Quick Reference Lighting Power Densities


 

Lighting Power Densities for Building Exteriors

ASHRAE 90.1-2004, Table 9.4.5

Tradable Surfaces LPD

Uncovered Parking Areas –Parking Lots and drives

0.15 W/ft²

Building Grounds –Walkways less than 10 feet wide

1.0 W/linear foot

Building Grounds –Walkways 10 feet wide or greater; Plaza areas; Special Feature Areas

0.2 W/ft²

Building Grounds –Stairways

1.0 W/ft²
Building Entrances and Exits –Main entries

30 W/linear foot of door width

Building Entrances and Exits –Other doors

20 W/linear foot of door width

Canopies and Overhangs –free standing and attached

1.25 W/ft²

Outdoor Sales –Open areas (including vehicle sales lots)

0.5 W/ft²
Outdoor Sales –Street frontage for vehicle sales lots in addition to “open area” allowance

20 W/linear foot

 

Lighting Power Density

AS per CPWD

Building Area Type

LPD (W/m2)
Automotive Facility

9.7

Multifamily Residential

7.5

Convention Centre

12.9
Museum

11.8

Dining : Bar Lounge/ Leisure

14

Office

10.8
Dining : Cafeteria/ Fast Food

15.1

Parking Garage

3.2
Dining : Family

17.2

Performing Arts Theatre

17.2
Dormitory/ Hostel

10.8

Police/ Fire Station

10.8
Gymnasium  

11.8

Post Office/ Town Hall

11.8
Health care-Clinic

10.8

Religious Building

14
Hospital/ Health Care

12.9

Retail/ Mall

16.1
Hotel

10.8

School/ University

12.9
Library

14

Sports Arena

11.8
Manufacturing Facility

14

Transportation

10.8
Motel

10.8

Motion Picture Theatre

12.9
Warehouse

8.6

Workshop

15.1

 

Interior Lighting Power Space Density As per  Function Method

AS per CPWD

Building Area Type

LPD (W/m2)
Office-enclosed

11.8

Office-open plan

11.8
Conference/ Meeting/ Multipurpose

14

Classroom/Lecture/ Training

15.1
Lobby

14

• For Hotel

11.8

• For Performing Arts Theatre

35.5

• For Motion Picture Theatre

11.8

Audience/ Seating Area

9.7

• For Gymnasium

4.3
• For Convention Centre

7.5

• For Religious Buildings

18.3
• For Sports Arena

4.3

• For Performing Arts Theatre

28

• For Motion Picture Theatre

12.9
• For Transportation

5.4

Atrium-first three floors

6.5

Atrium-each additional floor

2.2
Lounge/ Recreation

12.9

• For Hospital

8.6
Dining Area

9.7

• For Hotel

14
• For Motel

12.9

• For Bar Lounge/ Leisure Dining

15.1
• For Family Dining

22.6

• Food Preparation

12.9
Laboratory

15.1

Restrooms

9.7

Dressing/ Lockers/ Fitting Room

6.5
Corridor/ Transition

5.4

• For Hospital

10.8
• For Manufacturing facility

5.4

Stairs-active

6.5

Active Storage

8.6

• For Hospital

9.7

Inactive Storage

3.2
• For Museum

8.6

Electrical/ Mechanical Facility

16.1
For Indoor Field Area

15.1

Warehouse

• For Fine Material Storage

15.1

• For Medium/ Bulky Material

Storage

9.7

Workshop

20.5

Convention Centre – Exhibit Space

14

Library

• For Card File & Cataloguing

11.8

• For Stacks

18.3
• For Reading Area

12.9

Hospital

• For Emergency

29.1

• For Recovery

8.6

• For Nurse Station

10.8

• For Exam Treatment

16.1

• For Pharmacy

12.9
• For Patient Room

7.5

• For Operating Room

23.7
• For Nursery

6.5

• For Medical Supply

15.1
• For Physical Therapy

9.7

• For Radiology

4.3
• For Laundry – Washing

6.5

Automotive – Service Repair Manufacturing Facility

7.5
• For Low Bay (<8m ceiling)

12.9

• For High Bay (>8m ceiling)

18.3
• For Detailed Manufacturing

22.6

• For Equipment Room

12.9
• For Control Room

5.4

Hotel/ Motel Guest Rooms

11.8
Dormitory – Living Quarters

11.8

Museum

• For General Exhibition

10.8

• For Restoration

18.3
Bank Office – Banking Activity Area

16.1

Retail

• For Sales Area

18.3

• For Mall Concourse

18.3

Sports Arena

• For Rising Sports Area

29.1
• For Court Sports Area

24.8

Parking Garage – Garage Area

2.2
Transportation

• For Airport – Concourse

6.5
• For Air/ Train/ Bus-Baggage Area

10.8

• For Ticket Counter Terminal

16.1

 

Exterior Lighting Power Space Density

AS per CPWD

Exterior Lighting Applications Power Limits
Building entrance (with canopy) 13 W/m2 of canopied area
Building entrance (without canopy) 90 W/linear meter of door width
Building exit 60 W/linear meter of door width
Building facades 2 W/m2 of vertical facade area2

 

 

 

Lighting Power Densities for Buildings Except Low-Rise Residential Buildings

ANSI/ASHRAE/IES Standard 90.1-2010: Table 9.6.11

Common  Space Type LPD (W/ft²)
Conference/Meeting/Multipurpose 1.23
Corridor/Transition 0.66
Dining Area 0.65
Electrical/Mechanical 0.95
Food Preparation 0.99
Lobby 0.99
Lobby for Elevator 0.64
Lounge/Recreation 0.73
Office: Enclosed 1.11
Office: Open Plan 1.11
Restrooms 0.98
Stairway 0.69
Storage 0.63
Workshop 1.59

 

Lighting Power Densities Using the Building Area Method

ASHRAE-TABLE 9.5.1

Building Area Type LPD
Automotive facility 0.82W/ft2
Convention center 1.08W/ft2
Courthouse 1.05W/ft2
Dining: bar lounge/leisure 0.99W/ft2
Dining: cafeteria/fast food 0.90W/ft2
Dining: family 0.89W/ft2
Dormitory 0.61W/ft2
Exercise center 0.88W/ft2
Fire station 0.71W/ft2
Gymnasium 1.00W/ft2
Health-care clinic 0.87W/ft2
Hospital 1.21W/ft2
Hotel 1.00W/ft2
Library 1.18W/ft2
Manufacturing facility 1.11W/ft2
Motel 0.88W/ft2
Motion picture theater 0.83W/ft2
Multifamily 0.60W/ft2
Museum 1.06W/ft2
Office 0.90W/ft2
Parking garage 0.25W/ft2
Penitentiary 0.97W/ft2
Performing arts theater 1.39W/ft2
Police station 0.96W/ft2
Post office 0.87W/ft2
Religious building 1.05W/ft2
Retail 1.40W/ft2
School/university 0.99W/ft2
Sports arena 0.78W/ft2
Town hall 0.92W/ft2
Transportation –Airport 0.77W/ft2
Warehouse 0.66W/ft2
Workshop 1.20 W/ft2

 

Maximum Illumination Power Densities    

Building Code of Australia (BCA)

Lux Level of Rooms LPD
< 80 Lux: 7.5 Watt/M2
80 To 160 Lux 9 Watt/M2
160 To 240 Lux 10 Watt/M2
240 To 320 Lux 11 Watt/M2
320 To 400 Lux 12 Watt/M2
400 To 480 Lux 13 Watt/M2
480 To 540 Lux 14 Watt/M2
540 To 620 Lux 15 Watt/M2

 

 ILLUMINATION POWER DENSITY

Building Code of Australia (BCA)

Space LPD
Auditorium, church and public hall 10 Watt/M2
Boardroom and conference room 10 Watt/M2
Carpark – general 6 Watt/M2
Carpark – entry zone (first 20m of travel) 25 Watt/M2
Common rooms, spaces and corridors in a Class 2 building 8 Watt/M2
Control room, switch room, and the like 9 Watt/M2
Corridors 8 Watt/M2
Courtroom 12 Watt/M2
Dormitory of a Class 3 building used for sleeping only 6 Watt/M2
Dormitory of a Class 3 building used for sleeping and study 9 Watt/M2
Entry lobby from outside the building 15 Watt/M2
Health-care – children’s ward 10 Watt/M2
Health-care – examination room 10 Watt/M2
Health-care – patient ward 7 Watt/M2
Health-care – all patient care areas including corridors 13 Watt/M2
Kitchen and food preparation area 8 Watt/M2
Laboratory – artificially lit to an ambient level of 400 lx or more 12 Watt/M2
Library – stack and shelving area 12 Watt/M2
Library – reading room and general areas 10 Watt/M2
Lounge area for communal use in a Class 3 building or Class 9c 10 Watt/M2
Museum and gallery – circulation, cleaning and service lighting 8 Watt/M2
Office – artificially lit to an ambient level of 200 lx or more 9 Watt/M2
Office – artificially lot to an ambient level of less than 200 lx 7 Watt/M2
Plant room 5 Watt/M2
Restaurant, Cafe, bar, hotel lounge and a space for the serving of food or drinks 18 Watt/M2
Retail space including a museum and gallery whose purpose is the sale of objects 22 Watt/M2
School – general purpose learning areas and tutorial rooms 8 Watt/M2
Sole-occupancy unit of a Class 3 building 5 Watt/M2
Sole-occupancy unit of a Class 9c building 7 Watt/M2
Storage with shelving no higher than 75% of the height of the aisle lighting 8 Watt/M2
Storage with shelving higher than 75% of the height of the aisle lighting 10 Watt/M2
Service area, cleaner’s room and the like 5 Watt/M2
Toilet, locker room, staff room, rest room and the like 6 Watt/M2
Wholesale storage and display area 10 Watt/M2

 

MAXIMUM ILLUMINATION POWER DENSITY

Building Code of Australia (BCA)

Illumination LPD (Watt/M2)
Rooms to achieve
<80 lux 7.5
80 – 160 lux 9
160 – 240 lux 10
240 – 320 lux 11
320 – 400 lux 12
400 – 480 lux 13
480 – 540 lux 14
540 – 620 lux 15
>620 lux 80

 

