactly do you use the weights to test?  Normally around here, the weights are put on a truck scale for a yearly calibration or to test a floor scale out.  The customer said, he does stability testing on ships and other small craft such as yachts. With larger ships, large blocks of concrete (which are weighed before the test) are often used; however with smaller vessels where deck space is tight, your 500, 1000 and sometimes 2500 lb test weights are ideal and are easy to handle.

They have the added benefit of being certified weights, thus there is little question about accuracy. On some smaller vessels they used the 50lb weights and moved the weights by hand during the test. Basically the test weights are placed on board and then moved transversely from side to side to apply a known moment as the heel angle is measured. Using the principles of naval architecture, the vertical center of gravity is then calculated.