FURSE GUIDE TO BS EN 62305 PDF
Furse have now launched an updated Guide to BS EN Protection Against Lightning. This latest edition incorporates guidance on the. This handbook offers a guide for any designers of the structural Lightning protection system to comply with the requirements of BS EN range of standards. An overview of BS EN , its impact on lightning protection and the support and advice Earthing design considerations and full details of the Furse range of earthing materials .. illustrations and design examples, the Guide provides.
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On these occasions more down conductors at closer spacings on those sides that are accessible should be installed as a compensating factor. This is enhanced further by equipotential bonding to the conductive parts of the structure.
Additionally, Tables 2 and 4 from BS EN give information relating to the mechanical and electrical requirements of the conductors and earth electrodes. When considering RI indirect within R2, it is the inclusion of coordinated SPDs — to assist in reducing RI — that will provide the solution for protection as well as limiting any consequential losses from electromagnetic impulses. Typical methods of bonding to steel reinforcement within concrete BS EN Natural components www.
This is sub-divided into: This is especially valid for tall structures d These values are valid for single earthing electrodes with comparable earthing resistances. The protective angle method is suitable for simple shaped buildings.
Furse release 3rd edition of their renowned Guide to
For a simple box shaped structure, the collection area can be determined by: For more specific and detailed information relating to structures containing hazardous and solid explosives material, it is strongly recommended that Annex D be read and expert opinion sought. The standard advocates a low earthing resistance requirement and points out that can be achieved with an overall earth termination system of 10 ohms or less.
The greater the number of down conductors, the lesser the current that flows down each. Application of the protection angle method to catenary conductors forming an isolated system Protection at maximum conductor sag 2 1 View on arrow A Figure 4.
Furse release 3rd edition of their renowned Guide to Lightning Protection
Cumulatively these tto create a grid-like spatial shield as shown in Figure 5. It shall meet the requirements of BS EN B Mast A All yellow areas and the mast should be assessed for the need for air terminations Air termination required Mast Rolling sphere radius View on arrow A Fo 4.
A similar cone is created at every point along the suspended conductor. The screen of any antenna cable along with any shielded power supply to electronic appliances being routed into the structure should also be bonded at the equipotential bar. Short stroke parameters 17 www. If the services enter the structure above ground level, the bonding bars should be connected to a horizontal ring conductor either inside or outside the outer wall and in turn be bonded to the external down conductors and reinforcing bars ot the structure.
Protecting roof mounted equipment www. Although the equipotental bonding SPD is the first part of a coordinated SPD, it is appropriate to discuss their selection and application here due to their function. If the other electrical services do not have an effective outer core screen, then consideration should be given to bonding to the nearest equipotential bonding bar, via Type II overvoltage SPDs.
Short strokes with a duration less than 2 milliseconds ms and long strokes with a duration greater than 2ms. Continuous metal box – ideal Faraday Cage Welded or clamped joint at every reinforcing bar crossing or reinforcing huide to metal frame connection Table 5. They can involve injuries caused by step and touch voltages, physical damage t by dangerous sparking and failure of internal systems. This new standard is a departure from all the previous Gude Standards compiled on Lightning Protection.
The routeing or location of cable systems within effectively screened structures is less critical. Radio frequency interference www. The inspection should include the checking of all relevant technical documentation and a comprehensive visual ej of all parts of the LPS along with the LPMS measures.
The use of computers, electronic process controls and telecommunications has exploded during the last two decades. These are more numerous than flashes to the ground and a ratio of 6: Similarly the collection area of flashes striking near a line is determined by: For a three-phase 4 wire system, only 3.
A Guide to BS EN Protection Against Lightning_图文_百度文库
All metal pipes, power and data cables should, where possible, enter or leave the structure at the same point, so that it or its armouring can be bonded, directly or via equipotential bonding SPDs, to the main earth terminal at this single point.
The lightning discharge described is the most common seen by man ns is termed a negative descending stroke. This is typically the roof area of a structure. General principles BS EN part 1 is an introduction to the other parts of the standard and essentially describes how to design a Lightning Protection System LPS in accordance with the accompanying parts of the standard.
Disruption and data corruption Degradation of components, shortening equipment lifetime Physical damage All resulting in unnecessary systems downtime. Similarly the electromagnetic field is further reduced if suitable shielding measures are employed. A low soil resistivity is the main aim and factors that fkrse this are: