Chapter 1 — Lighting

Lighting

1.1        Scope

 The basic requirements for building lighting are that adequate light of the right quality is provided and that proper attention is given to the appearance and artistic features of the lighting fixtures and the effects they produce. This chapter, read together with Chapter 2 Electrical Installation covers the illumination level requirements in buildings and methods for achieving these requirements.

1.2        Terminology

 This section provides an alphabetical list of the terms used in and applicable to this chapter of the Code. In case of any conflict or contradiction between a definition given in this section and that in Part 1, the meaning provided in this section shall govern for interpretation of the provisions of this chapter.

        Brightness : The luminous intensity of any surface in a given direction per unit of projected area of the surface, as viewed from that direction.

 COLOUR :  Aspect of visual perception by which an observer may distinguish between two fields of view of the same size, shape and structure, as may be caused by differences in the spectral composition of the radiation concerned.

        Colour  Appearance :  One of the two factors characterizing the colour qualities of a lamp. Lamps are usually divided into three groups according to their colour appearance : warm, intermediate and cool.

        Colour Rendering  :  The colour rendering property of a lamp is described by its colour rendering index, Ra; the higher the index the better the colour rendering property. The colour rendering index of a lamp is a measure of the degree to which the psychophysical colours of objects illuminated by the lamp conform to those of the same objects illuminated by a reference lamp, under specified conditions.

        Contrast :  The contrast of a small object of uniform luminance seen against a background of uniform luminance is the difference between object luminance and background luminance expressed as a ratio of the background luminance.

 GLARE :  The sensation produced by luminance within the visual field that is sufficiently greater than the luminance to which the eyes are adapted to cause annoyance, discomfort, or loss in visual performance and visibility. The magnitude of the sensation of glare depends upon such factors as the size, position and luminance of a source, the number of sources and the luminance to which the eyes are adapted.

        Glare, Direct : Glare caused by a bright light source appearing in the normal field of view of an observer.

        Glare, Disability : Glare that impairs the vision, measured in terms of deterioration of visual performance (contrast sensitivity).

        Glare, Discomfort :  Glare that induces a feeling of discomfort; the degree of discomfort can only be measured subjectively.

        Glare, Reflected :  Glare caused by the reflection of bright light source on a glossy surface.

        Illuminance :  The quantity of light or luminous flux falling on unit area of a surface.

        Illumination  :  The application of visible radiation to an object.

        Incandescence :  Emission of visible radiation by thermal excitation.

        Lamp, Fluorescent :  Discharge lamp in which most of the light is emitted by a layer of fluorescent material excited by the ultraviolet radiation from the discharge.

        Lamp, Incandescent : Lamp in which light is produced by means of an element heated to incandescence by the passage of an electric current.

        Lighting, General : Lighting designed to illuminate an area in general, without particular provision for any special local requirements within that area.

        Lighting, Localized : Lighting designed to increase the illuminance at certain specified positions; for instance those at which work is carried on.

        Lumen : The luminous flux emitted within unit solid angle (one steradian) by a point source having a uniform intensity of one Candela.

        Luminaire : A complete lighting apparatus consisting of a lamp or lamps together with the parts designed to distribute, filter or transform the light, to fix and protect the lamps and to connect them to the supply circuit.

        Luminance (at a point) :  The ratio of the luminous intensity in a given direction of an infinitesimal element of the surface containing the point under consideration to the orthogonally projected area of the element on a plane perpendicular to the given direction.  It is proportional  to the product of the illuminance and the surface reflectance, the latter being the ratio of the reflected luminous flux to the incident luminous flux.

        Luminous Flux :  The quantity characteristic of radiant flux which expresses its capacity to produce visual sensation evaluated according to the values of relative luminous efficiency for the light-adapted eye.

        MAINTENANCE FACTOR:  The ratio of the average illuminance on the working plane, after a certain period of use of a lighting installation, to the average illuminance obtained under the same conditions for the same lighting installation when new.

        Reflection FACTOR:   The ratio of light reflected from a surface to the total light falling on the surface. The reflection factor varies with the roughness of the surface as well as the darkness of the colour.

