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Tubular Fluorescent Lamps in Industry

Tubular Fluorescent Lamps in Industry Workshop and Production Section C. W . M. Phillips, A.M.I.E.E., F.I.E.S.* LTHOUG H tubular fluorescent lamps have can, though, be no doub t whatsoever tha t seeing is a A further fact revealed by a study of the work is been used very extensively in industry since grea t deal easier in the latter case than the former. tha t many planes other than the horizontal arc of interest. Thus the number and position of the their introduction in March, 1940, there is Thus , the third desirable in easy seeing is tha t the sources is dictated by this, so that each plane may still doubt in many minds as to why they should be articles viewed should have adequate brightness. be rendered adequately bright. This is in distinct preferred to older and more conventional forms of Experience has shown that if the brightness light sources. There is a general tendency to think contras t to the usually prevailing method of using picture is painted in industry according to the prin­ of them only as sources similar to natural daylight th e minimum number of high powered sources ciples laid down above, seeing is made easy where in their colour rendering properties, and to overlook so tha t a specified illumination may be achieved in otherwise it would be difficult. Nevertheless, thei r other exceptional properties. To the lighting th e cheapest manner. seeing still requires some expenditure of energy, and engineer daylight rendering is only one, and prob­ if every effort is t o be made t o keep this expenditure Th e principle of the provision of cheap foot- abl y not the most important, of their qualifications. down to a minimum, it is well worth while consider­ candles on some specified horizontal plane, which In an attemp t to demonstrate the part which these ing purely psychological factors.' Here, however, ha s governed the design of industrial lighting instal­ lamp s can play in industry, especially a t the present a difficulty presents itself because whereas the lations for so long, has resulted in the design of time, this article has been written. physiological side of seeing has been extensively fittings which force as much of the light from the explored, the psychological aspect is littl e developed. bare lamp as possible down on to the horizontal In order to make seeing easier we must first If, however, some attempt is made to simulate plane. Light which arrived via the walls or ceiling consider the factors which make seeing difficult. natur e by endeavouring t o creat e a feeling of natural­ lias been regarded as light which would have been This can best be done if one adopt s immediately the ness in a factory, then it is very likely that the much better utilized if it could have been made to habi t of thinking in terms of brightness and not effort involved in prolonged seeing will be little come- direct . This has meant that all parts of the illumination. Light itself, and therefore illumina­ mor e than the effort needed for casual seeing; so factory, with the exception of the horizontal work tion, which is only the quantity and quality of ther e is a fourth factor to consider. For ease of plane and the sources themselves, have appeared light, is only the means t o the end. The end itself prolonged seeing, the object on which work is done dar k and gloomy because of the low level of their is brightness; for seeing, and therefore understand­ an d the general aspect of the factory should be brightness. As a consequence, not only does the ing, is largely a matter of brightness contrast. revealed as naturally as possible. factory seem depressing, but unduly high contrasts Now, seeing is made difficult if the brightness in brightness, resulting, in difficult seeing, ar e present. contrasts in the field of view are too pronounced, Acceptance of the above naturally leads one to a an d is made easy when the range of brightness desire to formulate a simple code which can guide Thus , if point 4 of the code is to be fulfilled, the lighting units employed must be provided with a is controlled. It is a well established principle th e approach to the problem of conserving energy distributio n which irradiates walls and ceilings tha t if a number of objects of widely varying bright­ by providing easy seeing conditions. This code jus t as adequately, from a brightness promoting ness arc visible a t one and the same time, then the might conceivably take the following form: viewpoint, as the work itself. eyes are automatically attracted to the object having the highest brightness, and in addition they Most people would agree that things look most Requisites for Good Lighting adap t themselves to evaluate most accurately the natura l out of doors and therefore if it is considered actua l level of tha t highest brightness. In so doing, psychologically desirable to have naturalness in a if the range is extreme, the actual brightness of the factory, then one good way of achieving it would be (1) The nature of the work to be done and the other articles is under evaluated, or, to pu t it more t o bring daylight naturally or artificially into the manne r in which it is performed must be exam­ simply, the y appear less brigh t than they really are. ined in detail. factory. So that applying point 5 of the code If proof of this is needed, one might refer to the practically involves the use of artificial daylight (2) The brightness distribution over the work must occasion of driving down a road straight into the lamps. be