ASTM E617-23

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E617 − 23
Standard Specification for
Laboratory Weights and Precision Mass Standards
This standard is issued under the fixed designation E617; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 The values stated in SI units are to be regarded as
standard.
1.1 This specification covers weights and mass standards
used in laboratories, specifically classes 000, 00, 0, 1, 2, 3, 4,
1.7 This international standard was developed in accor-
5, 6, and 7. This specification replaces National Bureau of
dance with internationally recognized principles on standard-
Standards Circular 547, Section 1, which is out of print.
ization established in the Decision on Principles for the
1.2 This specification and calibration method is intended for Development of International Standards, Guides and Recom-
use by weight manufacturers, national metrology institutes, mendations issued by the World Trade Organization Technical
weight calibration laboratories, accreditation bodies, users of
Barriers to Trade (TBT) Committee.
weights, and regulatory bodies.
2. Referenced Documents
1.3 This specification contains the principal physical char-
acteristics and metrological requirements for weights that are
2.1 ISO Standards:
used.
ISO/IEC 17025:2017 General Requirements for the Compe-
1.3.1 For the verification of weighing instruments;
tence of Testing and Calibration Laboratories
1.3.2 For the calibration of weights of a lower class of
2.2 NIST Standards:
accuracy; and
NIST Handbook 143 State Weights and Measures Laborato-
1.3.3 With weighing instruments.
ries Program Handbook (2019)
1.4 Maximum Permissible Errors (formerly tolerances) and
NIST SP 811 Guide for the Use of the International System
design restrictions for each class are described in order that
of Unit (SI) 2008 Edition
both individual weights or sets of weights can be chosen for
NIST SP 1038 The International System of Units (SI) –
appropriate applications.
Conversion Factors for General Use (May 2006)
1.5 Weight manufacturers must be able to provide evidence
NISTIR 5672 Advanced Mass Calibration and Measurement
that all new weights comply with specifications in this standard
Assurance Program for State Calibration Laboratories
(for example, material, density, magnetism, surface finish,
(2019)
mass values, uncertainties) to make any claim of compliance to
NISTIR 6969 Selected Laboratory and Measurement Prac-
Specification E617, Maximum Permissible Errors, weight
tices to Support Basic Mass Calibrations (2019)
classes, or metrological traceability.
NIST Technical Note 1297 Guidelines for Evaluating and
1.5.1 During subsequent calibrations, calibration laborato-
Expressing the Uncertainty of NIST Measurement Results
ries must meet the requirements of ISO/IEC 17025:2017.
(1994)
1.5.2 Subsequent calibrations must meet all the
requirements, including Sections 7, 8, and 9, Table 8 and Table
2.3 OIML Standards:
11 (environmental parameters) to make any claim of compli-
OIML D 28 Conventional Value of the Result of Weighing in
ance to Specification E617, Maximum Permissible Errors,
Air (2004)
weight classes, or metrological traceability.
OIML R 111–1 Weights of classes E1, E2, F1, F2, M1,
M1–2, M2, M2–3 and M3 Part 1: Metrological and
NOTE 1—Requirements set forth in NIST IR 6969 and NIST IR 5672
are compliant with all the requirements of Specification E617, Sections 7, Technical Requirements (Edition 2004)
8, and 9.
1 2
This specification is under the jurisdiction of ASTM Committee E41 on Available from International Organization for Standardization (ISO), 1, ch. de
Laboratory Apparatusand is the direct responsibility of Subcommittee E41.06 on la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Laboratory Instruments and Equipment. Available from National Institute of Standards and Technology (NIST), 100
Current edition approved Aug. 15, 2023. Published November 2023. Originally Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
approved in 1978. Last previous edition approved in 2018 as E617 – 18. DOI: Available from Organisation Internationale de Metrologie Legale, 11 Rue
10.1520/E0617-23. Turgot, 75009 Paris, France, http://www.oiml.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E617 − 23
2.4 BIPM Standards: dation OIML D 28. For a weight taken at 20 °C, the conven-
VIM: JCGM 200:2012 International Vocabulary of Metrolo- tional mass is the mass of a reference weight of a density of
–3 –3
gy–Basic and General Concepts and Associated Terms
8000 kg m which it balances in air of density of 1.2 kg m .
GUM: JCGM 100:2008 Evaluation of Measurement
3.1.6 correction—mass values are traditionally expressed by
Data–Guide to the Expression of Uncertainty in Measure-
two numbers, one being the nominal mass of the weight, and
ment
the second being a correction. The mass of the weight is the
SI Brochure: 2019 The International System of Units (SI),
th assigned nominal value plus the assigned correction. Positive
9 Edition
6 corrections indicate that the weight embodies more mass than
2.5 EURAMET Standards:
is indicated by the assigned nominal value. Negative correc-
EURAMET/cg-18/V. 4.0 Guidelines on the Calibration of
tions indicate that the weight embodies less mass than is
Non-Automatic Weighing Instruments (2015)
indicated by the assigned nominal value. The correction is
equivalent to the “error.”
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.7 kilogram—the SI base unit of mass. Formerly the
3.1.1 accuracy class of weights—a class of weights that international prototype kilogram (IPK), the platinum-iridium
meets certain metrological requirements intended to keep the
cylinder maintained at the International Bureau of Weights and
errors within specified limits.
Measures (BIPM) in Sèvres, France, was internationally ac-
cepted as having a defined mass of 1 kg. In 2018 the kilogram
3.1.2 balance—instrument indicating apparent mass that is
was redefined in terms of the Planck constant h (taken to be
sensitive to the following forces:
–34 2 –1
6.626 070 15 × 10 kg m s ) where the mass of primary
Force due to gravity
F 5 m·g
g
mass standards may be determined by any primary method
such as those described in the mise en pratique for the
Air buoyancy equal to the weight of
m
the displaced air. definition of the kilogram in the BIPM SI Brochure. The
F 5 v·ρ ·g 5 ρ ·g
b a a
ρ
redefinition process ensured continuity of mass measurements
before and after redefinition such that all mass values traceable
Vertical component of the magnetic
≠ H
interaction between the weight and
F 5 μ sM 1 χ Hd dV
eee to the IPK remained the same when the new definition came
z o
≠ z
v the balance or the environment, or
into effect, but the uncertainties of these mass values were
both.
increased by the relative standard uncertainty of the IPK
H and M are vectors; z is the vertical cartesian coordinate.
–8
immediately after the redefinition (1.0 × 10 ).
If magnetic effects are negligible, that is, the permanent
magnetization (M) of the weight and the magnetic suscepti-
3.1.8 magnetism—effect that generates an attractive or re-
bility (χ) are sufficiently small, and the balance is calibrated
pulsive force without the presence of charged species.
with reference weights of well-known mass, the balance can
3.1.8.1 (volume) magnetic susceptibility (χ)—measure of the
be used to indicate the conventional mass, m , of a body
c
ability of a medium to modify a magnetic field. It is related to
under conventionally chosen conditions.
the magnetic permeability (μ) by the relation: μ/μ = 1 + χ. The
3.1.3 calibration (of weights)—the acts of determining the
quantity μ/μ is sometimes referred to as the relative
mass difference between a standard of known mass value and
permeability, μ .
r
an “unknown” test weight or set of weights, establishing the
3.1.8.2 (permanent) magnetization (M)—parameter that
mass value and conventional mass value of the “unknown,”
specifies a magnetic state of material bodies such as weights, in
and of determining a quantitative estimate of the uncertainty to
the absence of an external magnetic field (most generally,
be assigned to the stated mass or conventional mass value of
the “unknown,” or both, and providing metrological traceabil- magnetization is a vector whose magnitude and direction are
ity to the “unknown.” not necessarily constant within the material). The magnetiza-
tion of a body generates an inhomogeneous magnetic field in
3.1.3.1 calibration (generally)—set of operations that
space and thus may produce magnetic forces on other materi-
establish, under specified conditions, the relationship between
als.
values of quantities indicated by a measuring instrument or
measuring system, or values represented by a material measure
3.1.9 mass—physical quantity, which can be ascribed to any
or a reference material, and the corresponding values realized
material object and which gives a measure of its quantity of
by standards.
matter. The unit of mass is the kilogram.
3.1.4 calibration certificate—certificate issued by calibra-
3.1.10 maximum permissible errors—the maximum amount
tion laboratories to document the results of a calibration.
by which the sum of the conventional mass correction of the
3.1.5 conventional mass—conventional value of the result
weight, and its associated uncertainty is allowed to deviate
of weighing in air, in accordance to International Recommen-
from the assigned nominal value.
3.1.11 metrological traceability—property of a measure-
Available from Bureau International des Poids et Mesures (BIPM), Pavilion de
ment result whereby the result can be related to a reference
Breteuil, F-92312, Sèvres Cedex, France, http://www.bipm.org.
6 through a documented unbroken chain of calibrations, each
Available from Euramet, Bundesallee 100, 38116 Braunschweig, Germany,
http://www.euramet.org. contributing to the measurement uncertainty. Metrological
E617 − 23
traceability requires an established calibration hierarchy. Ele-
Symbol Unit Definition
d m estimated distance between centers of
ments for confirming metrological traceability to be an unbro-
weights during loading
ken chain to a primary mass standard shall include a docu-
d m estimated distance from the center of
mented measurement uncertainty, a documented measurement the load receptor to one of the corners
F N air buoyancy equal to the weight of the
b
procedure, accredited technical competence, metrological
displaced air
traceability to the SI, and established calibration intervals (see
F N gravitational force
g
current VIM: JCGM 200).
F N magnetic force between a mass
z
comparator and a weight in the vertical
3.1.12 reference standard—a standard, generally of the
or z-direction
–2
highest metrological quality available at a given location, from g m s gravitational acceleration
–1
H A m magnetizing field strength
which measurements made at that location are derived.
h % relative humidity
r
3.1.13 roughness parameter or R-parameter (R or R )— I kg indication of the weighing instruments
a z
(scale division)
parameter that describes the assessed roughness profile of a
ΔI kg indication difference of the balance,
sample. The letter R is indicative of the type of assessed
where ΔI = I – I
t r
ΔI kg indication difference using an
profile, in this case R for roughness profile. The assessed 1
automatic exchange mechanism with
profile of a sample can be in terms of different profile types: a
weights in first position
roughness profile or R-parameter, primary profile or
ΔI kg indication difference using an
automatic exchange mechanism with
P-parameter, a waviness profile or W-parameter.
weights in reversed position
3.1.14 set of weights—a series of weights, usually presented
ΔI kg change in indication of balance due to
s
sensitivity weight
in a case so arranged to make possible any weighing of all
i – subscript used as an index in
loads between the mass of the weight with the smallest nominal
summations
value and the sum of the masses of all weights of the series
j – subscript for number of test weights or
number of series of measurements
with a progression in which the mass of the smallest nominal
k – coverage factor, typically 2 or 3
value weight constitutes the smallest step of the series.
–1
M A m permanent magnetization (see also
μ M)
3.1.15 temperature (t)—in degrees Celsius, is related to the
m kg mass of a rigid body (weight)
absolute thermodynamic temperature scale, called the Kelvin
Δm kg mass difference, usually between test
scale, by t = T – 273.15 K. and reference weight
δm kg maximum permissible error on the
3.1.16 test weight (m )—weight that is to be tested according
t weights
m kg mass, nominal value of the weight
to this standard.
