EN 17277:2019
(Main)Hydrometry - Measurement requirements and classification of rainfall intensity measuring instruments
Hydrometry - Measurement requirements and classification of rainfall intensity measuring instruments
This document considers liquid atmospheric precipitation and defines the procedures and equipment to perform laboratory and field tests, in steady-state conditions, for the calibration, check and metrological confirmation of liquid precipitation measurement instruments. It provides a classification of catching-type measurement instruments based on their laboratory performance. The classification does not relate to the physical principle used for the measurement, nor does it refer to the technical characteristics of the instrument assembly, but is solely based on the instrument calibration. Attribution of a given class to an instrument is not intended as a high/low ranking of its quality but rather as a quantitative standardized method to declare the achievable measurement accuracy in order to provide guidance on the suitability for a particular purpose, while meeting the user’s requirements.
Hydrometrie - Messbedingungen und Klassifizierung von Geräten zur Messung der Regenintensität
Dieses Dokument berücksichtigt flüssigen atmosphärischen Niederschlag und legt Verfahren und Ausrüstung zur Durchführung von Labor und Feldprüfungen unter stationären Bedingungen für die Kalibrierung, Prüfung und metrologische Bestätigung von Geräten zur Messung von flüssigem Niederschlag fest. Es enthält eine Klassifizierung von Messgeräten mit Auffangvorrichtung, basierend auf ihrer Leistung im Labor. Die Klassifizierung bezieht sich weder auf das für die Messung verwendete physikalische Prinzip noch auf die technischen Eigenschaften der Gerätebaugruppe, sondern basiert alleine auf der Gerätekalibrierung. Die Zuordnung einer bestimmten Klasse zu einem Gerät ist nicht als Einstufung der Qualität in hochrangig oder niederrangig vorgesehen, sondern eher als quantitatives standardisiertes Verfahren, um die erreichbare Messgenauigkeit anzugeben und somit Leitlinien zur Eignung für einen bestimmten Zweck zu geben und gleichzeitig die Anforderungen des Nutzers zu erfüllen.
Hydrométrie - Exigences de mesure et classification des instruments de mesure d'intensité pluviométrique
Le présent document couvre les précipitations atmosphériques liquides et définit les modes opératoires et l’équipement permettant d’effectuer des essais en laboratoire et sur le terrain, dans des conditions stables, pour l’étalonnage, le contrôle et la confirmation métrologique des instruments de mesure des précipitations liquides. Il fournit une classification des pluviomètres collecteurs d’après leurs performances en laboratoire. La classification ne concerne ni le principe physique utilisé pour le mesurage, ni les caractéristiques techniques de l’ensemble de l’instrument, mais uniquement l’étalonnage de l’instrument. L’attribution d’une classe à un instrument n’est pas destinée à servir de classement de sa qualité mais plutôt de méthode quantitative normalisée pour déclarer l’exactitude de mesure atteignable afin de fournir des recommandations sur l’adéquation avec un objectif particulier, tout en satisfaisant aux exigences de l’utilisateur.
Hidrometrija - Merilne zahteve in razvrstitev instrumentov za merjenje moči padavin
Ta standard obravnava tekoče padavine in določa razvrstitev instrumentov za merjenje moči padavin s posodo za zbiranje padavin na podlagi usposobljenosti laboratorija. Standardizirani preskusi umerjanja so opisani za oceno točnosti teh naprav za merjenje količine padavin v laboratoriju in na terenu. Razvrstitev ni povezana s fizikalnim načelom, ki se uporablja za merjenje, prav tako se ne navezuje na tehnične lastnosti sestava merilnih instrumentov. Razvrstitev temelji izključno na točnosti umerjanja naprave za merjenje moči padavin.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2019
Hidrometrija - Merilne zahteve in razvrstitev instrumentov za merjenje moči
padavin
Hydrometry - Measurement requirements and classification of rainfall intensity
measuring instruments
Messung der Regenintensität - Messbedingungen und Klassifizierung für auffangende
Regenmesser
Hydrométrie - Exigences de mesure et classification des instruments de mesure
d'intensité pluviométrique
Ta slovenski standard je istoveten z: EN 17277:2019
ICS:
07.060 Geologija. Meteorologija. Geology. Meteorology.
Hidrologija Hydrology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 17277
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2019
EUROPÄISCHE NORM
ICS 07.060
English Version
Hydrometry - Measurement requirements and
classification of rainfall intensity measuring instruments
Hydrométrie - Exigences de mesure et classification Messung der Regenintensität - Messbedingungen und
des instruments de mesure d'intensité pluviométrique Klassifizierung für auffangende Regenmesser
This European Standard was approved by CEN on 19 August 2019.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17277:2019 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 User requirements for RI measurements . 8
5 Measurement of RI . 8
6 Classification of RI gauges . 10
Bibliography . 18
European foreword
This document (EN 17277:2019 ) has been prepared by Technical Committee CEN/TC 318
“Hydrometry”, the Secretary of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by April 2020, and conflicting national standards shall be
withdrawn at the latest by April 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been developed from the following:
— CEN/TR 16469:2013 Measurement of the rainfall intensity: requirements, calibration methods
and field measurements,
— UNI 11452:2012 Hydrometry - Liquid precipitation intensity: measurements requirements and
calibration methods for catching-type gauges
— BS 7843-3:2012 Code of practice for the design and manufacture of storage and automatic
collecting rain gauges
— WMO Guide to Meteorological Instruments and Methods of Observation, WMO-n. 8, ed. 2014
(updated 2017). ISBN 978-92-63-10008-5.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Introduction
Precipitation gauges are one of the basic components of world hydro-metrological networks. A
requirement for more accurate instruments is crucial for many applications including water resources
management, public safety and disaster mitigation.
This standard provides a consistent process for classification of catching type rainfall intensity gauges
in laboratory conditions.
This standard will allow users to buy and use a rainfall intensity gauge knowing that it will perform to a
specific class of performance before it is deployed to the field.
1 Scope
This document considers liquid atmospheric precipitation and defines the procedures and equipment
to perform laboratory and field tests, in steady-state conditions, for the calibration, check and
metrological confirmation of liquid precipitation measurement instruments. It provides a classification
of catching-type measurement instruments based on their laboratory performance. The classification
does not relate to the physical principle used for the measurement, nor does it refer to the technical
characteristics of the instrument assembly, but is solely based on the instrument calibration.
Attribution of a given class to an instrument is not intended as a high/low ranking of its quality but
rather as a quantitative standardized method to declare the achievable measurement accuracy in order
to provide guidance on the suitability for a particular purpose, while meeting the user’s requirements.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN ISO 10012:2003, Measurement management systems - Requirements for measurement processes and
measuring equipment ISO 10012:2003)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
precipitation (snowfall and rainfall)
the liquid or solid product of the condensation of water vapour falling from clouds or deposited from air
onto the ground; it includes rain, hail, snow, dew, rime, hoar frost and fog precipitation
Note 1 to entry: The total amount of precipitation that reaches the ground in a stated period is defined “rainfall”
when precipitation is liquid and “snowfall” when the precipitation is snow.
Note 2 to entry: Rainfall (total amount of liquid precipitation) is expressed in terms of the vertical depth of water
(usually in millimetres, mm) to which it would cover a horizontal projection of the Earth’s surface.
Note 3 to entry: Snowfall (total amount of snow) is expressed in terms of the vertical depth of water equivalent to
which it would cover a horizontal projection of the Earth’s surface. Snowfall is also expressed by the depth of
fresh, newly fallen snow covering an even horizontal surface.
[SOURCE: WMO no.8 “CIMO Guide” Part I Chap. 6 new edition 2014]
3.2
rainfall intensity
RI
the amount of liquid precipitation (rainfall) collected per unit time interval; due to its variability from
minute to minute, RI is measured or derived (from the measurement of the amount) over 1 minute time
intervals and the measurement units are vertical depth of water per hour, usually in millimetres per
−1
hour or mm h
Note 1 to entry: The RI is derived or measured directly using only rainfall intensity gauges (see definition 3.4).
