Czech Metrology Institute  
Okružní 31, 638 00  Brno  
 
1. ------IND- 2018 0591 CZ - EN- ------ 20181217 --- --- PROJET 
‘Tyre pressure gauges for road motor vehicles’  may be placed on the market and put into use in the 
Czech Republic as specified measuring instruments  pursuant to Act No  505/1990 on metrology, as 
amended. According to the Act, specified measuring instruments are instruments which are included in 
the list of the types of specified measuring instruments (Implementing Decree No 345/2002) and, at the 
same time, intended (by the manufacturer/importer) for measurements of relevance to the protection of 
public interests in consumer protection, contractual relations, imposition of sanctions, fees, tariffs and 
taxes, health protecti on, environmental protection, occupational safety, or the protection of other public 
interests protected by separate legislation . This means that their purpose is similar to that used for 
defining specified products – measuring instruments and non -automati c weighing instruments – under 
Directives 2014/31/EU and 2014/32/EU. The requirements of this regulation do not apply to measuring 
instruments placed on the market in the Czech Republic for purposes other than the above purposes 
defined by Act No  505/1990 on metrology.  
The subject matter of this notified regulation is to lay down the metrological and technical requirements 
for specified measuring instruments of this type. This regulation also lays down the tests for the purposes 
of type approval and verific ation of specified measuring instruments of this type.  
(End of executive summary.)  
 
Contact person: Mgr. Tomáš Hendrych  
Telephone: +420 545 555 414  
 
P U B L I C   D E C R E E 
 
As the authority with substantive and territorial jurisdiction in the field of l aying down metrological and 
technical requirements for specified measuring instruments and laying down the methods for type 
approval and verification of specified measuring instruments under §  14(1) of Act No  505/1990 on 
metrology, as amended (hereinafter the ‘Metrology Act’), and in accordance with the provisions of §  172 
et seq. of Act No  500/2004, the Administrative Procedure Code (hereinafter the ‘APC’), the Czech 
Metrology Institute (hereinafter the ‘CMI’) commenced ex officio proceedings on 2  February  2017 
pursuant to §  46 of the APC, and, based on the supporting documents, issues the following:  
 
I. 
D R A F T   G E N E R A L  M  E A S U R E 
number: 0111 -OOP -C021 -17 
 
laying down the metrological and technical requirements for specified measuring instruments, 
including testing methods for verification of the following specified measuring instruments:  
‘tyre pressure gauges for road motor vehicles’  
 General Measure No  0111 -OOP -C021 -17 
2 1  Basic definitions  
For the purposes of this General Measure, terms and definitions pursuant to VIM and  VIML1 and the 
following shall apply:  
1.1 
tyre pressure gauges for road motor vehicles  
(hereinafter ‘tyre pressure gauges’)  
measuring instruments, which indicate the pressure difference between the air in the tyre and the 
atmosphere; they also include all those parts between the tyre and the indicating device  
1.1.1  
type A tyre pressure gauges – fixed devices  
devices with fixed measuring elements and a displaying device; they are generally connected to a source 
of air or compressed nitrogen and equipped with  a controller placed either near the indicating device or 
the end of the hose; they allow for tyre pressure to be increased, checked and adjusted  
1.1.2  
type B tyre pressure gauges – portable devices  
devices with portable measuring elements and a displaying  device; they may generally be connected to 
a source of air or compressed nitrogen and are equipped with a controller; they allow for tyre pressure 
to be increased, checked and adjusted  
1.1.3  
type C tyre pressure gauges – handheld devices  
devices with hand held measuring elements and a displaying device; they may be equipped with a 
controller and, depending on their design, allow for tyre pressure to be increased, checked and adjusted, 
or only checked.  
2 Metrological requirements  
The verification of the gauge s shall be subject to the metrological requirements applicable at the time 
they were put into circulation.  
Gauges put into circulation pursuant to separate legislation2 are subject to the requirements set out by 
that separate legislation.  
2.1 Working conditions  
The gauges shall be capable of measuring tyre pressure within an ambient temperature range of –10 °C 
to +40  °C. 
                                                      
1 TNI 01 0115 International Vocabulary of Metrology – Basic and General Concepts and Associated Terms 
(VIM) and International Vocabulary of Legal Metrology (VIML) are part of the technical harmonisation 
compendium ‘Terminology in the field o f metrology’, which is publicly available at www.unmz.cz.  
2 Implementing Decree No  337/2000 establishing the requirements for road vehicle tyre pressure gauges marked 
with the EEC symbol, as amended. EEC type -approval certificates issued on the basis of th e Implementing 
Decree shall remain valid in accordance with Article  IV of Implementing Decree No  125/2015 until the validity 
of those certificates expires.  General Measure No  0111 -OOP -C021 -17 
3 2.2 Measuring range  
The measuring range shall correspond to the intended use of the tyre pressure gauges for the given type 
of road vehicles.  