        Utilization FACTOR:  The ratio of the flux received on the working plane to the sum of the fluxes from all the lamps in the interior.

        Working Plane : A horizontal plane at a level at which work will normally be done. Where a visual task is required to be carried out throughout an interior, general illumination of the value recommended for the working plane is necessary; where the precise height and location of the task are not known or cannot be easily specified, the recommended value is that on a horizontal plane 850 mm above the floor level. For an industrial task, working plane for the purpose of general illumination levels may be taken at 760 mm above the floor level. For certain purposes, such as viewing the objects of art, the illumination levels recommended are for the vertical plane at which the art pieces are placed.

1.3 ILLUMINATION

1.3.1        Principle of Lighting

 The essential features of an efficient lighting system are :

- visual comfort through adequate illumination of the working surface, prevention of glare, and avoidance of shadows,  

- ease of maintenance.

 The design of a lighting system shall  involve :

a) careful planning of the brightness and colour pattern within both the working areas and the surroundings so that attention is drawn naturally to the important areas, detail is seen quickly and accurately, and the room is free from any sense of gloom or monotony,

b) use of directional lighting to assist perception of task detail,

c) controlling direct and reflected glare from light sources to eliminate visual discomfort,

d) minimizing flicker from certain types of lamps and paying attention to the colour rendering properties of the light,

e) the correlation of lighting throughout the building to prevent excessive differences between adjacent areas, so as to reduce the risk of accidents, and

f) the installation of emergency lighting systems, where necessary.

 Table 8.1.1  shows the general impressions associated with different illuminance and colour appearances of light. Table 8.1.2 gives the various colour rendering groups with examples of use.

Table 8.1.1

General Impressions Associated with Different Illuminance and Colour Appearances

Illuminance	Associated Impression
(lux)	(Colour Appearance)
	Warm	Intermediate	Cool
≤ 500 500 – 1000 1000 – 2000 2000 – 3000 ≥  3000	pleasant pleasant to stimulating stimulating stimulating to unnatural unnatural	neutral neutral  to pleasant pleasant pleasant  to stimulating stimulating	cool cool  to neutral neutral neutral to pleasant pleasant

        Table 8.1.2

Lamp Colour Rendering Groups

Colour rendering Group	Range of Index Ra	Colour Appearance	Examples of Use
		Cool	Textile industries, paint and printing industries
1	Ra ≥ 85	Intermediate	Shops, hospitals
		Warm	Homes, hotels, restaurants
2	70 ≤  Ra < 85	Intermediate	Offices, schools, department store, fine industrial work
3	40 ≤  Ra < 70		Interiors where colour rendering is of comparatively minor importance
Note :        Certain applications, e.g. colour matching, may be extremely critical with regard to the colour rendering properties of the lamps used. Here, the minimum colour rendering index used shall be 90.

1.3.2         Planning the Brightness Pattern

 The brightness pattern seen within an interior is composed of three parts - brightness of the task itself, brightness of the immediate background of the task and brightness of the general surroundings of walls, ceiling, floor, equipment, furnishing etc.

        1.3.2.1        The illumination of all work areas within a building shall be a minimum of 150 lux.

        1.3.2.2          Where work takes place over the whole utilizable area of a room, the general illumination over that area shall  be reasonably uniform and the diversity ratio of minimum to maximum illumination shall not be less than 0.7. This diversity ratio does not however take into account the effects of any local lighting provided for specific tasks.

        1.3.2.3          When the task brightness appropriate to an occupation has been determined, the brightness of the other parts of the room shall be planned to give proper emphasis to visual comfort and interest. The recommended brightness ratios is shown in Table 8.1.3.

1.3.3        Lighting Calculations

        1.3.3.1          In order to determine the necessary number of lamps and luminaires for a specified illumination level or the average illuminance obtained from a particular lighting design, the Lumen Method of calculation shall be employed.

        1.3.3.2        Unless the reflection factors are known to the lighting designer, the triplet 0.7/0.5/0.3 for the reflectances of ceiling, walls and working plane respectively shall be used for offices and the triplet 0.7/0.5/0.1 for other premises. Typical reflection factors of smooth coloured surfaces are given in Table 8.1.4.