Recommended LPD for Buildings

ECBC-2007

Building Area LPD (Watt/M2)
Automotive Facility 9.7
Convention Center 12.9
Dining: Bar Lounge/Leisure 14.0
Dining: Cafeteria/Fast Food 15.1
Dining: Family 17.2
Dormitory/Hostel 10.8
Gymnasium 11.8
Healthcare-Clinic 10.8
Hospital/Health Care 12.9
Hotel 10.8
Library 14.0
Manufacturing Facility 14.0
Motel 10.8
Motion Picture Theater 12.9
Multifamily Residential 7.5
Museum 11.8
Office 10.8
Parking Garage 3.2
Performing Arts Theatre 17.2
Police/Fire Station 10.8
Post Office/Town Hall 11.8
Religious Building 14.0
Retail/Mall 16.1
School/University 12.9
Sports Arena 11.8
Transportation 10.8
Warehouse 8.6
Workshop 15.1

 

Lighting Power Density

BEC-Table 5.4

Building Area LPD (Watt/M2)
Atrium / Foyer with headroom over 5m 17
Bar / Lounge 14
Banquet Room / Function Room / Ball Room 20
Canteen 11
Car Park 5
Classroom / Training Room 12
Clinic 15
Computer Room / Data Centre 15
Conference / Seminar Room 14
Corridor 8
Court Room 15
Dormitory 8
Entrance Lobby 14
Exhibition Hall / Gallery 17
Guest room in Hotel or Guesthouse 13
Gymnasium / Exercise Room 13
Kitchen 13
Laboratory 15
Lecture Theatre 13
Library – Reading Area, Stack Area or Audio Visual Centre 15
Lift Car 11
Lift Lobby 11
Loading & Unloading Area 8
Office, enclosed (Internal floor area at or below 15m2) 13
Office, open plan or with internal floor area above 15m2 12
Passenger Terminal Building 14
Arrival Hall /Departure Hall with headroom not exceeding 5m 18
Arrival Hall / Departure Hall with headroom over 5m 13
Passenger circulation area
Patient Ward / Day Care 15
Plant Room / Machine Room / Switch Room 10
Public Circulation Area 13
Railway Station
Concourse / Platform / Entrance / Adit / Staircase, with headroom not exceeding 5 m 14
Concourse / Platform / Entrance / Adit / Staircase, with headroom over 5 m 18
Refuge Floor 11
Restaurant 17
Retail 17
School hall 14
Seating Area inside Theatre / Cinema /Auditorium / Concert Hall / Arena 10
Server Room / Hub Room 10
Sports Arena, Indoor, for recreational purpose 17
Staircase 7
Storeroom / Cleaner 9
Toilet / Washroom / Shower Room 11
Workshop 13

 

Lighting Power Densities

ASHRAE –TABLE- 9.6.1

Building Area Type LPD (W/m2) LPD (W/m2)
Atrium (First 40 ft in height ) 0.03
Atrium (Above 40 ft in height ) 0.02
Audience/Seating Area
Permanent  For auditorium 0.79
For Performing Arts Theater 2.43
For Motion Picture Theater 1.14
Classroom/Lecture/Training 1.24
Conference/Meeting/Multipurpose 1.23
Corridor/Transition 0.66 Width<8 ft
Dining Area 0.65
For Bar Lounge/Leisure Dining 1.31
For Family Dining 0.89
Dressing/Fitting Room for Performing Arts Theater 0.40
Electrical/Mechanical 0.95
Food Preparation 0.99
Laboratory
For Classrooms                               1.28
For Medical/Industrial/Research 1.81
Lobby 0.90
For Elevator 0.64
For Performing Arts Theater 2.00
For Motion Picture Theater 0.52
Locker Room 0.75
Lounge/Recreation 0.73
Office
Enclosed 1.11
Open Plan 0.98
Restrooms 0.98
Sales Area 1.68
Stairway 0.69
Storage 0.63
Workshop 1.59
Automotive
Service/Repair 0.67
Bank/Office
Banking Activity Area 1.38
Convention Center
Audience Seating 0.82
Exhibit Space 1.45
Courthouse/Police Station/Penitentiary
Courtroom 1.72
Confinement Cells 1.10
Judges’ Chambers 1.17
Penitentiary Audience Seating 0.43
Penitentiary Classroom 1.34
Penitentiary Dining 1.07
Dormitory
Living Quarters 0.38
Fire Stations
Engine Room 0.56
Sleeping Quarters 0.25
Gymnasium/Fitness Center
Fitness Area 0.72
Gymnasium Audience Seating 0.43
Playing Area 1.20
Hospital
Corridor/Transition Width < 8 ft 0.89
Emergency 2.26
Exam/Treatment 1.66
Laundry/Washing 0.60
Lounge/Recreation 1.07
Medical Supply 1.27
Nursery 0.88
Nurses’ Station 0.87
Operating Room 1.89
Patient Room 0.62
Pharmacy 1.14
Physical Therapy 0.91
Radiology/Imaging 1.32
Recovery 1.15
Hotel/Highway Lodging
Hotel Dining 0.82
Hotel Guest Rooms 1.11
Hotel Lobby 1.06
Highway Lodging Dining 0.88
Highway Lodging Guest Rooms 0.75
Library
Card File and Cataloging 0.72
Reading Area 0.93
Stacks 1.71
Manufacturing
Corridor/Transition Width < 8 ft 0.41
Detailed Manufacturing 1.29
Equipment Room 0.95
Extra High Bay (>50 ft Floor to Ceiling Height) 1.05
High Bay (25–50 ft Floor to Ceiling Height) 1.23
Low Bay (<25 ft Floor to Ceiling Height) 1.19
Museum
General Exhibition 1.05
Restoration 1.02
Parking Garage
Garage Area 0.19
Post Office
Sorting Area 0.94
Religious Buildings
Audience Seating 1.53
Fellowship Hall 0.64
Worship Pulpit, Choir 1.53
Retail
Dressing/Fitting Room 0.87
Mall Concourse 1.10
Sales Area (for accent lighting) 1.68
Sports Arena
Audience Seating 0.43
Court Sports Arena—Class 4 0.72
Court Sports Arena—Class 3 1.20
Court Sports Arena—Class 2 1.92
Court Sports Arena—Class 1 3.01
Ring Sports Arena 2.68
Transportation
Air/Train/Bus—Baggage Area 0.76
Airport—Concourse 0.36
Audience Seating 0.54
Terminal—Ticket Counter 1.08
Warehouse
Fine Material Storage 0.95
Medium/Bulky Material Storage 0.58

 

 

 

Calculation of Crippling (Ultimate Transverse) Load on Electrical Pole


Calculation of Crippling (Ultimate Transverse) Load on Electrical Pole

  • Wind Speed = 89 Mile/Hr.
  • Height of Pole=10 Meter
  • Type of Pole =RCC
  • Height of Pole in Ground=1.5 Meter.
  • Pole Section on Bottom of Pole (Length x Width)=400mm x 150mm
  • Pole Section on Top of Pole (Length x Width)=127mm x 150mm
  • Conductor Mounting from top of Pole(g)=0.5 Meter.
  • Distance between Two Pole(s) =20 Meter.
  • No of Conductor on Pole(n)=3No’s
  • Size of Conductor(r)= 30mm

Calculations:

  • Wind Pressure = 00256 x 2x Wind Speed
  • Wind Pressure = 00256 x 2x 90 = 20.506 Pound /Sq.Foot
  • Wind Pressure(Wp) =4.882×20.506 = 100 Kgf/M2
  • Wind Load on Conductor/Span(ws)=2/3 x Wp x s x r x n
  • Wind Load on Conductor/Span(ws)=2/3 x 100 x 20 x 30 x 3 =120 Kg———–(I)
  • Height of Pole Above Ground (h)= 10-1.5 =8.5 Meter
  • Total Bending Movement at Ground Level due to Wind Load on All Conductor=ws x h
  • Total Bending Movement at Ground Level due to Wind Load on All Conductor(b)=120 x 8.5= 960 Kg.Mt
  • Equivalent Safe Working Load at said Meter from TOP of The Pole corresponding to Wind Load on All Conductors =b / (h- g) = 960 / 8.5-0.5 =120 Kg
  • Wind Load on Pole Surface above Ground Level (p1)=Wp x h /((l1+w1)/(2×1000))
  • Wind Load on Pole Surface above Ground Level (p1)=100×8.5/(400+150/2×1000) =233.75 Kg
  • Centre of Gravity of Tapering rectangular section of Pole(p2)= (h/3)x((l2+(l1*2))/(l1+l2))
  • Centre of Gravity of Tapering rectangular section of Pole(p2)= (5/3)x((127+(400×2)) /(127+400))=4.98Mt
  • Bending Movement at Ground Level due to Wind Load on Pole(p) =p1 x p2
  • Bending Movement at Ground Level due to Wind Load on Pole(p) =233.75×4.98=1164.98 Kg.Mt
  • Equivalent Safe Working Load at said meter from Top of The Pole corresponding to Wind Load on Pole(wt) = p /(h-g) =1164.98 / (8.5-0.5) = 62 Kg——————————(II)
  • Total Transverse Load at said meter from Top of The Pole (Due to wind Load on Conductors + Wind Load on Pole Surface) (T)=Ws + Wt = 120+145.62 =256.62 Kg
Type of Pole Safety Factor
Wooden Pole 3.5
RCC Pole 2.5
PCC Pole 2.5
Steel Tubular Pole 2
Rail/RSJ Pole 2
Struts (Steel Pole) 2.5
Struts (RCC/PCC) 3
PCC Pole for 33 KV 2

 

  • From Above Table Safety Factor=2.5
  • Total Transverse Load (Crippling Load) of Pole = T x Safety Factor
  • Total Transverse Load (Crippling Load) of Pole = 256 x 2.5 =664 Kg.
  • Total Transverse Load (Crippling Load) of Pole=664 Kg
Max. Length of Pole (Meter) Min. Ultimate Transverse Load from 0.6meter from Top (Kg)
17 3000
17 2300
17 2000
17 1400
16 1100
15 1050
14 1050
13 1000
12 800
11 600
10 500
9 300
8 200
7 200
6 200
5 150
4 150
3 150

 

  • From Above Table Min. Ultimate Transverse Load for 10 Meter Pole = 500 Kg and as per our calculation it is 664 Kg hence Selection of Pole if O.K

Results:

  • Calculated Transverse Load (Crippling Load) of Pole = 664 Kg

Various Factors for Illumination Calculations


Introduction:

  • Interior and exterior lighting design requires a reasonable uniform illuminance in all working areas.
  • There are two important factors in the planning or designing of lighting Scheme.
  • (1) Maintenance factors (MF)
  • (2) Utilization factor (UF)
  • The illuminance and luminance levels in a lighting installation do not remain constant over its period of operation. Over time, they decrease due to degradation and failure of light sources, soiling of lamps and luminaires due to the reduced reflectance values of the room surfaces. At g planning stage these factors need to be consider in the head of maintenance factor.
  • The right selection of maintenance factor for each lighting calculation at planning stage is depend upon some details like Type of Lighting Fixtures and Lamp, the environmental information , the cleaning intervals, Total Working Hours.
  • The Lighting Scheme may be satisfactory, economical, safe, colorful, effective, comfortable and energy efficient by choosing proper maintenance factor and utilization factor.

