EN IEC 60721-2-2:2024
(Main)Classification of environmental conditions - Part 2-2: Environmental conditions appearing in nature - Precipitation and wind
Classification of environmental conditions - Part 2-2: Environmental conditions appearing in nature - Precipitation and wind
IEC 60721-2-2:2024 presents fundamental properties, quantities for characterization, and a classification of environmental conditions dependent on precipitation and wind relevant to electrotechnical products. This third edition cancels and replaces the second edition published in 2012. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the layout of the information provided has been re-organized; b) the information provided has been extensively enhanced and revised; c) new information on wind severities has been included.
Klassifizierung von Umgebungsbedingungen - Teil 2-2: Natürliche Umgebungsbedingungen - Niederschlag und Wind
Classification des conditions d'environnement - Partie 2-2: Conditions d'environnement présentes dans la nature - Précipitations et vent
L'IEC 60721-2-2:2024 fournit les propriétés fondamentales, les grandeurs de caractérisation et une classification des conditions d'environnement qui dépendent des précipitations et du vent en ce qui concerne les produits électrotechniques. Cette troisième édition annule et remplace la deuxième édition parue en 2012. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: a) la présentation des informations fournies a été réorganisée; b) les informations fournies ont été largement améliorées et révisées; c) de nouvelles informations concernant les sévérités relatives au vent ont été ajoutées.
Klasifikacija okoljskih pogojev - 2-2. del: Okoljski pogoji v naravi - Padavine in veter
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN IEC 60721-2-2:2024
01-februar-2024
Klasifikacija okoljskih pogojev - 2-2. del: Okoljski pogoji v naravi - Padavine in
veter
Classification of environmental conditions - Part 2-2: Environmental conditions appearing
in nature - Precipitation and wind
Klassifizierung von Umgebungsbedingungen - Teil 2-2: Natürliche
Umgebungsbedingungen - Niederschlag und Wind
Classification des conditions d'environnement - Partie 2-2: Conditions d'environnement
présentes dans la nature - Précipitations et vent
Ta slovenski standard je istoveten z: prEN IEC 60721-2-2:2023
ICS:
19.040 Preskušanje v zvezi z Environmental testing
okoljem
oSIST prEN IEC 60721-2-2:2024 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN IEC 60721-2-2:2024
oSIST prEN IEC 60721-2-2:2024
104/1026/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60721-2-2 ED3
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2023-11-17 2024-02-09
SUPERSEDES DOCUMENTS:
104/975/CD, 104/994A/CC
IEC TC 104 : ENVIRONMENTAL CONDITIONS, CLASSIFICATION AND METHODS OF TEST
SECRETARIAT: SECRETARY:
Sweden Mr Henrik Lagerström
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft for
Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which
they are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In So me Countries”
clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for
submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).
TITLE:
Classification of environmental conditions - Part 2-2: Environmental conditions appearing in nature -
Precipitation and wind
PROPOSED STABILITY DATE: 2028
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.
oSIST prEN IEC 60721-2-2:2024
IEC CDV 60721-2-2 © IEC 2023 2 104/1026/CDV
1 Contents
2 1 Scope . 8
3 2 Normative references . 8
4 3 Terms and definitions . 8
5 4 Rain . 8
6 4.1 General . 8
7 4.2 Global Distribution of Rainfall . 8
8 4.3 Characteristics of Rain . 10
9 4.3.1 Formation . 10
10 4.3.2 Types of rain . 10
11 4.3.3 Distribution of raindrop sizes . 11
12 4.3.4 Terminal velocity . 11
13 4.4 Rates of rainfall . 12
14 4.4.1 Instantaneous rates and clock-hour totals . 12
15 4.5.2 Frequency of instantaneous rates . 13
16 4.6 Heavy rates of rainfall . 13
17 4.6.1 Thunderstorm Rain . 13
18 4.6.2 Prolonged Heavy Rain . 14