Table 8.1.3

Brightness Ratios Between Task, Adjacent Sources and Surroundings

For high task brightness  (above 100 cd/m2) :
Maximum ratio between task brightness and the adjacent sources like table tops	3 to 1
Maximum ratio between task brightness and illumination of the remote areas of the room not being used as work  areas	10 to 1
For low and medium task brightness (below 100 cd/m2)	The task must be brighter than both the background and the surroundings; the lower the task brightness, the less critical is the relationship.

Table 8.1.4

Reflection Factors of  Smooth Coloured Surfaces

Colour	Reflection Factor	Colour	Reflection Factor
Flat white Ivory Buff Yellow Light tan	0.75 – 0.85 0.70 – 0.75 0.60 – 0.70 0.55 – 0.65 0.45 – 0.55	Light green Grey Blue Red Dark brown	0.40 – 0.50 0.30 – 0.50 0.25 – 0.35 0.15 – 0.20 0.10 – 0.15

1.3.4        Recommended Illumination Values

 The recommended values of illumination required for  buildings of different Occupancies, based on activity, are given in Tables 8.1.5 through 8.1.11. The initial illuminance should be higher than the recommended value to allow for the fact that the illuminance will inevitably drop below this value by the end of  the cleaning and relamping period. A gradual transition of brightness from one portion to another within the field of vision is recommended so as to avoid or minimize glare discomfort.

1.3.5        Artificial Lighting to Supplement Daylight

Supplementary lighting shall be used when illumination by daylight falls below 150 lux on the working plane.

 For providing supplementary artificial lighting when daylight availability becomes insufficient, cool daylight fluorescent tubes with semi-direct luminaires are recommended. To ensure a good distribution of illumination, the mounting height should be between 1.5 and 2.0 m above the work plane for a separation of 2.0 to 3.0 m between the luminaires.

1.4 LIGHT FITTINGS

 An electric lamp and its fitting, globe reflector etc., shall be regarded as one unit; they shall  be designed to suit each other and to give the desired distribution of light. Any focussing fittings used which enable the light distribution to be varied by adjustment of the lamp position shall also be designed for the type and size of lamp to be used.

1.4.1        Classification of Lamp Fittings

 Lamp fittings shall be classified into five categories according to the proportion of the total light output in the lower hemisphere. These are: direct fittings, giving 90-100 per cent light downwards; semi-direct fittings, giving  60-90 per cent downwards; general diffusing fittings, giving 40-60 per cent light downwards; semi-indirect fittings, giving 10-40 per cent light downwards; indirect fittings, giving 0-10 per cent light downwards.

Table 8.1.5  

Recommended Values of Illumination for Residential Buildings

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity

Illuminance (lx)

Dwelling houses  Bedrooms General Bed-head, Dressing table Kitchens Dining rooms (tables) Bathrooms General Shaving, make-up Stairs Lounges Garages and porches Sewing and darning Reading (casual ) Home work and sustained reading Hotels Entrance halls Reception and accounts Dining rooms (tables) Lounges Bedrooms General Dressing tables, bed heads, etc. Writing rooms (tables) Corridors Stairs Laundries Kitchens Food stores Working areas Goods and passenger lifts Cloak-rooms and toilets Bathrooms Above mirror in bathrooms

50 150 200 100 100 300 100 100 70 600 150 300 150 300 100 150 100 150 300 70 100 200 100 250 70 100 100 300

Table 8.1.6

Recommended Values of Illumination for Educational Buildings

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity	Illuminance  (lx)
School and College   Assembly halls General When used for examinations Platforms Class and Lecture Rooms Desks Black boards Embroidery and sewing rooms Laboratories Art  rooms Offices Staff rooms and common rooms Corridors Stairs Gymnasia General Matches Library Living quarters	150 300 300 300 250 500 300 400 300 150 70 100 150 300 see Table 8.1.8 see Table 8.1.5