Importance of Maintenance Factor and Utilization Factor:

  • By choosing Constant M.F & U.F for any Project (Cost of Project)
  • We normally choose 0.8 as a Maintenance factor as a useful rule of thumb.
  • There is no reason why we choose M.F as 0.8 on every lighting installation project. Every project is different so the maintenance factor should be derive according to the circumstances and the lighting technology being used.
  • The Location and environment Condition (Cost and Life of Luminar):
  • The location where the luminaires is very important and which have an effect on light levels.
  • For close area like in industrial warehouse and in office we may select open type and without waterproof Lighting Fixtures.
  • For open Area, we should select close and waterproof fixtures.
  • Environment condition (Pollution, Clean) should effect on light levels hence directly effect on number of luminaire and space of luminar which effect Cost of Luminar.
  • For very long service life this criteria is impact on the overall maintenance factor.
  • Service life (Energy use and Cost)
  • It is very important to decide the service life of Luminar in calculations because it will lead to decisions on the initial light level and the number of installed luminaires.
  • This will mainly affect the amount of lighting required  and therefore have an impact on both capital and operational costs.
  • More Lights and Over Spacing (More Energy Bills)
  • The MF has a great impact on energy efficiency. If we select too much lighting in designing lighting project due to inaccurate maintenance factors, then the we will pay more electricity bills for that.
  • The products availability and Operating Time (Project Cost)
  • The correct maintenance factor for a lighting project has other benefits in terms of planning.
  • If we plan a 50,000-hour life in their lighting system (for 10Years of operation), But we use Luminars only a 7 years due to lease for an office space.
  • By changing this value, the LLMF will be changed and the amount of light and number of luminaires could be greatly reduced. This will save the money in the short and long-term.

Numbers of Factors for Illumination Calculation:

  • There are mainly below two Factors which are important while we design Illumination.
  • Utilization Factor (UF)
  • Maintenance Factor (MF)
  • Equation for Required Illumination is
  • E = N (n x φ) x MF x UF / A
  • N =( E x A) / MF x UF x (φx n)
  • Where:
  • N = Number of luminaires required
  • E = Maintained Illuminance (lux)
  • φ = Initial lamp output (lumens)
  • n = Number of lamps in luminaire
  • MF = Maintenance factor (sometimes also called light loss factor LLF)
  • UF = Utilization factor
  • A = Area of room (m2)

(1) UTILISATION FACTOR (UF):

  • The light flux reaching at the working plane is always less than the lumen output of the lamp due to some of the light is absorbed by the various surface textures.
  • Utilization Factor is Proportion of light reaching working plane to the light output of lamps.
  • UF = Lumens received on Working Plan / Lumens output of luminaires
  • The lighting manufacturers’ catalogues give Utilization Factors for standard conditions.
  • The UF is expressed as a number which is always <1.
  • A typical value might be 0.9 for a modern office building.
  • The Utilization Factor takes the account of Room Reflectance, Room shape, Polar distribution and Light output ratio of the fitting
  • Brighter colors with high reflectance result in a higher UF.
  • A high UF means Less Nos of lamps are required resulting in a more energy efficient light design.
  • Utilization Factor mainly depends on
  • (1) Type of light, light fitting.
  • (2) Color surface of walls and ceiling.
  • (3) Mounting height of lamps.
  • (4) Area to be illuminated.
  • (5) Room Index (Area and Mounting Height)
  • Room Surface Reluctance:
  • To determine the UF from the luminaire data sheet it is necessary to know the average room surface reflectance.
  • The ceiling is normally considered to be light in color and an average value of 70% (or 0.7) is normally used.
  • The Floor is usually considered to be dark and an average value of 20% (or 0.2) is normally used.
  • The walls, however, can vary from light to dark depending on the wall surface colors. Luminaire manufacturers usually provide UFs for three average wall reflectance of 50%, 30% and 10%. A value of 50% applies to walls of light decor, 30% moderate decor and 10% dark decor.

Table 1.7 Typical Reluctance Factors

Color

%

White

80% To 85%

Light gray

45% To 70%

Dark gray

20% To 25%

Ivory white

70% To 85%

Ivory

60% To 70%

Pearl gray

70% To 75%

Buff

40% To 70%

Tan

30% To 50%

Brown

20% To 40%

Green

25% To 50%

Olive

20% To 30%

Azure blue

35% To 40%

Sky blue

35% To 40%

Pink

50% To 70%

Cardinal red

20% To 25%

Red

20% To 40%

 Space Height Ratio (SHR):

  • The ratio of Distance between two luminaire centers, in a regular square array of luminaires, divided by their height above the working plane.
SPACING AND MOUNTING HEIGHT RATIO
Direct Concentrating 0.40
Direct Spreading 1.20
Direct Indirect Diffusing 1.30
Semi-direct-Indirect 1.50
  •  Room Index (RI):
  • This takes account of room proportions and height of the luminaire above the working plane.
  • It is used to determine the Utilization factor.
  • I. = L x W / (L + W) Hm
  • where
  • L = Length
  • W = Width
  • Hm = Height of luminaire above working plane. 
Utilization factor
Room Reflectance Room Index
Ceiling Wall Floor 0.75 1 1.25 1.5 2 2.5 3 4 5
0.7 0.5 0.2 0.43 0.49 0.55 0.6 0.66 0.71 0.75 0.8 0.83
0.7  0.3 0.2  0.35 0.41 0.47 0.52 0.59 0.65 0.69 0.75 0.78
0.7  0.1 0.2  0.29 0.35 0.41 0.46 0.53 0.59 0.63 0.7 0.74
0.5 0.5 0.2 0.38 0.44 0.49 0.53 0.59 0.63 0.66 0.7 0.73
 0.5 0.3 0.2  0.31 0.37 0.42 0.46 0.53 0.58 0.61 0.66 0.7
0.5  0.1 0.2  0.27 0.32 0.37 0.41 0.48 0.53 0.57 0.62 0.66
0.3 0.5 0.2 0.3 0.37 0.41 0.45 0.52 0.57 0.6 0.65 0.69
0.3  0.3 0.2  0.28 0.33 0.38 0.41 0.47 0.51 0.54 0.59 0.62
0.3  0.1 0.2  0.24 0.29 0.34 0.37 0.43 0.48 0.51 0.56 0.59
0 0 0 0.19 0.23 0.27 0.3 0.35 0.39 0.42 0.46 0.48

 (2) Maintenance factor (MF) / (Light Loss factor LLF):

  •  The Light Loss Factor has been replaced by maintenance factor in the 1994 CIBSE Guide.
  • Previously LLF and MF are differently mentioned but there is no account of the lamp lumen maintenance factor (LLMF).
  • In the 1994 Guide, maintenance factor (MF), LLMF and LSF are mention.
  • MF = RSMF x LMF x LLMF x LSF
  • Lamp Lumen Maintenance Factor (LLMF) decrease in luminous flux as per aging of the light source.
  • Lamp Survival Factor (LSF) takes into account the lamp’s service life without immediate replacement.
  • Luminaire Maintenance Factor (LMF) decrease in the output of the luminaires due to pollution.
  • Room Surface Maintenance Factor (RSMF) soiling or dusting in the Room space.
Quick Consideration of Maintenance factor
Room Classification Lamp Maintenance Factor Maintenance Factor for dirty lamp Total Maintenance Factor
Very clean 0.09 0.85 0.9
Clean 0.9 0.9 0.8
Average 0.9 0.8 0.7
Dirty 0.9 0.7 0.6

 

Environment Activity or Task Area

Very Clean Clean rooms, semiconductor plants, hospital clinical areas, computer centers
Clean Offices, schools, hospital wards
Normal dirty Dirty Shops, laboratories, restaurants, warehouses, assembly areas, workshops

Steelworks, chemical works, foundries, welding, polishing, woodwork

 

Quick Consideration of Maintenance Factor
Enclosed fixture, clean room 0.80
Average conditions 0.70
Open fixture or dirty room 0.60

 (A) Room Surface Maintenance Factor (RSMF): (dirt on the surfaces of the room)

  • It takes account of the effect of dirt and dust accumulation and other degradation of the reflectivity of the room surfaces.
  • The room surface maintenance factor is the ratio of the room surfaces reflectance before and after cleaning.
  • It depends highly on the conditions in a room like very clean, clean, dirty or very dirty.
  • The more dirty the room, the lower the maintenance factor.
  • RSMF is depending upon Room Surface Cleaning.
  • RSMF does not depend on LMF and LLMF.

Room Surface Maintenance Factor (Annual Clean) – RSMF

Type of Room

1 Year Room Clean

3 Year Room Clean

Direct Luminaires Direct /Indirect Luminaires Direct Luminaires Direct /Indirect Luminaires

Very Clean

0.97 0.96 0.97

0.95

Clean

0.95 0.91 0.94

0.91

Normal

0.91 0.84 0.9

0.83

Dirty

0.86 0.75 0.86

0.75

(B) Lamp Lumen Maintenance Factor (LLMF): (Lamp Aging)

  •  The lamp lumen maintenance factoris the ratio of light output of a lamp, after a specified number of hour’s operation, to the initial light output of the lamp.
  • It is describing the ageing of the lamp or the reduction of light intensity over time. Manufacturers offer comprehensive tables about their lamps luminous flux behavior.
  • Lamp Lumen Maintenance Factor takes accounts the effect of the decrease in Lumen of the light sources during its Life time Operation.
  • The LLMF expresses the usual reduction of the luminosity over the lifetime, e.g. by a factor of 0.92 after 2000 hours. After 2,000 hours the illuminant still emits 92% of the luminosity when new.
  • The lamp lumen maintenance factor considers the average decrease in luminous flux of the light source
Lamp Lumen Maintenance Factors (LLMF)
Lamp Type Operating Hours
4000 Hr. 6000 Hr. 8000 Hr. 10000 Hr. 12000 Hr.
High Pressure Sodium 0.98 0.97 0.94 0.91 0.9
Metal Halide 0.82 0.78 0.76 0.74 0.73
High Pressure Mercury 0.87 0.83 0.8 0.78 0.76
Low Pressure Sodium 0.98 0.96 0.93 0.9 0.87
Tubular Fluorescent 0.95 0.94 0.93 0.92 0.91
Compact Fluorescent 0.91 0.88 0.86 0.85 0.84

