7/29/2019 ECM216 BUILDING SERVICES Bab 1.6 Lightning
1/1
EDITED BY
AZUAN AHMAD FAUZI 2011803188
UITM PULAU PINANG MAC 2013
LIGHTNING
Lightning a high voltage electrical discharge between two
charged rain clouds or acloud & the earth, caused by build up
of electrical charge.
Air is the path of lightning ionizes (becomes conducting), and
expands. The suddenexpansion of air causes thunder.
Lightning produce currents of 20,000 A & temperature of
30,000C
Lightning Arrestors Device that protect a tall building by
providing an easier path for current to flow to
earth than through the building. Consists of a thick copper
strip, a huge metal plate buried in the damp earth. If direct
lightning strike, the current flows through the conductors &
melting or even
vaporize the metal. Therefore the building is safe. Lightning
strikes are electrical discharges caused by lightning, typically
during
thunderstorms. A lightning rod (or lightning protector) is a
metal strip or rod, usually of copper or
similar conductive material, used as part of lightning safety to
protect tall or isolatedstructures (such as the roof of a building
or the mast of a vessel) from lightningdamage.
Its formal name is lightning finial or air terminal. Sometimes,
the system is informallyreferred to as a lightning conductor,
arrester, or discharger; however, these termsactually refer to
lightning protection systems
Damage to electrical equipment Telephones, modems, computers and
other electronic devices can be damaged by
lightning, as harmful overcurrent can reach them through the
phone jack, Ethernet
cable, or electricity outlet. A secondary effect of lightning on
users of telephone equipment can behearing
damage, as the strike may cause bursts of extremely loud noise.
Close strikes can also generate electromagnetic pulses (EMPs) -
especially during
'positive' lightning discharges.
If a person is injured by lightning they do not carry an
electrical charge and can besafely handled to apply first aid
before emergency services arrive.
Lightning can affect the brainstem, which controls breathing. If
a victim appearslifeless, it is important to begin artificial
resuscitation immediately to prevent deathby suffocation
Lightning Arrestors are needed:
1. stormy area where possibility of lightning strikes is
frequent.2. structures at hilly or high area (telecommunication
tower).3. structures that more than 53m high (pylon)4. structures
& its contents are sensitive/highly prices (fuel tanks or
electronic
factories)Lightning Protection Key:
1. Minimum of two ground rods (electrodes) at least 10 feet
deep.2. Down conductors.3. Connect gutters or other grounded metals
as required.4. Air terminals (lightning rods) located within two
feet of outside corners of
chimney.5. Antenna must connected to roof conductor.6. Air
terminals (lightning rods) spaced 20 feet apart along the ridges
and within two
feet of ridge ends.7. Dormers protected.8. Roof projections such
as weather vanes or satellite dishes should be connected to
lightning protection system.9. Surge protection devices
installed at main electrical panel or meter.10. Surge protection
devices installed at electronics in house.
http://en.wikipedia.org/wiki/Electrical_dischargehttp://en.wikipedia.org/wiki/Lightninghttp://en.wikipedia.org/wiki/Thunderstormhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Conductor_(material)http://en.wikipedia.org/wiki/Lightninghttp://en.wikipedia.org/wiki/Lightning_protection_systemhttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Modemhttp://en.wikipedia.org/wiki/Computershttp://en.wikipedia.org/wiki/Overcurrenthttp://en.wikipedia.org/wiki/Jack_(connector)http://en.wikipedia.org/wiki/Ethernet_cablehttp://en.wikipedia.org/wiki/Ethernet_cablehttp://en.wikipedia.org/wiki/AC_power_plugs_and_socketshttp://en.wikipedia.org/wiki/Hearing_damagehttp://en.wikipedia.org/wiki/Hearing_damagehttp://en.wikipedia.org/wiki/Hearing_damagehttp://en.wikipedia.org/wiki/Hearing_damagehttp://en.wikipedia.org/wiki/Noisehttp://en.wikipedia.org/wiki/Electromagnetic_pulsehttp://en.wikipedia.org/wiki/Positive_lightninghttp://en.wikipedia.org/wiki/First_aidhttp://en.wikipedia.org/wiki/First_aidhttp://en.wikipedia.org/wiki/Positive_lightninghttp://en.wikipedia.org/wiki/Electromagnetic_pulsehttp://en.wikipedia.org/wiki/Noisehttp://en.wikipedia.org/wiki/Hearing_damagehttp://en.wikipedia.org/wiki/Hearing_damagehttp://en.wikipedia.org/wiki/AC_power_plugs_and_socketshttp://en.wikipedia.org/wiki/Ethernet_cablehttp://en.wikipedia.org/wiki/Ethernet_cablehttp://en.wikipedia.org/wiki/Jack_(connector)http://en.wikipedia.org/wiki/Overcurrenthttp://en.wikipedia.org/wiki/Computershttp://en.wikipedia.org/wiki/Modemhttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Lightning_protection_systemhttp://en.wikipedia.org/wiki/Lightninghttp://en.wikipedia.org/wiki/Conductor_(material)http://en.wikipedia.org/wiki/Copperhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Thunderstormhttp://en.wikipedia.org/wiki/Lightninghttp://en.wikipedia.org/wiki/Electrical_discharge
