LPI Guardian System 5
Product Name：LPI Guardian System 5
Product Model：CAT I,CAT II,CAT III
LPI Guardian System 5
LPI offers a family of air terminals and accessories. Our product design is based on the most recent advances in the field whilst maintaining proven principles associated with the successes of the past.
LPI IS Guardian System 5 provides a purpose-designed package for direct lightning protection.
2. A Fibreglass Reinforced Plastic (FRP) mast which provides an insulated mast for mounting of LPI CAT series air terminals.
3. A purpose designed LPI High Voltage Shielded Cable (HVSC) specifically designed for the conveying of lightning energy to ground. Alternatively, depending on the local codes and applications, other materials such as flat copper tape or stranded cable may be used.
4. LPI Lightning Strike Recorder (LSR) which confirms system efficiency and effectiveness.
5. An earthing system consisting of earth rods, clamps, copper tapes and earth enhancing compounds such as LPI Ground Resistance Improvement Powder (GRIP) or LPI Reslo.
The LPI Guardian System 5 provides a safe and efficient system for the protection of your facility from direct lightning strikes. The LPI CAT terminal captures the lightning discharge at a preferred point and the energy is transferred to ground via the High Voltage Shielded Cable with minimal risk of electrifying the structure.
Once the energy enters the dedicated lightning earth, it is safely dissipated without risk to personnel and equipment.
LPI Guardian CAT series terminals consist of
A finial with a blunt tip
An electrically “floating” medium consisting of 4 electrically isolated panels
A triggering procedure which allows for an intercepting streamer to be released at the correct time, thus providing the greatest possible area of protection
A high voltage connection at the base of the finial
LPI offers 4 models within the family of CAT terminals
CAT I - G
CAT I GI-G
CAT II - G
CAT III - G
GI Model – For direct mounting to 2 inch GI Pipe.
The LPI GuardianTM CAT series are Controlled Advanced Triggering devices which intercept lightning discharges for the safe passage to a low impedance down-conductor system. The GuardianTM terminals have been designed to emit a “streamer” of ionised air at precisely the right time so that an approaching “down leader” is intercepted and brought under control.
The concept of controlled triggering is important because if a “streamer” is launched too early the median or ambient field will not be strong enough to sustain propagation and the “streamer” will stall or die. This will leave space charge behind which may inhibit future “streamer” development. An electric field of ~3MV/m is essential at the tip of the air terminal to initiate a corona streamer but an electric field of ~300KV/m is needed in the region between the air terminal and the down-leader to convert the streamer into an up-leader and to sustain propagation.
The dynamic response of the Guardian terminals to the approach of a lightning down leader is the key – detrimental space charge generation prior to leader approach is suppressed and the GuardianTM launches its streamer at the correct time to ensure both electric field criteria are met thus giving the greatest possible area of protection.
How does an LPI Guardian Terminal operate
A Guardian CAT terminal consists of a grounded blunt lightning rod surrounded by electrically floating metal panels. Rounded or blunt tips have now been proven to be more efficient than sharp points because of a reduced space charge effect. This has been clearly proven in tests conducted at South Baldy Peak in central New Mexico, USA. (Source: “The Measurement of Lightning Rod Responses to Nearby Strikes” by C.B.
Moore, G.D. Aulich and W. Rison / 2001.)
During the static thunderstorm phase when the electric fields are steady at 5-15 KV/m the panels present as a relatively low field intensification surface aided by the blunt configuration of the finial tip. This restricts the production of “corona” or “point discharge” ions and is critical because excessive production of ions (corona) results in a “space charge cloud” above the air terminal which tends to mask the electrical field and inhibit the formation and progression of an up-leader. (See step 1).
The panels are isolated from each other as well as from the lightning rod to allow the panel facing the down-leader to rise in voltage due to capacitive coupling with the approaching down-leader. The electric field increases as the lightning downleader approaches closer causing increased voltage difference between the facing panel and the lightning rod. Eventually the voltage rises to the point where a triggering arc is generated between the facing panel and the lightning rod. (See step 2).
By design and appropriate terminal placement this arc occurs at the right time to ensure the resulting streamer will form a stable progressive up-leader. (See step 3).
The triggering arc has two key effects, namely:
(i) It produces a large number of ions to aid the initiation of an up-leader.
(ii) It causes a large increase in the electric field at a critical distance from the air terminal, aiding propagation through this critical area. This ensures a more efficient mode of protection with an enhanced area of protection.
Following the successful interception of a lightning discharge by the Guardian terminal, the installation of LPI IS High Volatge Shielded Cable allows for the safe passage of the lightning energy to the dedicated lightning earth with reduced risk of side flashing.
LPI HVSC Down Conductor
HVSC is a high integrity low impedance cable which is particularly effective on structures containing high density human occupancy and those which contain sensitive electronic equipment, volatile liquids and other sensitive applications.
LPI also offers a range of conventional downconductors of all types such as copper tape and stranded cable, bare aluminium, galvanised steel cable and tapes or any of the above in PVC insulated form.
Benefits of HVSC
- Reduced risk of side flashing
- Selection of route to ground
- Single Earth System
- Bonding of building not required
- Most of energy contained in core
- Relatively easy to retrofit
- Reduced induction to nearby electronic equipment
Ground Resistance ImprovementPowder (GRIP)
Ground Resistance Improvement Powder is a ground enhancing material which is applied in and around an earthing system to reduce the soil resistivity and lower ground impedance. GRIP is supplied in 10kg and 40kg kits and is particularly useful in difficult sites such as sandy soils and rocky ground. LPI recommends the installation of a radial lightning earth to aid in the efficient dissipation of the lightning energy.
Contact LPI or an authorised representative for design assistance and for further details on LPI IS complete range of earth enhancing compounds.
LPI IS Guardian CAT series terminals come in three sizes which permits the user to select a terminal which suits his particular application. See the accompanying chart for an indication of the model which best suits your requirements. For a more accurate design for your project, LPI uses a software based program which accurately takes into consideration important factors relating to your project such as thunderdays per year, height above sea level, level of protection desired / recommended (Standard – High – Very High), physical dimensions of your structures and materials used. Such additional care ensures that competing features (which themselves also have the ability to create streamer development) are taken into consideration.
Unlike other lightning terminal suppliers, LPI consider the development of competing structural features as particularly critical on very tall buildings and on sites that comprise more than one major structure.
Such designs are certified by LPI and therefore offer additional security with regard to the provision of satisfactory lightning protection levels particularly in relation to the lightning activity.
|Sructure height + installed CAT terminal (typically 5m about structure)||Protection level - very height||Protection level - height||Protection level - standard|
|CAT I||CAT II||CAT III||CAT I||CAT II||CAT III||CAT I||CAT II||CAT III|
|80 - 150||75||92||115||124||128||134|