(e.g. 1 kg)
3.1.17 tolerance test—verification that the sum of the con-
m kg conventional mass of the weight
c
Δm kg conventional mass difference between
ventional mass corrections of the weights and their correspond- c
test weight and reference weight
ing uncertainties as calibrated are correct within the maximum
¯
kg average conventional mass difference
Δm
c
permissible errors of the respective weight class.
between test weight and reference
weight
3.1.18 uncertainty—non-negative parameter characterizing
m kg conventional mass of the reference
cr
the dispersion of the quantity values being attributed to a
weight
m kg conventional mass of the test weight
ct
measurand, based on the information used.
m kg mass of the sensitivity weight
s
3.1.19 units—the units used are: (1) for mass, the milligram
m kg mass of the test weight
t
n – subscript for number of measurement
(mg), the gram (g) and the kilogram (kg); (2) for density, the
sequences
–3
kilogram per cubic meter (kg m ).
p Pa barometric pressure
R μm mean height of roughness profile (R-
a
3.1.20 weight—material measure of mass, regulated in re-
parameter)
gard to its physical and metrological characteristics: shape,
R μm maximum height of roughness profile
z
(R-parameter)
dimensions, material, surface quality, nominal value, density,
r – subscript for reference weight
magnetic properties and maximum permissible error.
s – subscript for sensitivity weight
s kg standard deviation
NOTE 2—The term “weight” is also used as the physical quantity of the
2 2
s kg variance
gravitational force of a body. From the context it is usually clear in which
T K thermodynamic temperature using the
sense the term is used. If the sense is not clear, one may use the words
International Temperature Scale of
“weight force” or “weight piece,” depending on its meaning.
1990 (ITS-90)
ΔT* °C initial difference between weight tem-
3.2 Symbols:
perature and laboratory temperature
Symbol Unit Definition t – subscript for test weight
A – represents weighing the reference t °C temperature in degrees Celsius, where
weight in a weighing cycle t = T– 273.15 K
B – represents weighing the test weight in U kg uncertainty, expanded uncertainty
a weighing cycle u kg uncertainty, standard uncertainty
C – correction factor for air buoyancy u kg uncertainty of air buoyancy correction
b
D kg difference of balance readings u kg uncertainty of the balance
ba
between minimum and maximum
u kg combined standard uncertainty
c
values from eccentricity test u kg uncertainty due to the display resolu-
d
d kg scale interval
tion of a digital balance
E617 − 23
5. Physical Characteristics
Symbol Unit Definition
u kg uncertainty due to eccentricity
E
–3
5.1 Construction:
u kg m uncertainty of the formula used to
F
calculate air density
5.1.1 Type—Weights are divided into two types based upon
u % uncertainty in relative humidity
hr
the design:
u kg uncertainty due to instability of the
inst
reference weight
5.1.1.1 Type I—These weights are of one-piece construction
u kg uncertainty due to magnetism
ma
and contain no added adjusting material. They must be
u Pa uncertainty in barometric pressure
p
specified when weights are to be used as standards for the
u kg uncertainty due to the sensitivity of the
s
balance
calibration of weights of Classes 000, 00, 0, 1, 2, and 3, and
u °C uncertainty in temperature
t
where maximum stability is required. A precise measurement
u kg uncertainty due to the weighing
w
process of density can only be made for one-piece weights.
V m volume of a solid body (weight)
5.1.1.2 Type II—Weights of this type can be of any appro-
z m vertical cartesian coordinate
–2
priate design such as screw knob, ring, or sealed plug.
μ N A magnetic permeability
–2
μ N A magnetic constant (magnetic
0 Adjusting material can be used provided it is of a material at
permeability of vacuum), μ = 4π ×
least as stable as the base material and is contained in such a
–7 –2
10 N A
way that it will not become separated from the weight.
μ M T magnetic polarization
μ – relative magnetic permeability (μ/μ )
r 0
5.1.2 Class 000, 00, and 0 shall be Type I, one piece
v – effective degrees of freedom
eff
–3 construction.
ρ kg m mass of a rigid body (weight)
–3
ρ kg m density of air as a reference value
0 5.1.3 Class 1, 2, 3, 4, 5, 6, and 7 may be either Type I or
–3
equal to 1.2 kg m
Type II depending on the application.
–3
ρ kg m density of moist air
a
–3
ρ kg m density of moist air during the last
al
5.2 Design—A weight may have any shape that does not
(previous) calibration of the reference
introduce features that reduce the reliability. Weights with
weight
–3
ρ kg m density of a reference weight with
r nominal values less than 1 g shall have unique shapes to
mass m
r
differentiate the weights from one another. See Table 2. The
–3
ρ kg m density of the weight being tested
t
shape of weights smaller than 1 mg shall be discussed and
χ – magnetic susceptibility
verified with the customer. All weights shall be free of ragged
4. Maximum Permissible Errors or sharp edges or ends. Both sheet metal and wire weights shall
be free of cracks such as may be formed from bending.
4.1 For each weight, the expanded uncertainty U at approxi-
mately 95 % confidence (see Section 9) of the conventional 5.3 Surface Area—For classes 000, 00, 0, 1, 2, 3, and 4 the
mass shall be less than or equal to one-third of the maximum surface area is not to exceed twice the area of a cylinder of
permissible error given in Table 1 as defined in Section 9. equal height and diameter for weights 1 g and above. Sheet
Subsequent calibrations must meet all the requirements (in-
metal weights or wire weights may be used below 1 g. For
cluding environmental parameters as shown in Table 11, of Classes 5, 6, and 7 the total surface areas should be minimized
Sections 7, 8, and 9; and the requirements of ISO/IEC
to the extent possible.
