Created by: Glen Zhu | Updated Date: November 14th, 2023
Churches, often featured by tall structures with steeples or towers, are particularly susceptible to lightning strikes due to their height. From a religious perspective, protecting churches from lightning and surges is seen as a responsible and prudent act, reflecting the care and respect believers have for their places of worship. Many religious texts emphasize the importance of protecting one’s property and ensuring the safety of congregants.
The Bible encourages believers to be good stewards of their possessions, which includes protecting their places of worship (1 Corinthians 6:19-20). Surge protective devices (SPDs) and lightning measurements are needed for churches, temples, and other places of worship.
Height: Churches with steeples, crosses, minarets, and other symbols of faith are vulnerable to lightning strikes due to their height and prominent architectural features.
Occupancy: Places of assembly such as sanctuaries and community halls necessitate heightened lightning protection. Similarly, daycares, schools, and shelters within religious facilities also demand extra safeguarding against lightning.
Construction Materials: Churches often have spires, domes, and other architectural elements made of metal, which conduct electricity. These structures can attract lightning strikes.
Electronics: The valuable audio-visual and electronic equipment used in worship and ministry are at risk of damage from power surges caused by lightning.
A comprehensive lightning protection system comprises the following components:
Air Terminals: These are also known as grounding rods, made of copper or aluminum, placed at regular intervals along the roof of a structure to intercept lightning strikes.
Main Conductors: Braided cables connecting air terminals to system components and grounds. A metal rod at the building’s highest point, like a church spire, connects to a stake in the ground through ribbons made from conductive materials.
Grounds: Grounding electrodes, such as ground rods or grounding plates, are buried in the earth and connected to the down conductors. Lightning current could travel through the path into the ground.
Bonds: Materials linking roof components and grounded building systems to the main conductor, preventing side flashing, where lightning jumps between objects.
A grounding system is the fundamental component of the whole system. A well-designed grounding system provides a low-resistance path for the lightning discharge to follow, directing the immense electrical energy safely into the ground. This prevents the lightning from traveling through the building’s electrical systems or other conductive materials, thereby protecting people and property from harm. That’s why we emphasized the necessity of earthing.
However, lightning can also damage appliances and electronics if it strikes a power line or utility nearby. In such cases, the current may travel through electrical, cable, or phone lines, entering the building. Therefore, surge protection installation is necessary to ensure the essential electrical equipment safe inside the churches.
Some buildings of churches were primarily constructed and continue to be built using brick or stone materials. The method of monolithic construction using prefabricated reinforced concrete is mostly used in modern churches. Understanding the key to lightning protection should take the constructional material of religious buildings into account.
Metaled church architecture: that has a metal frame and a sheet steel or copper coating sometimes with gilding. All these elements can be used to receive a direct lightning strike without installing a lightning rod.
Wooden church architecture: is the most fire-hazardous when meeting lightning strikes. A safe and comprehensive external lightning system is necessary to protect the wooden structure.
Steeples are tall towers or spires, typically made of stone or metals. We often find a lightning rod on the top of the steeple, but it is not enough to resist lightning, only a complete lightning protection system can protect the entire building.
A partial lightning protection installation could be more dangerous than not protecting at all. If lightning strikes a specific component of a structure, such as a grounded cupola, steeple, or single-point mast, it can lead to side-flashing, potentially damaging other conductive elements within or on the building.
This phenomenon has the potential to harm building wiring, computer systems, and electronics, and may even result in fires. There is no safe way to discharge huge transient overvoltage into the ground.
The use of religious symbols such as the cross and crescent on temple spires as lightning rods is feasible under specific conditions.
The cult object must be conductive or made of metal.
The material used must include steel with a thickness of 2.5 mm and a cross-section of 50 mm². For stainless steel products, a wall thickness of 2 mm and a cross-section of 50 mm² are acceptable.
To design an effective external lightning protection system, we construct down conductors from crosses or metal structures supporting them to a grounding device. Protection zones against potential lightning strikes need to be confirmed. If the protection zone is insufficient, additional measures such as installing air-terminal masts or lightning protection mesh on the temple’s dome are necessary.