Table 8.1.7

Recommended Values of Illumination for Health Care Buildings

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity	Illuminance  (lx)
Hospitals and Clinics Reception and waiting rooms Out patient department Wards  General Beds Operating theatres General Tables (with adjustable operation lamp lighting) Minor Major Doctor's examination rooms Radiology departments Casualty Stairs and corridors Dispensaries	150 150 100 150 300 2000 5000 150 100 150 100 250

Table 8.1.8

Recommended Values of Illumination for Assembly Buildings

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity

Illuminance  (lx)

Cinemas  Foyers  Auditorium  Corridors  Stairs Libraries Shelves (stacks) Reading rooms (newspapers and magazines) Reading tables Book repair and binding Cataloguing, sorting and stock rooms   Museums and Art Galleries Museums       General Displays Art galleries General Paintings Restaurant Dining rooms Cash desks Self-carrying counters Kitchens Cloak-rooms and toilets Theatres Foyers Auditorium Corridors Stairs Sports Centre Halls Swimming pools Lawn or table tennis, badminton, volley ball Tournament Club Recreational Shooting ranges On target Firing point Range Football

150 50 70 100 100 200 300 300 150 150 special lighting 100 200 100 300 300 200 100 150 70 70 100 150 150 300 200 100  300 200 50 500

        Table 8.1.9

Recommended Values of Illumination for Business and Mercantile Buildings

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity

Illuminance  (lx)

Airport Building Reception areas (desks) Baggage, customs and immigration halls Circulation areas, lounges Banks Counter, typing and accounting book areas Public areas, lobby Offices Book binding Pasting, punching and stitching Binding and folding and miscellaneous machines Finishing, blocking and inlaying Dental Surgeries Waiting rooms Surgeries General Chairs Laboratories Doctor's Surgeries Waiting rooms and consulting rooms Corridors Stairs Eyesight testing (acuity) wall charts          and near vision types Jewellery and watch-making Fine processes Minute processes Gem cutting, polishing and setting Laundries and dry-cleaning works Receiving, sorting, washing, drying, ironing          (calendering) and despatch Dry-cleaning and bulk machine work Fine hand ironing, pressing, inspection,           mending and spotting Offices Entrance lobby and reception areas Conference rooms and executive offices General offices Business machine operation Drawing office General Boards and tracing Corridors and lift cars Stairs Lift landings Telephone exchanges Manual exchange rooms (on desk) Main distribution frame room   Shops and Stores General areas Stock rooms Display windows

300 300 150 300 150 200 200 300 300 150 300 special lighting 300 150 70 100 450 700 3000 1500 200 200 300 150 300 300 450 300 450 70 100 150 200 150 150 to 300 200 500

Table 8.1.10

Recommended Values of Illumination for Industrial Buildings and Processes

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity	Illuminance (lx)
Aircraft Factories and Maintenance Hangars
Stock parts productions	450
Drilling, riveting, screw fastening, sheet aluminium layout and template work, wing sections, cowing, welding, sub-assembly, final assembly and inspection	300
Maintenance and repair (hangars)	300
Assembly Shops
Rough work, for example frame assembly and assembly of heavy   machinery	150
Medium work, for example machined parts, engine assembly	300
Fine work, for example  radio and telephone   equipment, typewriter  and office machinery  assembly	700
Very fine work, for example  assembly of very small precision          mechanisms and instruments	1500
Automobile Manufacturing
Frame assembly Chassis assembly line  Final assembly and inspection line Body manufacturing	200 300 600
Parts Assembly Finishing and inspection	200 300 700
Automobile Service Garages
Repairs Active traffic areas Storage	250 100 25
Bakeries
General working area Decorating and icing	150 250
Breweries and Distilleries
General working areas Brewhouse, bottling and canning plants Bottle inspection	150 200 special lighting
Carpet Factories
Winding and beaming Designing, Jacquard card cutting, setting pattern, tufting, topping, cutting,         hemming and fringing Weaving, mending and inspection	200 300 450
Chemical Works
Hand furnaces, boiling tanks, stationary driers, stationary and gravity           crystallizers Mechanical furnaces, evaporators, filtration, mechanical crystallizers, bleaching  Tanks for cooking, extractors, percolators	150 200 200
Chocolate and Confectionery Factories
Mixing, blending and boiling Chocolate husking, winnowing, fat extraction, crushing and refining,          feeding, bean cleaning, sorting, milling and cream making Hand decorating, inspection, wrapping and packing	150 200 300
Clay Products and Cements
Grinding, filter presses, kiln rooms moulding, pressing, cleaning  and  trimming Enameling Colour and glazing - rough work Colour and glazing - fine work	150 150 400 750

        (Continued to next page)

Table 8.1.10  (Contd.)