19 4.6.3 Worldwide Extremes . 14
20 4.7 Spatial Variations of Rainfall Rate . 14
21 4.7.1 General . 14
22 4.7.2 Rainfall Rates Below 2 mm/h . 15
23 4.7.3 Rainfall Rates Between 2 mm/h and 10 mm/h . 15
24 4.7.4 Rainfall Rates Between 10 mm/h and 25 mm/h . 15
25 4.7.5 Rainfall Rates Exceeding 25 mm/h . 16
26 4.8 Rainfall Probabilities Along a Line . 16
27 5 Snow . 16
28 5.1 General . 16
29 5.2 Global distribution of the incidence of snowy weather . 17
30 5.3 Global distribution of the incidence and depth of lying snow . 19
31 5.4 Mass, size, and fall-speed of snow . 19
32 6 Hail . 22
33 6.1 General . 22
34 6.2 Global Distribution of Hailstones . 22
35 6.3 Seasonal Variations in Global Distribution . 23
36 6.4 Diurnal Variation . 23
37 6.5 Size of Hail . 23
38 6.6 Terminal Velocity . 25
39 6.7 Duration and Diameter of Hail Cell . 26
40 7 Ice . 26
41 7.1 General . 26
42 7.2 Hoar Frost . 26
43 7.3 Rime Ice (including In-Cloud Icing and Freezing Fog) . 27
44 7.4 Glazed Frost (including Freezing Rain and Freezing Drizzle) . 28
oSIST prEN IEC 60721-2-2:2024
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45 7.5 Wet Snow Accretion . 28
46 7.6 Water Content of Fog and Cloud at Temperatures Below 0 °C . 29
47 7.7 Altitude Variations . 29
48 8 Wind . 29
49 8.1 General . 29
50 82 Mean Wind Speed . 30
51 8.2.1 General . 30
52 8.2.2 Variation of Mean Wind Speed with Height . 30
53 8.2.3 Frequency of Winds . 32
54 8.3 Gustiness . 39
55 8.3.1 General . 39
56 8.3.2 Gust Factor . 39
57 8.3.3 Gust Ratios . 39
58 8.3.3 Variation of Gust Speed with Height . 40
59 8.4 Effects of Topography . 40
60 8.5 Wind Types and Extreme Winds . 41
61 8.6 The Effects of Wind . 42
62 8.7 Wind in Conjunction with Other Damaging Agents . 44
63 Bibliography . 45
65 Figure 1 – Average Annual Rainfall (AAR) for global land areas, based on 1961 to 1990 data [1]. . 7
66 Figure 2 – Estimated conversion factor for converting to hours at instantaneous rate [1] . 11
67 Figure 3– Average decay of correlation with distance, of 1 minute rainfall rate and total storm rainfall
68 rate [1]. 13
69 Figure 4 – Estimated percentage of days on which an amount of snow equivalent to at least 1 mm
70 of rainfall falls in northern and southern hemispheres [1] [8] . 17
71 Figure 5 – Satellite derived average rainfall equivalent of lying snow and ice [1] [9]. . 20
72 Figure 6 – Estimated average annual number of days per year with hail of diameter ≥15mm [1] . 22
73 Figure 7 – Estimated Average Seasonal Number of Days per Year with Hail of Diameter ≥15mm,
74 based on Post-Processed Global Model Data(oceans excluded) [1] . 23
75 Figure 8 – Relationship between diameter and terminal velocity of spherical hailstones [1] . 25
76 Figure 9 – Air Temperature and wind speed criteria for the formation of different types of ice [1]
77 [15] . 27
78 Figure 10– The power spectrum of wind speed fluctuations.[1] . 29
79 Figure 11 – Annual mean 10 m wind speed (m/s) for global land areas, averaged over the period
80 1961 to 1990.[1] . 30
81 Figure 12 – Measurement stations with station numbers. . 32
82 Figure 13 – Vortex formation produced when wind strikes the corner of a structure . 42
83 Figure 14 -- Contours of pressure coefficients produced by vortices . 42
85 Table 1 – Estimated number of raindrops per cubic metre for various rates of rainfall [1] . 9
86 Table 2 – Terminal velocity of raindrops in still air [1] . 10
87 Table 3 – Duration in the average year of instantaneous point rainfall equalling or exceeding
88 specified rates [1] . 11
89 Table 4 – Predicted worldwide extremes of rainfall [1] . 12
90 Table 5 – Observed world maximum rates of rainfall [1] . 12
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91 Table 6 –- Estimated duration (h) in the average year when stated distances along given tracks
92 simultaneously have rainfall at or exceeding specific rates [1] . 14
93 Table 7 – Snow crystals: relation between mass (mg) and diameter (mm) of the sphere which just
94 contains the crystal [1] .
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