Legislation regarding thatched roofs
17 National Building Regulations and Directives
(6) Any provision occurring in a specification, standard specification, code of practice or standard method may be incorporated in a directive by mere reference, and in regard to such an incorporation the provisions of section 33 of the Standards Act shall mutatis mutandis apply as if it were an incorporation in a law.
24 General Penalty Clause
Any person convicted of an offense under this Act in respect of which a fine or imprisonment is not expressly provided for, shall be liable to a fine not exceeding R4000 or to imprisonment for a period not exceeding 12 months
If in any prosecution for an offense in terms of this Act it is necessary, in order to establish the charge against the accused, to prove that he failed to comply with the requirements of this Act relating to standard or quality of materials, design or workmanship, an allegation in the charge sheet that such accused so failed, shall be sufficient proof thereof unless the contrary is proved
2 Application of Act
(1) Subject to the provisions of any notice published in terms of subsection
(2) The provisions of this Act shall apply in the area of jurisdiction of any local authority.
PART T – FIRE PROTECTION
T1 GENERAL REQUIREMENT
(2) The requirements of sub-regulation (1) shall be deemed to be satisfied where the design, construction and equipment of any building complies with SANS 10400-T: Provided that where any local authority is of the opinion that such compliance would not comply with all the requirements of sub-regulation (1), such local authority shall, in writing, notify the owner of the building of its reasons for its opinion and may require the owner to submit for approval a rational design prepared by an approved competent person
18.104.22.168 Buildings and lapas with thatched roofs in areas with a lightning flash density greater than 7 (see SANS 10313) or where conductors (wire sways) are used in the thatch layer shall be provided with a lightning protection system designed and installed by competent persons inaccordance with the relevant requirements of SANS 10313 and SANS 62305-3.
22.214.171.124 Buildings and lapas in which conductors (wire sways) are used in the thatch layer shall, in areas with a lightning flash density greater than 3 (see SANS 10313), be provided with a lightning protection system, designed and installed by competent persons in accordance with the relevant requirements of SANS 10313 and SANS 62305-3.
1.1 The scopes of all parts of SANS 62305 apply, with the inclusion of
- a) thatched roof structures, and
- b) buildings with explosive or flammable substances.
1.2 This standard makes provision for the issuing of a Lightning protection system installation safety report by an LPS designer or an LPS installer, and a Lightning protection system maintenance certificate
5 External lightning protection system
5.1 The requirements of SANS 62305-3 apply.
5.2 Products that artificially enhance the height of the air terminal (also referred to as “early, streamer emission devices”) have not been proven and therefore, for the determination of the volume protected, only the real physical dimension of the metal air termination system shall be considered.
5.3 Radioactive air terminals are prohibited.
5.4 Earth electrodes shall be designed in accordance with SANS 10199.
NOTE The earth resistance of the electrode systems should preferably not be measured whilst the soil is wet.
7 Maintenance and inspection of an LPS
7.1 The requirements of SANS 62305-3 apply.
7.2 An Installation safety report, as specified in annex A, shall be issued in respect of an inspected and compliant LPS by an LPS designer or an LPS installer.
7.3 In the case of an existing LPS installed before the approval of this edition of SANS 10313, where clearances complied with the requirements of another standard at the time of installation, this shall be noted on the Maintenance certificate as given in annex B.
7.4 Testing of the LPS system shall include testing of the integrity of the earth continuity and equipotential bonding, and the readings shall be recorded on the Maintenance certificate. Testing should be performed before the start of each lightning season.
11.5 Protection by masts
At least lightning protection level III (see SANS 62305-3) will apply in the case of thatched structures. If a metallic mast is used as an LPS, it shall be designed in accordance with SANS 10225
4.1 Design requirements
Each lighting mast or component thereof shall be designed to safely and effectively resist all loads and influences that may reasonably be expected to act upon it, having regard to the expected service life of
the lighting mast
The documentation and plans prepared for the erection of a lighting mast shall include the following:
a) details of the materials to be used, together with the strength, grade and unit mass of each material;
b) the dimensions, location and size of all structural members in sufficient detail to enable the design to be checked; and
c) details of all effects and loads, other than self-weight loads, used in the design of the mast and its components.
The engineer shall inspect the site in order to ensure that the design is suited to the site conditions and to the proposed works.