Recommended Values of Illumination for Industrial Buildings and Processes

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity	Illuminance (Ix)
Clothing Factories
Matching-up Cutting, sewing	450
Light Medium Dark	300 450 700
Inspection
Light Medium Dark	450 1000 1500
Hand tailoring
Light Medium Dark Pressing	450 1000 1500 300
Dairies
General working areas Filling and bottle inspection Cooling equipment Laboratories Pasteurizers  Separators	200 450 150 450 150 150
Electrical Industries
Impregnating	250
Winding and insulating	500
Assembly works
Fine  Very fine	500 750
Testing	500
Electricity Generating Stations (Indoor Locations)
Turbine halls Auxiliary equipment, battery rooms, blowers, auxiliary  generators, switchgear and transformer chambers Boiler house (including operating floors) platforms, coal conveyors, pulverizers, feeders, precipitators,  soot and slag   Boiler house and turbine house Basements Conveyor house, conveyor gantries and junction towers	150 100 70 to 100 100 70 70 to 100
Emergency lighting - all areas	30
Control rooms
Vertical control panels  Control desks  Rear of control panels  Switch houses	200 to 300 300 150 150
Electricity Generating Stations (Outdoor Locations)
Switchyard Conveyors  Fuel oil delivery headers  Oil storage tanks      Cat-walks  Platforms, boiler and turbine decks  Transformer and outdoor switchgear Emergency lighting - all areas	50 50 50 50 50 50 100 30
Flour Mills
Rolling   Sifting  Packing Purifying Product control Cleaning screens, man lifts, aisleways and walkways, bin checking	150 150 150 150 300 100

        (Continued to next page)

Table 8.1.10  (Contd.)

Recommended Values of Illumination for Industrial Buildings and Processes

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity	Illuminance (lx)
Forge Shops and Foundries
Forge shop Annealing (furnaces)  Cleaning  Core making (fine)  Core making (medium)  Grinding and chipping  Inspection (fine)  Inspection (medium)  Moulding (medium)  Moulding (large)  Pouring  Sorting  Cupola Shake out	150 150 100 300 150 200 1000 300 300 150 150 200 100 150
Garages
Parking areas (interior)  Washing and polishing, greasing, general servicing and pits	70 150
Gas Works
Retort houses, oil gas plants, purifiers, coke screening and coke handling plants (indoor) Governor, meter, compressor, booster and exhauster houses Open type plants	30 to 50 100
Cat-walks Platforms	20 50
Glass Works
Furnace rooms, bending, annealing lehrs  Mixing rooms, forming (blowing, drawing, pressing and rolling) Cutting to size, grinding, polishing and toughening  Finishing (bevelling, decorating, etching and  silvering) Brilliant cutting	100 150 200 300
General  Fine Inspection, etching and decorating	200 500 500
Glove Making
Pressing, knitting, sorting and cutting Sewing	300
Light Medium  Dark	300 450 700
Inspection
Light Medium  Dark	450 1000 1500
Hosiery and Knitwear
Circular and flat knitting machines, universal winders, cutting out,  folding        and pressing Lock-stitch and overlocking machines	300
Light Medium  Dark	300 450 700
Mending  Examining and hand finishing, light, medium and dark   Linking or running on	1500 700 450

        (Continued to next page)

Table 8.1.10  (Contd.)

