OIML R 111 Classes E1, E2, F1 and F2 Calibration Weights and Weight Sets
> General Information
> OIML R 111 Class Tolerances
> Construction and General Shape
> Surface Finish
> Suggested Applications
> Weight Set Configuration Information
> Ordering a Certificate With Your Weight
or Weight Set
> Ordering Tables
Troemner OIML Calibration Weights conform to the standards of the Organisation
Internationale de Metrologie Legale International Recommendation (OIML R
111). They are manufactured from the finest stainless steels available
including Troemner Alloy 8 Stainless Steel that has low magnetic
permeability, uniform consistency and high resistance to corrosion. Troemner
OIML Calibration Weights are available in Classes E1, E2, F1 and F2, where
Class E1 has the smallest tolerances and Class F2 has the largest
tolerances. The letter "E" for Classes E1 and E2 refers to "extra fine"
where the letter "F" for Classes F1 and F2 refers to "fine". OIML R 111
weight specifications are designed so the specifications on surface finish,
markings, construction, material density and magnetic properties get more
restrictive as the weight tolerances get smaller in order to enable the
weight to maintain its tolerance over time. The tolerances for the various
classes are established in a manner that enables weights of higher classes
to calibrate weights of the next lowest class. For example, Class E2 weights
can be used to calibrate Class F1 weights. Troemner OIML Calibration Weights
and Weight Sets are supplied with
Troemner's Statement of Accuracy,
which details the date of calibration and accuracy class of each weight. If your
laboratory requires more stringent documentation, please review the Weight
Calibration and Certificate Options section of the website.
**Caution** Class E1 weights have extremely small tolerances and are
intended to be used as primary reference standards with direct traceability
to national reference standards. They should be used in extremely stable
environments and handled with the highest level of care. Otherwise, Class E1
weights will not maintain their measured value within the tolerance class.
One may be tempted to purchase the weights with the tightest tolerances in
order to reduce measurement uncertainty. However, frequency of use, care,
handling, and environmental conditions all play a major role in long term
stability of weights and these factors should be considered before
purchasing Class E1 weights.
OIML R 111 Class Tolerances
Please see the Tolerance Chart within the Mass Standards Handbook for
specific information on the tolerances of each weight of a given OIML Class.
As specified in OIML R 111, Troemner's OIML Calibration Weights are available
in one or two-piece construction.
Construction and General Shape
- Troemner OIML Calibration Weights 500 mg and below are made of sheet metal
and are one-piece construction with one side turned up to make them easy to
handle with forceps. Corners and edges are smooth. There are no markings
permitted on any sheet metal weight 500 mg and below. The nominal value of
weights 500 mg and below are determined by the shape of the weight according
to the table below.
- Weights 500 mg and below are also available in wire construction as
opposed to sheet metal with the same shape configuration as listed in the
above table. Troemner's OIML wire weights have one end turned up as well to
allow for easy handling with forceps. Contact a Troemner sales
representative for more information on wire milligram weights. To order wire
milligram weights, specify the Troemner part number listed in the Ordering
Tables below followed by "-WIRE".
- Weights 1 g and above can be either one or two-piece construction.
Troemner OIML Calibration Weights 1 g and larger are cylindrical in shape with
a tapered neck for easy gripping. They are perfectly flat on top to stack
easily on center. Weight bottoms are slightly recessed to expose the
smallest possible area to wear.
- One-piece construction indicates the weight is manufactured from a single
uniform piece of raw material, the weight has no other material added to it,
and it has no method of adjustment other than removing material by grinding
or polishing. One-piece weights are difficult to manufacture as the only
method of final adjustment is removing material by fine grinding, polishing
or electro-polishing. Class E1 and E2 weights 1 g and larger are cylindrical
in shape and are of one-piece construction.
- Two-piece construction indicates that the weight is constructed of
multiple pieces of raw material. In the case of Troemner OIML Calibration Weights, this means that the weight body is constructed from one piece of
material and the lifting knob or head is constructed from a different piece
of raw material. Although the head and body may come from different bars of
raw material, they are the same grade and type of raw material with the same
densities. The knob or head typically screws into the body and one can
barely tell the weight is not constructed of one piece of material. There is
a cavity below the knob thread in the body, which contains adjusting
material that is typically the same material from which the weight is made.
Class F1 and F2 weights 1 g and larger are cylindrical in shape and are of
- Click here to view a table that describes the material used in the
construction of all of Troemner's OIML Calibration Weights.
