DownloadLightning is one of the biggest threats to mankind and animals apart from property loss. When there is a threat, risk will be there always, which needs to be mitigated. Otherwise there will be damages which results in losses.Due to the enormous increase of the high rise buildings, the risk has only increased to manifold. To address the issue, BIS Bureau of Indian Standards has recently adopted IEC 62305 as Indian Standard, which means it is IS/IEC 62305 from now on and replaces IS 2309 Code of practice for the protection of buildings and allied structures against lightning.
IS/IEC 62305 Protection against lightning has 4 parts
IS/IEC 62305-1: Basic Principles
IS/IEC 62305-2: Risk Assessment
IS/IEC 62305-3: Protection of structures & Life Hazards.
IS/IEC 62305-4: Protection of electrical & electronic systems within structure.
The relation between these 4 parts is best explained in the figure below:
LPS Lightning Protection System
SPM Surge Protection Measures
Lightning threat is mainly due to 4 sources of damages
Source S1: Lightning striking the structure
Source S2: Lightning striking near the structure
Source S3: Lightning striking a service
Source S4: Lightning striking near the service.
To mitigate the risks, the damages need to be ascertained. There are basically 3 types of damages.
- Injury/death to the living beings
- Physical damage to the structure
- Failure of electrical & electronic equipment
The above damages have to be controlled within TOLERABLE LEVELS to minimise 4 types of losses.
- Loss of Human life
- Loss of essential public services (wherever applicable)
- Loss of cultural damage (wherever applicable)
- Economic loss.
The relation between SOURCES/DAMAGES & LOSSES is explained below.
Then, risk has to be calculated for the building that needs protection. If the calculated risk is above the tolerable level, then the most economical protection technique can be employed to bring the calculated risk level below the tolerable level.
To reduce the losses due to lightning protection measures may be required. Whether they are needed & to what extent can be determined by using Risk assessment software. A snap shot of the software is given below.
Inadequate protection the structural Increase Protection Levels!!
- Lightning protection as per LPL 1 to 4
- Co-ordinated SPD protection
- Fire protection (manual or automatic)
- Soil equi-potentialisation
- Warning notices
- Physical restriction
- Electrical insulation
An important unique feature of this software is that, by having different permutations & combinations, most economical solution can be easily arrived within very little iterations. It means the just adequate protection for the typo of building is achieved without the risk of over design or under design.
In a broader perspective, Risk assessment using the software helps in 3 following key areas.
- Proof as per IS/IEC 62305-2 that, the calculated risk is below the tolerable risk levels & in case of any loss, insurance can be claimed.
- Menu driven step by step technique which does not need any expertise in any software language.
- Cheap & nest solution can be arrived easily for the building under consideration which gives the best Cost vs. Performance ratio.
This software is based on the current edition of IS/IEC 62305-2.
Published in IEEME Journal, December 2015