17025:2017, 7.8.6 to make any claim of compliance to Speci-
5.4 Material:
fication E617, Maximum Permissible Errors, weight classes, or
5.4.1 Class 000, 00, 0, 1, 2, 3, 4, and 5 Weights—Shall be
metrological traceability.
made of austenitic stainless steel or a material whose hardness
4.1.1 For each weight, the conventional mass, m (deter-
c
and resistance to corrosion is similar to or better than that of
mined with an expanded uncertainty), shall not differ by more
austenitic stainless steel.
than the difference: maximum permissible error δm minus
5.4.2 Class 6 Weights—Class 6 weights below 5 kg shall be
expanded uncertainty, from the nominal value of the weight,
made of austenitic stainless steel or a material whose hardness
m :
o
and resistance to corrosion is similar to or better than that of
m 2 ~δm 2 U! # ~m ! # m 1~δm 2 U! (1)
o c o
austenitic stainless steel. Class 6 weights of 5 kg or greater
shall be made of grey cast iron or of another material whose
4.2 Maximum permissible errors for classes 000, 00, 0, 1, 2,
brittleness and resistance to corrosion is similar to or better
3, 4, 5, 6, and 7 are given in Table 1. These maximum
than that of grey cast iron. The surface of the weights may be
permissible errors apply to conventional mass values.
treated with a suitable coating in order to improve their
4.3 Maximum Permissible Errors for weights of denomina-
corrosion resistance. This coating shall withstand shocks and
tion intermediate between those listed, the maximum permis-
outdoor weather conditions.
sible error shall be interpolated from the nearest values shown.
5.4.3 Class 7 Weights—Class 7 weights below 100 g shall
Maximum permissible errors for nominal values outside the
be made of austenitic stainless steel or a material whose
ranges listed in Table 1 shall be interpolated from the nearest
hardness and resistance to corrosion is similar to or better than
metric equivalents.
that of austenitic stainless steel. Class 7 weights of 100 g or
4.4 For class 000, 00, and 0 weights, which are always greater shall be made of grey cast iron or of another material
accompanied by certificates giving the mass values and whose brittleness and resistance to corrosion is similar to or
uncertainties, the deviation from the nominal value, m – m , better than that of grey cast iron. The surface of the weights
c 0
shall be taken into account by the user. may be treated with a suitable coating in order to improve their
E617 − 23
TABLE 1 Maximum Permissible Errors
NOTE 1—Maximum Permissible Errors are reported in SI units, typically milligrams.
NOTE 2—The “grain” is the same in avoirdupois, troy, and apothecaries units of mass.
NOTE 3—See NIST SP 811 and NIST SP 1038 for conversion and units of measure.
NOTE 4—For nominal values not listed, see 4.3.
±mg except as noted
Denomination
Class 000 Class 00 Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
Metric
5000 kg 25 g 50 g 100 g 250 g 500 g 750 g
3000 kg 15 g 30 g 60 g 150 g 300 g 450 g
2000 kg 10 g 20 g 40 g 100 g 200 g 300 g
1000 kg 5.0 g 10 g 20 g 50 g 100 g 150 g
500 kg 2.5 g 5.0 g 10 g 25 g 50 g 75 g
300 kg 1.5 g 3.0 g 6.0 g 15 g 30 g 45 g
200 kg 1.0 g 2.0 g 4.0 g 10 g 20 g 30 g
100 kg 500 mg 1.0 g 2.0 g 5.0 g 10 g 15 g
50 kg 13 mg 25 mg 63 mg 120 mg 250 500 mg 1.0 g 2.5 g 5.0 g 7.5 g
30 kg 7.5 15 38 75 150 300 600 mg 1.5 g 3.0 g 5.1 g
25 kg 6.25 12.5 31 62 125 250 500 1.3 g 2.5 g 4.5 g
20 kg 5.0 10 25 50 100 200 400 1.0 g 2.0 g 3.8 g
10 kg 2.5 5.0 13 25 50 100 200 500 mg 1.0 g 2.2 g
5 kg 1.3 2.5 6.0 12 25 50 100 250 500 mg 1.4 g
3 kg 0.75 1.5 3.8 7.5 15 30 60 150 300 1.0 g
2 kg 0.5 1.0 2.5 5.0 10 20 40 100 200 750 mg
1 kg 0.25 0.5 1.3 2.5 5.0 10 20 50 100 470
500 g 0.13 0.25 0.60 1.2 2.5 5.0 10 35 70 300
300 g 0.075 0.15 0.38 0.75 1.5 3.0 6.0 30 60 210
200 g 0.05 0.10 0.25 0.50 1.0 2.0 4.0 20 40 160
100 g 0.025 0.05 0.13 0.25 0.50 1.0 2.0 10 20 100
50 g 0.015 0.030 0.060 0.12 0.25 0.60 1.2 5.0 10 62
30 g 0.014 0.026 0.037 0.074 0.15 0.45 0.90 3.0 6.0 44
20 g 0.013 0.025 0.037 0.074 0.10 0.35 0.70 2.0 4.0 33
10 g 0.010 0.020 0.025 0.050 0.074 0.25 0.50 1.0 2.0 21
5 g 0.005 0.010 0.017 0.034 0.054 0.18 0.36 0.75 1.5 13
3 g 0.005 0.010 0.017 0.034 0.054 0.15 0.30 0.64 1.3 9.4
2 g 0.005 0.010 0.017 0.034 0.054 0.13 0.26 0.56 1.1 7.0
1 g 0.005 0.010 0.017 0.034 0.054 0.10 0.20 0.45 0.90 4.5