All surfaces are polished to a perfect, mirror like finish and meet or
exceed OIML R 111 specifications. For OIML R 111 Surface Finish specifications see the Mass Standards Handbook.
- Class E1 weights are intended for use in metrology laboratories as primary
reference standards where the stability of the environment and careful
handling are assured. Although very stable, one-piece construction Class E1
weights have no method of adjustment and are not suitable for general
- Class E2 weights can be also be used as reference standards as well as
calibrating Class I balances as specified in OIML R 76. Class E2 weights can
also be used to calibrate Class F1 weights.
- Class F1 weights can be used to calibrate certain Class I balances and
scales as specified in OIML R 76. Class F1 weights can also be used to
calibrate Class F2 weights.
- Class F2 weights can be used to calibrate weighing instruments for
important commercial transactions like gold and precious stones. They can
also be used to calibrate Class M2 weights.
- Weight sets where the largest weight in the set is 200 g and lower are
supplied in attractive, durable polypropylene cases with a compartment for
each weight within the case. There is also a compartment for forceps. The
cases are designed so that each weight will stay in its compartment. A wood
case may be substituted for the polypropylene case for an extra charge.
- Troemner weight sets 500 g and larger are supplied in wood cases. Within
the interior of the wood case is contained a polypropylene case to hold
weights 200 g and below with compartments for each weight. For weights
larger than 200 g, a velvet lined compartment for each weight exists within
the wood case. There are also compartments for lifters and forceps supplied
with each weight set.
- Troemner supplies appropriate lifting devices such as forceps, gloves and
other lifting forks sufficient to handle every weight in the set.
- Individual weights are supplied in polypropylene cases. For weights larger
than 5 kg, weight cases have reinforced corners.
- Wood cases for individual weights are available for an extra charge. The
wood cases feature a fine wood exterior with an interior compartment that is
either fully lined with padded velvet or velour for the weight or the case
has a foam interior.
**Caution** Weight cases are not intended to be used as shipping containers.
When you ship your weights to be calibrated, the weights and weight sets
must be overpacked in larger containers and/or cartons to protect your
Weight Set Configuration Information
Troemner OIML Weight Sets are supplied in a 5-2-2-1 series. 5-2-2-1 series
means that weights beginning with a "2" are doubled in each decade and
weights beginning with a "5" and "1" are single in each decade. For example,
for a set with 5-2-2-1 series from 50 g to 1 g, there is one 50 g, two 20 g,
one 10 g, one 5 g, two 2 g, and one 1 g. The OIML Weight Sets Configuration
Table that follows shows the contents of each set.
OIML Weight Sets Configuration Table
There is a choice of certificates available for your Troemner OIML Calibration Weights or Weight Sets to meet your traceability and compliance needs.
Complete information on our calibration certificates and samples of
certificates are located in the Mass Calibration and Certificate Options
section of the website.
Ordering a Certificate With Your Weight or Weight Set
- Weights and Weight Sets supplied without weight certificates come with
Troemner's Statement of Accuracy (view sample of certificate).
- To order Troemner's NVLAP Weight Calibration Certificate (view sample of certificate), specify the
Troemner part followed by "W". For part numbers, please reference the Ordering Tables below.
- To order Troemner's UKAS Certificate of Calibration (view sample of certificate), specify the Troemner
part number followed by "NA". For part numbers, please reference the Ordering Tables below.
- To order Troemner's Traceable Certificate (view sample of certificate), specify the Troemner part
number followed by "T". For part numbers, please reference the Ordering Tables below.
- To order Troemner's Mass Code Report of Mass Values (please contact Troemner for more information), specify the Troemner
part number followed by "M". For part numbers, please reference the Ordering Tables below.
- To order Troemner's NVLAP Density Determination Calibration Certificate (view sample of certificate)
(view sample of certificate) for one-piece construction Weights and Mass
Standards, specify the Troemner part number of the weight or weight set and
also include part number WDC-1111. For part numbers, please reference the
Ordering Tables below.
- To order Troemner's NVLAP Magnetic Susceptibility Determination
Calibration Certificate (view sample of certificate) for one-piece construction
Weights and Mass Standards, specify the Troemner part number of the weight
or weight set and also include part number MAGCAL-1111. For part numbers,
please reference the Ordering Tables below.
OIML Individual Weights
OIML Weight Sets
Troemner can provide you with all the accessories you need to properly
handle and protect your OIML Calibration Weights and Weight Sets. Please
contact us for specific information on new cases, replacement cases, or
special cases you need to store and protect your OIML Calibration Weights and
OIML Weight Accessories
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