controlled. There must not be present any setting summer sun. It is possible to see the other undesirably high levels of brightness such as To summarize, if the lighting engineer is to pro­ cars, the road itself and the margins, but very glitter points, which destroy the ability to assess duce a form of lighting which will reduce the ex­ considerable effort is required. If, however, an other brightness levels, and which, therefore, penditur e of wasteful energy to a minimum, and abou t turn is made, seeing immediately becomes preven t appreciation of detail. thu s make more energy available for useful work, easy although the brightness of those things (3) The actual levels of brightness mus t be adequate. h e must first be provided with sources of relatively! which were previously hardly visible is still generally (4) Brightness levels materially higher or lower than large area and low brightness. These sources can th e same as it was before the reverse was made. thos e present in the local or concentration field best consist of a lamp which in itself has a low Thus, the first desirable in easy seeing is th e control mus t not occur in the general field. surface brightness and which is carried in a fitting of brightness levels in th e general field of view. (5) The work itself and the factory as a whole must designed to modify the lamp distribution in the required manner. These sources must then be Controlling the brightness does not of course appea r as natural as possible. distributed , not necessarily on some symmetrical imply that the striving should be towards uniform­ I n applying this code to the lighting of factories, pla n dictated largely by the nature of the roof ity , for if this were attained seeing would be made th e starting point is a study of the work. This almost invariably reveals the fact that it is of a structure , but by the specific requirements of each difficult once more in most cases. For example, polished or specular character and is therefore likely operato r and the work he has to perform. In addi­ in tool making it is frequently necessary to check a t o reflect images of the light sources used. It tion, for the creation of an appearance of natural­ face for trueness by aligning it with a test piece of known accuracy. In doing so the normally avail­ immediately becomes difficult to pu t point 2 of the ness, the lamps themselves should yield light of a-j able natural backgrounds against which the degree code into practice unless control is exercised over near an approach to daylight quality as possible. of contact of th e two articles is assessed, are usually th e brightness of the sources. The brightness All practical lamps available for industrial light­ of th e same approximate colour and texture as the of glitter points or reflected images arc a function ing purposes, with the exception of the Tubulat subjects under view and are therefore nearly the only of the brightness of the source causing them Fluorescent lamps, are of th e high source brightness same in brightness. Difficult seeing is the conse­ an d removing this source to a distance will only character, and therefore if they are to be used t<3 quence and a naturally brighter background is serve to reduce the size of the glitter point and not provide energy-saving lighting, they must be usee! needed to mak e seeing.easy again. Thus the second it s brightness. On the other hand, the brightness in fittings which reduce their brightness to a satis desirable in easy seeing is th e provision of reason­ of the surround is dependent on th e amount of light factory low level. This involves a very 'Consider; falling on it. Thus the harmful brightness contrast able controlled contrast in th e local or concentration able amount of absorption, with consequent heal occasioned by the presence of glitter points can be field of view. generation, of th e bare lamp output. Furthermore reduced by reducing the source brightness, and thus in order t o obtain a large area of source, a number o I t has been shown above that in both the local reducing the glitter point brightness, or by increas­ low wattage lamps need to be carried in one fitting an d general fields of view, th e brightness of objects ing the amount of light falling on the surround This, together with the need to produce adequati relative to each other determines the ease or diffi­ (without increasing the source brightness) and thus brightness levels, involves a very high first cost t< culty of seeing, but the actual physical levels of increasing the surround brightness, or both. In­ th e installation. brightness is a further important factor. For variably it is a question of doing both. example, on a clear moonlight night a stretch of On the other hand, Tubular Fluorescent lamp roadway may be twice a s bright as the grass verge; However low th e brightness of th e source may be, hav e a very low surface brightness, and one lamp in I an d on a fine day with overcast sky the brightness i t is usually many times brighter than any back­ suitable fitting can provide a source area of abou ratio of road to verge may be still th e same. There ground against which it may be seen, so that it is 5 ft. by 1 ft. In addition, the low surface bright-* necessary to screen it from normal view. This ness feature is accompanied by a light outpu t value, does not mean that the screens are necessarily expressed in lumens per watt, of a satisfactorily opaque . high order. *Of the Lighting Section. The British Thomson-Houston Co., Ltd. Il l http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

