1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 7963:2000 ICS 13.100;
2、13.180; 13.340.01 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Ergonomics of the thermal environment Guide to the assessment of heat strain in workers wearing personal protective equipmentThis British Standard, having been prepared under the direction of the Health and Envi
3、ronment Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 July 2000 BSI 07-2000 The following BSI references relate to the work on this standard: Committee reference PH/9/1 Draft for comment 98/541260 DC ISBN 0 580 33180 6 BS 7963:2000 Amendme
4、nts issued since publication Amd. No. Date Comments Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee PH/9 Applied ergonomics, to Subcommittee PH/9/1, Thermal environments, upon which the following bodies were represented:
5、British Occupational Hygiene Society British Textile Technology Group Cold Storage and Distribution Federation Consumer Policy Committee of BSI Health and Safety Executive Home Office Institute of Occupational Medicine Institution of Fire Engineers Ministry of Defence Transport and General Workers U
6、nionBS 7963:2000 BSI 07-2000 i Contents Page Committees responsible Inside front cover Foreword ii Introduction 1 1 Scope 1 2 Normative references 1 3 Terms and definitions 1 4 PPE and heat balance 2 5 Analysis of work situations 4 6 The individual 8 Annex A (informative) Application of the measurem
7、ent methods given in BS EN 27243:1994 and BS EN 12515:1997 to workers wearing PPE 9 Annex B (informative) Worked examples 13 Annex C (informative) Examples of clothing worn and corresponding thermal insulation values 17 Annex D (informative) Theory behind modifications to BS EN 12515:1997 for worker
8、s wearing PPE 19 Bibliography 23 Figure 1 Routes of heat loss from the body 4 Table 1 Examples of metabolic rates for typical industrial activities 5 Table 2 Estimated increases in metabolic rate due to wearing PPE 6 Table 3 Body coverage of garments (from BS ISO 9920:1995) 8 Table A.1 Correction fa
9、ctors to be applied to BS EN 27243:1994 WBGT reference values when PPE is worn (from ACGIH, 1990 1) 10 Table B.1 Thermal insulation of clothing ensemble 14 Table B.2 Calculation of proportion of the body covered 15 Table C.1 Intrinsic thermal insulation values for typical clothing and footwear 18 Ta
10、ble C.2 Typical thermal insulation values of clothing ensembles 19ii BSI 07-2000 BS 7963:2000 Foreword This British Standard has been prepared by Subcommittee PH/9/1. This standard is intended to be one of a series concerned with the assessment of thermal environments. The other standards published
11、so far in this series are as follows: BS 7915, Ergonomics of the thermal environment Guide to design and evaluation of working practices for cold indoor environments. BS EN 563, Safety of machinery Temperatures of touchable surfaces Ergonomics data to establish temperature limit values for hot surfa
12、ces. BS EN 12515, Hot environments Analytical determination and interpretation of thermal stress using calculation of required sweat rate. BS EN 27243, Hot environments Estimation of the heat stress on working man, based on the WBGT-index (wet bulb globe temperature). BS EN 27726, Thermal environmen
13、ts Instruments and methods for measuring physical quantities. BS EN 28996, Ergonomics Determination of metabolic heat production. BS EN ISO 7730, Moderate thermal environments determination of the PMV and PPD indices and specification of the conditions for thermal comfort. BS ISO 9920, Ergonomics of
14、 the thermal environment Estimation of the thermal insulation and evaporative resistance of a clothing ensemble. BS ISO 10551, Ergonomics of the thermal environment Assessment of the influence of the thermal environment using subjective judgement scales. BS ISO 11399, Ergonomics of the thermal envir
15、onment Principles and application of relevant International Standards. 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 does not of itself confer imm
16、unity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 23 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. BSI 07-2000 1 BS 7963:2000 Introduction Person
17、al protective equipment (PPE) is used to protect against hazards to an individuals health and safety, such as dust, chemicals, sharp edges which could cause lacerations, and impact, and can impose heat stress on the wearer. This British Standard considers the effect of PPE on heat stress and heat st
18、rain, and how existing standards concerning the thermal environment need to be interpreted for workers wearing PPE. NOTE Attention is drawn to health and safety legislation regarding the selection and use of PPE which is suitable for the task to be carried out. 1 Scope This British Standard gives gu
