R137/2012-A-NL1-25.06 Rev. 0
OIML Certificate
OIML Member State The Netherlands
Number R137/2012-A-NL1-25.06 revision 0 Project number 4023314 Page 1 of 4
Issuing authority
NMi Certin B.V. Person responsible: M.Ph.D. Schmidt
Applicant and Manufacturer
Transus Instruments B.V. Bloesemlaan 4 3897 LN Zeewolde The Netherlands
Identification of the certified type
An Ultrasonic Gas Meter
Manufacturers mark: Type:
Transus Instruments B. V. LPM-zD
Characteristics
See following pages
This OIML Certificate is issued under scheme A.
This Certificate attests the conformity of the above identified type (represented by the sample(s) identified in the OIML Type Evaluation Report) with the requirements of the following Recommendation of the International Organization of Legal Metrology (OIML):
R 137-1:2012 "Gas meters"
Accuracy class
This Certificate relates only to the metrological and technical characteristics of the type of measuring instrument covered by the relevant OIML International Recommendation identified above. This Certificate does not bestow any form of legal international approval.
Important note: Apart from the mention of the Certificate's reference number and the name of the OIML Member State in which the Certificate was issued, partial quotation of the Certificate and of the associated OIML Type Evaluation Report(s) is not permitted, although either may be reproduced in full.
Issuing Authority
NMi Certin B.V., OIML Issuing Authority NL1 17 November 2025
Certification Board
This document is issued under the provision that no liability is accepted and that the applicant shall indemnify third-party liability.
OIML Certificate
Number R137/2012-A-NL1-25.06 revision 0 Project number 4023314 Page 2 of 4
The conformity was established by the results of tests and examinations provided in the associated report(s):
No. NMi-3628146-01 dated 17 November 2025 that includes 56 pages.
Characteristics of the measuring instrument
In Table 1 the general characteristics of the measuring instrument are presented.
In Table 2 the characteristics of the family of instruments are presented.
The construction of the measuring instrument is recorded in the Documentation folder no. T13135-1.
Table 1 General characteristics
| Destined for the measurement of | Gas Volume |
| Intended for the measurement of | Natural Gas |
| Accuracy class | 1,0 |
| Minimum-maximum flow rate | See table 2 |
| Minimum-maximum pressure | 1-20 bar(a) |
| Ambient temperature range | -25-+55℃;Condensing humidity |
| Gas temperature range | -25-+55℃ |
| Designed for | Condensing humidity |
| Orientation | All orientations |
| Flow direction | Uni-Directional-forward |
| Environmental classes | M1/E2 |
| Transducer | Transducer types L3-253-path250kHz |
| Path angle | 60° |
| Inlet/Outlet Piping | 0D/0D |
| Power supply voltage | External14-28VDCpower supplyor a14,4VDCbattery.When powered by external14-28VDCpower supply,the internal battery pack is available as abackup power supply.During a power failure theinternal battery keeps the meter running. |
| Software identification | See table3 |
OIML Certificate
OIML Member State The Netherlands
Number R137/2012-A-NL1-25.06 revision 0 Project number 4023314
Page 3 of 4
Table 2 Flow characteristics of the gas meter
| Meter Size | Internal flow channel bore diameter | Minimum flow velocity $V_{\min}$ | Minimum Transitional flow velocity $V_{t}$ | Maximum flow velocity $V_{\max}$ | |
| Inch | DN | [mm] | [m/s] | [m/s] | [m/s] |
| 2" | DN50 | 43 | 0,2 | 3,5 | 35 |
| 3" | DN80 | 66 | |||
| 4" | DN100 | 84 | |||
| 6" | DN150 | 105 | |||
The corresponding flow rates can be calculated as follows:
Q=v $ \cdot \frac{1}{4} \cdot \pi \cdot D^{2} \cdot 3 6 0 0 $
Where:
Q = flow rate [m $ ^{3} / \mathrm{h} ]$
v = velocity [m/s]
D = internal flow channel bore diameter [m].
Note:
If higher values are chosen for $ Q_{\min} $ or $ Q_{t} $ and/or lower values for $ Q_{\max} $ it has to be taken into account that:
If ratio 5 $ \leq $ Qmax:Qmin $ < $ 50 then ratio Qmax:Qt $ \geq $ 5
If ratio Qmax:Qmin $ \geq 5 0 $ then ratio Qmax:Qt $ \geq 1 0 $
Table 3 Software identification of the gas meter
| SW identifier | Version | CRC |
| Firmware/FPGA | 1.3.0.92/01.00.01.16 | 0x38860BC1 |
The software versions can be read out on the gas meter display by navigating Menu $ \rightarrow $ System Info.
Installation conditions:
Installation requirements
Any components which could affect the gas flow must be avoided within the prescribed inlet pipe length of 0 DN and at least 3 DN for the outlet pipe length. The inlet and outlet pipe must be designed as a straight pipe section of the same nominal diameter as the gas meter.
OIML Certificate
OIML Member State The Netherlands
Number R137/2012-A-NL1-25.06 revision 0 Project number 4023314
Page 4 of 4
Certificate history:
| Revision | Date | Description of the modification |
| 0 | 17 November 2025 | - Initial - Parallel certificate of R137/2012-A-NL1-25-05 issued by NMi. |