Transcript light - Dr Muhammad Razaq Malik

Dr. Muhammad Razzaq Malik
LIGHT
Good lighting is essential for efficient
vision. If the lighting conditions are
not ideal, the visual apparatus is put
to strain which may lead to general
fatigue and loss of efficiency.
Natural lighting is derived partly from
the visible sky and partly from
reflection. In fact, much light comes to
the rooms by reflection from light
colored objects.
Dr. Muhammad Razzaq Malik
REQUIREMENT OF GOOD LIGHTING
SUFFICIENCY
 DISTRIBUTION
 ABSENCE OF GLARE
 ABSENCE OF SHARP SHADOWS
 STEADINESS
 COLOUR OF LIGHT
 SURROUNDINGS
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Dr. Muhammad Razzaq Malik
NATURAL LIGHTING
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Natural light is accompanied by
radiant heat; all attempts should be
made to exclude radiant heat while
admitting daylight.
Dr. Muhammad Razzaq Malik
SUGGESTIONS FOR IMPROVING
DAYLIGHT
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ORIENTATION
Buildings should be oriented, wherever
possible towards north and south for
uniform illumination.
REMOVAL OF OBSTRUCITONS:
WINDOWS
INTERIOUR OF THE ROOMS
The ceiling should be white; the upper
portions of the walls light tinted and lower
portion somewhat darker so as to give
comfortable contrast to the eyes.
Dr. Muhammad Razzaq Malik
ARTIFICIAL LIGHT
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DIRECT LIGHTING
SEMI DIRECT
INDIRECT
SEMI-INDIRECT
Dr. Muhammad Razzaq Malik
METHODS OF ARTIFICIAL LIGHTING
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1. FILAMENT LAMPS
Light 5% and heat 95%
2. FLUORESCENT LAMPS
Light 21% and heat 79%
Dr. Muhammad Razzaq Malik
NOISE
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Noise is often defined as “unwanted sound”,
Noise is wrong sound in the wrong place, at the
wrong time.
Noise has become a very important “stress
factor”
Normal conversation produces a noise of 60-65
dB
Whispering, 20-30 dB;
Heavy street traffic 60-80 dB;
Boiler factories about 120 dB;
Normal tolerable limit is 85 dB;
Dr. Muhammad Razzaq Malik
PROPERTIES
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Noise has two important properties:
Loudness
Loudness depends upon the amplitude of the
vibrations which initiated the noise. The loudness
of noise is measured in decibels (dB).
Frequency:
The frequency is denoted as Hertz (Hz.) One Hz
is equal to one wave per second. The human ear
can hear frequencies from about 20 to 20000 Hz.
This range is reduced with age and other
subjective factos. Many animals (e.g., dogs) can
hear sounds inaudible to the human ear.
Dr. Muhammad Razzaq Malik
NOISE POLLUTION
To signify the vast cacophony of
sounds that are being produced in
the modern life, are leading to
health hazards.
These hazardous effects are:
1. Auditory effects
2. Non-Auditory effects
Dr. Muhammad Razzaq Malik
AUDITORY EFFECTS OF NOISE
a. Auditory Fatigue:
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It appear in the 90 dB region and greatest
at 4000 Hz.
b. Deafness:
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The hearing loss may be temporary or
permanent. Repeated or continuous
exposure to noise around 100 decibels
may result in a permanent hearing loss.
c. Occupational hearing loss:
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When there is exposure to noise above
than 100 dB the result is hearing loss.
Exposure to noise above 160 dB may
rupture the tympanic membrane and
cause permanent loss of hearing.
Dr. Muhammad Razzaq Malik
NON- AUDITORY EFFECTS
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Interference with speech
Annoyance
Efficiency
Physiological changes
Economic loss
Dr. Muhammad Razzaq Malik
CONTROL OF NOISE
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CAREFUL PLANNING OF CITIES
CONTROL OF VEHICLES
BUILDING ACOUSTIC INSULATION
INDUSTRIES AND RAILWAYS
PROTECTION OF EXPOSED PERSON BY
USING EAR PLUGS, etc.
LEGISLATION
EDUCATION
Dr. Muhammad Razzaq Malik
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RADIATION
Radiation is part of man’s environment.
SOURCES:
The sources of radiation are man – made and
natural
Natural
Man – Made
1. Cosmic rays
1. Medical and dental
X-rays, Radioisotopes
2. Environmental:
2. Occupational
exposure
a. Terrestrial
3. Nuclear:
b. Atmospheric
radioactive fallout
3. Internal:
4. Miscellaneous:
Potassium-40
Carbon – 14
tagged
Television sets
radioactive dial
Watches, Isotope
products,
Luminous markers.
Dr. Muhammad Razzaq Malik
TYPES OF RADIATIONS
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1. IONIZING RADIATION:
Is applied to radiation which has the
ability to penetrate tissues and deposit its
energy within them. Ionizing radiation
may be divided in to two groups:
Electromagnetic radiations e.g., X- rays
and gamma rays,
Corpuscular radiations e.g., alpha particles
and beta particles (electrons) and protons.
Cosmic rays also contain ionizing
radiations
Dr. Muhammad Razzaq Malik
NON – IONIZING RADIATIONS
These are electromagnetic
radiations of wavelength longer
than those of ionizing radiation. All
non-ionizing form of radiations have
less energy than cosmic, gamma,
and X-radiation.
Dr. Muhammad Razzaq Malik
RADIATION UNITS
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Roentgen:
Roentgen is the unit of exposure. It is now
replaced by Coulomb per kilogram
Rad:
Is the unit of absorbed dose. It is now
replaced by SI units as Gray
Rem:
Is the product of the absorbed dose and
the modifying factors. The Rem indicates
the degree of potential danger to health.
Dr. Muhammad Razzaq Malik
BIOLOGICAL EFFECTS OF RADIATION
1. SOMATIC EFFEXTS
 A dose of 400 to 500 roentgens on the whole
body is fatal.
 Immediate effects:
 Radiation sickness
 Acute radiation syndrome
 Delayed effects:
 i. Leukemia
 ii. Carcinogenesis
 iii.Foetal developmental abnormalities
 iv. Shortening of life
2. GENETIC
 Chromosome mutations
 Point mutations
Dr. Muhammad Razzaq Malik
RADIATION PROTECTION
1. Avoiding Exposure to X-ray:
Of the man – made sources, a dose of 4 rad is
delivered a part of body when exposed to X-ray
in about one minute. So unnecessary X-ray
examination should be avoided in children and
pregnant women.
2. Lead aprons:
.5mm of lead apron will reduce the intensity of
scattered X-ray over 90 per cent. Workers must
wear a film badge or dosimeter which shows
accumulated exposure to radiation.
3. Safe operation of nuclear power plants and
enunciating the basic principles of radiation
protection.
Dr. Muhammad Razzaq Malik