Best Practices For Calibration Test Weights

Rice Lake’s Metrology department has retained its world class reputation through its highly trained staff and adherence to stringent handling procedures–from receiving, to calibrating, to shipping. The information below from Rice Lake highlights the standard procedure that they use upon receipt of your test weights. Here you’ll also find the best practices that Rice Lake recommends for handling weights and standards to help you maintain the best quality and integrity of your weights.

Recommended shipping procedures for weights
Ship weights in cases and materials designed to withstand and repel the abuses of shipping.
Packaging peanuts should not be used with weights, as this type of packaging clings to the weights creating static electricity which can compromise the lab environment.
Alternative packing material is recommended as follows:
Styrofoam (not peanuts or smaller pieces)
Paper (not shredded as this also conducts static electricity)
Bubble wrap
Loose small weights should have crumpled paper (not shredded) packed soundly in between all weights and box.
Clean room cases should only be used for weight storage and are not recommended for the shipment of weights.
Shipping of heavy weights (10 lb or larger) in cardboard boxes is not recommended.
Larger weights should be individually wrapped or protected, supported with stiff packing material and double boxed for structural durability.
Small weight kits should be held shut with secure latches, rubber bands, or tape, and placed inside boxes or bags.

Rice Lake Weight Handling Procedure
All weights and cases are inspected for damage and scheduled for calibration upon arrival to the lab.
All stickers and marker are removed from the weights.
Precision weights receiving NVLAP Calibration are checked for magnetism.
A tolerance test is conducted.
Any follow up with the client is completed.

Required Standards Conditions
* All delivered standards to this laboratory are required to arrive with the following conditions:

All weights should be clean and in good repair.
Any cleaning, repair, or painting of standards in the metrology lab will incur an extra charge.

Mass Standards
Weights should be clean and in good repair.
Weights shall be identified with a permanent serial number or mark into the surface of the weight.
Stickers and marker are not allowed and will be removed. The added mass of the sticker may change the mass of the weight, possibly causing the weight to be out of tolerance which will invalidate the reported value on the certificate.
Individual weight kits shall also be identified with unique serial numbers.
Cast iron weights should have no evidence of rust, loose paint or adhering debris.
Analytical weights should be handled carefully. Tolerances are small, so dirt or abuse can throw them out of tolerance.

Interior of cases for weight kits should also be wiped out or vacuumed.
Cases should be sound with secure latches.