19、idance on assessing the effects of personal protective equipment (PPE) on heat stress and its consequences for possible heat-related health problems (heat strain). This standard gives guidance on the application of the methods for measuring heat stress given in BS EN 12515:1997 and BS EN 27243:1994
20、to workers wearing PPE. NOTE 1 The conditions in which BS EN 12515:1997 and BS EN 27243:1994 are applicable (as outlined in the scope of each of these standards) are not extended by this British Standard. NOTE 2 Guidance on the application of the methods given in BS EN 12515:1997 and BS EN 27243:199
21、4 to measurement of heat stress in workers wearing PPE is given in annex A and worked examples are given in annex B. Examples of the thermal insulation values of clothing are given in annex C. The theory behind the modifications to the method given in BS EN 12515:1997 for workers wearing PPE is give
22、n in annex D. This British Standard is intended for use by all who: a) have a responsibility for the health and safety of workers wearing PPE in situations which could lead to heat strain; b) advise those with this responsibility; c) provide information to those with this responsibility. This Britis
23、h Standard applies to all PPE, which includes clothing worn in the workplace to protect the wearer. It does not consider special thermal protective clothing (e.g. water-cooled suits, ventilated suits, heated clothing) because the effect of these items requires special consideration. It does not appl
24、y to heat stress in hypo- or hyperbaric environments, or when the body is immersed in water. This British Standard is not concerned with thermal comfort. Methods for assessing thermal comfort are given in BS EN ISO 7730 and BS ISO 10551. This British Standard applies to workers wearing PPE in cool a
25、nd moderate thermal environments, as well as hot environments, as wearing PPE can contribute to heat stress even in cool or moderate thermal environments. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this
26、British Standard. For dated references, subsequent amendments to or revisions of, any of these publications do not apply. For undated references, the latest edition of the publication referred to applies. BS EN 143:1991, Specification for particle filters used in respiratory protective equipment. BS
27、 EN 12515:1997, Hot environments Analytical determination and interpretation of thermal stress using calculation of required sweat rate. BS EN 27243: 1994, Hot environments Estimation of the heat stress on working man, based on the WBGT-index (wet bulb globe temperature). BS EN 27726, Thermal enviro
28、nments Instruments and methods for measuring physical quantities. BS EN 28996, Ergonomics Determination of metabolic heat production. BS ISO 9920:1995, Ergonomics of the thermal environment Estimation of the thermal insulation and evaporative resistance of a clothing ensemble. ISO 9886, Evaluation o
29、f thermal strain by physiological measurements. 3 Terms and definitions For the purposes of this British Standard, the following terms and definitions apply. 3.1 air temperature dry bulb temperature of the air surrounding the human body (measured in degrees Celsius) 3.2 clothing ensemble clothing wh
30、ich is worn by an individual, including all the component parts 3.3 core temperature (t cr ) mean temperature of the thermal core of the body (measured in degrees Celsius) 3.4 DuBois body surface area (A Du ) total surface area of a nude person as estimated by the formula of DuBois based on the heig
31、ht and mass (measured in square metres) 3.5 hazard potential for injury and/or damage2 BSI 07-2000 BS 7963:2000 1) 1 clo = 0.155 m 2 KW 21 3.6 mean radiant temperature uniform temperature of an imaginary black enclosure in which an occupant would exchange the same amount of radiant heat as in an act
32、ual non-uniform enclosure (measured in degrees Celsius) 3.7 metabolic rate rate of transformation of chemical energy into heat and mechanical work by aerobic and anaerobic metabolic activities within an organism, usually expressed in terms of unit area of the total body surface (measured in watts pe
33、r square metre) 3.8 personal protective equipment (PPE) device, appliance or clothing designed to be worn by an individual for protection against one or more health and/or safety hazards, including clothing which covers or replaces personal clothing 3.9 pumping effect ventilation through a garment w
34、orn by an individual caused by body movement NOTE It depends on the closeness of fit of the garment, the PPE and the movements of the wearer. It usually helps to cool the individual. 3.10 respiratory protective equipment (RPE) device or appliance designed to be worn by an individual for protection o