Recommended Values of Illumination for Industrial Buildings and Processes

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity	Illuminance (lx)
Iron and Steel Works
Manufacturing by open hearth
Stock yard  Charging floor   Slag pits  Control platforms Mould yard Hot top  Hot top storage Stripping yard Scrap stockyard Mixer building Calcining building	20 100 100 100 25 100 100 100 20 100 50
Rolling mills
Blooming, slabbing, hot strip, hot sheet    Cold strip, plate  Pipe, rod, tube, wire drawing Merchant and sheared plate	100 150 200 100
Tin plate mills
Tinning and galvanizing   Cold strip rolling Motor room, machine room	200 200 150
Sheet metal works
Miscellaneous machines, ordinary bench work  Pressing, folding, stamping, shearing, punching and medium  bench work	200 200
Tin plate and galvanized sheet inspection	500
Structural Steel Fabrication
Fabrication and general work  Marking and cutting	150 300
Plating shops
Vat, baths, buffing and polishing   Final  buffing and polishing	200 500
Leather Manufacturing
Cleaning, tanning and stretching, vats   Cutting, fleshing and stuffing  Finishing and scarfing	150 200 200
Machine shops
Rough bench and machine work  Medium bench and machine work, ordinary automatic machines, rough grinding medium buffing and polishing Fine bench and machine work , fine automatic machines, medium grinding,   fine buffing and polishing Extra fine bench and machine work, grinding fine work	150 300 700 1000
Paint Works
General, automatic processes  Special batch mixing  Colour matching	200 450 700
Paper Manufacturing
Beaters, grinding, calendering   Finishing, cutting, trimming, paper making machines   Hand counting, wet end of paper machine   Paper machine reel, paper inspection and laboratories  Rewinder Paper box manufacturing	150 200 350 500 500 200

        (Continued to next page)

Table 8.1.10  (Contd.)

Recommended Values of Illumination for Industrial Buildings and Processes

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity	Illuminance (lx)
Pharmaceuticals and Fine Chemical Works
Raw material storage   Grinding, granulating, mixing and drying,  tableting, sterilizing,            preparation of solutions, filling, labelling, capping, wrapping and cartoning Control laboratories and testing  Fine chemical processing  Fine chemical finishing	200 300 300 200 300
Printing Industries
Photo-engraving
Block-making, etching and staging  Finishing, routing and proofing	200 300
Masking and tint laying	300
Colour Printing  Inspection area	700
Type foundries
Matrix making, dressing type   Front assembly and sorting Hand casting Machine casting	250 200 300 200
Printing plants
Machine composition and imposing stones   Presses   Composition room   Proof reading   Colour inspection and appraisal	200 300 450 300 1000
Electrotyping Block-making, electroplating, washing and baking  Moulding, finishing and routing	200 300
Rubber Tyre and Tube Manufacturing
Stock preparation
Plasticating, milling   Calendering	100 150
Fabric Preparation
Stock cutting, bead building   Tube tubing machines   Tread tubing machines	250 250 250
Tyre building
Solid tyre Pneumatic tyre	150 250
Curing department
Tubing curing, casing curing	350
Final Inspection
Tube, casing   Wrapping	1000 200
Shoe Manufacturing (Leather)
Cutting and stitching
Cutting tables Marking, buttonholing skiving, sorting and counting	450 450
Stitching
Light materials	300
Dark materials	1000
Making and finishing
Nailers, sole layers, welt beaters and scarfers, trimmers, welters, lasters, edge setters, sluggers, randers, wheelers, treers, cleaning, spraying,   buffing, polishing, embossing	600

        (Continued to next page)

Table 8.1.10  (Contd.)