Temples with multiple domes require lightning rods for each dome. Down conductors, starting from the zero level should connect lightning rods every 15-20 m to form a unified lightning protection system.
Other parts of the temple, such as domes and roofs made of metal, can also serve as natural lightning rods. But to make sure electrical continuity between roof elements and adhering to specified metal thickness standards meet the standard and avoid roof insulation but keep an anti-corrosion coating.
For wooden churches with conductive crosses and domes, lightning rods can be constructed in the form of rods attached to the cross using insulating fasteners or staples. Alternatively, standalone mast lightning protection systems are occasionally used.
Each lightning rod must be connected to the ground electrode via two down conductors. To ensure the even distribution of lightning current, it is advisable to establish a current-collecting system positioned uniformly along the perimeter, typically placed at the building corners.
In the case of fireproof temple structures, the down conductors can be directly affixed to the building walls, either beneath plaster or using natural down conductors in the form of metal construction bodies made from prefabricated or monolithic reinforced concrete. The lightning protection system should have minimum cross-sections ranging from 16 mm² (for copper) to 50 mm² (for steel).
In the case of some churches or temples constructed with flammable materials, down conductors are attached to insulators or metal clips securely fastened within the building frame, maintaining a distance of at least 0.1 m from the wall surface to prevent human contact within reachable height limits.
It is recommended to apply a protective coating of materials such as asphalt, gravel, or other dielectric substances within a 3-meter distance along the building’s perimeter rather than our normal guidelines at a distance of no less than 1 meter.
Calculations indicate that even when grounding is done, a “step voltage” can occur, especially in areas where the ground resistivity ranges from 500 to 1000 Ohm. In such cases, the step voltage can exceed 50 kV with a lightning current of 30 kA, posing a risk of electric shock in places with high congregation, like churches and temples.
In addition to the organization of external lightning protection systems of churches, one should not forget about the provision of internal lightning protection systems: SPDs.
Equipotential bonding strives to balance the electrical potential among diverse conductive elements within a building. This process ensures that all these elements share the same electric potential, effectively reducing the damaging impact of a lightning strike.
Proper equipotential bonding is a critical aspect of a comprehensive lightning protection system for buildings and structures. In Churches, where congregations gather, children attend classes, and various events take place, equipotential bonding safeguards sensitive electronic equipment and prevents costly damages. It must be established for the low-voltage supply and other cables.
As the external lightning system has discussed, internal surge protection is also necessary to be installed in order to prevent indirect lightning strikes. Churches are encouraged to have surge protection (compliance with IEC 61643).
Modern churches are equipped with various electronic devices. Sound systems, phone systems, computers, and electric organs are all very sensitive to damage caused by power surges.
The cables in the bell tower and nave, such as those used for the electric clock mechanism and bell controller, are often lengthy and may form loops.
Additionally, the electrical hymn board, the pipe heating system, the electronic organ and the sound system are highly susceptible to electromagnetic coupling.
When two conductors are placed close to each other, electromagnetic fields from one conductor can induce voltages or currents in the adjacent conductor, leading to electromagnetic coupling.
Enough distance should be maintained between down conductors, any possible current-carrying components, and installed cables in the steeple, if not, surge protective devices must be mounted.
Lightning rods, down conductors and grounding system build external lighting protection system to prevent direct strikes and protect the entire building.
Figure 1 – Principle of external and internal lightning protection for a church with a steeple
MOV surge protectors are installed to safeguard the electric system of the church. FLP25 series is developed as the best solution available to protect service entrances at an industrial site, especially those with existing lightning protection systems or meshed cage applications. A Type 1 SPD discharges the excess energy to the ground and a Type 2 surge protector is installed close to the electric terminals to protect the electric system.
Figure 2- Example of surge protective devices for the bell controller
The circuit of the control line of the bell controller is illustrated in detail.
In the example shown, the Type 2 surge protector in the power supply system does not need to connect the earthing conductor again since the first surge protector has earthed.
Type 2 surge protection devices are designed to be installed at the service entrance of low voltage systems or close to sensitive equipment to protect against transient overvoltages, applying for TN-S, TN-C, and TT system.
LSP’s reliable surge protection devices (SPDs) are designed to meet the protection needs of installations against lightning and surges. Contact our Experts!
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