35、f the respiratory system against one or more relevant hazards NOTE Breathing apparatus (BA) is one form of RPE. 3.11 risk product of: the probability of occurrence of heat strain to be expected in a given technical operation or state; and the consequence or extent of damage to be expected on the occ
36、urrence of heat strain. 3.12 standard working garment clothing ensemble which is permeable to air and steam, with a thermal insulation index I cl = 0.6 clo 1) BS EN 27243:1994, clause 7, note 1 3.13 thermal insulation of clothing (I cl ) resistance to heat flow of a theoretical uniform layer of insu
37、lation covering the entire body that has the same effect on sensible heat flow as the actual clothing under standardized (static, wind-still) conditions (measured in clo 1) ) NOTE The definition of clothing insulation also includes the uncovered parts of the body, such as the head and hands. 3.14 wa
38、ter vapour permeable fabric fabric which allows water vapour to pass through, but is impermeable to liquid water NOTE 1 Also known as breathable fabric or microporous fabric. NOTE 2 Water vapour permeable fabric has a lower evaporative resistance than a water vapour impermeable fabric, and this can
39、reduce thermal stress. PPE constructed from a water vapour permeable fabric can give satisfactory protection against liquids, dust, fibres and aerosols. PPE for protection against gases and vapours of low molecular weight normally requires water vapour impermeable fabrics. 3.15 workwear clothing whi
40、ch is worn at work and which is not specifically designed to provide protection against health and safety hazards 4 PPE and heat balance 4.1 Heat stress, heat strain and heat acclimatization 4.1.1 Heat stress When human thermal environments cause a tendency for a rise in body heat storage, the body
41、is in a state of heat stress. There are six basic factors that can contribute to heat stress: air temperature, mean radiant temperature, humidity, air velocity, thermal properties of clothing and metabolic rate. 4.1.2 Heat strain This is the resultant effect of the heat stress on the individual. Hea
42、t strain can be manifest in heat related health problems, such as heat cramps, prickly heat, headaches, nausea, vertigo, weakness, thirst, giddiness and fainting. More severe heat stress can cause unconsciousness, convulsions or mental confusion (heat stroke), and can result in death. 4.1.3 Heat acc
43、limatization This is the state resulting from a physiological adaptation process which increases the tolerance of an individual when he/she has been exposed to a given environment for a sufficient period of time. In comparison with an individual who is not acclimatized, an individual who is acclimat
44、ized generally shows less physiological strain for the same heat stress. BSI 07-2000 3 BS 7963:2000 4.2 The heat balance equation To maintain health in a hot environment, the body needs to be in heat balance within a physiologically acceptable level, i.e. the heat loss from the body needs to equal t
45、he heat gain by the body. Heat strain occurs if heat gain exceeds heat loss. Heat is constantly produced by the human body, although the amount produced depends on the type and level of physical activity. Depending on the environmental conditions, heat can be lost to the environment or gained from t
46、he environment (i.e. negative heat loss) by convection, evaporation, radiation and conduction. The heat balance equation for the body is given in BS EN 12515:1997 as: M2 W = C res + E res + C + E + R + K + S (1) where M is the metabolic energy production rate in watts per square metre (Wm 22 ); W is
47、 the mechanical work done by the body during the physical activity in watts per square metre (Wm 22 ); M2W is the internal heat production of the body in watts per square metre (Wm 22 ); C res is the heat lost from the respiratory tract by convection in watts per square metre (Wm 22 ); E res is the
48、heat lost from the respiratory tract by evaporation in watts per square metre (Wm 22 ); C is the heat lost from the skin and clothing by convection in watts per square metre (Wm 22 ); E is the heat lost from the skin and clothing by evaporation in watts per square metre (Wm 22 ); R is the heat lost
49、from the skin and clothing by radiation in watts per square metre (Wm 22 ); K is the heat lost from the skin and clothing by conduction in watts per square metre (Wm 22 ); S is the heat storage in the body in watts per square metre (Wm 22 ). These routes of heat loss are illustrated in Figure 1. The principles for calculation of these terms are detailed in BS EN 12515:1997. The factors in maintaining heat balance are the metabolic rate, the thermal properties of the clothing and the thermal environment. 4.3 Effe
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