500 mg 0.002 0.003 0.005 0.010 0.025 0.080 0.16 0.36 0.72 3.0
300 mg 0.002 0.003 0.005 0.010 0.025 0.070 0.14 0.31 0.61 2.2
200 mg 0.002 0.003 0.005 0.010 0.025 0.060 0.12 0.27 0.54 1.8
100 mg 0.002 0.003 0.005 0.010 0.025 0.050 0.10 0.22 0.43 1.2
50 mg 0.002 0.003 0.005 0.010 0.014 0.042 0.085 0.17 0.35 0.88
30 mg 0.002 0.003 0.005 0.010 0.014 0.038 0.075 0.15 0.30 0.68
20 mg 0.002 0.003 0.005 0.010 0.014 0.035 0.070 0.13 0.26 0.56
10 mg 0.002 0.003 0.005 0.010 0.014 0.030 0.060 0.10 0.21 0.40
5 mg 0.002 0.003 0.005 0.010 0.014 0.028 0.055 0.083 0.17
3 mg 0.002 0.003 0.005 0.010 0.014 0.026 0.052 0.071 0.14
2 mg 0.002 0.003 0.005 0.010 0.014 0.025 0.050 0.062 0.12
1 mg 0.002 0.003 0.005 0.010 0.014 0.025 0.050 0.050 0.10
0.5 mg 0.002 0.003 0.005 0.010 0.014 0.025 0.050 0.0540 0.080
0.3 mg 0.002 0.003 0.005 0.010 0.014 0.025
0.2 mg 0.002 0.003 0.005 0.010 0.014
0.1 mg 0.002 0.003 0.005 0.010
0.05 mg 0.002 0.003 0.005 0.010
Avoirdupois Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
Pound mg mg mg g & mg g & mg g & mg g & mg g & mg
10000 lb 45 g 91 g 230 g 450 g 680 g
5000 lb 23 g 45 g 110 g 230 g 340 g
3000 lb 14 g 27 g 68 g 140 g 200 g
2500 lb 11 g 23 g 57 g 110 g 170 g
2000 lb 9.1 g 18 g 45 g 91 g 140 g
1000 lb 4.5 g 9.1 g 23 g 45 g 68 g
500 lb 2.3 g 4.5 g 11 g 23 g 34 g
300 lb 1.4 g 2.7 g 6.8 g 14 g 20 g
200 lb 910 mg 1.8 g 4.5 g 9.1 g 14 g
100 lb 57 110 230 450 910 mg 2.3 g 4.5 g 6.8 g
50 lb 29 57 110 230 450 1.1 g 2.3 g 4.1 g
30 lb 17 32 68 140 270 680 mg 1.4 g 2.7 g
25 lb 14 28 57 110 230 570 1.1 g 2.4 g
20 lb 12 23 45 91 180 450 910 mg 2.0 g
10 lb 5.5 11 23 45 91 230 450 1.3 g
5 lb 2.7 5.4 11 23 45 110 230 780 mg
3 lb 1.7 3.4 6.8 14 27 68 140 580
E617 − 23
TABLE 1 Continued
±mg except as noted
Denomination
Class 000 Class 00 Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
2 lb 1.2 2.3 4.5 9.1 18 45 91 440
1 lb 0.55 1.1 2.3 4.5 9.1 35 70 270
0.5 lb 0.27 0.54 1.1 2.3 4.5 23 45 170
0.3 lb 0.17 0.34 0.68 1.4 2.7 14 27 120
0.2 lb 0.12 0.23 0.45 0.91 1.8 9.0 18 97
0.1 lb 0.055 0.11 0.23 0.57 1.1 4.5 9.1 59
0.05 lb 0.037 0.074 0.11 0.36 0.77 2.3 4.5 37
0.03 lb 0.029 0.059 0.083 0.32 0.59 1.4 2.7 26
0.02 lb 0.024 0.047 0.070 0.23 0.45 0.91 1.8 20
0.01 lb 0.017 0.034 0.054 0.16 0.34 0.73 1.5 12
0.005 lb 0.017 0.034 0.054 0.14 0.27 0.58 1.2 7.8
0.003 lb 0.017 0.034 0.054 0.11 0.22 0.50 0.99 5.4
0.002 lb 0.015 0.030 0.049 0.091 0.19 0.44 0.87 4.2
0.001 lb 0.0050 0.010 0.024 0.078 0.15 0.35 0.70 2.9
0.0005 lb 0.0045 0.0091 0.023 0.064 0.13 0.28 0.56 2.0
Avoirdupois Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
Ounce mg mg mg mg mg mg mg mg
10 oz 0.35 0.70 1.4 2.8 5.4 28 57 200
8 oz 0.27 0.54 1.1 2.3 4.5 23 45 170
5 oz 0.18 0.35 0.71 1.4 2.8 14 28 130
4 oz 0.14 0.28 0.57 1.1 2.3 11 23 110
3 oz 0.10 0.21 0.43 0.91 1.8 8.5 17 90
2 oz 0.070 0.14 0.28 0.64 1.3 5.7 11 70
1 oz 0.037 0.074 0.14 0.43 0.86 2.8 5.4 42
1/2 oz 0.030 0.060 0.085 0.30 0.59 1.4 2.8 27
1/4 oz 0.020 0.041 0.062 0.20 0.43 0.84 1.7 17
1/8 oz 0.017 0.034 0.054 0.16 0.31 0.67 1.3 10
1/16 oz 0.017 0.034 0.054 0.12 0.24 0.50 1.1 6.5
1/32 oz 0.014 0.029 0.047 0.095 0.19 0.43 0.87 4.2
1/64 oz 0.0050 0.010 0.023 0.077 0.15 0.35 0.69 2.8
0.5 oz 0.030 0.060 0.085 0.30 0.59 1.4 2.8 27
0.3 oz 0.068 0.23 0.45 0.89 1.8 19
0.2 oz 0.057 0.19 0.38 0.78 1.6 14
0.1 oz 0.054 0.14 0.29 0.63 1.3 9.0
0.05 oz 0.054 0.11 0.23 0.50 1.0 5.7
0.03 oz 0.045 0.095 0.19 0.43 0.85 4.1
0.02 oz 0.029 0.077 0.18 0.38 0.75 3.2
0.01 oz 0.023 0.064 0.14 0.30 0.60 2.2
Troy Ounce Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
mg mg g & mg
1000 oz t 310 mg 620 mg 1.6 g 3.1 g
500 oz t 160 310 780 mg 1.6 g
300 oz t 91 190 470 930 mg
200 oz t 62 120 310 620
100 oz t 31 62 160 310
50 oz t 16 31 78 160
30 oz t 9.1 19 47 93
20 oz t 6.2 12 39 77
10 oz t 3.1 6.2 30 61
5 oz t 1.6 3.1 16 31
3 oz t 0.91 1.9 9.3 19
2 oz t 0.71 1.4 6.2 12
1 oz t 0.45 0.91 3.1 6.2
0.5 oz t 0.31 0.62 1.6 3.1
0.3 oz t 0.24 0.49 0.92 1.8
0.2 oz t 0.20 0.40 0.80 1.6
0.1 oz t 0.15 0.30 0.65 1.3
0.05 oz t 0.12 0.23 0.52 1.0
0.03 oz t 0.097 0.19 0.44 0.88
0.02 oz t 0.084 0.17 0.39 0.77
0.01 oz t 0.071 0.14 0.31 0.62
0.005 oz t 0.056 0.11 0.25 0.50
Pennyweight Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
mg mg mg g & mg
10000 dwt 155 310 780 1.6 g
5000 dwt 78 160 390 780 mg
3000 dwt 47 91 230 470
2000 dwt 31 62 160 310