2.3 Maximum permissible errors  
The maximum permissible errors (MPE) for the reference ambient temperature range of +15  °C to 
+25 °C are given in Table  1. 
Table  1 – Maximum permissible errors  
Values in bars (kilopascals)  
Measured pressure  pm Maximum permissible errors  
 pm ≤ 4 
(400)  0.08 
(8) 
4 
(400)  < pm ≤ 10 
(1,000)  0.16 
(16) 
 pm > 10 
(1,000)  0.25 
(25) 
2.4 Maximum permissible errors outside the ambient temperature reference range  
Maximum permissible errors for temperatures lying outside the ambient temperature reference range 
are given in Table  2. 
Table  2 – Maximum permissible errors outside the ambient temperature reference range  
Measured pressure  pm Maximum permissible errors depending on ambient 
temperature tamb 
tamb < 15 °C tamb > 25 °C 
 pm ≤ 4 bar  
(400 kPa)  [0.005 ∙ (15  − tamb) + 0.08]  bar 
[0.5 ∙ (15  − tamb) + 8]  kPa [0.005 ∙ ( tamb − 25) + 0.08]  bar 
[0.5 ∙ (t amb − 25) + 8]  kPa 
4 
(400 kPa) < pm ≤ 10 bar  
(1,000  kPa) [0.005 ∙ (15  − tamb) + 0.16]  bar 
[0.5 ∙ (15  − tamb) + 16]  kPa [0.005 ∙ ( tamb − 25) + 0.16]  bar 
[0.5 ∙ (t amb − 25) + 16]  kPa 
 pm > 10 bar  
(1,000  kPa) [0.005 ∙ (15  − tamb) + 0.25]  bar 
[0.5 ∙ (15  − tamb) + 25]  kPa [0.005 ∙ ( tamb − 25) + 0.25]  bar 
[0.5 ∙ (t amb − 25) + 25]  kPa 
2.5 Hysteresis error  
Within the reference temperature range, hysteresis error shall not exceed the absolute value of the 
maximum permissible error according to Table  1. The temperature shall remain constant during the test.  
2.6 Return of the instrument’s index to a predetermined mark  
In the case of mechanical tyre press ure gauges, at atmospheric pressure, the pressure gauge index shall 
stop opposite the zero mark or opposite a predetermined mark clearly differentiated from the scale 
intervals, within the limits of the maximum permissible error. A pressure gauge may posse ss a stop at a General Measure No  0111 -OOP -C021 -17 
4 distance corresponding to at least twice the value of the maximum permissible error below zero or below 
the predetermined mark.  
In the case of electronic tyre pressure gauges, at atmospheric pressure, the indicating device of the 
gauges shal l display zero pressure or zero pressure within the limits of the maximum permissible error.  
3 Technical requirements  
The verification of the gauges shall be subject to the technical requirements applicable at the time they 
were put into circulation.  
Gauges  put into circulation pursuant to separate legislation2 are subject to the requirements set out by 
that separate legislation.  
3.1 In general  
The design  of tyre pressure gauges shall ensure that the gauges retain their metrological properties 
throughout the relevant period of use.  
Tyre pressure gauges are measuring instruments that are part of fixed (type A) or mobile (type B and C) 
devices for increasin g road vehicle tyre pressure.  
For the purposes of this regulation, the following classification of tyre pressure gauges is used:  
type A: fixed devices;  
type B: portable devices;  
type C: handheld devices.  
Depending on the type of the pressure sensor and indicating device used, for the purposes of this 
regulation, tyre pressure gauges are divided into:  
a) electronic instruments (tyre pressure gauges with at least one electronic component in the 
measuring chain),  
b) mechanical instruments (tyre pressure gauges wi th no electronic components in the measuring 
chain).  
3.2 Pressure sensor  
In the case of mechanical tyre pressure gauges, the pressure sensor may be e.g. a flexible (Bourdon) 
tube, box or membrane. The elastic deformation of these flexible elements is mechanica lly transmitted 
to the indicating device.  
Electronic tyre pressure gauges may use pressure sensors or pressure transducers that convert the 
information about pressure to an electrical output signal, which is further processed and converted to be 
indicated  digitally.  
3.3 Indicating device  
In the measurement range, the indicating device shall make it possible to read off, directly and 
accurately, the value of the pressure measured. The indicating device shall display the pressure value in 
kilopascals (kPa) or ba rs (bar).  
3.3.1 Analogue indicating device  
The analogue scale shall have the scale interval fixed at 0.1  bar (10  kPa). The scale increments shall not 
be less than 1.25  mm. The arc of the scale usually covers an angle of 270°.  