Cube tests shall be undertaken by an approved authority and the results shall be made available
Reference should be made to SANS 10120-1 for guidance on the preparation and contents of a
contract document for the design and construction, or construction only, of free-standing masts.
A.2 Supporting codes and specifications
In addition to this standard, the following standards should form part of the contract document:
a) project specification;
b) SANS 1200 A (SABS 1200-A) or SANS 1200 AA (SABS 1200 AA), as applicable;
c) SANS 10161 (SABS 0161);
d) SANS 1200 GA (SABS 1200 GA);
e) SANS 2001-CS1; and Amdt 1
f) SANS 1200 HC:1988 (SABS 1200 HC).
This part of SABS 62305-3 provides the requirements for protection of a structure against physical damage by means of a lightning protection system (LPS), and for protection against injury to living beings due to touch and step voltages in the vicinity of an LPS
This standard is applicable to:
a) design, installation, inspection and maintenance of an LPS for structures without limitation of their height,
b) establishment of measures for protection against injury to living beings due to touch and step voltages.
4 Lightning protection system (LPS)
4.1 Class of LPS
The characteristics of an LPS are determined by the characteristics of the structure to be protected and by the considered lightning protection level. Four classes of LPS (I to IV)
4.2 Design of the LPS
A technically and economically optimized design of an LPS is possible, especially if the steps in the design and construction of the LPS are coordinated with the steps in the design and construction of the structure to be protected. In particular, the design of the structure itself should utilize the metal parts of the structure as parts of the LPS. The design of the class and location of the LPS for existing structures shall take into account the constraints of the existing situation. The design documentation of an LPS shall contain all the information necessary to ensure correct and complete installation. The LPS should be designed and installed by well-trained and expert LPS designers and
5 External lightning protection system
5.1.1 Application of an external LPS
The external LPS is intended to intercept direct lightning flashes to the structure, including flashes to the side of the structure, and conduct the lightning current from the point of strike to ground. The external LPS is also intended to disperse this current into the earth without causing thermal or mechanical damage, or dangerous sparking which may trigger fire or explosions.
5.1.2 Choice of external LPS
In most cases, the external LPS may be attached to the structure to be protected. An isolated external LPS should be considered when the thermal and explosive effects at the point of strike, or on the conductors carrying the lightning current, may cause damage to the structure or to the contents (see Annex E). Typical examples include structures with combustible covering, structures with combustible walls and areas at risk of explosion and fire. An isolated external LPS may also be considered when the susceptibility of the contents warrants the reduction of the radiated electromagnetic field associated with the lightning current pulse in the down-conductor.
5.2 Air-termination systems
The probability of structure penetration by a lightning current is considerably decreased by the presence of a properly designed air-termination system. Air-termination systems can be composed of any combination of the following elements:
a) rods (including free-standing masts);
b) catenary wires;
c) meshed conductors.
To conform to this standard, all types of air-termination systems shall be positioned in accordance with 5.2.2, 5.2.3 and Annex A. All types of air terminals shall comply in full with this standard. For all types of air terminals only the real physical dimensions of the metal air-termination systems shall be used for the determination of the volume protected. The individual air-termination rods should be connected together at roof level to ensure current division.
Radioactive air terminals are not allowed.
Air-termination components installed on a structure shall be located at corners, exposed points and edges (especially on the upper level of any facades) in accordance with one or more of the following methods. Acceptable methods to be used in determining the position of the air-termination system include:
– the rolling sphere method
The rolling sphere method is suitable in all cases.
Air-terminations of an LPS not isolated from the structure to be protected may be installed as follows:
– if the roof is made of non-combustible material the air-termination conductors may be positioned on the surface of the roof;
– if the roof is made of readily-combustible material, due care needs to be taken with regard to the distance between the air-termination conductors and the material. For thatched roofs, where no steel bars are used for mounting of the reed, a distance of at least 0,15 m is adequate. For other combustible materials a distance not lower than 0,10 m is considered adequate;
– easily-combustible parts of the structure to be protected shall not remain in direct contact with the components of an external LPS and shall not remain directly under any metallic roofing membrane that might be punctured by a lightning flash (see 5.2.5).
Account shall also be taken of less combustible membranes such as wooden sheets.