1000 dwt 16 31 78 160
500 dwt 7.8 16 43 87
300 dwt 4.7 9.1 34 68
200 dwt 3.1 6.2 30 61
100 dwt 1.6 3.1 16 31
50 dwt 0.78 1.6 7.8 16
E617 − 23
TABLE 1 Continued
±mg except as noted
Denomination
Class 000 Class 00 Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
30 dwt 0.58 1.2 4.7 9.3
20 dwt 0.46 0.91 3.1 6.2
10 dwt 0.31 0.62 1.6 3.1
5 dwt 0.22 0.44 0.89 1.7
3 dwt 0.17 0.34 0.73 1.5
2 dwt 0.15 0.3 0.65 1.3
1 dwt 0.12 0.23 0.52 1.0
Grain Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
mg mg mg mg
10000 gr 6.5 13 36 79
5000 gr 3.2 6.5 31 61
3000 gr 1.9 3.9 19 39
2000 gr 1.3 2.6 13 26
1000 gr 0.71 1.4 6.5 13
500 gr 0.48 0.91 3.2 6.5
300 gr 0.35 0.65 1.9 3.9
200 gr 0.28 0.57 1.3 2.6
100 gr 0.20 0.40 0.82 1.6
50 gr 0.15 0.30 0.65 1.3
30 gr 0.12 0.25 0.55 1.1
20 gr 0.11 0.21 0.48 0.91
10 gr 0.084 0.17 0.42 0.77
5 gr 0.071 0.14 0.31 0.62
3 gr 0.060 0.12 0.25 0.53
2 gr 0.054 0.11 0.22 0.45
1 gr 0.045 0.091 0.17 0.37
0.5 gr 0.039 0.078 0.14 0.31
Carat Class 0 Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
mg mg
5000 c 10 20
3000 c 6.0 12
2000 c 4.0 8.0
1000 c 2.0 4.0
500 c 1.0 2.0
300 c 0.69 1.3
200 c 0.52 1.0
100 c 0.35 0.7
50 c 0.25 0.50
30 c 0.19 0.40
20 c 0.16 0.33
10 c 0.13 0.26
5 c 0.10 0.20
3 c 0.086 0.17
2 c 0.075 0.15
1 c 0.060 0.12
0.5 c 0.050 0.10
Apothecary Ounce mg
12 oz ap 64
10 oz ap 61
6 oz ap 37
5 oz ap 31
4 oz ap 25
3 oz ap 19
2 oz ap 12
1 oz ap 6.2
Apothecary Dram mg
6 dr ap 4.7
5 dr ap 3.9
4 dr ap 3.1
3 dr ap 2.3
2 dr ap 1.8
1 dr ap 1.4
Apothecary mg
Scruple
2 s ap 1.2
1 s ap 0.91
corrosion resistance. This coating shall withstand shocks and 5.5 Magnetism—Weights shall not exceed maximum per-
outdoor weather conditions. missible magnetic properties as listed in Tables 3 and 4 for any
E617 − 23
TABLE 2 Shape of Weights 1 g or Less
bration laboratories. For Class 000 and 00, the manufacturer
Nominal Values Polygonal Sheets Wires shall provide a measured value for the density of the weights at
5, 50, 500 mg Pentagon Pentagon time of manufacture. Use of a sample taken adjacent to the
3, 30, 300 mg Circle Circle
material from which the weight is manufactured to measure the
2, 20, 200 mg Square Square
density is permitted, however an additional uncertainty com-
1, 10, 100, 1000 mg Triangle Triangle
–5
ponent equal to 5 × 10 must be combined with the standard
uncertainty of the density determination process. For subse-
TABLE 3 Maximum Polarization, μ M, (μT) quent calibrations, the density may be verified by the calibrat-
ing laboratory if there are concerns and capability for the
000, 00,
Weight Class 1 2 and 3 4 and 5 6 and 7
and 0
measurement is available. As lower precision of measurement
Maximum
is required, so the range of density is broadened. See Table 5.
Not
polarization, 2.5 8 25 80
applicable 5.6.1 The determination of the minimum and maximum
μ M, (μT)
density limits for nominal values not listed in Table 5 shall be
converted to metric values and the limits of the metric value
next greater than the converted value used. (Example: 1
TABLE 4 Maximum Magnetic Susceptibility, χ
apothecary ounce class 4 is equal to 31.1034768 g, therefore
000, 00,
Weight Class 1 2 and 3 4 and 5 6 and 7
and 0 the density limits are equal to values listed in Table 5 for 50 g.)
m # 1 g 0.25 0.9 10 Not Not
NOTE 4—Materials used to make weights for special applications that
applicable applicable
do not fall within the density limits stated above, should have stated
2 g # m # 10 g 0.06 0.18 0.7 4 Not
densities or density determinations performed.
applicable
20 g # m 0.02 0.07 0.2 0.8 Not
5.7 Finish—The surface of the weights (including the base
applicable
and corners) shall be smooth, the edges shall be rounded, and
the weights shall not be porous.
5.7.1 The surface quality of a weight shall not exceed
portion of the weight. If the values of all local measurements of
maximum values of surface roughness, R and R through
a z
magnetization and susceptibility are less than these limits, then
visual inspection using a hand held gage. See Table 6.
it may be assumed that the uncertainty components due to the
5.7.2 The surface roughness of all weight surfaces must
magnetism of the weight are negligible. The maximum perma-
meet the limits established in Table 6 for the weight classifi-
nent magnetization and magnetic susceptibilities given in
cation.