The thickness of the part of the index which covers the scale marks shall not be greater than the thickness 
of the scale marks themselves and shall cover approximately half the length of the shortest scale mark.  General Measure No  0111 -OOP -C021 -17 
5 The maximum distance between the index and the plane of the scale of the circular dial shall not exceed 
2 mm or (0.02 L + 1) mm, where L is the distance between the axis of rotation of the pointer and its 
extremity.  
The scale numbering shall express the value of the measured pressure directly, witho ut using a 
coefficient.  
Within a distance corresponding to double the maximum permissible error given in Table  1, the 
movement of the pointer shall not be impeded by an index stop on either side of the zero mark or opposite 
a predetermined mark with.  
3.3.2 Digital indicating device  
Electronic tyre pressure gauges shall be equipped with a display. The height and width of the numerals 
shall be such as to ensure that the displayed data are clearly and unambiguously legible. The height of 
the displayed character s shall not be less than:  
 20 mm in the case of fixed devices (type A instruments),  
 10 mm in the case of portable devices (type B instruments),  
 6 mm in the case of handheld devices (type C instruments).  
The digital indicating device shall have a resolution of no more than 0.1  bar (10  kPa); for the purposes 
of type approval and initial and subsequent verification, the resolution may be changed to a maximum 
of 0.02  bar (2  kPa).  
3.4 Additional design requirements  
3.4.1 Maximum supply gas pressure  
Pressure gauges shall be  capable of withstanding a short -term pressure overload of up to 125  % of the 
largest value on the scale without any changes to their metrological properties.  
If the supply pressure exceeds 125  % of the largest value on the scale, the pressure gauges shall  be 
protected by an effective protective device (a safety valve, pressure reducer or relief valve).  
3.4.2 Installation position  
The installation or working position of the gauges shall either be clearly determined by the working 
position of the gauges or clearly  schematically indicated on the gauges.  
Changes in the nominal position at a plane angle of 10° shall not cause changes in indication of the 
measured quantity that are greater than 50  % of the maximum permissible error.  
3.4.3 Supply voltage  
Electronic tyre pressure gauges may be powered from the mains or replaceable batteries.  
3.5 Software  
In the case of electronic tyre pressure gauges, the software used for the gauges shall be identifiable 
(except for cases where its only function is to display the measured quantity without any other 
functions). The software shall be secured against accidental or intentional tampering and damage.  
3.6 Resistance to environmental influences  
3.6.1 Mechanical resistance  
The design of tyre pressure gauges and the materials used shall guaran tee sufficient strength, stability 
and resistance to mechanical shocks.  General Measure No  0111 -OOP -C021 -17 
6 3.6.2 Resistance to climatic conditions  
The gauges shall withstand the limit storage temperatures of –40 °C to +70  °C without damage or 
deterioration of their metrological properties.  
Tyre pressure gauges shall not be sensitive to relative humidity of the ambient air.  
3.6.3 Protection against water ingress and foreign particles (degree of protection offered by the 
cover)  
The tyre pressure gauges shall provide sufficient protection from contact wit h dangerous parts, 
infiltration of foreign particles and water ingress corresponding to the use of the gauges specified by the 
manufacturer.  
The minimum degree of protection for tyre pressure gauges intended for outdoor use shall be IP  44; the 
minimum deg ree of protection for tyre pressure gauges intended exclusively for indoor use shall be 
IP 31.  
3.6.4 Electromagnetic compatibility (EMC)  
Electronic tyre pressure gauges shall either not be affected by electrical or electromagnetic interference 
or shall respond to it in a defined manner (e.g. by reporting an error, inhibiting measurement, etc.). In 
addition, they shall not emit unwanted electromagnetic fields.  
4 Instrument markings  
4.1 In general  
Any inscriptions and markings shall be easily visible, legible and indel ible under normal working 
conditions and shall not impede reading the instrument indication.  
4.2 Inscriptions  
Tyre pressure gauges shall bear inscriptions:  
a) on the front side of the gauges (on the dial or the display, or outside the display, but close to the 
indication of the measured quantity):  
 the symbol for the measured quantity: Pe; 
 the symbol for the unit of measurement: bar or kPa;  
 where necessary, a sign indicating the working position of the instrument;  
b) on the dial, data plate or the instrument itself:  
 identification details of the manufacturer (brand or name);  
 name, type and serial number of the instrument;  
 pressure measuring range;  
 working temperature range (if other than −25  °C to +55  °C); 
 type-approval mark.  
4.3 Marking with official marks  
A suitable pl ace shall be provided for affixing the official mark(s).  
