An Introduction to Lightning Protection System Design

LPI Group are launching our technical blog section with an introduction to lightning protection system design. This will clearly outline over 3 steps the series of considerations, parameters and data required to ensure a system is designed to code compliant standards and meets the client’s project requirements and design criteria.

Step 1

Establish whether there are any project requirements issued from the client or if there is a project specification and design criteria document.

If yes, seek the project documentation, learn about the client’s requirements and conduct a strike risk assessment should it be required. Following this, then examine the following factors:

  • If the level of protection has been specified.
  • If any general diagrams exist for locating the Surge Protection Devices (SPD) in different Lightning Protection Zone (LPZ 1,2,..).
  • Whether an isolated system is a requirement, if there are any restrictions to use isolated cable and whether the client is happy to use cable as an option within the design. Furthermore, if a non-isolated system is a requirement, identify the type of bonding network that is needed for the project.
  • If electronic equipment is going to be employed within the building and if the client has any requirements to use Part 4 of standard IEC 62305?
  • If there are any three-dimensional types of bonding networks required to provide shielding effects against electromagnetic interference.
  • All the above-stated factors shall be specified in accordance with standard guidelines and requirements.

If no, conduct a strike risk assessment study and examine the following factors:

  • The level of lightning protection is required.
  • The best type of system (isolated/non-isolated) for the structure.
  • The most appropriate shielding level for the project based on Part 4 of IEC 62305.

Findings from Step 1:

  • The level of protection required.
  • The type of lightning protection system (isolated/non-isolated).
  • The districts of LPZ.
  • The protection measures needed for each LPZ.
  • If additional requirements of shielding and the three-dimensional bonding network are required based on Part 4 of IEC 62305.

Step 2

Important Investigations and Considerations

Investigation 1:

If there are any telecommunication buildings in adjacent to the telecommunication tower?

Key Considerations 1:

  • Refer to ITUT.K standards to find out the requirements for the typical factors accounted for in the risk assessment study, the bonding requirements of waveguide conductor, the direct lightning protection of the antennas and the best solution for the earthing system at the telecommunication tower.
  • The SPD requirements for the entrance waveguide to the telecommunication building.

Investigation 2:

Are there any hazardous classification areas?

Key Considerations 2:

  • The hazardous classification drawing shall be reviewed to identify.
  • Strike risk assessment to be completed for each zone of different explosive material.
  • The lightning exposure level of all the tanks containing explosive material shall be calculated.
  • All the vents on the tank roof shall be detected and assessed.
  • The safety standards for the hazardous areas shall be used in line with lightning protection design standards.
  • The pipe rack locations shall be identified and protection measures for direct exposure on pipes shall be considered.
  • The SPD requirements shall be investigated for insulating gasket, cathodic protection systems etc.

Investigation 3:

Foundation earth electrode.

Key Considerations 3:

  • If the foundation electrode is a part of an integrated electrode system and is going to conduct the lightning discharge current, all requirements stated in the standard DIN18014 shall be respected.

Investigation 4: 

The architectural drawing shall be reviewed.

Key Considerations 4:

  • Identify the restrictions surrounding the installation of the LPS.
  • The equipment locations on the roof shall be investigated.
  • The feasibility of the lightning current distribution network shall be reviewed.
  • The building facades, parapet structure and it’s material shall be investigated.

Investigation 5:

If there are any lighting poles or CCTV equipment located at the concerned site.

Key Considerations 4:

  • Identify the solution for the protection of direct strike to CCTV and Lightning fixture.
  • Investigate the SPD requirements for the CCTV.

Findings from Step 2:

  • The points and areas that are going to be protected against a direct strike.
  • The restrictions for the installation of the LPS components at roof level and on the wall are ascertained.
  • All the locations that require SPD.

Step 3

Perform the Calculations

  • Zonal coverage study by software (XGSlab – SES Shield – AUTOCAD – Dehn Support, etc.)
  • Consider different types of air termination networks (air rod, mesh, catenary wire, etc.)
  • Choose the most appropriate and cost-effective air termination network.
  • Calculate the separation distance manually or by software such as XGSLAB, Dehn Support, MAT Lab, PSpice, etc.
  • Conduct the surge study to detect the locations of the SPDs in power, data and telecommunication circuits manually or with the manufacturer’s software.Result Outcome for SES Shield Software

Complete the Drawing and Issue the Technical Drawings

Generate 2D/3D DWG drawings and include the following information:

  • Installation locations of the air terminals.
  • The distance between all the air terminals.
  • Side view of all the sections of the buildings to highlight the LPS component on it.
  • Issue all the technical and installation notes (Maximum bending radius of the conductor or tape, separation distances to be maintained, corrosion prevention treatment, the location of polarization cells, bonding requirements, etc.)

Produce Typical Installation Details

  • The standard detail for the down conductor connection on the roof and walls.
  • The installation drawing for the spacer and holder.
  • The installation detail for the air terminal and the down conductor connection to the earthing system.
  • The detail for the inspection chambers.
  • The installation drawing for bonding the embedded concrete rebars to the LPS components.
  • The installation drawing for the SPD installation.

Generate the Technical Submittal

  • The technical submittal should the following subjects; calculation reports consisting of the zonal protection study, all assumptions made, strike-risk assessment study, separation distance study, AUTO-CAD drawing and surge study calculation.

By Hadi Beik Daraei, Technical Designer at LPI Group