(C) Luminaire Maintenance Factors (LMF): (Dirt on lamp)

  • The luminaire maintenance factor is the ratio of the luminaires luminous flux before and after cleaning.
  • It depends on the luminaire construction and design (open housing or closed one) as well as on environmental conditions (dirty or clean).
  • The higher the luminaires protection degree from dust, and the cleaner the room, the higher the maintenance factor.
  • LMF is depending upon Type of Laminar, Location and Frequency of cleaning.
  • LMF Luminaire Maintenance Factor takes account of the effect of dust and dirt accumulation on the luminaire.
  • Luminaires are classified according to their degree of sealing and their distribution, obviously dust accumulation on an open up light is far more onerous than on a sealed downlight.
  • Dust and dirt build up on the rear Heatsink Increases LED temperature, lowers output and effects life

 

Luminar Maintenance Factor (LMF)
Type of Distribution Environment Condition Expose Time
1 Year 2 Year 3 Year 4 Year 5 Year 6 Year
Open Distribution Very Clean 0.96 0.94 0.92 0.9 0.88 0.87
Clean 0.93 0.89 0.85 0.82 0.79 0.77
Normal 0.89 0.84 0.79 0.75 0.7 0.67
Dirty 0.83 0.78 0.73 0.69 0.65 0.62
Direct Distribution Very Clean 0.95 0.92 0.89 0.86 0.84 0.82
Clean 0.9 0.84 0.79 0.74 0.7 0.67
Normal 0.86 0.8 0.74 0.69 0.64 0.6
Dirty 0.83 0.75 0.68 0.62 0.57 0.53
 Closed Distribution Very Clean 0.94 0.91 0.89 0.87 0.86 0.85
Clean 0.88 0.83 0.79 0.75 0.72 0.7
Normal 0.82 0.77 0.73 0.69 0.65 0.62
Dirty 0.77 0.71 0.66 0.61 0.57 0.53
Indirect-Distribution Very Clean 0.93 0.88 0.85 0.82 0.79 0.77
Clean 0.86 0.77 0.7 0.64 0.59 0.55
Normal 0.81 0.66 0.55 0.48 0.43 0.4
Dirty 0.74 0.57 0.45 0.38 0.33 0.3
  • Dirt on acclimation on Lamp Surface can be minimized by proper sealing of lamp compartment against entry of moisture and dust. This can be achieved by selecting proper IP rating of fixture.

(D) Lamp Survival Factor (LSF): (Lamp Failure Rate)

  • The % of lamps still operating in an installation after a specified number of hour’s operation.
  • LSF Lamp Survival Factor takes account of the effect of the failure of light sources during the maintenance period. (reduced light output due to lamps failing)
  • It is determined by the failure rate at the end of the estimated period of use of light sources.
  • The lamp survival factor depends on the service lifetime of a lamp.
  • Some lamp lifetimes are reduced by frequent switching.
  • The lamp manufacturers provide tables indicating the lamp survival factor.
  • If a lamp is not working any more, the decision for immediate replacement or group replacement needs to be taken. If the lamp is replaced immediately (mostly in areas where the luminaire is easily reachable) the LSF can be 1.
  • LSF 1 is saying that there will be no loss of light because of lamp failure.
  • On the other hand, the decision could be to replace lamps in special terms or GroupWise. This could be the case in huge halls, where machines need to be stopped to reach the luminaires. The stopping of the machines is connected to less production rates of the factory, so they won’t change each single lamp. 
Lamp Survival Factors (LSF)
Lamp Type Operating Hours
4000 Hr 6000 Hr 8000 Hr 10000 Hr 12000 Hr
High Pressure Sodium 0.98 0.96 0.94 0.92 0.89
Metal Halide 0.98 0.97 0.94 0.92 0.88
High Pressure Mercury 0.93 0.91 0.87 0.82 0.76
Low Pressure Sodium 0.92 0.86 0.8 0.74 0.62
Tubular Fluorescent 0.99 0.99 0.99 0.98 0.96
Compact Fluorescent 0.98 0.94 0.9 0.78 0.5

Example:

  • Calculate Utilization Factor and Maintenance Factor for Office having following Details.
  • Length of Room is 10meter and width of Room is 20Meter.
  • Lighting Fixture mounting Height is 3 Meter.
  • Room Wall color is ivory White. Ceiling Color is ivory White and Flooring Color is Dark Gray
  • Office Working hours: 5 days a week, 16h each day, 50 working weeks a year (4000h/a)
  • Type of Lamp : Compact Fluorescent
  • Type of Fixtures : Direct Luminaires
  • Room Surface: Cleaned
  • Room Cleaning Frequency: 1 time in Annum.
  • Total Lamp Working Hour : 16Hour/Day , 5Day/Week, 50Week/Year (4000H/Annum)

 Calculations:

Utilization Factor

  • Room Refection from above Table are
  • Wall=0.5. Ceiling=0.7and Flooring=0.2
  • Fixture Mounting Height is 3 Meter.
  • Room Index = L x W / ((L + W)x Hm)
  • Room Index=(10×20) / ((10×20)x3) =2
  • From Above Table Utilization Factor is 0.6

Maintenance Factor

  • Room Surface Maintenance Factor (RSMF):
  • Room is Clean and Frequency of Room Cleaning is 1time/Annum.
  • From Above Table RSMF if 0.95
  • Lamp Luminaire Maintenance Factor (LLMF):
  • Type of Lamp is Compact Fluorescent and Lamp Working hour is 4000Hr/Annum.
  • From Above Table LLMF if 0.91
  • Luminaire Maintenance Factors (LMF):
  • Lamp distribution is direct and Frequency of Room Cleaning is 1time/Annum..
  • From Above Table LMF if 0.9
  • Lamp Survival Factor (LSF):
  • Type of Lamp is Compact Fluorescent and Lamp Working hour is 4000Hr/Annum.
  • From Above Table LSF if 0.98.
  • Maintenance Factor = RSMF x LMF x LLMF x LSF
  • Maintenance Factor = 0.95×0.9×0.91×0.98
  • Maintenance Factor =0.76

 

 

Calculate Transformer Regulation & Losses (As per Transformer Name Plate)


Calculate Transformer Regulation and Losses for following Transformer Name Plate Details

  • KVA rating of Transformer(P)=16000VA
  • Primary voltage(Vp)=11000V
  • Secondary voltage(Vs)=433V
  • No load losses(W0)=72Watt
  • No load current(I0)=0.59Amp
  • Full load losses(W)=394Watt
  • Impedance voltage(Vi)=480Volt
  • LV resistance(Rs) =219.16 miliΩ
  • HV resistance(Rp) =215.33 Ω
  • Amb temperature(c)=30 Deg C
  • Total Connected Load on Transformer(Pl)=10000VA

Calculation:

  • % Loading of Transformer=Pl/P
  • % Loading of Transformer=10000/16000 = 63%

I2R Calculation:

  • HV Full load current (Ip) =P/Vpx1.732
  • HV Full load current (Ip) =16000/11000×1.732=0.84 Amp
  • LV Full load current (Is)=P/Vsx1.732
  • LV Full load current (Is)==16000/433×1.732=21.33 Amp
  • HV Side I2R losses= IpxIpxRp
  • HV Side I2R losses= 0.84×0.84×215.33=227.8 Watt—–(A)
  • LV Side I2R losses= IsxIsxRs
  • LV Side I2R losses==21.33×21.33×219.16=149.63 Watt—(B)
  • Total I² R losses @ Amb temp(Ir)=A+B
  • Total I² R losses @ Amb temp(Ir)=227.8+149.63=377.43 Watt
  • Total Stray losses @ Amb temp (Ws) =Full Load Losses-I2R Losses
  • Total Stray losses @ Amb temp (Ws) =394-377.43=16.57 Watt
  • I² R losses @75° c temp =Irx310/235xc =149.63×310/235×30 =441.52Watt
  • Stray loses @ 75° c temp  =(Wsx(235+c))/310
  • Stray loses @ 75° c temp  =(16.57x(235+30))/310=14.16 Watt
  • Total Full load losses at @75° c=441.52+14.16=455.69 Watt
  • Total Impedance at ambient temp (Ax)=Vix1.732/Ip
  • Total Impedance at ambient temp(Ax)=480×1.732/0.84=989.94Ω
  • Total Resistance at amb temp (Ar)=Ir/IpxIp
  • Total Resistance at amb temp (Ar)=377.43/0.84×0.84=535.15Ω
  • Total Reactance (X)=√AxxAx+ArxAr
  • Total Reactance (X)=√989.98×989.94+535.15×535.15=832.82Ω
  • Resistance at@ 75° c (R)= (310xAr)/(235+c)=310×535.15/235+30 = 626.03Ω
  • Impedance at 75° c (X1)=√2X+2R=√2×626.03+2×832.82 = 1041.88Ω
  • Percentage Impedance = (X1x0.5774xIpx100)/Vp
  • Percentage Impedance = (1041.88×0.5774×0.84×100)/11000=4.59%
  • Percentage Resistance (R%)  =(Rx0.5774xIpx100)/Vp
  • Percentage Resistance(R%) =(626.03×0.5774×0.84×100)/11000=2.76%
  • Percentage Reactance(X%) = (Xx0.5774xIpx100)/Vp
  • Percentage Reactance(X%) = (832.82 x0.5774×0.84×100)/11000=3.67%

Regulation

  • Regulation at Unity P.F =2.76
  • Regulation at Unity at 0.8 P.F =((R% x cosØ)+(X% x SinØ))+(0.005x((R% x SinØ)+(X% x CosØ)))
  • Regulation at Unity at 0.8 P.F =((2.76 x 0.8)+(3.67 x 0.6))+(0.005x((2.76 x0.6)+(3.67 x 0.8)))=4.43

Results

  • Total I² R losses @ Amb. temp(Ir)= 377.43Watt
  • Total Stray losses @ Amb. temp (Ws) =16.57 Watt
  • Regulation at Unity P.F =2.76
  • Regulation at Unity at 0.8 P.F =4.43

 

 

Type of Lighting Bulbs (Shapes and Sizes) Part-5


(5) BT (Blown or Bulbous Tube) Type HID Bulbs (Code: ET)

  • BT means “Blown or Bulbous Tube”.
  • (BT )The blown tube light bulb is a HID Tube Type (T) light bulb that has had the glass blown in the middle so that it appears to have a bubble in the middle of the tube.
  • BT halogen light bulbs can be used to replace incandescent light bulbs.
  • Nomenclature: BT28, BT37.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • BTR20 bulb: 20/8 = 2-1/2″ diameter
  • Lighting direction: illuminates its light in one direction.
  • Bulb Technology: High Intension Discharge Lamps, Metal Halide Lamp, Sodium Discharge, Mercury Vapor Lamp and LED.