Tubular Fluorescent Lamps in Industry

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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0002-2667
DOI
10.1108/eb030896
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Abstract

Workshop and Production Section C. W . M. Phillips, A.M.I.E.E., F.I.E.S.* LTHOUG H tubular fluorescent lamps have can, though, be no doub t whatsoever tha t seeing is a A further fact revealed by a study of the work is been used very extensively in industry since grea t deal easier in the latter case than the former. tha t many planes other than the horizontal arc of interest. Thus the number and position of the their introduction in March, 1940, there is Thus , the third desirable in easy seeing is tha t the sources is dictated by this, so that each plane may still doubt in many minds as to why they should be articles viewed should have adequate brightness. be rendered adequately bright. This is in distinct preferred to older and more conventional forms of Experience has shown that if the brightness light sources. There is a general tendency to think contras t to the usually prevailing method of using picture is painted in industry according to the prin­ of them only as sources similar to natural daylight th e minimum number of high powered sources ciples laid down above, seeing is made easy where in their colour rendering properties, and to overlook so tha t a specified illumination may be achieved in otherwise it would be difficult. Nevertheless, thei r other exceptional properties. To the lighting th e cheapest manner. seeing still requires some expenditure of energy, and engineer daylight rendering is only one, and prob­ if every effort is t o be made t o keep this expenditure Th e principle of the provision of cheap foot- abl y not the most important, of their qualifications. down to a minimum, it is well worth while consider­ candles on some specified horizontal plane, which In an attemp t to demonstrate the part which these ing purely psychological factors.' Here, however, ha s governed the design of industrial lighting instal­ lamp s can play in industry, especially a t the present a difficulty presents itself because whereas the lations for so long, has resulted in the design of time, this article has been written. physiological side of seeing has been extensively fittings which force as much of the light from the explored, the psychological aspect is littl e developed. bare lamp as possible down on to the horizontal In order to make seeing easier we must first If, however, some attempt is made to simulate plane. Light which arrived via the walls or ceiling consider the factors which make seeing difficult. natur e by endeavouring t o creat e a feeling of natural­ lias been regarded as light which would have been This can best be done if one adopt s immediately the ness in a factory, then it is very likely that the much better utilized if it could have been made to habi t of thinking in terms of brightness and not effort involved in prolonged seeing will be little come- direct . This has meant that all parts of the illumination. Light itself, and therefore illumina­ mor e than the effort needed for casual seeing; so factory, with the exception of the horizontal work tion, which is only the quantity and quality of ther e is a fourth factor to consider. For ease of plane and the sources themselves, have appeared light, is only the means t o the end. The end itself prolonged seeing, the object on which work is done dar k and gloomy because of the low level of their is brightness; for seeing, and therefore understand­ an d the general aspect of the factory should be brightness. As a consequence, not only does the ing, is largely a matter of brightness contrast. revealed as naturally as possible. factory seem depressing, but unduly high contrasts Now, seeing is made difficult if the brightness in brightness, resulting, in difficult seeing, ar e present. contrasts in the field of view are too pronounced, Acceptance of the above naturally leads one to a an d is made easy when the range of brightness desire to formulate a simple code which can guide Thus , if point 4 of the code is to be fulfilled, the lighting units employed must be provided with a is controlled. It is a well established principle th e approach to the problem of conserving energy distributio n which irradiates walls and ceilings tha t if a number of objects of widely varying bright­ by providing easy seeing conditions. This code jus t as adequately, from a brightness promoting ness arc visible a t one and the same time, then the might conceivably take the following form: viewpoint, as the work itself. eyes are automatically attracted to the object having the highest brightness, and in addition they Most people would agree that things look most Requisites for Good Lighting adap t themselves to evaluate most accurately the natura l out of doors and therefore if it is considered actua l level of tha t highest brightness. In so doing, psychologically desirable to have naturalness in a if the range is extreme, the actual brightness of the factory, then one good way of achieving it would be (1) The nature of the work to be done and the other articles is under evaluated, or, to pu t it more t o bring daylight naturally or artificially into the manne r in which it is performed must be exam­ simply, the y appear less brigh t than they really are. ined in detail. factory. So that applying point 5 of the code If proof of this is needed, one might refer to the practically involves the use of artificial daylight (2) The brightness distribution over the work must occasion of driving down a road straight into the