1、BRITISH STANDARD BS7527-2.7: 1991 IEC721-2-7: 1987 Classification of environmental conditions Part2: Environmental conditions appearing in nature Section2.7 Fauna and flora (Implementation of CENELEC HD478.2.7S1)BS7527-2.7:1991 This BritishStandard, having been prepared under the directionof the Gen
2、eral Electrotechnical Standards PolicyCommittee, was publishedunder the authorityofthe Standards Boardand comes into effect on 29November1991 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference GEL/15 Special announcement in BSINews July1991 ISBN 0 580 2
3、0171 6 Committees responsible for this BritishStandard The preparation of this BritishStandard was entrusted by the General Electrotechnical Standards Policy Committee (GEL/-) to Technical CommitteeGEL/15, upon which the following bodies were represented: Directorate of Telecommunications EEA (the A
4、ssociation of Electronics, Telecommunications and Business Equipment Industries) Electronic Components Industry Federation Ministry of Defence National Supervising Inspectorate Society of Environmental Engineers Society of Motor Manufacturers and Traders Limited Amendments issued since publication A
5、md. No. Date CommentsBS7527-2.7:1991 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Object 1 3 General 1 4 Occurrence of fauna and flora 2 Publication(s) referred to Inside back coverBS7527-2.7:1991 ii BSI 12-1999 National foreword This Section
6、 of BS7527 has been prepared under the direction of the General Electrotechnical Standards Policy Committee. It is identical with IECPublication721-2-7:1987 “Classification of environmental conditions Part2:Environmental conditions appearing in nature. Fauna and flora”, published by the Internationa
7、l Electrotechnical Commission (IEC). This Section of BS7527 implements CENELEC Harmonization Document(HD)478.2.7S1. For the purposes of this BritishStandard, any references to IEC page numbers in the text should be ignored. Other Parts of this BritishStandard are as follows. Part1: Environmental par
8、ameters and their severities; Part2: Environmental conditions appearing in nature; Section2.1: Temperature and humidity; Section2.2: Precipitation and wind; Section2.3: Air pressure; Section2.4: Solar radiation and temperature; Section2.5: Dust, sand, salt mist; Section2.6: Earthquake vibration and
9、shock; Part3: Classification of groups of environmental parameters and their severities; Section3.0: Introduction; Section3.1: Storage; Section3.2: Transportation; Section3.3: Stationary use at weatherprotected locations; Section3.4: Stationary use at non-weatherprotected locations; Section3.5: Grou
10、nd vehicle installations; Section3.6: Ship environment; Section3.7: Portable and non-stationary use. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard
11、 does not of itself confer immunity from legal obligations. Cross-reference International Standard Corresponding BritishStandard IEC721-1:1990 BS7527 Classification of environmental conditions Part1:1991 Environmental parameters and their severities (Identical) Summary of pages This document compris
12、es a front cover, an inside front cover, pagesi andii, pages1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS7527-2.7:1991 BSI 12-199
13、9 1 1 Scope This part of the standard presents fauna and flora, including fungus, appearing in nature and describes influences emanating from these environmental parameters. It is intended to be used as part of the background information when selecting appropriate severities for product application.
14、 When selecting severities of parameters related to fauna and flora for product application, the specifications given in IEC Publication721-1 should be applied. 2 Object To describe influences from fauna and flora to which products are liable to be exposed during storage, transportation and use. 3 G
15、eneral Fauna and flora can affect products in various ways, the most important of which are given in the following examples. 3.1 Deterioration by mechanical forces The functioning of products may be affected by physical attacks of fauna and flora. 3.1.1 Causes of deterioration The materials of produ
16、cts may be attacked by fauna, particularly by rodents and insects, by actions such as: feeding from material, gnawing at material, eating into material, chewing material, cutting holes into material. NOTESevere damage by termites is especially emphasized in this respect. Among material susceptible t
17、o attack are natural materials such as wood, paper, leather, textiles, but also plastic materials including elastomers and even some metals such as tin and lead. Another type of attack by all kinds of animals is brought about by actions such as: stroke or impact, thrust. Attacks by flora, especially
18、 mould growth and detached parts of plants, can affect products by actions such as: overgrowth, thrust, impact. 3.1.2 Kinds of damage The effects mentioned above may lead to the following damage: physical breakdown of material, parts, units, devices, mechanical deformation or compression, mechanical
19、 failure, for example of moving parts, surface deterioration, electrical failure by mechanical deterioration as above. 3.2 Deterioration by deposits The functioning of products may be affected by deposits originating from fauna and flora. These surface deposits affect the products by chemical and me
20、chanical reactions. 3.2.1 Causes of deterioration Deposits from fauna, especially from insects, rodents, birds, etc., may consist of elements such as: presence of the animal itself, building of nests or settlements, feed stocks, metabolic products such as excrements, enzymes. Deposits from all kinds
21、 of flora may consist of material such as: detached parts of plants (leaves, blossom, seeds, fruits, etc.), growth layers of cultures of moulds or bacteria and effects of their metabolic products. 3.2.2 Kinds of damage The effects mentioned above may lead to the following damage: deterioration of ma
22、terial, corrosion, etc., mechanical failure of moving parts, electrical failure due to: increased conductivity of insulators, failure of insulation, increased contact resistance, electrolytic and ageing effects in the presence of humidity or chemical substances, moisture absorption and adsorption, d
23、ecreased heat dissipation. NOTETwo examples of damage by these effects are: interruption of electrical circuits, clouding of optical surfaces (including glass).BS7527-2.7:1991 2 BSI 12-1999 4 Occurrence of fauna and flora With only few exceptions, fauna and flora may be present at all locations wher
24、e products may be stored, transported or used. While fauna may be the cause of damage inside buildings as well as at open-air locations, damage by flora will predominantly occur in open-air conditions. Moulds and bacteria may be present inside buildings and in open-air conditions. The frequency of o
25、ccurrence of fauna and flora with a possibility of damaging products depends very much on conditions of temperature and humidity. Ingeographical areas with warm damp climates, fauna and flora, especially insects and micro-organisms such as mould and bacteria, will find favourable conditions of life.
26、 However, humid or wet rooms in buildings, or rooms for processes producing humidity, are suitable living spaces for rodents, insects and micro-organisms. The range of temperature in which, for instance, moulds may grow is from0 C to40 C, the most favourable temperatures for many cultures being betw
27、een22 C and28 C. If the surfaces of products carry layers of organic substances (e.g.grease, oil, dust) or deposits of animal or vegetable origin, such surfaces are ideal for the growth of moulds and bacteria.BS7527-2.7:1991 BSI 12-1999 Publication(s) referred to See national foreword.BS7527-2.7: 19
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