[SOURCE: WMO no.8 “CIMO Guide” Part I Chap. 6 new edition 2014]
3.3
catching type rain gauge
rain gauge which collects precipitation through an orifice, often a funnel, of well-defined size and
measures its water equivalent, volume, mass or weight that has been accumulated in a certain amount
of time
Note 1 to entry: This type of gauge includes storage, level monitoring, tipping bucket and weighing rain gauges.
These are the most common type of recording rain gauge in use in operational networks at the time of preparing
this text.
3.4
rainfall intensity gauge
RI gauge
automatic recording rain gauge which measures RI at a resolution of at least one minute
3.5
delay time of the output of a RI gauge
possible time delay between the output signal of a RI gauge and the time when the measurement was
performed
Note 1 to entry: This delay is usually due to internal calculations of the rain gauge.
Note 2 to entry: The internal calculation of the rainfall intensity in some rain gauges can cause a delay of the
output data message (e.g. 1 min) that can easily be shifted automatically to the correct time without any
degradation in measurement accuracy. This is typical of software corrected tipping bucket rain gauges through
embedded electronic chips or interfaces. The delay time should not be confused with the time constant. If real-
time output is not needed, software induced delay times are less critical than longer time constants or any other
effects, because delay times can easily be corrected to retrieve the original RI information.
[SOURCE: WMO IOM – 99]
3.6
measurand
quantity intended to be measured
[SOURCE: VIM 3rd edition, JCGM 200:2012]
3.7
measurement uncertainty
non-negative parameter characterizing the dispersion of the quantity values being attributed to a
measurand, based on the information used
[SOURCE: VIM 3rd edition, JCGM 200:2012]
Note 1 to entry: The parameter may be, for example, a standard deviation called standard measurement
uncertainty (or a specified multiple of it), or the half-width of an interval, having a stated coverage probability.
Note 2 to entry: Measurement uncertainty comprises, in general, many components. Some of these may be
evaluated by Type A evaluation of measurement uncertainty from the statistical distribution of the quantity values
from series of measurements and can be characterized by standard deviations. The other components, which may
be evaluated by Type B evaluation of measurement uncertainty, can also be characterized by standard deviations,
evaluated from probability density functions based on experience or other information.
Instrumental measurement uncertainty (VIM 3rd edition, JCGM 200:2012): component of measurement
uncertainty arising from a measuring instrument or measuring system in use
Instrumental uncertainty is used in a Type B evaluation of measurement uncertainty
Achievable measurement uncertainty (WMO no. 8, Part I Annex 1.B): it is intended as the measurement
uncertainty achievable in field and/or operational conditions
3.8
non-catching rain gauge
rain gauge where the rain is not collected in a container/vessel
Note 1 to entry: The rainfall intensity or amount is either determined by a contact-less measurement using
optical or radar techniques or by an impact measurement. This type of gauge includes optical disdrometers,
impact disdrometers, microwave radar disdrometers, optical/capacitive sensors.
3.9
resolution
smallest change in a quantity being measured that causes a perceptible change in the corresponding
indication
[SOURCE: VIM 3rd edition, JCGM 200:2012]
3.10
step function or unit step function
input signal that switches on at a specified time and stays switched on indefinitely for determining the
response (output) of a dynamic instrument system
[SOURCE: CEN/TR 16469:2013]
3.11
step response
time-varying response of an instrument system to a step function (heaviside step function)
[SOURCE: CEN/TR 16469:2013]
3.12
step response time
duration between the instant when an input quantity value of a measuring instrument or measuring
system is subjected to an abrupt change between two specified constant quantity values and the instant
when a corresponding indication settles within specified limits around its final steady value
[SOURCE: VIM 3rd edition, JCGM 200:2012]
3.13
time constant
rise time characterizing the response of an instrument classified as a system of first order response (the
way the system responds is approximated by a first order differential equation)
Note 1 to entry: It represents the time that the step response of an instrument system takes t
...
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