lamps. be controlled. There must not be present any setting summer sun. It is possible to see the other undesirably high levels of brightness such as To summarize, if the lighting engineer is to pro­ cars, the road itself and the margins, but very glitter points, which destroy the ability to assess duce a form of lighting which will reduce the ex­ considerable effort is required. If, however, an other brightness levels, and which, therefore, penditur e of wasteful energy to a minimum, and abou t turn is made, seeing immediately becomes preven t appreciation of detail. thu s make more energy available for useful work, easy although the brightness of those things (3) The actual levels of brightness mus t be adequate. h e must first be provided with sources of relatively! which were previously hardly visible is still generally (4) Brightness levels materially higher or lower than large area and low brightness. These sources can th e same as it was before the reverse was made. thos e present in the local or concentration field best consist of a lamp which in itself has a low Thus, the first desirable in easy seeing is th e control mus t not occur in the general field. surface brightness and which is carried in a fitting of brightness levels in th e general field of view. (5) The work itself and the factory as a whole must designed to modify the lamp distribution in the required manner. These sources must then be Controlling the brightness does not of course appea r as natural as possible. distributed , not necessarily on some symmetrical imply that the striving should be towards uniform­ I n applying this code to the lighting of factories, pla n dictated largely by the nature of the roof ity , for if this were attained seeing would be made th e starting point is a study of the work. This almost invariably reveals the fact that it is of a structure , but by the specific requirements of each difficult once more in most cases. For example, polished or specular character and is therefore likely operato r and the work he has to perform. In addi­ in tool making it is frequently necessary to check a t o reflect images of the light sources used. It tion, for the creation of an appearance of natural­ face for trueness by aligning it with a test piece of known accuracy. In doing so the normally avail­ immediately becomes difficult to pu t point 2 of the ness, the lamps themselves should yield light of a-j able natural backgrounds against which the degree code into practice unless control is exercised over near an approach to daylight quality as possible. of contact of th e two articles is assessed, are usually th e brightness of the sources. The brightness All practical lamps available for industrial light­ of th e same approximate colour and texture as the of glitter points or reflected images arc a function ing purposes, with the exception of the Tubulat subjects under view and are therefore nearly the only of the brightness of the source causing them Fluorescent lamps, are of th e high source brightness same in brightness. Difficult seeing is the conse­ an d removing this source to a distance will only character, and therefore if they are to be used t<3 quence and a naturally brighter background is serve to reduce the size of the glitter point and not provide energy-saving lighting, they must be usee! needed to mak e seeing.easy again. Thus the second it s brightness. On the other hand, the brightness in fittings which reduce their brightness to a satis desirable in easy seeing is th e provision of reason­ of the surround is dependent on th e amount of light factory low level. This involves a very 'Consider; falling on it. Thus the harmful brightness contrast able controlled contrast in th e local or concentration able amount of absorption, with consequent heal occasioned by the presence of glitter points can be field of view. generation, of th e bare lamp output. Furthermore reduced by reducing the source brightness, and thus in order t o obtain a large area of source, a number o I t has been shown above that in both the local reducing the glitter point brightness, or by increas­ low wattage lamps need to be carried in one fitting an d general fields of view, th e brightness of objects ing the amount of light falling on the surround This, together with the need to produce adequati relative to each other determines the ease or diffi­ (without increasing the source brightness) and thus brightness levels, involves a very high first cost t< culty of seeing, but the actual physical levels of increasing the surround brightness, or both. In­ th e installation. brightness is a further important factor. For variably it is a question of doing both. example, on a clear moonlight night a stretch of On the other hand, Tubular Fluorescent lamp roadway may be twice a s bright as the grass verge; However low th e brightness of th e source may be, hav e a very low surface brightness, and one lamp in I an d on a fine day with overcast sky the brightness i t is usually many times brighter than any back­ suitable fitting can provide a source area of abou ratio of road to verge may be still th e same. There ground against which it may be seen, so that it is 5 ft. by 1 ft. In addition, the low surface bright-* necessary to screen it from normal view. This ness feature is accompanied by a light outpu t value, does not mean that the screens are necessarily expressed in lumens per watt, of a satisfactorily opaque . high order. *Of the Lighting Section. The British Thomson-Houston Co., Ltd. Il l

Journal

Aircraft Engineering and Aerospace Technology – Emerald Publishing

Published: Apr 1, 1942

There are no references for this article.