5.3 Down-conductor systems
In order to reduce the probability of damage due to lightning current flowing in the LPS, the down-conductors shall be arranged in such a way that from the point of strike to earth:
a) several parallel current paths exist;
b) the length of the current paths is kept to a minimum;
c) equipotential bonding to conducting parts of the structure is performed according to the requirements of 6.2.
5.3.2 Positioning for an isolated LPS
The positioning shall be as follows:
a) If the air-termination consists of rods on separate masts (or one mast) not made of metal or interconnected reinforcing steel, at least one down-conductor is needed for each mast. No additional down-conductors are required for masts made of metal or interconnected reinforcing steel.
NOTE In several countries, the use of reinforced concrete as a part of the LPS is not allowed.
b) If the air-termination consists of catenary wires (or one wire), at least one down-conductor is needed at each supporting structure.
c) If the air-termination forms a network of conductors, one down-conductor is needed at least at each supporting wire end.
5.3.3 Positioning for a non-isolated LPS
For each non-isolated LPS the number of down-conductors shall be not less than two and should be distributed around the perimeter of the structure to be protected, subject to architectural and practical constraints.
An equal spacing of the down-conductors is preferred around the perimeter.
5.3.6 Test joints
At the connection of the earth-termination, a test joint should be fitted on each down conductor, except in the case of natural down-conductors combined with foundation earth electrodes. For measuring purposes, the joint shall be capable of being opened with the aid of a tool. In normal use it shall remain closed.
5.4 Earth-termination system
When dealing with the dispersion of the lightning current (high frequency behavior) into the ground, whilst minimizing any potentially dangerous over voltages, the shape and dimensions of the earth-termination system are the important criteria. In general, a low earthing resistance (if possible lower than 10 W when measured at low frequency) is recommended. From the viewpoint of lightning protection, a single integrated structure earth-termination
system is preferable and is suitable for all purposes (i.e. lightning protection, power systems and telecommunication systems).
Earth-termination systems shall be bonded in accordance with the requirements of 6.2.
5.4.2 Earthing arrangement in general conditions
For earth-termination systems, two basic types of earth electrode arrangements apply
126.96.36.199 Type A arrangement
This type of arrangement comprises horizontal or vertical earth electrodes installed outside the structure to be protected connected to each down-conductor or foundation earth electrodes not forming a closed loop.
In type A arrangements, the total number of earth electrodes shall be not less than two.
188.8.131.52 Type B arrangement
This type of arrangement comprises either a ring conductor external to the structure to be protected, in contact with the soil for at least 80 % of its total length, or a foundation earth electrode forming a closed loop. Such earth electrodes may also be meshed.
5.4.3 Installation of earth electrodes
The ring earth electrode (type B arrangement) should preferably be buried at a depth of at least 0,5 m and at a distance of about 1 m away from the external walls.
The earth electrodes (type A arrangement) shall be installed at a depth of upper end at least 0,5 m and distributed as uniformly as possible to minimize electrical coupling effects in the earth.
NOTE 1 If the type A earth electrode is positioned within an inspection housing which, in turn, is located in high resistance paving or adjoining concrete, then the 0,5 m requirement can be disregarded.
Earth electrodes shall be installed in such a way as to allow inspection during construction. The embedded depth and the type of earth electrodes shall be such as to minimize the effects of corrosion, soil drying and freezing and thereby stabilize the conventional earth resistance. It is recommended that the upper part of a vertical earth electrode equal to the depth of freezing soil should not be regarded as being effective under frost conditions.
NOTE 2 Hence, for every vertical electrode, 0,5 m should be added to the value of the length l1, calculated in 184.108.40.206 and 220.127.116.11.
For bare solid rock, a type B earthing arrangement is recommended.
For structures with extensive electronic systems or with high risk of fire, type B earthing arrangement is preferable.
Components of LPS shall withstand the electromagnetic effects of lightning current and predictable accidental stresses without being damaged. This can be achieved by choosing components that have successfully been tested in accordance with the future SABS 62561 series. Components of an LPS shall be manufactured from the materials listed in Table 5 or from other materials with equivalent mechanical, electrical and chemical (corrosion) performance
Air-terminations and down-conductors shall be firmly fixed so that the electrodynamics or accidental mechanical forces will not cause conductors to break or loosen
The number of connections along the conductors shall be kept to a minimum. Connections shall be made secure by such means as brazing, welding, clamping, crimping, seaming,screwing or bolting.To achieve this, connections of steelworks within reinforced concrete structures shall conform to 4.3 and shall comply with the requirements and tests according to the future SABS 62561-1.