Recommended Values of Illumination for Industrial Buildings and Processes

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity	Illuminance (lx)
Shoe Manufacturing (Rubber)
Washing, coating, mill run compounding   Varnishing, vulcanizing, calendering, upper and sole cutting Sole rolling, lining, making and finishing  process	100 300 500
Soap Factories
Kettle houses and ancillaries, glycerine evaporation  and distillation and continuous indoor soap making
General  areas Control panels	150 200 to 300
Batch or continuous soap cooling, cutting and  drying, soap milling and plodding
General areas   Control panels and key equipment	150 200 to 300
Soap stamping, wrapping and packing, granules  making, granules storage and handling, filling and packing granules
General areas Control panels and machines Edible products processing and packing	150 200 to 300 200
Textile Mills (Cotton)
Bale breaking and picking   Carding  and drawing   Slubbing, roving, spinning, spooling   Beaming and slashing on comb	150 200 200
Grey goods  Denims	200 300
Weaving
Patterned cloth and fine counts, light   Patterned cloth and fine counts, dark   Plain grey cloth   Cloth inspection	300 500 200 700
Textile Mills (Silk and Synthetics)
Manufacturing Soaking, fugitive tinting, conditioning, setting or twist	200
Winding, twisting, rewinding and coining, quilting and slashing
Light thread   Dark thread	200 300
Warping (silk or cotton system) on creel, on running ends, on reel, on beam, on warp at beaming	300
Healding (drawing-in)  Weaving Inspection	700 300 - 500 1000
Textile Mills (Woollen and Worsted)
Scouring, carbonizing, testing, preparing, raising, brushing, pressing, back-washing, gilling, crabbing  and blowing Blending, carding, combing(white), tentering, drying  and cropping Spinning, roving, winding, warping, combing (coloured)  and twisting Healding (drawing-in)  Weaving	150 200 450 700
Fine worsteds  Medium worsteds and fine woollens   Heavy woollens	700 450 300
Burling and mending Perching	700
Grey Final	700 2000
Wood Working
Rough sawing and bench work Sizing, planing, rough sanding, medium machine and bench work glueing, veneering Fine bench and machine work, fine sanding and finishing	150 200 300

Table 8.1.11

Recommended Values of Illumination for Storage Buildings

(for Occupancy classification see Chapter 2, Part 3)

Area or Activity	Illuminance (lx)
Storage Rooms of Ware House  Inactive Rough bulky Medium Fine	25 50 100 250

        1.4.1.1        Direct fittings shall  be used in situations where efficiency of illumination is the major criterion, while contract of the light source with the surroundings, shadows, and direct/reflected glare may be considered to be of relatively minor importance.

        1.4.1.2        Semidirect fittings shall be used in areas where it felt that the reduction of contrast resulting from the small indirect component of light directed towards the ceiling shall be sufficient for the purpose.

        1.4.1.3          General diffusing fittings shall be used where, in addition to a substantial indirect component of light aiding materially to the diffused character of the general illumination, an upward component providing a brighter background against which to view the luminance, especially for interiors with light-coloured ceiling and walls, is desirable.

        1.4.1.4          Semi-indirect fittings shall be used when a comfortable brightness ratio between the ceiling and the luminaire is desirable but an efficiency of illumination, higher than that obtainable from indirect fittings is required.

        1.4.1.5         Indirect fittings shall  be used in situations where an environment of evenly distributed illumination is to be achieved, efficiency of illumination not being a dominant factor.

1.5 ILLUMINATION OF EXIT SIGNS AND MEANS OF ESCAPE

1.5.1        Exit Signs

        1.5.1.1        All required exit signs shall be illuminated at night, or during dark periods within the area served.

        1.5.1.2        Exit signs  may be illuminated either by lamps external to the sign or by lamps contained within the sign. The source of illumination shall provide not less than 50 lux at the illuminated surface with a contrast of not less than 0.5. Approved self-luminous signs which provide evenly illuminated letters having a minimum luminance of 0.2 cd/m2 may also be used.

        1.5.1.3        Exit signs within an area where the normal lighting may be deliberately dimmed or extinguished, such as places of entertainment, shall be illuminated either by lamps contained within the sign or by approved self-luminous signs.

1.5.2        Means of Escape Lighting

        1.5.2.1        The means of escape and exit access in buildings requiring more than one exit shall be equipped with artificial lighting. The lighting facilities so installed shall provide the required level of illumination continuously during the period when the use of the building requires the exits to be available.

        1.5.2.2        The intensity of illumination at floor level in the means of escape shall not be less than 10 lux, except that the minimum required floor level illumination of aisles in assembly halls, theatres and cinema during projection of motion or still pictures by directed light shall be 2 lux.

        1.5.2.3        The illumination of exit signs and the lighting of the means of escape and exit access shall be powered by an alternate or emergency electrical system to ensure continued illumination for a duration of not less than 30 minutes after the failure of primary power supply.