  • Applications:
  • These are used in sports arenas, car dealerships, canopy lighting, and industrial applications.

Lighting Bulb according to Applications:

(1) Flood Light (Code: F)

  • A flood light is a large, powerful fixture which has a wide beam spread.
  • It is a high-intensity to illuminate a large area. Most often used outside.
  • Floodlights are mostly used to illuminate outdoor playing fields and sports events. It can also be used indoors for lighting stages to create an artificial daytime setting.
  • When choosing a floodlight, some points to be considering like Fixture types, Bulb Type, Type of mounting wall-mounted, ground-mounted and post top.
  • Nomenclature: F40, F20.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • Bulb Technology: Fluorescent , Metal halide lamps, LED, Halogen

  • Application:
  • Advertisement board and Subway
  • Airport and Architecture lighting
  • Football and tennis field
  • Tunnels and parks
  • Clubs, Bars, Hotels and Art galleries
  • Villa and parking lot

(2) Panel Lighting:

  • LED panel lights are very thin either surface or recessed mounted ceiling light.
  • Panel lights are square, Round or rectangular.
  • LED panel lights are high-grade indoor lighting lamps.
  • They are made of aluminum alloy by anodic oxidation.
  • It has simple design and appearance with adorable illumination effects.
  • It comes with different powers like 12W, 18W, 21W, 36W, 48W, 72W, and 85W.
  • It used for home application and easy to install by recessed application with clamping springs.
  • Recess mounted Slim Circular type LED color changing panel light in white finish with anti-glare diffuser and separate energy efficient electronic driver.
  • Nomenclature: Panel
  • Lighting direction: illuminates its light in one direction.
  • Bulb Technology: LED, CFL.

  • Applications:
  • Low-profile 6″ Round LED Panel Light for kitchen lighting, living room lighting, office lighting, basement lighting, museum lighting, hospital lighting.

(3) Down Light

  • Downlights in help to create a feeling of more space, clean lines, and a clutter-free environment.
  • A downlight is mostly hidden in or above the ceiling. The only visible part of the light fitting is the decorative rim, and the light bulb in the middle. Everything else is held in place in the ceiling by spring clips that stop the whole thing giving in to gravity and falling out.
  • Nomenclature: Down Light.
  • Lighting direction: illuminates its light in one direction.
  • Bulb Technology: LED, CFL.

  • Applications:
  • Downlight especially in kitchens and bathrooms have become very popular, as they provide a modern appearance to the room. More recently the trend has spread to every other room. Lounges, bedrooms and hallways all look great when fitted with recessed downlight.

Difference Between Panel Light and Down Light.

  • There is confusion between Panel light and Down Lights. Both Lights are either Round or Square shaped, so we cannot easily difference between them.
  • There are some differences between LED panel light and downlight in following points.
  • Structure
  • Both have a diffuser to spread out light. The panel light has a light guide plate (LGP) which guides light across the panel so that it is evenly spread. There is a reflector plate right at the back of the LED guide plate (LGP) which reflect lighting source.
  • The downlight does not have this type of arrangement.
  • Lighting
  • Inside LED panel light, the LED is fitted around (In a circular frame). The LGP and the diffuser gather the light and spread it creating an evenly soft lighting.
  • The downlight lighting on the other hand have a LED in the middle. Consequently, the light produced is brighter than in the round panel light.
  • Size of Heat Sink:
  • Typically, the downlight has a thicker heat sink than the panel light.
  • Fixture Thickness:
  • LED panel light is super thin, looks simple but stylish.
  • Fixture Size Vs Lumen:
  • To spread light uniformly all Panel light are made with high dimension fixture. As you increase output watt you will have to choose bigger and bigger.
  • Power Saving:
  • Panel lights are less power saver compared to Down Light.
  • Panel lights have efficiency of only 60-80 Lm/watt compared to down light which has efficiency of 100-120 Lm/watt.
  • Applications:
  • If you are looking for bright LED lighting, your best choice will be the downlight. However, if you are angling for a softer and relatively polished feel to the room, then go for the round panel.

(4) Strip Light

  • Strip lights are available in both tape and rope configurations.
  • Nomenclature: Strip
  • Lighting direction: illuminates its light in one direction.
  • Bulb Technology: LED

  • Applications:
  • Under-counter Lights, cove Lights, Display lighting and Exterior Lighting

 

Bulb Shapes and Applications

Code Bulb Shape Designations Type of Bulbs Applications
A Arbitrary Incandescent ,CFL ,LED, Metal Halide, High Pressure Sodium ,Mercury vapor, In household light.

Table lamps.

Wall Light, Ceiling lights.

AR Arbitrary with Reflector Incandescent ,CFL ,LED, Metal Halide, High Pressure Sodium ,Mercury vapor, In household light.

Table lamps.

Wall Light, Ceiling lights.

B Bulged Incandescent ,CFL ,HID,LED In various light fixtures,

Decorative Lights.

BT Blown Tubular Incandescent ,CFL ,HID,LED Less in general used,

In various light fixtures.

Table Lamp.

BR Bulged Reflector Incandescent ,CFL ,HID,LED In Track lighting (spot lights)

In recessed lighting.

MR Mirror Reflector LED In Track lighting
C Candle Incandescent ,CFL ,HID,LED Widely used in ceiling and table chandeliers and decorative light fixtures.

In small appliances and indicator lamps

They have a smaller base.

CA Candle Angular Incandescent ,CFL ,HID,LED Like Candle bulbs, used in chandeliers and similar light fixtures.

They also often have a smaller base.

CW Candle Twisted Incandescent ,CFL ,HID,LED These are used in chandeliers and have smaller bases.
CP Crystalline Pear Incandescent ,CFL ,HID,LED Used in various decorative light fixtures

in wall lights, ceiling lights and table lamps.

To create interesting reflective effects.

E Ellipsoidal Incandescent ,CFL ,HID,LED Widely used in various light fixtures.
ER Extended Reflector Incandescent ,CFL ,HID,LED in track lighting and other fixtures for spot lights.
F Flambeau Incandescent ,CFL ,HID,LED in chandeliers and similar decorative interior lighting fixtures.
G Globe Incandescent ,CFL ,HID,LED Widely used in ceiling and table lamps.

in Bathrooms.

In ornamental lighting and some floodlights

GA Decorator Incandescent ,CFL ,LED Used in ceiling lamps, table lamps and other decorative fixtures.
HX Hexagonal Candle Incandescent ,CFL ,LED Used in chandeliers and other decorative light fixtures to create beautiful reflective light effects.
P Pear Incandescent ,CFL ,LED Used in various light fixtures.

In standard for streetcar and locomotive headlights

PAR Parabolic Aluminum Reflector Incandescent ,CFL ,LED Widely used in track lighting and spot light fixtures.

used in floodlights

PC Ogive Incandescent ,CFL ,LED Used in decorative light fixtures.
PS Pear Straight Incandescent ,CFL ,LED Used in various light fixtures.
R Reflector Incandescent ,CFL ,LED Widely used in Recessed cans  and track lighting ,spot light fixtures.
S Straight Sided Incandescent ,CFL ,LED Used in various light fixtures.

lower wattage lamp as sign and decorative

ST Straight Tubular Incandescent ,CFL ,LED Used in various light fixtures.
T Tubular Incandescent ,CFL ,LED Used in various light fixtures according to functional rather than decorative purposes.

Showcase and appliance lighting =In closets/garages.

TA Tubular Angular Incandescent ,CFL ,LED Used in various light fixtures, often for decorative effect.

 

 

 

 

Type of Lighting Bulbs (Shapes and Sizes) Part-4


What is difference between R,BR,MR and PAR bulbs

(1) Difference between an R and BR Bulb

  • There is confusion between selecting R and BR type of Bulbs.
  • There is minor difference between R and BR type Bulb.
  • Both types of Bulbs have a reflector flood, and that is what the R stands for in the code.
  • The R is an old design for reflectors that are not as energy efficient as a BR reflector.
  • The BR was designed to replace the older R.
  • For same Light output and size in length and width, BR Bulb use less watts (due to the reflector in a BR is more directed) hence BR Bulb produce less heat and more efficient.
  • Both of these lamp types are interchangeable.
  • BR is an upgraded version of R 

(2) Difference between PAR and BR / MR Bulb:

  • The main difference between PAR and MR is according to its Size, variety, and heat transformation.
  • The primary difference between these bulbs is according to Beam Angle, internal construction and as per Reflector.
  • Different Type of Beam Angles.
  • BR (for bulged reflector) bulbs are lamps with “wide flood” beam angles, which means that they provide more than a 45 degree angle when lighting an area.
  • PAR (Parabolic Aluminized Reflector) bulbs are available in these angles:
  • Narrow spot (5 to 15 degrees)
  • Spot, (16 to 22 degrees)
  • Narrow flood,( 23 to 32 degrees)
  • Flood, (33 to 45 degrees(
  • Wide flood beam, over 45 degrees.

  • Different Type of Reflector and Application of Bulb.
  • The BR bulbs have a frosted/patterned coating of reflector (for broad beam angle ) allows to less concentrated light and provides better coverage thus eliminating shadows in the intended area hence BR Bulb produces less shadow than PAR bulbs.
  • BR Bulbs are commonly used indoors in household ceilings like in kitchens, family rooms, and stair lighting with high ceilings with recessed type.
  • The reflective surface of PAR does not allow light to spread much further than the angle of the beam spread hence PAR lamps deliver strong, narrow to wide, directional light , which is little harsher where the light starts and where it ends.
  • A PAR bulb is used in indoor/outdoor security lighting, theatre, performance sets, and spot-lighting signs and restaurant lighting applications as well.
  • Different Type of Construction and Heat dissipation.
  • BR bulbs are a common reflector lamp with a bulged reflector. They are incandescent, LED bulbs. The sides of the outer part of the blown glass bulb are coated with a reflecting material that directs light. The light transmission pattern can be clear, frosted, or even patterned.
  • PAR bulbs are incandescent, tungsten-halogen, metal halide, LED Bulbs. They have a hard glass cover which is hermetically (airtight) sealed to the reflecting surface. Inside there is a lenses that controls beam spread and cannot be altered in position in relation to the filament. There are flood bulbs and spot bulbs. Flood bulbs diffuse or scatter light, while spots focus all light in one direction.
  • MR type bulbs have dichotic glass reflectors while PAR bulbs have aluminized glass reflectors which direct the heat generated by the bulb to the front of the bulb. Due of this, PAR bulbs are not suitable for ceiling installations of 8 feet or lower.
  • PAR bulbs also produce more directional yet duller lighting and have a standard, medium screw-in type of base and work in medium sized E26 sockets.
  • MR on the other hand, generates heat to the rear of the bulb and produces a lot more light for the wattage because of the multi-faceted reflector (MR).