6 Internal lightning protection system
The internal LPS shall prevent the occurrence of dangerous sparking within the structure to be protected due to lightning current flowing in the external LPS or in other conductive parts of the structure.
Dangerous sparking may occur between the external LPS and other components such as:
– metal installations;
– internal systems;
– external conductive parts and lines connected to the structure.
Dangerous sparking between different parts can be avoided by means of
– equipotential bonding in accordance with 6.2, or
– electrical insulation between the parts in accordance with 6.3.
6.2 Lightning equipotential bonding
Equipotentialization is achieved by interconnecting the LPS with
– metal installations,
– internal systems,
– external conductive parts and lines connected to the structure.
When lightning equipotential bonding is established to internal systems, part of the lightning current may flow into such systems and this effect shall be taken into account.
Interconnecting means can be
– bonding conductors, where the electrical continuity is not provided by natural bonding,
– surge protective devices (SPDs), where direct connections with bonding conductors are
– isolating spark gaps (ISGs), where direct connections with bonding conductors are not
The manner in which lightning equipotential bonding is achieved is important and shall be discussed with the operator of the telecommunication network, the electric power, gas pipes operator, and other operators or authorities concerned, as there may be conflicting requirements.
SPDs shall be installed in such a way that they can be inspected.
6.2.2 Lightning equipotential bonding for metal installations
In the case of an isolated external LPS, lightning equipotential bonding shall be established at ground level only. For an external LPS which is not isolated, lightning equipotential bonding shall be installed at the following locations:
a) in the basement or approximately at ground level. Bonding conductors shall be connected to a bonding bar constructed and installed in such a way that it allows easy access for inspection. The bonding bar shall be connected to the earth-termination system. For large structures (typically more than 20 m in length), a ring bonding bar may be used or more than one bonding bar can be installed, provided that they are interconnected;
b) where insulation requirements are not fulfilled (see 6.3).
Lightning equipotential bonding connections shall be made as direct and straight as possible.
6.2.4 Lightning equipotential bonding for internal systems
It is imperative that lightning equipotential bonding is installed in accordance with 6.2.2 a) and6.2.2 b). If cables of internal systems are screened or located in metal conduits, it may be sufficient to bond only these screens and conduits .
If cables of internal systems are neither screened nor located in metal conduits, they shall be bonded via SPDs. In TN systems, PE and PEN conductors shall be bonded to the LPS directly or with an SPD. Bonding conductors shall have the same current withstand as indicated in 6.2.2 for ISGs. SPDs shall comply with SANS 61643-1 and SANS 61643-21.
6.2.5 Lightning equipotential bonding for lines connected to the structure to be
Lightning equipotential bonding for electrical and telecommunication lines shall be installed in accordance with 6.2.3. All the conductors of each line should be bonded directly or with an SPD. Live conductors shall only be bonded to the bonding bar via an SPD. In TN systems, PE or PEN conductors shall be bonded directly or via an SPD to the bonding bar. Lightning equipotential bonding of the cable screens or of the conduits shall be performed near the point where they enter the structure. Bonding conductors shall have the same current withstand as indicated in 6.2.3 for ISGs. SPDs shall comply with SABS 61643-1 and SABS61643-21. If protection against surges of internal systems connected to lines entering the structure is required, a coordinated SPD system conforming to the requirements of Clause 7 of SABS 62305-4:2010 shall be used.
7 Maintenance and inspection of an LPS
The effectiveness of any LPS depends on its installation, maintenance, and testing methods used. Inspections, testing and maintenance shall not be conducted during threat of thunderstorms.
7.2 Application of inspections
The objective of the inspections is to ascertain that
a) the LPS conforms to the design based on this standard,
b) all components of the LPS are in good condition and capable of performing their designed functions, and that there is no corrosion,
c) any recently added services or constructions are incorporated into the LPS.
