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Lightings for AB Structures

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1.    What is light, intensity of light and its unit of measure in mks and fps system?

Light is defined as visually evaluated radiant energy. Intensity of light is measured in footcandles (fc) in English system and lux (lx) in the SI system.  It constitutes only a small portion of the electromagnetic spectrum.

2.    Provide the values for the suggested lighting intensity for AB structures, farmstead areas and commercial applications.

3.    What are the common types of lighting sources? What is a LED Bulb and its advantage to other materials?

a.    Incandescent lamps.

Advantages:

Cheap; instant start and re-start; simple inexpensive dimming; simple and compact installation; high power factor; focusable; life is independent of number of starts; good color.

Disadvantages:

Low efficacy; short life; sensitive and critical on voltage changes; high maintenance cost; more heat is produced than light.

b.    Fluorescent lamps

Advantages:

Efficacy is higher than incandescent lamp. 20% of input energy is converted to light, 80% to heat.

Disadvantages:

Long life but life span is affected by number of times lamp is switched on and off.

c.    Mercury lamp

Advantages:

Mercury vapor lamps have more energy efficient than incandescent lamps and have a much longer life.

Disadvantage:

It does not flatter the human skin color thereby making them not an ideal technology for indoor applications. They are exceptional sources, though, for landscape lighting applications.

d.    Metal halide lamp

e.    High pressure sodium lamp

f.     Low pressure sodium lamp

g.    Tungsten-halogen lamp

A LED lamp or LED light bulb is an electric light that produces light using light-emitting diodes (LEDs). LED lamps are significantly more energy-efficient than equivalent incandescent lamps and can be significantly more efficient than most fluorescent lamps. The most efficient commercially available LED lamps have efficiencies of 200 lumens per watt (Lm/W).

 

·         Advantages of LED Light Bulb

a.    Long life

b.    Energy efficiency

c.    High brightness and intensity

d.    Exceptional colour range

e.    Low radiated heat

f.     Reliability

g.    Instantaneous illumination

h.    Directional lighting

 

4.    What is a luminaire and its types? Illustrate.

Luminaire is the complete lighting unit made of a light source together with other parts.

Classification of luminaires

a. Direct - have the most efficient use of light

b. Semi-direct

c. General diffuse (direct-indirect)

d. Semi-indirect

e. Indirect- tend to give better glare control

 

5.    Discuss the lighting methods and the use of room index and coefficient of utilization in the computation on the number of lights.

 

            The zonal cavity method involves the procedure of dividing the room into zones.

 

Maintained illumination = (Lamp lumens per luminaire × CU × LLF) / Area per luminaire

 

                        where:            CU = coefficient of illumination

                                                LLF = light loss factor

 

Coefficient of utilization

Fixture description

CU

Efficient fixture, large unit colored room

0.45

Average fixture, medium size room

0.35

Inefficient fixture, small or dark room

0.25

Light loss or maintenance factor

Room and fixture description

LLF

Enclosed fixture, clean room

0.80

Average conditions

0.70

Open fixture or dirty room

0.60

           

The coefficient of useful utilization of lamps and other luminaires in closed rooms depends on a number of factors.

 

The main factors are as follows:

 

(1) The light distribution from the lamp (diffusing, direct or semi-direct);

 

(2) The reflection factors of ceiling, walls and floor; and

 

(3) The geometrical shape of the illuminated room.

 

The geometrical shape of the room and the relationship between the width, length and height of the room play the most important role in the utilization of light sources

applied.

 

For this purpose. all possible rooms have been divided to 10 classes, signed with letters from A to J. The J class is the worst, whilst the A class is the best in usefut utilization of  the light. The coefficient of utilization of class A 1s 2% to 3 times higher, than that of class J. Other classes have the intermediate values of the coefficient of utilization.

 

 

The so-called Room Ratio is calculated as follows:

 

 

 

6.    As per PAES, discuss lighting requirements of at least 5 structures in terms of lighting intensity and number of bulbs required per unit area in square meter or square.

 

6.1 Housing for Swine Production (PAES 401:2001)

Lighting

Artificial lighting shall always be available for use during the night or darkened periods of the day.

The recommended lighting intensity for swine housing

 

Area

Light Intensity

Lux (Lumen/m²)

Breeding, gestation and farrowing

150

Nurseries

100

Growing and finishing

50

Inspection areas

200

 

 

 

 

Lighting Requirements

Lighting Intensity lux

No. of Bulbs Required per m²

Incandescent lamp

Fluorescent Lamp

25W

40W

60W

100W

150W

200W

20W

40W

500

3.935

1.989

1.052

0.520

0.314

0.226

0.682

0.266

400

3.148

1.591

0.842

0.416

0.251

0.181

0.546

0.213

300

2.361

1.193

0.631

0.312

0.189

0.136

0.409

0.160

200

1.574

0.796

0.421

0.208

0.126

0.090

0.273

0.107

150

1.180

0.597

0.316

0.156

0.094

0.068

0.205

0.080

100

0.787

0.398

0.210

0.104

0.063

0.045

0.136

0.053

50

0.393

0.199

0.105

0.052

0.031

0.023

0.068

0.027

0

0.079

0.040

0.021

0.010

0.006

0.005

0.014

0.005

 

6.2 Housing For Broiler Production (Paes 402:2001)

Artificial light

§  During the first 48 hours, chicks shall receive a total of 23 hours of light at 35 watt/m² of illumination. This amount should be supplied by approximately 3.5 watts of light bulb for each 0.37 m² of floor space when the bulb is approximately 2.4 m above the floor and under a good clean reflector.