For gauges with built -in adjustment elements or means of changing their metrological parameters, the 
access to these elements shall be protected in an effective manner.  General Measure No  0111 -OOP -C021 -17 
7 The software relevant to metro logical characteristics shall be identified as such and secured to prevent 
accidental or intentional tampering and damage. The measuring instrument shall make it possible to 
readily identify the software.  
5 Type approval of the measuring instrument  
5.1 In genera l 
The type -approval process for tyre pressure gauges shall include the following tests:  
a) external inspection;  
b) functional tests:  
 accuracy test;  
 determination of hysteresis error;  
 ambient temperature impact test;  
 stability test;  
c) test of the instrument’s resistance to mechanical influences:  
 free-fall test;  
 installation position influence test;  
d) tests of resistance to environmental influences:  
 test of resistance to limit temperatures;  
 damp heat test;  
 salt spray test;  
 test of resistance to water ingress and foreign particles;  
 vibration resistance test;  
e) test of supply voltage influence;  
f) electromagnetic compatibility (EMC) tests.  
5.2 External inspection  
The purpose of external inspection of tyre pressure gauges shall be to assess:  
a) the completeness of the required technical documentation;  
b) the conformity of the metrological and technical characteristics specified by the manufacturer in 
the documentation with the technical and metrological requirements of this regulation as 
specified in Articles  2 and 3;  
c) the completeness and condition of the tyre pressure gauges according to the prescribed technical 
documentation;  
d) conformity of the software version of the tyre pressure gauges with the version specified by the 
manufacturer.  
5.3 Test conditions during type approval  
5.3.1 Test equipment requirements  
The following equipment shall be used to test metrological properties:  
 a pressure measurement standard based on an arbitrary physical principle with a measuring range 
corresponding to that of the tested gauges and with an expand ed uncertainty of measurement (for General Measure No  0111 -OOP -C021 -17 
8 k = 2) less than or equal to 1/5 of the maximum permissible error of the tested gauges as specified 
in Article  2.3; 
 a thermometer for measuring temperature during the test whose measuring range is at least ( –25 
to +55)  °C and whose indicating device has a resolution of at least 0.2  °C. 
Measuring instruments used as testing equipment shall have valid metrological traceability.  
5.3.2 Test conditions  
During the accuracy test, ambient temperature must be within the reference tempera ture range of +15  °C 
to +25  °C. Changes in ambient temperature during the period of the test may not exceed 5  °C.  
When determining hysteresis error, ambient temperature shall be constant, within the reference 
temperature range of +15  °C to +25  °C.  
For ot her tests, ambient temperature must meet the requirements for each type -approval test.  
For the accuracy test, the relative ambient humidity must be within the range of 30  % to 70  %.  
For other tests, the relative ambient humidity must meet the requirements  for each type -approval test.  
During measurement, vibrations and shocks may not cause pointer oscillation greater than 1/10 of the 
maximum permissible error specified in Article  2.3. 
The pressure in the gauges shall be generated by a non -corrosive gaseous pressure medium. Dry clean 
air or nitrogen are recommended.  
The working position of the tested gauges shall correspond to that specified by the manufacturer of the 
tyre pressure gauges (or manufacturer of the pressure gauge).  
During the test, the differenc e between the pressure level at the point of connection of the tested gauges 
and that at the point of connection of the measurement standard may not cause an error greater than 1/10 
of the maximum permissible error specified in Article  2.3. 
The tightness o f the ‘measurement standard – tested gauge’ system shall be such that a pressure drop 
while reading the indications on the measurement standard and the tested gauges may not cause an error 
greater than 1/10 of the maximum permissible error specified in Art icle 2.3. 
5.4 Functional tests  
5.4.1 Accuracy test  
The accuracy test shall be performed by taking readings at not fewer than five points distributed evenly 
over the measuring range of the tested tyre pressure gauges (including the upper and lower limits of the 
meas uring range).  
Prior to the test itself, the gauges shall be continuously loaded three times up to the upper limit of their 
measuring range.  
If the tested tyre pressure gauges are designed as deformation pressure gauges, the pressure values must 
be read after lightly tapping the casing of the gauges. The reading of values on the scale of the gauges 
must be interpolated within 1/4 to 1/10 of the distance between two scale marks.  
Every point shall be tested at increasing and decreasing pressure (except for gauges not intended for 
measuring decreasing pressures). After the increasing pressure test and prior to the decreasing pressure 
test, the gauges shall be kept at the upper limit of the measuring range at a pressure equal to the upper 
limit of the measurin g range for 10  minutes.  
Measurement errors at the individual points may not exceed the maximum permissible errors given in 
Table  1. General Measure No  0111 -OOP -C021 -17 
9 5.4.2 Determination of hysteresis error  
This test shall only be performed on instruments designed to measure decreasing pressures  in normal 
use. 