7.3 Order of inspections
Inspections should be made according to 7.2 as follows:
– during the construction of the structure, in order to check the embedded electrodes;
– after the installation of the LPS;
– periodically at such intervals as determined with regard to the nature of the structure to be protected, i.e. corrosion problems and the class of LPS;
– after alterations or repairs, or when it is known that the structure has been struck by lightning. During the periodic inspection, it is particularly important to check the following:
– deterioration and corrosion of air-termination elements, conductors and connections;
– corrosion of earth electrodes;
– earthing resistance value for the earth-termination system;
– condition of connections, equipotential bonding and fixings.
Regular inspections are among the fundamental conditions for reliable maintenance of an LPS. The property owner shall be informed of all observed faults and they shall be repaired without delay.
8 Protection measures against injury to living beings due to touch and step voltages
8.1 Protection measures against touch voltages
In certain conditions, the vicinity of the down-conductors of an LPS, may be hazardous to life even if the LPS has been designed and constructed according to the above-mentioned requirements.
The hazard is reduced to a tolerable level if one of the following conditions is fulfilled:
a) under normal operation conditions there are no persons within 3 m from the down conductors;
b) a system of at least 10 down-conductors complying with 5.3.5 is employed;
c) the contact resistance of the surface layer of the soil, within 3 m of the down-conductor, is
not less than 100 kW.
NOTE A layer of insulating material, e.g. asphalt, of 5 cm thickness (or a layer of gravel 15 cm thick) generally reduces the hazard to a tolerable level.
If none of these conditions is fulfilled, protection measures shall be adopted against injury to living beings due to touch voltages as follows:
– insulation of the exposed down-conductor is provided giving a 100 kV, 1,2/50 μs impulse withstand voltage, e.g. at least 3 mm cross-linked polyethylene;
– physical restrictions and/or warning notices to minimize the probability of down-conductors being touched.
Protection measures shall conform to the relevant standards (see ISO 3864-1).
8.2 Protection measures against step voltages
In certain conditions, the vicinity of the down-conductors may be hazardous to life even if the LPS has been designed and constructed according to the above-mentioned rules. The hazard is reduced to a tolerable level if one of the following conditions is fulfilled:
a) under normal operation conditions there are no persons within 3 m from the down conductors ;
b) a system of at least 10 down-conductors complying with 5.3.5 is employed;
c) the contact resistance of the surface layer of the soil, within 3 m of the down-conductor, is not less than 100 kW.
NOTE A layer of insulating material, e.g. asphalt, of 5 cm thickness (or a layer of gravel 15 cm thick) generally
reduces the hazard to a tolerable level.
If none of these conditions is fulfilled, protection measures shall be adopted against injury to living beings due to step voltages as follows:
– equipotentialization by means of a meshed earth-termination system;
– physical restrictions and/or warning notices to minimize the probability of access to the dangerous area, within 3 m of the down-conductor.
Protection measures shall conform to the relevant standards (see ISO 3864-1).
The design and installation of earth electrodes
This standard is intended to give authoritative guidance on the methods to be used in providing an earthing system and in calculating and measuring the essential characteristics of earth electrodes.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. All standards are subject to revision and, since any reference to a
standard is deemed to be a reference to the latest edition of that standard, parties to agreements based on this standard are encouraged to take steps to ensure the use of the most recent editions
of the standards indicated below. Information on currently valid national and international standards can be obtained from the SABS Standards Division.
EN 13509, Cathodic protection measurement techniques. Amdt 1
EN 50162, Protection against corrosion by stray current from direct current systems. Amdt 1
SANS 1063, Earth rods, couplers and connections.
Earth rods, couplers and connections
1.1 This standard specifies requirements for metallic earth rods, couplers and connections intended to be driven direct into the ground or installed into predrilled holes as part of an earthing system.
1.2 The following types of earth rod are covered:
a) copper rods;
b) copper-electroplated steel rods;
c) stainless steel rods;
d) galvanized steel rods; and
e) fusion copper bonded steel rods.
1.3 The following methods of coupling are covered:
a) mechanical coupling; and
b) welded coupling.
1.4 The following methods of connection are covered:
a) mechanical connection by clamping or bolting; and
b) connection by exothermic welding.
1.5 Information regarding the selection and installation of the appropriate earth rod as part of an
earth electrode for various types of installation and types of soil is given in SANS 10199.