§  After the first 48 hours, the intensity of light shall be reduced. At floor level it should be about 10 watt/m². Provide approximately 1 watt of bulb, at 2.4 m above the floor, and under a good and clean reflector for every 0.40 m² of floor space.

Lighting

Artificial lighting with an intensity of 200 lux (refer to Table 1) shall always be available for use during the night or darkened periods of the day. All electrical design and installation shall conform to Philippine Electrical Code.

 

 

 

 

 

 

 

 

Table 1: Lighting Requirements

Lighting Intensity lux

No. of Bulbs Required per m²

Incandescent lamp

Fluorescent Lamp

25W

40W

60W

100W

150W

200W

20W

40W

500

3.935

1.989

1.052

0.520

0.314

0.226

0.682

0.266

400

3.148

1.591

0.842

0.416

0.251

0.181

0.546

0.213

300

2.361

1.193

0.631

0.312

0.189

0.136

0.409

0.160

200

1.574

0.796

0.421

0.208

0.126

0.090

0.273

0.107

150

1.180

0.597

0.316

0.156

0.094

0.068

0.205

0.080

100

0.787

0.398

0.210

0.104

0.063

0.045

0.136

0.053

50

0.393

0.199

0.105

0.052

0.031

0.023

0.068

0.027

0

0.079

0.040

0.021

0.010

0.006

0.005

0.014

0.005

 

6. 3 PAES 403-2001: Agricultural Structures – Housing for Layer Production

Lighting

Artificial lighting with an intensity of 200 lux shall always be available for use during the night or darkened periods of the day. All electrical design and installation shall conform to Philippine Electrical Code.

Lighting Requirement

6.4 PAES 404-2001: Agricultural Structures – Housing for Goat and Sheep

Lighting and Electrical installation

The housing shall be provided with lighting intensity of 200 lux.

Lighting Requirement

All electrical installations shall be inaccessible to all animals and it shall conform to Philippine Electrical Code.

 

6.5 PAES 405:2001: CATTLE FEEDLOT

Lighting

The housing shall be provided with lighting intensity of 200 lux (refer to Annex B).

 All electrical installations shall be inaccessible to all animals and it shall conform to Philippine Electrical Code.

 

7.    Discuss at least two methods used in computing for the lighting requirement of an area or a structure. Give example for each method.

 

a.    Watts per Square Metre Method

This is principally a “rule of thumb” method, very handy for rough calculation or checking. It consists in making an allowance of watts per square metre of area to be illuminated according to the illumination desired on the assumption of an average figure of overall efficiency of the system.

Divide the wattage consumed in the room by its area in square feet to calculate watts per square foot.

In our example, 650 watts divided by 192.89 square feet is 3.37 watts per square feet. This is principally a “rule of thumb” method, very handy for rough calculation or checking. It consists in making an allowance of watts per square metre of area to be illuminated according to the illumination desired on the assumption of an average figure of overall efficiency of the system.

 

b.    Lighting calculations for interior areas.

Maintained illumination = (Lamp lumens per luminaire × CU × LLF) / Area per luminaire

 

                        where:            CU = coefficient of illumination

                                    LLF = light loss factor

Example 1. An 8 m × 20 m inside incubator (hatchery) is to be lighted at an average maintained footcandle of 50 fc (See table below). How many 3-lamp fixtures of 120 cm long F 40 T12 WW start fluorescent lamps are required assuming the CU is 0.38 and the LLF is 0.75?

 

            Lamp lumens             = (maintained fc × area) / (CU × LLF)

           

                                    = [50 fc × (8 m × 20 m)] / (0.38 × 0.75) = 28,070 lumens

 

            Each 40 watt fluorescent lamp has an output of 3200 lumen.  Therefore, the number of lamps will be:

 

                  Number of lamps = 28,070 / 3,200 = 8.77 lamps

 

            Since there are 3 lamps for each fixture, 3 fixtures (8.77/3 = 2.93) are necessary

REFERENCES

 

AENG 70 (Farm Electrification) Lecture Notes.

IIEE. 2002. Philippine Electrical Code Part 1. 2000 Edition. Volume 1. Bookman Inc. Quezon City, Philippines.

 

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Comments

Wow. It's like that I am again completing my physics class which about lights.It's really great information I think.I don't know why, I like fluroscent light topics.

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