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Mass Standards

Approximately 900 validated weights (mass stacks not included) are currently available in Working Group 1.12, with values ranging between 1 mg and 20 kg. The accuracy classes are E1 (reference standards only), E2, F1, F2, M1 and M3. The material for F1 and better is stainless steel, for F2 and worse brass is also used, and some of the 10 kg and 20 kg weights are of cast iron. The working standards are calibrated by  1.12, the reference standards by the PTB working group 1.11.

Figure 1a.
Figure 1b.

Figure 2.
Three mass stacks of stainless steel with specified relative uncertainty Urel.

  • 6×5kg + 9×10 kg = 120kg with Urel=1×10-6
  • 20×50kg = 1t with Urel=1×10-6
  • 6×500kg = 3t with Urel=3.1×10-6

Figure 3.
Five tons load cell test assembly with 4 mass stacks.

  • 20 × 20kg = 400kg with Urel=2.7×10-6
  • 20 × 40kg = 800 kg with Urel=2.5×10-6
  • 20 × 100kg = 2t with Urel=5×10-6
  • 12 × 250kg + 4 × 500kg = 5t with Urel=5×10-6

These mass stacks connect to the test chamber in Fig. 5 through the ceiling.