E.7 Maintenance and inspection of the LPS
E.7.1 Scope of inspections
Inspection of the LPS should be conducted by a lightning protection specialist in accordance with the recommendations of Clause E.7. The inspector should be provided with the LPS design report containing the necessary documentation of the LPS such as design criteria, design description and technical drawings. The LPS inspector should also be provided with previous LPS maintenance and inspection reports.
All LPS should be inspected on the following occasions:
– during installation of the LPS, especially during installation of components which are
concealed in the structure and will become inaccessible;
– after the completion of the LPS installation;
– on a regular basis according to Table E.2.
The inspection frequencies given in Table E.2 should apply where no specific requirements are identified by the authority having jurisdiction.
NOTE If national authorities or institutions require regular tests of the electrical system of a structure, it is
recommended to test the lightning protection system with regard to the functioning of the Internal lightning
protection measures including the lightning protection equipotential bonding with electric systems at the same time.
Older installations analogously should be related to a lightning protection class or the test intervals should be
taken from the local or any other test specifications such as construction guide lines, technical regulations,
instructions, industrial safety and protection of labor laws.
The LPS should be visually inspected at least annually. In some areas where severe weather changes and extreme weather conditions occur, it is advisable to visually inspect the system more often than indicated in Table E.2. Where the LPS forms part of the client’s planned maintenance program, or is a requirement of the building insurers, the LPS may be required to be fully tested annually. The interval between the LPS inspections should be determined by the following factors:
– classification of structure protected, especially with regard to the consequential effects of damage;
– class of LPS;
– local environment, for example a corrosive atmosphere environment should have short intervals between inspections;
– the materials of the individual LPS components;
– the type of surface to which the LPS components are attached;
– the soil condition and associated corrosion rates.
In addition to the above, an LPS should be inspected whenever any significant alteration or repairs are made to a protected structure and also following any known lightning discharge to the LPS. A total inspection and test should be completed every two to four years. Systems in critical environmental conditions, for example parts of the LPS exposed to severe mechanical stresses such as flexible bonding straps in high wind areas, SPDs on pipelines, outdoor
bonding of cables etc., should have a complete inspection every year. In most geographical areas, and especially in areas which experience extreme seasonal changes in temperature and rainfall, the variation of the earthing resistance should be taken into account by measuring the resistivity depth profile in different weather periods. An improvement of the earthing system should be considered when the measured resistance values show larger changes in the resistance than anticipated in the design; especially when the resistance increases steadily between inspections.
E.7.2 Order of inspections
E.7.2.1 Inspection procedure
The purpose of this inspection is to ensure that the LPS conforms to this standard in all respects. The inspection includes checking technical documentation, visual inspections, testing and logging in an inspection report.
E.7.2.2 Checking of technical documentation
Technical documentation should be checked for completeness, conformity to this standard and agreement with the plant as executed.
E.7.2.3 Visual inspections
Visual inspections should be made to ascertain that
– the design conforms to this standard,
– the LPS is in good condition,
– there are no loose connections and no accidental breaks in the LPS conductors and joints,
– no part of the system has been weakened by corrosion, especially at ground level,
– all visible earth connections are intact (functionally operational),
– all visible conductors and system components are fastened to the mounting surfaces and components which provide mechanical protection are intact (functionally operational) and in the right place,
– there have not been any additions or alterations to the protected structure which would require additional protection,
– there has been no indication of damage to the LPS, to SPDs or any failures of fuses which protect SPDs,
– correct equipotential bonding has been established for any new services or additions which have been made to the interior of the structure since the last inspection, and that continuity tests have been performed for these new additions,
– bonding conductors and connections inside the structure are present and intact (functionally operational),
– separation distances are maintained,
– bonding conductors, joints, shielding devices, cable routing and SPDs have been checked and tested.
Inspection and testing of the LPS includes visual inspections and should be completed by the
– performing continuity tests, especially continuity of those parts of the LPS which were not visible for inspection during the initial installation and are not subsequently available for visual inspection;
– conducting earth resistance tests of the earth-termination system. The following isolated and combined earth measurements and checks should be made and the results recorded in an LPS inspection report.
a) The resistance to earth of each local earth electrode and where reasonably practical the resistance to earth of the complete earth-termination system. Each local earth electrode should be measured in isolation with the test joint between the down-conductor and earth electrode in the disconnected position (isolated measurement).
