Metrologi och mätning. Fysikaliska fenomen

Kommittébeteckning: SIS/TK 424 (Kemiska vattenundersökningar)
Källa: CEN
Svarsdatum: den 14 okt 2018
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This document specifies a method for the measurement of 99Tc in all types of waters by liquid scintillation counting (LSC).

The method is applicable to test samples of supply/drinking water, rainwater, surface and ground water, as well as cooling water, industrial water, domestic, and industrial wastewater after proper sampling and handling, and test sample preparation. A filtration of the test sample is necessary.

The detection limit depends on the sample volume and the instrument used. The method described in this standard, using currently available LSC counters, has a detection limit of approximately 5 Bq·kg-1 to 20 Bq·kg-1, which is lower than the WHO criteria for safe consumption of drinking water (100 Bq·l-1). These values can be achieved with a counting time of 30 min for a sample volume varying between 14 ml to 40 ml. The method presented in this standard is not intended for the determination of ultra-trace amount of 99Tc.

The activity concentration values in this document are expressed by sample mass unit instead of sample volume unit as it is usually the case in similar standards. The reason is that 99Tc is measured in various matrix types such as fresh water or sea water, which have significant density differences. The activity concentration values can be easily converted to sample volume unit by measuring the sample volume. However, it increases the uncertainty on the activity concentration result.

The method described in this standard is applicable in the event of an emergency situation, but not if 99mTc is present at quantities that could cause interference and not if 99mTc is used as a recovery tracer.

The analysis of Tc adsorbed to suspended matter is not covered by this method.

It is the user’s responsibility to ensure the validity of this test method for the water samples tested.

Kommittébeteckning: SIS/TK 424 (Kemiska vattenundersökningar)
Källa: CEN
Svarsdatum: den 14 okt 2018
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This document specifies a method for the measurement of 99Tc in all types of waters by inductively coupled plasma mass spectrometry (ICP-MS).

The method is applicable to test samples of supply/drinking water, rainwater, surface and ground water, as well as cooling water, industrial water, domestic, and industrial wastewater. A filtration of the test sample is necessary.

The detection limit depends on the sample volume and the instrument used. The method described in this standard, using currently available ICP-MS, has a detection limit of approximately 0,2 ng·kg-1 to 0,5 ng·kg-1 (0,1 Bq·kg-1 to 0,3 Bq·kg-1), which is much lower than the WHO criteria for safe consumption of drinking water (100 Bq·l-1). The method presented in this standard is not intended for the determination of ultra-trace amount of 99Tc.

The mass concentration values in this document are expressed by sample mass unit instead of sample volume unit as it is usually the case in similar standards. The reason is that 99Tc is measured in various matrix types such as fresh water or sea water, which have significant density differences. The mass concentration values can be easily converted to sample volume unit by measuring the sample volume. However, it increases the uncertainty on the mass concentration result.

The method described in this standard is applicable in the event of an emergency situation, but not if 99mTc is present at quantities that could cause interference.

The analysis of Tc adsorbed to suspended matter is not covered by this method.

It is the user’s responsibility to ensure the validity of this test method for the water samples tested.

Ämnesområden: Flöde i öppen kanaler
Kommittébeteckning: SIS/TK 432 (Hydrometri)
Källa: ISO
Svarsdatum: den 15 okt 2018
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ISO 18320 specifies methods of determining the stage-discharge relationship for a gauging station. A

sufficient number of discharge measurements, complete with corresponding stage measurements, are

required to define a stage-discharge relationship to the accuracy required by this Standard.

Stable and unstable channels are considered, including brief descriptions of the effects on the

stage-discharge relationship of the transition from inbank to overbank flows, shifting controls, variable

backwater and hysteresis. Methods of determining discharge for twin-gauge stations, ultrasonic

velocity-measurement stations, electromagnetic velocity-measurement stations and other complex

rating curves are not described in detail. These types of rating curves are described separately in other

International Standards, Technical Specifications and Technical Reports, which are listed in the

Bibliography.

Kommittébeteckning: SIS/TK 110 (Akustik och buller)
Källa: ISO
Svarsdatum: den 20 okt 2018
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This document specifies methods for calculating monopole source levels by converting radiated noise level values obtained in deep water according to ISO 17208-1, or directly from measurements made in deep water with specific hydrophone geometry. For measurements made in deep water according to ISO 17208-1, a fitted Formula is provided to correct the radiated noise level values obtained in this document to convert source level. The conversion Formulas is derived based on the assumption that the surface is a perfect pressure release boundary.

Kommittébeteckning: SIS/TK 424 (Kemiska vattenundersökningar)
Källa: CEN
Svarsdatum: den 6 nov 2018
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The document specifies the determination of radium-226 (226Ra) and radium-228 (228Ra) activity concentrations in drinking water samples by chemical separation of radium and its measurement using liquid scintillation counting. 226Ra and 228Ra are present in the environment as radionuclides from the 238U and 232Th decay series, as shown in Annex A.

The test method applies to the analysis of 0,5 kg of drinking water containing less than 100 mg/kg barium. If the barium concentration is higher than 100 mg/kg, it is recommended to reduce the volume of the test sample to be analysed so that the total content of barium in the sample does not exceed 50 mg.

Activity concentrations of 226Ra and 228Ra can vary widely according to local geological and climatic characteristics. 226Ra activity concentration range from some mBq/l in surface waters up to several tens of Bq/l in some natural groundwaters[8]; the guidance level for 226Ra in drinking water as recommended by WHO is 1 Bq/l[3][9]. 228Ra activity concentration range from a few mBq/l in surface waters up to several Bq/l in some natural groundwaters[8]; the guidance level for 228Ra in drinking water as recommended by WHO is 0,1 Bq/l[3][9].

Activity concentrations of 226Ra and 228Ra which can be measured by this test method utilizing currently available liquid scintillation counters goes down to 0,01 Bq/kg for 226Ra and 0,06 Bq/kg for 228Ra for a 0,5 kg sample mass and a 1 h counting time in a low background liquid scintillation counter.[10]

NOTE Adjustment of the test sample mass and counting time can lead to lower detection limits. As an example, a limit of detection of 0,04 Bq/kg can be achieved for 228Ra using a 0,5 kg test sample and a 2 h counting time; similarly a limit of detection of 0,02 Bq/kg can be achieved for 228Ra using a 1 kg test sample and a 2 h counting time.

The test method can be used for the fast detection of contamination of drinking water by radium in emergency situations or for routine environmental monitoring purposes.

Kommittébeteckning: SIS/TK 189 (Innemiljö och energianvändning i byggnader)
Källa: CEN
Svarsdatum: den 18 nov 2018
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This document specifies definitions, requirements and test methods for thermostatic radiator valves referred to hereafter as thermostatic valves.

This standard applies to two port thermostatic valves with or without pre-setting facility and thermostatic integrated valves with or without pre-setting facility for fitting to radiators in wet central heating installations up to a water temperature of 120 °C and a nominal pressure of PN 10.

This standard further specifies the dimensions, the materials and the connection details of four series of straight and angle pattern thermostatic radiator valves of nominal pressure ≤ PN 10.

This standard can be used as reference in a CEN/CENELEC Certification Mark System on thermostatic radiator valves.