Tables 3 and 4 are such that, at magnetic fields and magnetic
5.8 Adjustment:
field gradients possibly present on balance pans, they produce
5.8.1 Type I Weights—Weights shall be adjusted by
a change of the conventional mass of less than one tenth of the
abrasion, grinding or any appropriate method. The surface
maximum permissible error of the test weight.
requirements shall be met at the end of the adjustment process.
NOTE 3—Magnetic susceptibility may be tested in accordance with
5.8.2 Type II Weights—Weights with adjusting cavities shall
OIML R 111-1, Annex B. Cast iron cannot have a susceptibility specifi-
be adjusted with the same material from which they are made,
cation of any real value.
or with materials that are at least as stable and of similar
5.6 Density—Because of the effect of the buoyant force of
density as the base material. For weights which have sealing
air on a weight, precision measurements of mass require that
caps, the cap may be made of aluminum. The back-up spacer
the volume of the weight be known, as well as the density of
should be of a similar material as the weight. Adjusting
the air in which it is being measured, so that appropriate
material and back-up disc must meet the magnetic require-
corrections can be made. For weights of higher precision, the
ments specified for the accuracy class of the weight.
range of density is limited to values at or near the density of
well-established standards, such as are used by primary cali- 5.9 Marking:
TABLE 5 Minimum and Maximum Limits for Density
3 –3
ρ , ρ (10 kg m )
min max
Nominal
Class of Weight
Value
000 00 and 0 1 2 and 3 4 and 5 6 and 7
$ 100 g 7.967 – 8.033 7.934 – 8.067 7.81 – 8.21 7.39 – 8.73 6.4 – 10.7 $ 4.4
50 g 7.960 – 8.040 7.92 – 8.08 7.74 – 8.28 7.27 – 8.89 6.0 – 12.0 $ 4.0
20 g 7.900 – 8.090 7.84 – 8.17 7.50 – 8.57 6.6 – 10.1 4.8 – 24.0 $ 2.6
10 g 7.87 – 8.14 7.74 – 8.28 7.27 – 8.89 6.0 – 12.0 $ 4.0 $ 2.0
5 g 7.87 – 8.13 7.62 – 8.42 6.9 – 9.6 5.3 – 16.0 $ 3.0
2 g 7.62 – 8.42 7.27 – 8.89 6.0 – 12.0 $ 4.0 $ 2.0
1 g 7.28 – 8.90 6.9 – 9.6 5.3 – 16.0 $ 3.0
500 mg 7.50 – 8.60 6.3 – 10.9 $ 4.4 $ 2.2
200 mg 6.7 – 9.6 5.3 – 16.0 $ 3.0
100 mg 6.0 – 12 $ 4.4
50 mg $ 4.8 $ 3.4
20 mg $ 2.5 $ 2.3
E617 − 23
TABLE 6 Maximum Values of Surface Roughness
to those of high stability. Appendix X1 should serve as a guide
Classes 000, Classes Classes Class Classes in selecting weights for specific applications.
00, 0 1, 2 3, 4 5 6, 7
6.2 Class—Maximum permissible errors for Classes 000
R (μm) 0.1 0.2 0.4 1 25
A
through 7 are shown in Table 1. Lower numbers indicate
R (μm) 0.5 1 2 5 100
Z
smaller maximum permissible errors.
6.3 Lifters:
6.3.1 Classes 000, 00, 0, 1, 2, 3, and 4 shall be supplied with
5.9.1 Class 000, 00, and 0 weights shall not bear any
lifters when sets of weights are ordered. Individual weights
indication of nominal value and shall not be marked unless
shall be supplied with lifters when specified by the purchaser.
used to distinguish from another class 000, 00, or 0 weight,
Lifters or forceps shall securely hold the weights for which
provided that the surface quality and stability of the weights are
they are designed. Additional pressure shall not cause the
not affected by the markings or by the process used to mark it.
dropping of small weights or the forceful ejection of large
5.9.2 Numerical Value for Classes 1, 2, 3, 4, 5, 6, and
weights.
7—The nominal value of each weight shall appear on the
6.3.2 For weights 500 g or larger, the parts of the lifter that
surface of each weight. Only the numerical portion of the
come in contact with the weights shall be covered with a
weight value needs to be on the surface of weights. Weights
non-magnetic material softer than the surface of the weight,
made of wire or too small to be marked shall not be marked but
such as plastic or chamois skin from which the grease has been
should be identifiable by their shape or number of bends.
removed.
5.9.3 Units of Weight—Weights 100 g and greater may be
6.3.3 For smaller weights, the lifters may be of the same
marked with the unit name or abbreviation. In the case of sets
design where practical or may be of a non-magnetic material
of non-metric weights, at least the largest weight of a particular
softer than the weights, such as close-grained wood or plastics
set should be marked with the unit name or abbreviation. In
not affected by alcohol. When the parts of the lifters or forceps
any case the unit shall not be included where such marking
which come in contact with the weights are not covered by a
would be illegible.
soft material, they shall be smooth and polished and the edges
5.9.4 Abbreviations—The accepted abbreviation may be
on which the weight may be lifted shall be well rounded.
used in marking. Abbreviations are shown in Appendix X2.