Hysteresis error shall be determined by comparing the pressure readings taken at not fewer than five 
points (including points at the upper and lower limits of the measuring range) distributed evenly over 
the measuring range, at increasing a nd decreasing pressure.  
Prior to the pressure drop, the tyre pressure gauges must be kept at a pressure equal to the upper limit of 
the measuring range for 10  minutes.  
The hysteresis error may not exceed the absolute value of the maximum permissible error given in 
Table  1. 
5.4.3 Ambient temperature impact test  
The test consists of performing accuracy tests according to Article  5.4.1  at the following temper atures:  
 reference temperature (+20  °C); 
 lower limit of the temperature range (unless equal to −10  °C); 
 –10 °C; 
 0 °C; 
 +40 °C; 
 upper limit of the temperature range (unless equal to +40  °C); 
 reference temperature (+20  °C). 
During the test at the reference temperature, measurement errors at the individual test points may not 
exceed the maximum permissible error given in Table  1. For other tests, measurement errors at the 
individual test points may not exceed the maximum permissible error given in Table  2. 
5.4.4 Test of the stability of properties  
During the stability test, the tyre pressure gauges shall be subjected to:  
a) a pressure exceeding the upper limit of the measuring range by 25  % for 15 minutes;  
b) 10,000 cycles of a pressure varying slowly from approximately 20 % to approximately 90  % of 
the upper limit of the measuring range at a frequency not exceeding 60 cycles per minute.  
On completion of the tests referred to in points (a) and (b), the tyre pressure gauges shall be left to stand 
for one hour, after which the test referred to in Article  5.4.1  shall be performed; the gauges must meet 
the requirements set out in Articles  2.3, 2.5 and 2.6. 
5.5 Tests of resistance to mechanical influences  
5.5.1 Free -fall test  
During the free -fall test, the tested gauges shall be allowed to fall freely from a height specified below 
onto a concrete test surface.  
For type B tyre pressure gauges, 10 free falls from a height of 250  mm above the test surface and, for 
type C gauges, 10 free falls from a height of 500  mm, shall be performed.  
The gauges shall be checked for changes in appearance immediately after the fre e falls. No changes in 
indication may occur after the test. When one hour has elapsed after the completion of the test, the 
gauges shall must the requirements set out in Articles  2.3, 2.5 and 2.6 when tested within the reference 
temperature range.  General Measure No  0111 -OOP -C021 -17 
10 5.5.2 Installation position influence test  
The installation position influence test shall be performed for type A and B gauges by taking pressure 
readings in the prescribed installation position and wi th the gauges tilted by ±10°.  
Pressure indication changes may not exceed 50  % of the maximum permissible error given in Table  1. 
5.6 Tests of resistance to environmental influences  
5.6.1 Test of resistance to limit temperatures  
The complete tyre pressure gauge, under no pressure load, must be placed in a climatic chamber for a 
period of at least 24  hours at both limit temperatures – –40 °C and +70  °C. 
Immediately after the completion of the test, it shall be checked for changes in appearance. The 
appearance of th e gauge may not be changed and the material and surface may not be cracked, swollen 
or changed in colour.  
When three hours have elapsed after the completion of the test, the gauge must meet the requirements 
set out in Articles  2.3, 2.5 and 2.6 when tested within the reference temperature range.  
5.6.2 Damp heat test  
The test using cyclic damp heat (12  h + 12  h) shall be performed in two cycles with the lower 
temperature limit at +55  °C or +40  °C, depending on the gauge’s temperature range according to 
Article  2.1. The gauge’s air inlet must be closed during the test.  
Immediately after th e test, the gauge shall be checked for changes in appearance.  
After three hours have elapsed, the gauge must meet the requirements set out in Articles  2.3 and 2.6 
when tested within the reference temperature range.  
5.6.3 Salt spray test  
The salt spray test shall be performed for a period of 48  hours. The gauge’s air inlet must be closed 
during the test.  
Imme diately after the test, the gauge shall be checked for changes in appearance.  
When one hour has elapsed after the completion of the test, the gauge must meet the requirements set 
out in Articles  2.3 and 2.6 when tested within the reference temperature range.  
5.6.4 Test of protection against water in gress and foreign particles (degree of protection offered 
by the cover)  
This test shall examine whether the gauges comply with the degree of protection specified by the 
manufacturer according to Article  3.6.3 . 
5.6.5 Vibration resistance test  
This test shall examine the influence of random vibrations on the gauges.  
The gauges shall be exposed to the effects of random vibrations in three axes perpendicular to each 
other. The gauges shall be exposed to the effects of vibrations for a period of at least 2  minutes along 
each axis. During the test, the gauges shall be con nected to a solid holding device using standard 
connecting elements.  
