![]() ![]() When a thatch roof is constructed, wire mesh is used to reinforce and secure the bundles of thatch. However, prior to providing these protective measures, it is important to analyse the risk effects described in standards guide, such as SABS 0313: 1999, SABS IEC 61662-1: 1995 and IEC 62305-2. If recommended protective measures are not considered, the effects of lightning can cause serious damage. Thatch is particularly prone to ignition because it becomes “fluffy” at the surface and, if moist, methane and other flammable gases can be formed. ![]() Constructed of soft material, such as straw, reed, grass or coconut leaves, a thatched roof is more susceptible to catching alight as a result of a lightning strike than any other roof type, according to the South African National Standard (SANS). and 1 500 V d.c.It’s a reality that thatched roofs are extremely popular in South Africa, both within many rural communities and a number of upmarket developments. IEC 61557-4, Electrical safety in low-voltage distribution systems up to 1 000 V a.c. IEC 60079-14:2007, Explosive atmospheres – Part 14: Electrical installations design, selection and erection IEC 6:2009, Explosive atmospheres – Part 10-2: Classification of areas – Combustible dust atmospheres IEC 6:2008, Explosive atmospheres – Part 10-1: Classification of areas – Explosive gas atmospheres For undated references, the latest edition of the referenced document (including any amendments) applies. For dated references, only the edition cited applies. These references are listed in the standard. The following referenced documents are indispensable for the application of this national standard. ![]() The design of the type and location of an LPS should take into account the features of the existing structure. If lightning protection is to be added to an existing structure, every effort should be made to ensure that it conforms to the principles of SANS 62305-3. Regular consultation between LPS designers and installers, architects and builders is essential in order to achieve the best result at minimum cost. This information is fundamental to the design of an earth-termination system and may influence the foundation design work for the structure. Therefore, soil resistivity and the nature of the earth should be considered at the earliest possible stage of a project. Once construction work on a site has started, access to the ground and the proper use of foundation steelwork for the purpose of forming an effective earth-termination, may well be impossible. By doing so, design and construction of an integrated installation is made easier, the overall aesthetic aspects can be improved, and the effectiveness of the LPS can be increased at minimum cost and effort. The type and location of an LPS should be carefully considered in the initial design of a new structure, thereby enabling maximum advantage to be taken of the electrically conductive parts of the structure. occurrence of dangerous touch and step voltages by physical restrictions and/or warning notices.dangerous current flowing through bodies by insulating exposed conductive parts, and/or by increasing the surface soil resistivity,.The main protection measures against injury to living beings due to touch and step voltages are intended to reduce the: disperse the lightning current into the earth (using an earth-termination system).Īn internal LPS prevents dangerous sparking within the structure using either equipotential bonding or a separation distance (and electrical insulation) between the external LPS components and other electrically conducting elements internal to the structure.conduct the lightning current safely towards earth (using a down-conductor system),.intercept a lightning flash to the structure (with an air-termination system),.This usually consists of both external and internal lightning protection systems. The main and most effective measure for protection of thatch structures against physical damage is considered to be the lightning protection system (LPS). This part of IEC 62305 deals with the protection, in and around a structure, against physical damage and injury to living beings due to touch and step voltages. Introduction to the Regulations for Thatch Roofs and Lightning Remember that anything related to electrics must be dealt with by a qualified and registered electrician. Part 3 deals with “physical damage to structures and life hazard”. SANS 62305-3: Protection against Lightning (published in 2011) is drawn from an international standard, IEC 62305. ![]() For the protection of the public and property the South African National Standard 62305-3 was introduced in 2011. Thatch roofs are most susceptible to be set alight by lightning than any other roof type. ![]()
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