6.3.4 If forceps are used for lifting small weights, stainless
Periods shall not be used with abbreviations in marking
steel forceps with nonmetallic tips may be used, where the tips
weights.
that come in contact with the weights are covered with a
5.9.5 Multiple Weights—Multiple weights of the same
material softer than the surface of the weight, such as plastic or
nominal value included in a set of weights shall have distin-
chamois skin from which the grease has been removed. The
guishing marks.
forceps may also be made of a material softer than the weights,
5.9.6 Depth of Markings—Markings shall be clear, shallow,
such as close-grained wood or plastics not affected by alcohol.
relatively broad, and free of burrs and sharp angles. Markings
When the parts of the forceps which come in contact with the
shall not perforate or crack sheet metal weights.
weights are not covered by a soft material, they shall be smooth
5.9.7 User Marking—It is recommended for a user to clearly
and polished and the edges on which the weight may be lifted
identify individual weights as it helps to link a weight to its
shall be well rounded.
calibration certificate or verification document. The recom-
6.4 Cases:
mended maximum values for user markings are given in Table
6.4.1 Classes 000, 00, 0, 1, 2, 3, and 4 weights, when
7.
supplied in sets, may be supplied with one or more cases or
6. Ordering Information shall meet customer specifications for cases. The case shall be
designed so that as long as the lid remains closed, the weights
6.1 Selection of type and class depends upon the application
shall be held secure, and when possible the pocket depth shall
of the weights. For reference standards, stability and informa-
be such that the shoulder of the weight does not extend above
tion about the values of the weights is more important than the
the edge of the pocket. The hinges and locks shall be adequate
closeness of the values to nominal. Weights to be used with
to hold the lid closed with any reasonable handling. There shall
balances of low precision do not require small maximum
be no discoloration of weights due to the lining of the case,
permissible errors, nor need the choice of materials be limited
such as might result from long storage in a warm or damp
location. This condition does not apply to weights not designed
to be handled manually.
TABLE 7 Recommended Maximum Number of User Markings
6.4.2 Pockets—A separate pocket shall be supplied for each
Maximum Number
Nominal Height of
Class of Signs, Numerals, weight and for each forceps and lifter, except that extremely
Value Lettering
or Letters
large lifters may not require pockets. All pockets shall be large
000 – 7 < 1 g 1 mm 2
enough so that no appreciable friction shall be encountered in
000, 00, 0 $ 1 g 2 mm 3
inserting or removing weights. If the cover is not lined, the
1 $ 1 g 3 mm 5
2 – 7 1 g to 100 g 3 mm 5 individual holes in the cover shall be smooth or lined. Pockets
2 – 7 200 g to 10 kg 5 mm 5
for weights 1 g or equivalent or larger shall be constructed of
2 - 3 $ 20 kg 7 mm 5
a smooth nonabrasive material, or lined with a smooth,
4 – 7 $ 20 kg 12 mm 5
nonabrasive material.
E617 − 23
6.5 Denominations—The customer’s purchase order or con- maintained their metrological properties. Any weights found
tract shall define the contents of the weight set. defective at the time of re-calibration shall be reviewed with
the customer.
6.6 Density Identification—Weights that are to be calibrated
7.2.2 For subsequent calibration, as a minimum, the
shall carry identification of the density of the various materials
weights shall be visually inspected for design and surface
of which the weights are manufactured. Identification of
conditions and the conventional mass or conventional mass
density shall be displayed on the certificate, or on the cover or
correction reported, with the associated measurement
interior of the box.
uncertainty, on a calibration certificate as specified in 7.1.1.
6.7 Special Requirements—If a customer has specific re-
quirements that deviate from this standard (that is, material,
8. Calibration Procedures
shape, maximum permissible errors, and so forth) the manu-
8.1 Weight manufacturers must be able to provide evidence
facturer may use this specification as a reference, not a
that all new weights comply with specifications in this standard
requirement, to provide the customer with the weights that they
(for example, material, density, magnetism, surface finish,
need.
mass values, uncertainties) to make any claim of compliance to
7. Certificates Specification E617, Maximum Permissible Errors, weight
classes, or metrological traceability.
7.1 Calibration—Laboratories issuing calibration certifi-
8.1.1 During subsequent calibrations, calibration laborato-
cates for weights and weight sets shall have evidence of
ries must meet the requirements of ISO/IEC 17025:2017.
metrological traceability to the International System of Units
8.1.2 Subsequent calibrations must meet all the
(SI). Calibration certificates shall be issued only by laborato-
requirements, including Sections 7, 8, and 9, Table 8 and Table
ries having a quality system complying with the requirements
11 (environmental parameters) to make any claim of compli-
of ISO/IEC 17025:2017, which has preferably been verified by
ance to Specification E617, Maximum Permissible Errors,
third party assessment (accreditation).
weight classes, or metrological traceability.
7.1.1 Calibration Certificates—A calibration certificate
shall state, as a minimum: the conventional mass of each
NOTE 5—Requirements set forth in NIST IR 6969 and NIST IR 5672
weight, m , an indication of whether a weight has been adjusted are compliant with all the requirements of Specification E617, Sections 7,
c
8, and 9.
prior to calibration, its expanded uncertainty, U, and the value
of the coverage factor, k, and meet the requirements of
8.2 Cleaning Weights:
ISO/IEC 17025:2017 and the GUM, as interpreted by ILAC,
8.2.1 Before calibration, dust and any foreign particles shall
for metrological traceability.
be removed by brushing with a clean soft-bristle brush or
7.1.2 Class 000, 00, and 0 weights shall be accompanied by
gentle wiping with a non-abrasive lint-free wipe. Cleaning
a calibration certificate meeting the requirements of 7.1.1.
should not remove any significant amounts of weight material.
7.1.2.1 The certificate for Class 000, 00, and 0 weights shall
Weights should be handled and stored in such a way that they
state, as a minimum, the values of conventional mass, m , the
c
stay contamination-free. Care must be taken to not change the
expanded uncertainty, U, and the coverage factor, k, and the
surface properties of the weight (that is, by scratching the
density or volume for each weight. In addition, the certificate
weight).
shall state if the density or volume was measured or estimated.
8.2.2 If a weight contains significant amounts of contami-
7.2 Calibration, Initial Verification from the Manufacturer nation that cannot be removed by brushing with a clean
and Subsequent Calibration: soft-bristle brush or gentle wiping with a non-abrasive lint-free
7.2.1 Table 8 gives the required tests for initial calibration wipe, the weight or some part of it can be washed with solvents
from the manufacturer and subsequent calibration. The catego- leaving no significant amount of resid
...