Lighting Bulb according to HID Technology:

(1) E (Elliptical) Type HID Bulbs (Code: E)

  • E means HID Type light bulb that has a shape of “Elliptical”.
  • E Type Halogen light bulbs can be used to replace incandescent light bulbs. High intensity discharge light bulbs.
  • Nomenclature:
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • E20 bulb: 20/8 = 2-1/2″ diameter
  • Lighting direction: illuminates its light in one direction.
  • Bulb Technology: incandescent, CFL, High Intension Discharge Lamps, Metal Halide Lamp, Sodium Discharge, Mercury Vapor Lamp and LED.

(2) ED (Elliptical Dimple) Type HID Bulbs (Code: ED)

  • ED means “Elliptical Dimple”.
  • ED light bulbs have an elliptical shape to house the arc tube of a high intensity discharge light bulb.
  • They are not as efficient as their alternatives, but their use may be dictated by color rendering requirements. The lamps require only ballast for additional control.
  • Inside surfaces coated with europium-activated phosphor which converts the UV elements in ’warm’ light to produce a cool white light. They are an acceptable alternative to fluorescent lighting
    Nomenclature: ED17.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • EDR20 bulb: 20/8 = 2-1/2″ diameter
  • Lighting direction: illuminates its light in one direction.
  • Bulb Technology: High Intension Discharge Lamps, Metal Halide Lamp, Sodium Discharge, Mercury Vapor Lamp and LED.
  • Applications:

  • ED light bulbs are used in sports arenas, high bay industrial lighting, parking lots and garages and car dealerships.
  • These lamps are used in some industrial, warehousing applications as a floodlight and other suitable light fittings with appropriate ballast gear.
  • FEATURES & BENEFITS
  • Metal Halide HID light bulb produces high light output
  • Ideal for various commercial and industrial applications where color rendering is important
  • RECOMMENDED USES
  • Retail areas
  • Area lighting
  • Accent lighting
  • Sports lighting
  • Security lighting
  • Parking garages

(3) ER (Elliptical Reflector) Type HID Bulbs (Code: ER)

  • ER means “Elliptical Reflector”.
  • In ER bulb, the elliptical reflector increases the overall lumen output by redirecting side light of Bulb (Which is normally lost) to the redirect it to the forward Side of Bulb.
  • Elliptical (ellipsoidal) reflector light bulbs are uniquely designed to project light further than other reflector bulbs. They are a great option for use in deep recessed can lights as they lose less light in baffles than standard BR or R type bulbs. 
  • ER halogen light bulbs can be used to replace incandescent light bulbs. High intensity discharge light bulbs.
  • An incandescent lamp with a built-in elliptically-shaped reflecting surface. This shape produces a focal point directly in front of the lamp which reduces the light absorption in some types of luminaires. It is particularly effective at increasing the efficacy of baffled down lights.
  • Nomenclature: ER28, ER37.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • ER20 bulb: 20/8 = 2-1/2″ diameter
  • ER30 bulb: 30/8 = 3-3/4″ diameter
  • ER36 bulb: 36/8 = 4-1/2″ diameter
  • Lighting direction: illuminates its light in one direction.
  • Bulb Technology: incandescent, CFL, High Intension Discharge Lamps, Metal Halide Lamp, Sodium Discharge, Mercury Vapor Lamp and LED.

  • Applications:
  • The most common size is ER30. These light bulbs are used for down lighting in recessed cans for residential, hotel, and office applications.

Type of Lighting Bulbs (Shapes and Sizes) Part-3


Lighting Bulbs According to Reflector:

(1) R (Reflector) Type Bulb (Code: R)

  • “R” stands for Reflector.
  • This light bulb contains a mirrored coating on the back of the light bulb that maximizes the direction of the light which emitted by Bulb.
  • Traditionally, inside of R type Bulb was covered with a reflector material coating that used to gather light and cast it away from the bulb. Nowadays, R type bulbs have an evenly frosted coating that works to diffuse light and prevents glare.
  • Unlike the PAR bulb, the entire envelope of R type bulb, excluding the base is constructed by using blown glass and the exterior part of the bulb is very smooth. The few components of this bulb which includes a brass base, a thin glass and filament make it lightweight.
  • Reflective Coating of Bulb In Reflector (R) or Bulged Reflector (BR) bulbs directs light forward side , while Flood types (FL) bulb spread light and Spot types (SP) concentrate the light.
  • Reflector (R) bulbs put approximately double the amount of light (Lumen) on the front central area as General Standard “A” Shape Bulb for same wattage
  • Nomenclature:
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • R20 bulb: 20/8 = 2-1/2″ diameter
  • Lighting direction: one direction.
  • Bulb Technology: incandescent , LED,  tungsten-halogen, CFL

  • Application:
  • The R type bulb is usually not waterproof but can be used in a fixture protected from the weather as long as it is not sealed.
  • Reflector light bulbs are used mainly in recessed Lights for hotels, restaurants, retail and residential lighting.
  • R bulbs are ideal for display lights as well as for providing soft ambient and directional light. The right place to use R bulbs is in hallways, in a kitchen, living room, media rooms or pool area.
  • R Type floods provide a wider beam angle with a soft edge and are perfect for recessed down lights, track lighting, display lighting and various outdoor fixtures.

(2) BR (Bulged Reflector) Type Bulb (Code: BR)

  • BR stands for “Bulged Reflector”.
  • The ‘bulge’ allows the light to be distributed in a manner which is very pleasing to our eye.
  • R shapes have largely been replaced by the more efficient “bulged reflector” BR shape. 
  • BR lamps are a new and improved version of the R Type reflector lamp. The primary difference is the “bulge” in the shape of lamp. This shape focuses more light into the beam of light to direct it out of the recessed fixture.
  • In traditional, the inside surface of BR bulb is covered in reflector material that is used to gather and cast a wide beam of light away from the bulb.
  • It is considered a wide-angle floodlight often exceeding 100-degree beam angles.
  • However in LED BR bulbs do not require the reflector material coating.
  • These bulbs can have a frosted, clear, or patterned dome-shaped lens that diffuses light and provides a gradual fade into no illuminated areas.
  • BR bulbs also produce less shadow compared to PAR bulbs. They have a bit longer than PAR bulbs and tend to protrude from light housings but are used in similar applications, such as track lights, recessed lights, display lights, or can lights.
  • As per the comparison to the R20 and BR20, the glass part of BR20 is more curved.
  • One disadvantage of the BR lamp is that it’s a little longer than the PAR and MR, which means it tends to sit lower in the recessed fixture and perhaps, protrude from the bottom of the recessed light fixture.
  • The light transmission pattern can be clear, frosted, or even patterned.

  • Nomenclature: BR20, BR40.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • BR20 bulb: 20/8 = 2-1/2″ diameter
  • Lighting direction: one direction.
  • Bulb Technology: incandescent , LED,  tungsten-halogen, CFL
  • Application:
  • The BR bulbs kind of balloon out of Light fixtures. Often they are bulging down just below the ceiling from recessed fixtures.

(3) MR (Mirror / Multi Reflector) Type Bulb (Code: MR)

  • MR stands for “Multi-faceted Reflector”.
  • MR Bulb use mirror as a technique for reflecting the maximum light out in the front of a lamp, It help gather light from the filament to create a very concentrated light beam (narrower light beam).
  • It is normally used for small lamps. It is the narrowest of the bulb types (2 inches in diameter or less) mostly used as a spotlight.
  • MR Lamps provide various beam spread (narrow flood, flood and spotlight).
  • LED MR doesn’t require tiny mirrored squares to put the light where we want it to be.

  • Nomenclature: MR11, MR16.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • MR11 bulb: 11/8 = 1-3/8″ diameter
  • Lighting direction: one direction.
  • Bulb Technology: incandescent , LED
  • Applications:
  • It is used for accent and spot lighting in various retail, residential, commercial applications, track lighting and all kinds of display case lighting.
  • These bulbs are available in a variety of colors and can be used for many applications, including track lighting, recessed lighting, desk lights, and display case lighting.
  • Many MR bulbs operate on low-voltage wiring systems, which makes them great for outdoor and landscape applications such as driveway lights, path lights, gazebo lights, paver lights that have weatherproof housings.
  • A light bulb, often a halogen style, that plugs into the socket with two prongs, it’s often used in kitchen settings.

 (4) PAR (Parabolic Aluminized Reflector) Type Bulb (Code: PAR)

  • PAR means “Parabolic Aluminized Reflector”.
  • PAR Bulb uses an aluminized reflector in a parabola shape for directing the light.
  • Bulb is covered with a hard glass lens to control the light beam, which is available in a variety of beam spreads from narrow spot to wide flood. This hard glass covering also helps to withstand harsh environmental conditions.
  • Parabola shape Reflector (U-shaped) collect and reflect the light out the front of the bulb, produces a tighter and more controlled beam of light than standard reflector bulbs.
  • PAR bulbs are commonly used in stage and theatrical lighting, as well as in the home for accent and art lighting. Many halogen spot and flood lights use a parabolic (however this technique is generally not required in LED lamps).
  • It is best used for a focused, narrow beam of light.
  • Most PARs do not exceed a beam angle of 45 degrees in most cases. 
  • If brightness is priority in a recessed light, than we need to select a PAR lamp in the appropriate size.
  • These bulbs have a shorter body than BR bulbs and usually install flush with ceilings or fixtures, which reduces glare.
  • PAR’s look a more modern, and often have a clear lens
  • Unlike R Type bulbs, PAR bulbs feature an aluminum reflector with a special pattern of impressions that amplifies and concentrates light in a single area.
  • The bulb envelope is made of two pieces, the glass face and the shiny aluminum wall of the envelope. The texture of the bulb will be either rough or textured and the bulb will be heavier than an R Type bulb due to thicker glass construction.
  • Both LED PAR bulbs and CFL PAR bulbs are easy to find, though they are not always weatherproof like traditional halogen so be sure to check their IP listing before installing them outdoors.  
  • This PAR shape is very similar to the R shape and in some cases the PAR and R is interchangeable as per shapes but PAR LED bulbshave a shorter body than R type bulbs.