Parameters of the vibration resistance test:  
 total frequency range:  10 Hz to 150  Hz; 
 total RMS level:  7 m∙s−2; 
 spectral density acceleration within the range of 10  Hz to 20  Hz: 1 m2∙s−3; General Measure No  0111 -OOP -C021 -17 
11  spectral density acceleration within the range of 20  Hz to 150  Hz: –3 dB/octave.  
During the test, the gauges shall be exposed to an overpressure of 200  kPa and the requirement specified 
in Article  2.3 must be met throughout the test.  
After completing the test, the gauge must meet the requirements set out in Articles  2.3 and 2.6 when 
tested within the reference temperature range.  
5.7 Test of supply voltage influence  
The test of supply voltage influence shall be performed for electronic tyre pressure gauges for a given 
pressure, under the reference conditions and with supply voltage sequentially set to:  
a) Umax = 1.1UN and Umin = 0.85UN for mains -powered electronic tyre pressure gauges with single 
nominal supply voltage UN; 
b) Umax = 1.1 UN2 and Umin = 0.85UN1 for mains -powered  electronic tyre pressure gauges with 
nominal voltage range between the lower limit value UN1 and the upper limit value UN2; 
c) Umax = Ubat.max  and Umin = Ubat.min  for battery -powered electronic tyre pressure gauges, where 
Ubat.min  is the battery’s lowest operating voltage as specified by the supplier of the gauges for 
ambient temperature of 20  °C, and Ubat.max  is the voltage of a new battery under zero load.  
In the case of battery -powered electronic tyre pressure gauges, low batter y voltage must be indicated if 
the voltage falls outside the nominal range specified by the manufacturer.  
During testing, the gauges must exhibit normal function within the limits of the maximum permissible 
error given in Table  1. 
5.8 Electromagnetic compatib ility (EMC) tests  
EMC tests shall be performed for electronic tyre pressure gauges. When tested for EMC, the gauges 
shall be exposed to a pressure of approximately 2  bars (200  kPa). When tested for EMC, the tyre 
pressure gauges are allowed to behave as fol lows:  
 the gauges exhibits normal function within the limits of the maximum permissible error given in 
Table  1, or 
 the indications on the gauges cannot be interpreted as measurement results due to intermittent 
variations, etc., or measurement is inhibited d ue to an error message, for example.  
After the EMC tests, the gauges must exhibit normal function within the limits of the maximum 
permissible error given in Table  1. 
5.8.1 Immunity to voltage dips and short interruptions  
The supply voltage is reduced to 75  % of the nominal supply voltage for a period of 5  seconds. In order 
to rule out transients, the ramp -up period should not be shorter than 100  ms. 
For DC -powered devices, the interruptions must last 5  ms, 20  ms, 100  ms and 500  ms. 
For AC -powered devices, dips always begin when the voltage crosses the zero point, sequentially before 
both the positive and negative cycle. The interruptions shall last for 1, 5, 10, and 25  AC voltage cycles.  
5.8.2 Immunity to electrical fast transient/burst disturbances  
Immunity to electrical fast transient/burst disturbances shall be tested with the gauges switched on using 
the following voltages:  
±2 kV on the terminals for connecting AC or DC mains;  
±1 kV on terminals for connecting signal and control lines longer than 3  m.  
The im pulse repetition frequency shall be 5  kHz, the burst disturbance repetition interval shall be 
300 ms, the total duration of the test for each input and impulse polarity shall be at least 1 minute.  General Measure No  0111 -OOP -C021 -17 
12 5.8.3 Immunity to electrostatic discharge  
Immunity to electrostat ic discharge shall be tested with the gauges switched on, preferably using a 6  kV 
contact discharge or an 8  kV air discharge. The discharges shall be applied to the enclosure of the gauges 
or a coupling plane adjacent to the tyre pressure gauges.  
5.8.4 Immunity to surges  
Immunity to surges shall be tested with the gauges switched on, with a surge of tr/th = 1.2/50 (8/20) µs 
at the following voltages:  
±1 kV asymmetrical or 0.5  kV symmetrical, on signal and control lines longer than 30  m; 
±2 kV asymmetrical and ±1  kV symmetrical on AC or DC mains inputs.  
5.8.5 Immunity to voltage dips and short interruptions  
Immunity to voltage dips, short interruptions and slow voltage variations on AC mains inputs with an 
input current of less than 16  A shall be tested with the gauges switched on, by applying a supply voltage 
dip to:  
0 % of the nominal voltage for 0.5 periods;  
0 % of the nominal voltage for 1 period;  
70 % of the nominal voltage for 25 periods.  