NOTE 2 For earth networks incorporating both vertical earth rods and a partial or full ring earth electrode, disconnection and testing should be performed at the earth inspection pit. If such inspection is difficult to perform, routine test should be completed by high frequency or impulse tests. If the resistance to earth of the earth-termination system as a whole exceeds 10 ohm , a check should be made to ascertain that the electrode conforms to Figure 3. If there is a significant increase or decrease in the value of the earth resistance, additional investigations should be made to determine the reason for the change. For earth electrodes in rocky soil, the requirements of E.18.104.22.168 should be followed.
The 10 ohm requirement is not applicable in this case.
b) The results of a visual check of all conductors, bonds and joints or their measured
If the earth-termination system does not conform to these requirements, or checking there requirements is not possible because of a lack of information, the earth-termination system should be improved by installing extra earth electrodes or installing a new earth-termination system. SPDs without a visual indicator need to be tested, preferably using the guidelines or equipment provided by the manufacturer.
E.7.2.5 Documentation of inspection
LPS inspection guides should be prepared to facilitate LPS inspections. They should contain sufficient information to guide the inspector through the inspection process so that all areas of importance are documented such as the method of LPS installation, the type and condition of the LPS components, test methods and the proper recording of the test data obtained. The inspector should compile an LPS inspection report, which should be kept together with
the LPS design report and the previously compiled LPS maintenance and inspection reports. The LPS inspection report should contain the following information:
– general conditions of air-termination conductors, and other air-termination components;
– general level of corrosion and the condition of the corrosion protection;
– security of attachment of the LPS conductors and components;
– earth resistance measurements of the earth-termination system;
– any deviation from the requirements of this standard;
– documentation of all changes and extension of the LPS and any changes to the structure. In addition, the LPS construction drawings and the LPS design description should be reviewed;
– the results of the tests performed.
The LPS should be maintained regularly to ensure that it does not deteriorate but continues to fulfill the requirements to which it was originally designed. The design of an LPS should determine the necessary maintenance and inspection cycle according to Table E.2. The LPS maintenance program should ensure a continuous updating of the LPS to the current issue of this standard.
E.7.3.1 General remarks
LPS components tend to lose their effectiveness over the years because of corrosion, weather-related damage, mechanical damage and damage from lightning strokes. The inspection and maintenance program should be specified by an authority, the LPS designer or the LPS installer, in conjunction with the owner of the structure or an appointed representative. To carry out maintenance work and to perform inspections of an LPS the two program, inspection and maintenance, should be coordinated. Maintenance of an LPS is important even though the LPS designer has taken special precautions to provide corrosion protection and has dimensioned the LPS components according to their particular exposure to lightning damage and weather elements in addition to the requirements of this standard. The mechanical and electrical characteristics of the LPS should be fully maintained throughout the entire lifetime of the LPS in order to conform to the design requirements of this standard. It may be necessary to modify the LPS if modifications are carried out on the building or its equipment or if the purpose for which the building is utilized is altered.If an inspection shows that repairs are necessary, those repairs should be executed without delay and not be postponed until the next maintenance cycle.
E.7.3.2 Maintenance procedure
Periodic maintenance program should be established for all LPS. The frequency of maintenance procedures is dependent on the following:
– weather- and environment-related degradation;
– exposure to actual lightning damage;
– protection level assigned to the structure.
LPS maintenance procedures should be established for each particular LPS and should become a part of the overall maintenance program for the structure. A maintenance program should contain a list of routine items to serve as a checklist so that definite maintenance procedures are followed regularly in order to make it possible to compare recent results with previous ones.
A maintenance program should contain provisions for the following:
– verification of all LPS conductors and system components;
– verification of the electrical continuity of the LPS installation;
– measurement of the resistance to earth of the earth-termination system;
– verification of SPDs;
– re-fastening of components and conductors;
– verification to ensure the effectiveness of the LPS has not been reduced after additions to, or changes in, the structure and its installations.
E.7.3.3 Maintenance documentation
Complete records should be kept of all maintenance procedures and should include corrective actions taken or required. Maintenance procedure records should provide a means of evaluating LPS components and the LPS installation.
The LPS maintenance record should serve as a basis for reviewing maintenance procedures as well as for updating maintenance program. The LPS maintenance records should be kept together with the LPS design and the LPS inspection reports.