Lightning Protection
System Design
Horizon Specialist Contracting Limited offer an advisory service, including the design, specification and subsequent submission of firm cost quotations, all of which will be in full accordance with the new guidelines of BS EN 62305:2006 or BS 6651:1999 'Protection of Structures Against Lightning, BS7430:, 'Earthing', CENELEC & IEC Standards for existing systems. Please be advised that the new BS EN 62305:2006 document came in to force for systems which have been designed and/or installed from 1st September 2008. Quotations can be compiled either from supplied installation plans, or be based on our own designs, working from existing drawings or details obtained from a site survey. Where ground conditions are thought to be 'difficult', soil resistivity tests can be carried out in order to determine the precise Earthing System required.
Surge Protection
We can supply a site assessment for surge protection. To arrange a site visit or for further information please contact our office and speak with one of our technical team on 0115 9657 400
Installation
All installations are carried out by fully experienced engineers who are C.I.T.B. registered and CSCS carded,& who have undergone formal training in their chosen field. Upon completion, the system is tested and relevant certificates are produced to confirm compliance with the standard. Also provided are 'as fitted' drawings and maintenance manuals, primarily designed to assist in the subsequent maintenance of the system.
Maintenance
Horizon Specialist Contracting Limited also offer a complete maintenance programme, which can be tailored to meet the exact needs of the client. The programme can be designed simply to include for the annual testing of the resistences to earth, or for a complete and thorough visual inspection of the entire system.
BS EN 62305 - An Overview BS 6651:1999: Protection of structures against lightning has been the standard for guidance on the design and installation of lightning protection systems since 1985. Ever since 1985, the UK has become more involved with EU regulations, particularly with regard to standardisation. Consequently British Standards are now published in agreement with the European equivalent standard. The electrical side of the European standards are called CENELEC (CLC) and there are 28 countries which constitute the CENELEC committee. This group is now responsible for compiling and producing new standards relevant to lightning protection. Following various research and committee meetings the new four part standard of BS EN 62305 was created to provide a more comprehensive document on the implication of lightning and the need for enhanced protection for structures by lightning protection and surge protection systems. The structure of BS EN 62305 is as follows: Part 1: General PrinciplesPart 2: Risk ManagementPart 3: Physical damage to structures and life hazardPart 4: Electrical and electronic systems within structures In essence the content of the BS EN 62305 has been significantly increased to provide in depth risk analysis and calculative solutions throughout the document. A brief overview of the information in the BS EN 62305 standard compared to BS 6651 is noted below: Part 1: Increased information regarding type of damage (S1, S2, S3, S4) & zones of protection as well as increased component factors for the risk of strike damage. Part 2: The risk management section has become significantly more complex and the content of the risk calculations has been enhanced to include many external factors. Part 3: The document has been significantly augmented by the changes to meshing arrangements and the further understanding of zones of protection. It also documents the need to use natural down conductors such as rebar to create system continuity and provide increased path to earth. This section also gives information regarding the equipotential bonding of systems using surge devices as additional protection measures. Part 4: This part of the document has not been included at any point in BS 6651 and therefore may provide the biggest difficulty in terms of systems design when in a practical situation. It considers the protection of electrical and electronic services as an important factor in the design of a lightning protection system. Zones of protection and bonding configurations are considered throughout.
BS EN 62305 – Requirements The new standard will run in parallel with the existing standard for a transitional period and will replace the existing standard (BS 6651:1999) on 1st September 2008. There are four separate risks that can be addressed depending upon the clients requirements: 1. Risk of loss of human life (R1)2. Risk of loss of service to the public (R2)3. Risk of loss of cultural heritage (R3)4. Risk of loss of economic value (R4) Initially it should be established which risk the client needs to protect their structure against. R1 is addressed under the existing BS 6651 standard; R2 is partially addressed under the existing standard in an appendix, however this does not form part of the main standard. R3 and R4 are considered for the first time within BS EN 62305. In order to determine the levels of risk for each of the above components, a risk assessment must be undertaken determine what level of protection is required, if any. The outcomes of this assessment should also detail what protection measures will need to be applied in order to reduce the risk to below a tolerable level. The risk assessments require the following information in addition to that already required under the current standard: - dimensions of the structure to be protected- use of the structure to be protected- type and characteristics of equipment to be protected- type of cabling used for power and telecommunications/data systems- characteristics of the structure feeding the lines- location of the structure relative to services and other structures - type of floor surfaces i.e. concrete, asphalt, granite, wood etc…- any risk of fire/explosion- provision for fire protection- any inherent or built in spatial shielding against electromagnetic influences.- various financial information if requiring a calculation of Risk 4. This information required to fulfil an assessment of a structure to the new standard is much more detailed than any current requirement. These risk assessments will ascertain what level of protection, if any, the client requires and will determine what measures are needed to protect the structure against the risk presented. The information required to produce effective risk assessments, designs and costs may be delayed due to existing tendering practices in the UK unless lightning protection specialists are involved much earlier in the design phase of the project. Finally, in the new BS EN 62305 standard there is a much greater emphasis on equipotential bonding or ensuring separation distances between the protection system and any conductive building services. This new requirement will involve significant coordination of the lightning protection system with other building services.
For further information or advice please call Horizon on 0115 9657 400 or email on sales@horizonsc.co.uk