Each of the above disturbances shall be applied ten times at an interval of 1 0 s. 
5.8.6 Immunity to a radiated radio -frequency electromagnetic field  
Immunity to a radiated radio -frequency electromagnetic field shall be tested with the gauges switched 
on, within the following frequency ranges:  
80 MHz to 800  MHz, with test field intensity  amplitude of 3  V/m;  
800 MHz to 960  MHz, with test field intensity amplitude of 10  V/m;  
960 MHz to 1,400  MHz, with test field intensity amplitude of 3  V/m;  
1,400  MHz to 2,000  MHz, with test field intensity amplitude of 10  V/m;  
2,000  MHz to 2,700  MHz, with test field intensity amplitude of 1  V/m.  
The test field intensity amplitude values given above are for measurement without modulation. The test 
field shall be amplitude modulated to a depth of 80  % and the modulation signal shall have a sinusoidal 
waveform  with a modulation frequency of 1  kHz. The frequency step when sweeping the test field shall 
be no more than 1  %; the delay period for each frequency may not be less than the time needed to 
examine the tested instrument or for the tested instrument to reac t to the disturbances; however, it may 
never be less than 0.5 seconds. The test field shall be applied to all sides of the enclosure of the tyre 
pressure gauge.  
5.8.7 Immunity to conducted disturbances induced by radio -frequency fields  
Immunity to conducted dist urbances induced by radio -frequency fields shall be tested with the gauges 
switched on, within the frequency range of 150  kHz to 80  MHz, at an open -circuit test voltage amplitude 
of 3 V. The disturbances shall be applied to signal lines longer than 3  m, al l mains inputs and outputs 
and all connections to the functional earthing.  
The open -circuit test voltage amplitude given above is for measurement without modulation. The test 
voltage shall be amplitude modulated to a depth of 80  % and the modulation signal  shall have a 
sinusoidal waveform with a modulation frequency of 1  kHz. The frequency step when sweeping the test 
field shall be no more than 1  %; the delay period for each frequency shall not be less than the time 
needed to examine the tested gauges or fo r the tested gauges to react to disturbances; however, in no 
case may it be less than 0.5 seconds.  General Measure No  0111 -OOP -C021 -17 
13 6 Initial verification  
Initial verification shall follow a procedure identical to that used for subsequent verification referred to 
in Article  7. 
Tyre pressure gauges that have undergone EEC type approval and that carry the EEC type -approval 
mark and have a valid EEC type -approval certificate shall be subject to initial EEC verificati on pursuant 
to separate legislation3 prior to being put into circulation. Initial EEC verification shall follow a 
procedure identical to that used for subsequent verification referred to in Article  7. 
7 Subsequent verification  
The following tests shall be performed when carrying out subsequent verification of road vehicle tyre 
pressure gauges:  
a) visual inspection;  
b) functional tests:  
 accuracy test;  
 determi nation of hysteresis error.  
7.1 Visual inspection  
The purpose of the visual inspection is to check that:  
a) the gauges submitted for verification conforms to the approved type;  
b) the gauges are not mechanically damaged, none of its parts are loose and there are no  signs of 
corrosion on the gauges;  
c) the content and implementation of markings and inscriptions correspond to the information and 
requirements specified in the type -approval certificate for the gauges.  
If the gauges fail to meet visual inspection requiremen ts, no further tests are performed.  
7.2 Test conditions during verification  
7.2.1 Test equipment  
The following equipment must be used to test metrological properties:  
 a pressure measurement standard based on an arbitrary physical principle with a measuring range 
corresponding to that of the tested gauges and with an expanded uncertainty of measurement (for 
k = 2) less than or equal to ¼ of the maximum permissible error of the tested gauges as specified 
in Article  2.3; 
 a thermometer for measuring temperature during the test whose measuring range is at least ( –10 
to +40)  °C and whose indicating device has a resolution of at least 0.2  °C. 
7.2.2 Test conditions  
The requirements pu rsuant to Article  5.3.2  et seq. shall apply to verification tests.  
During the accuracy test and determination of hysteresis error, the ambient temp erature range shall be 
extended to –10 °C to +40  °C. Changes in ambient temperature during the period of the tests shall not 
exceed 5  °C. 
                                                      
3  Implementing Decree No  332/2000 establishing certain procedures for type approval and verificatio n of 
specified measuring instruments bearing the EEC mark, as amended.  General Measure No  0111 -OOP -C021 -17 
14 The requirement relating to relative ambient humidity shall not apply during verification.  
The working position of the  tested gauges must correspond to that specified by the manufacturer or to 
the position specified in the type -approval certificate for the tyre pressure gauges.  