  • Nomenclature: PAR36, PAR20.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • PAR20 bulb: 20/8 = 2-1/2″ diameter
  • PAR30 bulb: 30/8 = 3-3/4″ diameter
  • Lighting direction: PAR illuminates its light in one direction having various Beam Angles.
  • 12° to 20° = Spot
  • 25° to 30° = Narrow Flood
  • 35° to 40° = Flood
  • >45° = Wide Flood
  • Bulb Technology: incandescent, tungsten-halogen, metal halite and LED.
  • Applications:
  • PAR Type floods provide a tighter beam angle with a hard edge and act more like a spot light and used both indoor and outdoor applications.
  • PAR LEDs are perfect for track lighting, recessed lighting and Down Lighting and flood lights.
  • Unlike R or BR bulbs that offer general area lighting, PAR shaped bulbs have more sharply focused light to help highlight specific areas or objects like in indoors to emphasize one area of a room over the rest of the room, or to highlight a piece of art, furniture or retail items in commercial .
  • These bulbs come in a variety of “beam angles” or “beam spreads” to meet these highlighting needs; the smaller the beam angle, the smaller an area the light will cover.
  • Ceiling Light Fixtures, Flood Light, soft light fixtures, garage security light, kitchen can light.
  • These bulbs run on low-voltage and suitable for outdoor fixtures as either spotlights (narrower beam angle) or floodlights (wider beam angle) and other outdoor applications like landscape lighting applications such as architectural lights, driveway lights, path lights, gazebo lights, and paver lights, clothing store, museum and gallery applications..
  • They’re commonly found in outdoor emergency light, spot light, or floodlight fixtures but can also be used indoors for track lights, recessed lights, display lights, or can lights.

Type of Lighting Bulbs (Shapes and Sizes) Part-2


(6) S (Straight Side) Type Bulb (Code: S)

  • “S” means Straight Side.
  • Nomenclature:
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • S20 bulb: 20/8 = 2-1/2″ diameter
  • Lighting direction: Uni direction.
  • Bulb Technology: incandescent , LED,  tungsten-halogen, CFL

  • Application:
  • S type miniature light bulbs are found in many applications including: indicator, auto stop and turn signal lights, scientific and medical instruments, microscopes and aircraft.

(7) T (Tubular) Type Bulb (Code: T)

  • T means “Tubular”.
  • It is known as “T” type because it has a shape of cylindrical Tube.
  • (T )Tubular type light bulb is available in wide bulb technology like Incandescent, Linear fluorescent, HID and LED.
  • T light bulbs have very different applications according to its shape.
  • Incandescent T6 light bulbs are used in exit and stairway signs and picture lights.
  • Linear fluorescent T12, T10, T8, and T5 light bulbs come in a variety of lengths, ranging from 2 to 8 feet. These light bulbs are used for general lighting in offices, retail outlets, hospitals, and parking garages.
  • High intensity discharge light bulbs also come in T shapes, including T9 and T15. These light bulbs are used in sports arenas, billboard signage, and industrial applications.
  • Tube Type bulbs are available in different shape like
  • Linear Tube Light Shape:
  • T12, T8 and T5 are naming convention for tube lights where “12” is the thickest and “5” is the slimmest tube light. 
  • U-Bend :
  • U-Bend Tube light bulbs T8 is created by bending a 4-foot length T light bulb into a U shape in order to reduce the maximum overall length of the light bulb. This is desirable in some locations that have limited space. By bending a 4-foot light bulb into a U configuration that is comparable to a 2 foot light bulb in length, the end user will receive double the light output in the smaller space. This light bulb is used in offices, hospitals, and retail applications.
  • Spiral Shape:
  • The spiral light bulb is the shape of a compact fluorescent light bulb. A smaller diameter fluorescent T light bulb, such as T4, T3, T2, or T1, is twisted into a spiral or coil configuration in order to provide the most amount of light output in the least amount of space.
  • Spiral light bulbs are typically used to replace incandescent light bulbs and can be used virtually anywhere, including residential, commercial, retail, hospitality, and restaurant applications.
  • Nomenclature: T4, T8.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • T8 bulb: 8/8 = 1″ diameter
  • Lighting direction: illuminates its light in Omni direction.
  • Bulb Technology: Incandescent, CFL, High Intension Discharge Lamps, Metal Halide Lamp, Sodium Discharge, Mercury Vapor Lamp and LED.

  • Applications:
  • Depending on their size, these bulbs can be used in applications ranging from chandeliers, wall sconces, and pendant lights to basement and garage light fixtures.
  • Exhibition hall, showing and advertising board
  • Industry plant, workshop, warehouse
  • Sports lighting, stadium, gymnasium and car parking area
  • Flood lighting for tunnel, port, viaduct, Public Square and construction site etc.

(8) Double Ended Type Bulb (Code: T3)

  • It is “T” Type cylindrical Tube Blub having a both end connection.
  • Double ended Bulb (T3) is installed in horizontal position.
  • These light bulbs are a cost-effective alternative to standard light bulbs and a completely dimmable in multiple lighting applications
  • Nomenclature:
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • T3 bulb: 3/8 = 0.3″ diameter
  • Lighting direction: illuminates in Omni direction.
  • Bulb Technology: Incandescent, Metal Halide, halogen, LED.

 

  • Application:
  • Mostly used in commercial lighting, ambient lighting and flood lighting.
  • It can be horizontally installed. With a compact size it provides a uniform lighting for a large area.

 (9) PS (Pear shape) Type Bulbs (Code: PS)

  • PS means “Pear shape”.
  • Pear shape light bulbs are similar to A Type light bulbs, except they have a larger diameter, which causes the bulb to look like a pear.
  • Nomenclature: PS30,PS40.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • PS15 bulb: 15/8 = 1-7/8″ diameter
  • Lighting direction: illuminates its light in Omni direction.
  • Bulb Technology: incandescent, LED, CFL.

  • Application:
  • Office buildings and retail stores, Radio towers, cellular towers, bridge power lines, and high tension wires.

(10) S (Sign) Type Bulbs (Code: S)

  • S means “Sign light”.
  • Sign light bulbs also known as the “original light bulb” of the incandescent.
  • Sign Bulbs also used in low-wattage lights.
  • Sign Bulbs come in clear, frosted and colored options.
  • Sign Bulbs available in transparent amber, blue, green, pink, red and yellow.
  • Nomenclature: S30, S40.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • S15 bulb: 15/8 = 1-7/8″ diameter
  • Lighting direction: illuminates its light in Omni direction.
  • Bulb Technology: incandescent, LED, CFL.

  • Application:
  • Ideal for multiple residential and commercial uses with incandescent lamps features excellent light output and good optic control along with dimming capabilities.
  • Sign light bulbs are found in outdoor signs used by casinos, hotels, restaurants, and theatres.
  • Sign lamps can be as simple as a way to promote your business by eye-catching company Signage installations.

Type of Lighting Bulbs (Shapes and Sizes) Part-1


Introduction:

  • There are various Shapes of bulbs available in market. Some lamp shape is widely used on other hand some lamp shape is used in special requirements.
  • If we properly understand bulb codes, it’s easy to select appropriate bulb for a light fixture.
  • Bulbs shapes are mostly classified according to direction of lights, lighting glare and Bulb size.
  • Every light bulb has identifying characteristics that are represented by a letter or series of letters and a number, these are known as light bulb codes.

Types of Lamps in a Lighting system

  • There are following types of lamps which are available in different shapes.
  • Incandescent lamps
  • Fluorescent tube
  • Compact fluorescent lamps (CFL)
  • Halogen lamps
  • Light Emitting Diode (LED)
  • Neon lamps
  • High intensity discharge lamps
  1. Metal Halide.
  2. High-Pressure Sodium
  3. Low-Pressure Sodium
  4. Mercury Vapor

Nomenclature of Bulb:

  • The Bulb Code is indicating as a Letter-Number-Letterformat, the last letter is optional.
  • The First Letter in a bulb code indicates either shape or special features such as reflector type.
  • The Second Letter (Number) in a bulb code indicates size of Bulb in millimeters or eighths of an inch .It will tell us whether the bulb will fit in fixture or not.
  • The Third Letter is optional which indicate Bulb length.
  • Example: BR30S
  • First Letter: BR=” Bulged Reflector”
  • Second Letter = diameter of Light Bulb =30/8 inches, or 3 and 3/4 inches.
  • We can say that PAR30, R30 and BR30 all have same size bulb.
  • Knowing the diameter and sizes of these light bulbs is important because in some unique cases the R and PAR are interchangeable as LED bulb replacements.
  • If in Code there is “S” or an “L” indication in last, that stands for either short neck or long neck.

Shapes of Lighting Bulbs:

  • There are following Shapes of Lamps, Some are very common in everyday uses while some are use in special requirements.
  • According to Shape:
  1. A (Arbitrary) Type Bulb (Code: A)
  2. B (Blunt Tip) Type Bulb (Code : C )
  3. C (Candle / Flame Tip ) Type Bulb (Code : C , CA)
  4. F (Flame Tip ) Type Bulb (Code : F)
  5. G (Globe) Type Bulb (Code: G)
  6. S (Straight Side) Type Bulb (Code: S)
  7. T (Tubes) Type Bulb: (Code : T,T3)
  8. Double Ended Type Bulb (Code:T3)
  9. Pear Shape Type Bulb (Code: PS)
  10. Sign Type Bulb (Code : S)
  11. H (Chimney ) Type Bulb (Code: H)
  • According to Reflector:
  1. R (Reflector) Type Bulb (Code : R)
  2. BR (Bulged Reflector) Type Bulb (Code : BR)
  3. MR (Mirror Reflector) Type Bulb (Code : MR)
  4. PAR (Parabolic Aluminized Reflector) Type Bulb (Code : PAR)
  • According to HID:
  1. E (Elliptical) Type Bulb (Code : E)
  2. ED (Elliptical Dimple) Type Bulb (Code : ED)
  3. ER (Elliptical Reflector) Type Bulb (Code : ER)
  4. BT (Blown or Bulbous Tube) Type Bulb (Code : ET)
  • According to Application:
  1. Flood Light (Code: E)
  2. Panel Light (Code: Panel Light)
  3. Strip Light
  4. Down Light (Code: GU)
  5. Recess Down Light (Code: Down light)
  6. Spot Light
  7. Corn Type Bulb
  8. Flat Tube
  9. High Bay
  10. RGB Light
  11. Street Light

Lighting Bulb according to Shape:

(1) A (Arbitrary) Type Bulb (Code: A):

  • A Means “Arbitrary”. It shape looks like ordinary Light Bulb.
  • It is also known as “Classic Globe Type” or “Standard shape Type” Bulb.
  • Thislamp is the most commonly used as household lamp.
  • It is normally used in fixtures where the bulb is visible.
  • It is not known that why it known as A Type. It doesn’t look like an A Shape until we turn it down.
  • We can assume that this is the first type of light bulb introduce in market hence it called “A” Type.
  • Nomenclature: A35, A20.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • A15 bulb: 15/8 = 1-7/8″ diameter
  • Lighting direction: Omni direction.
  • Bulb Technology: incandescent, LED, CFL.

  • Application:
  • Standard / arbitrary (A) bulbs are normally widely used in Household lighting.
  • These bulbs work well for a variety of applications, such as ceiling lights, lamps, vanity lights, kitchen lights, closet lights, porch light fixtures, Room lighting, Reading lamps, Ceiling Light, Wall Light and Hallways Light. It also used in some chandeliers.

(2) B (Blunt Tip) Type Bulb (Code: B):

  • “B” means Blunt-tip.
  • This is a slimmer version of the Type A Bulb.
  • The bulb is generally in narrow and bullet shape.
  • B bulbs are very similar to C-type bulbs but they have a bulged base that tapers to a pointed tip hence look like a torpedo or bullet shape.
  • It is available in Clear or Frosted(opal)
  • Nomenclature:
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • B10 bulb: 10/8 = 1-1/4″ diameter
  • Lighting direction: Omni direction.
  • Bulb Technology: incandescent, LED, Tungsten-halogen, CFL.

  • Application:
  • This is most often used for decorative purposes and chandeliers, wall sconces, pendant lights.
  • It is also used in low wattage applications as a home lighting applications and night lights.

(3) C (Candle / Flame Tip) Type Bulb (Code: C, CA):

  • “C” means Conical or Candle and “CA” means Conical Angular.
  • CA bulbs are shaped like a cone but have a bent tip.
  • The shape of this Bulb is look like as a candle flame and referred to as candle bulbs.
  • Candelabra Light Bulbs are similar as B Shaped bulbs but bulb’s tip is bent giving the slight look of a flicking flame.
  • It is available in Clear or Frosted(opal)
  • Nomenclature:
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • C7 bulb: 7/8 = 7/8″ diameter
  • Lighting direction: Omni direction.
  • Bulb Technology: incandescent , LED,  Tungsten-halogen , CFL

  • Application:
  • These bulbs are common in chandeliers and decorative light strands, holiday light strands, pendant lights, and night lights.
  • We choose a blunt shape in more contemporary chandeliers if the bulb were seen.
  • It also use in low voltage application and as s night lights.

(4) F (Flame Tip) Type Bulb (Code: F):

  • “F” means “Flame” .
  • F light bulbs are similar in size and shape to C Type light bulbs.
  • However the glass of the bulb is blown or etched in such a way that causes the light to look as though it is flickering like a flame.
  • This bulb comes with a white finish, but to achieve candle-like appearance, a clear finish is preferred.
  • If the bulb is colored, a transparent color allows the filament to be visible.
  • It is available in clear or frosted(opal)
  • Nomenclature:
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • F10 bulb: 10/8 = 1-1/4″ diameter.
  • Lighting direction: Omni direction.
  • Bulb Technology: incandescent , LED,  Tungsten-halogen , CFL

  • Application:
  • F light bulbs are used in decorative applications such as chandeliers, bathrooms, and restaurants and commercial applications..

 (5) G (Globe) Type Bulb (Code: G)

  • G means “Globe.
  • Globe (G) bulbs have a full, round shape and are available in various sizes
  • It is available in candelabra or medium base.
  • Nomenclature: G15, G20.
  • Numbers in each code refer to the bulb’s diameter in one-eighths of an inch.
  • G15 bulb: 15/8 = 1-7/8″ diameter.
  • Lighting direction: Omni direction.
  • Bulb Technology: incandescent , LED,  tungsten-halogen

  • Application:
  • Globe light bulbs are used in decorative applications in theatres, restaurants, and hotels
  • Globe light bulbs are used in a variety of applications where a decorative ball shaped light source is required such as ceiling fans, accent fixtures, kitchen lights, bathroom and makeup vanities, chandeliers, ornamental fixtures and table lamp, wall and floor lamps.

Methods of Earth Resistance Testing (Part-3)


(3) Two Point (Dead Earth) Method.

  • This method is used where the driving of ground spike is neither practical nor possible
  • To perform this test we have access to a good known ground such as an all metal water pipe. The water pipe should be extensive enough and be metallic throughout without any insulating couplings or flanges.
  • This method is not as accurate as three-point methods (62% method), as it is particularly affected by the distance between the tested electrode and the dead ground or water pipe

Required  Equipment:

  • Earth Tester (4 Terminal or 3 Terminal)
  • 2 No’s of Insulated Wires
  • Hammer

Connections:

  • In This method, the resistance of two electrodes in a series is measured by connecting the P1 and C1 terminals to the ground electrode under test; P2 and C2 connect to a separate all-metallic grounding point like a water pipe or building steel.
  • The earth electrode under test must be far enough away from the secondary grounding point to be outside its sphere of influence.

Testing Procedure:

  • Press START and read out the resistance value. This is the actual value of earthing resistance of the ground electrode under test.
  • Record the reading on the Field Sheet at the appropriate location. If the reading is not stable or displays an error indication, double check the connections.
  • Two terminals testing of earth resistance is appropriate for most general purpose testing in normally conductive soil.
  • Two terminal measurements include less test lead and contact resistance in the measurement and the result will be a reading slightly higher than the true earth resistance.
  • When measured results are higher than desired or if measurement directives require multi terminal techniques, switch to the 3 or 4 terminal techniques as needed.

1

Advantage:

  • It does Not Require Disconnecting Equipment
  • This is the simplest way to obtain a ground resistance reading.
  • It is most effective for quickly testing the connections and conductors between connection points.
  • Required Less Test Lead.
  • Required small area for Measurement.

Disadvantage:

  • This is not as accurate as the three-point method and should only be used as a last resort.
  • Non-metallic (high resistance) return Resistance areas should not overlap.

  (4) Clamp-on test method

  • For the clamp-on method to be effective there must be a complete grounding circuit in place. The tester measures the complete resistance path (loop) that the signal is taking. All elements of the loop are measured in series.
  • The Induced Frequency testing or commonly called the “Clamp-On” test is one of the newest test methods for measuring the resistance-to-ground of a grounding system or electrode.
  • This is Convenient, Quick ,easy and safe Method
  • It does Not Require Disconnecting Equipment

Required equipment:

  • Clamp-on Ground Resistance Meter.
  • 2 No’s of Insulated Wires

Connections setup:

2

Testing Procedure:

  • Press START and read out the resistance value. This is the actual value of earthing resistance of the ground electrode under test.
  • The clamp-on methodology is based on Ohm’s Law (R=V/I).
  • The source coil inside the clamp of the earth tester inducing the voltage. This voltage is inductively applied to a complete circuit .The resulting current flow in the earthing circuit due to the induced voltage is measured by the current coil installed in the same clamp of the earth tester.
  • The resistance of the circuit can then be calculated by taking the ratio of the induced voltage and the circulated current in the earthing circuit.
  • It has to be ensured that the earthing system under test is included in the current circulation loop. The clamp-on earth tester measures the resistance of the path traversed by the induced current.
  • All elements of the loop are measured in series. This method assumes that only the resistance of the earthing system under test contributes significantly.
  • A low return path is required for readings. A high resistance return path will yield high readings.

Advantage

  • There is no need to turn off the equipment power or disconnect the earth rod.
  • Not disconnecting the connections between the earthed body and the metal work of the electrical Earthing Point.
  • Not dangerous to human life because no any DC current injected in Probe.

Disadvantages:

  • If the frequency of AC current injected into the earth by the tester is the same as that of disturbance current in the earth then accuracy of the readings are seriously affected.
  • The mutual inductance between the voltage and current loops of the clamp tester may affect accuracy of the readings.
  • The clamp-on method is only effective in situations with multiple earthing electrodes are in parallel and a closed circuit is available for the current circulation.
  • It cannot be used on isolated grounds, as there is no return path.
  • Measurement of low earth resistance (0.5Ω) is difficult with this method.
  • This method id effective only in situations with multiple grounds in parallel.
  • This method cannot be used on isolated grounds, not applicable for installation checks or commissioning new sites.
  • This method cannot be used if an alternate lower resistance return exists not involving the soil, such as with cellular towers or substations.

 (5) Star Delta Method

  •  If the testing area is so limited that an required spacing cannot be found then it may be necessary to use the Star-Delta Method. Named for the configuration of the test probes and lines of measurement (a graphic of it resembles the familiar symbols for “delta” and “star” windings).
  • This method saves space by employing a tight configuration of three probes around the test ground

Required equipment:

  • Earth Tester (4 Terminal or 3 Terminal)
  • 2 No’s of Insulated Wires
  • Hammer

Connections:

  • The ground electrode under test (E) is connect to C1 Terminal of Tester.
  • Three Potential and current probes (P2, P3 and P4) are placed equidistant from “E” with a 120º angle between them. Separation of potential and current circuits is abandoned, and a series of two-point measurements made between all pairs of probes, and probes to the ground under test.

3

Testing Procedure:

  • Press START and read out the resistance value. This is the actual value of earthing resistance of the ground electrode under test.

Application:

  • Ground systems located in congested urban areas or rocky area where probe positioning is difficult
  • where required probe positioning is difficult

Advantage:

  • Knowledge of electrical center not necessary

Disadvantage:

  • number of calculations required
  • Long distances to test probes is still required;

(6) Slope Method

  •  If soil is non homogeneous Soil Slope Method is useful for earth resistance measurement.

Required equipment:

  • Earth Tester (4 Terminal or 3 Terminal)
  • 4 No’s of Insulated Wires
  • Hammer
  • Measuring Tap

Connections:

  • First, isolate the grounding electrode under measurement by disconnecting it from the rest of the system.
  • The earth electrode under measurement (E) is connected to C1 Terminal of Earth Tester.
  • E is either one of many paralleled rods forming the complex earth system.
  • Insert the current probe C2 at a distance (D) from E (distance D is normally 2 to 3 times the maximum dimension of the system).
  • Insert potential probes P1,P2 and P3 at distances equal to 20% of D, 40% of D and 60% D.

4

 Testing Procedure:

  • Press START and read out the resistance value. This is the actual value of earthing resistance of the ground electrode under test.
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