7.3 Functional tests  
7.3.1 Accuracy test  
The accuracy test shall be performed using the method referred t o in Article  5.4.1 . 
Instrument errors at the individual points may not exceed:  
 the maximum permissible errors given in Table  1, when measuring within the reference ambient 
temperature between +15  °C and +25  °C, or  
 the maximum permissible errors given in Table  2, when measuring within the ambient 
temperature ranges of −10  °C to +15  °C and +25  °C to +40  °C. 
7.3.2 Determination of hysteresis error  
Hystere sis error shall be determined using the method referred to in Article  5.4.2 . 
The difference between the values indicated by the tested gauges at th e same pressure test point while 
increasing and decreasing pressure (hysteresis error Δ H) may not exceed the maximum permissible error 
of the gauges specified in Article  2.3.  
8 Measuring instrument examination  
When examining measuring instruments pursuant to §  11a of the Metrology Act at the request of a 
person who may be affected by incorrect measurement, the procedure under Chapter  7 shall be follow ed, 
except for the last sentence of Article  7.1. The maximum permissible error used shall be 1.25 times the 
maximum permissible errors referred to in Chapter  7. 
9 Notified standards  
For the purposes of specifying the metrological and technical requirements f or measuring instruments 
and specifying the testing methods for their type approval and verification arising from this general 
measure, the CMI shall notify Czech technical standards, other technical standards or technical 
documents of international or for eign organisations, or other technical documents containing more 
detailed technical requirements (hereinafter ‘notified standards’). The CMI shall publish a list of these 
notified standards attached to the relevant measures, together with the general measu re, in a manner 
accessible to the public (on www.cmi.cz ). 
Compliance with notified standards or parts thereof is considered, to the extent and under the conditions 
stipulated by a general measure, to be compliance with  the requirements stipulated by this measure to 
which these standards or parts thereof apply.  
Compliance with notified standards is one way of demonstrating compliance with the requirements. 
These requirements may also be met by using another technical sol ution guaranteeing an equivalent or 
higher level of protection of legitimate interests.  General Measure No  0111 -OOP -C021 -17 
15 II. 
REPEALING AND TRANSI TIONAL PROVISIONS  
General Measure number: 0111 -OOP -C021 -11, laying down the metrological and technical 
requirements for specified measuring instruments, including the testing methods for type approval and 
verification of the following specified instruments: ‘Road motor vehicle tyre pressure gauges, except 
for pressure gauges used exclusively for the measurement of tyre pressure by motor vehicl e users’ is 
hereby repealed.  
III. 
G R O U N D S 
The CMI has issued this General Measure laying down metrological and technical requirements for 
specified measuring instruments and tests for type approval and verification of specified measuring 
instruments – tyre pressure gauges for road motor vehicle – pursuant to §  14(1)(j) of the Metrology Act, 
to implement §  6(2), §  9(1) and (9) and §  11a(3) of the Metrology Act.  
Under item 2.3.3 in the Annex ‘List of the Types of specified Measuring Instruments’ to Implementing 
Decree No  345/2002 specifying the measuring instruments whose verification is mandatory and 
measuring instruments subject to type approval, as amended, thi s type of measuring instruments is 
classified as an instrument subject to mandatory verification.  
This legislation (General Measure) will be notified in accordance with Directive (EU) 2015/1535 of the 
European Parliament and of the Council of 9  September  2015 laying down a procedure for the provision 
of information in the field of technical regulations and of rules on Information Society services.  
IV. 
I N S T R U C T I O N S 
In accordance with §  172(l) APC, in conjunction with §  39(l) APC, the CMI has stip ulated a time limit 
for comments of 30  days from the date of posting the draft on the official notice board. Comments 
submitted after this time limit will not be considered.  
The persons concerned are hereby invited to comment on this draft general measure . In light of the 
provisions of §  172(4) APC, the comments are to be submitted in written form.  
Pursuant to the provisions of §  174(1) APC, in conjunction with the provisions of §  37(1) APC, it must 
be clearly stated who is submitting the comments, which g eneral measure the comments concern, how 
the draft contradicts legislation or how the general measure is inaccurate. The comments must also 
contain the signature of the person making the comments.  
The supporting documents for this draft general measure ma y be consulted at the Czech Metrology 
Institute, Legal Metrology Department, Okružní 31, 638 00 Brno, after making arrangements by 
telephone.  
This draft general measure shall be posted for 15  days.  
 
 ................................ .......................   
RNDr. Pavel Klenovský m.p.  
Director General  
 General Measure No  0111 -OOP -C021 -17 
16 Person res ponsible for accuracy: Mgr. Tomáš Hendrych  
Posted on: 1  June 2018   
Signature of the authorised person confirming posting:  Mgr. Tomáš Hendrych m.p.