IEC 62305 risk assessment, computed clause by clause
Lumex runs the complete IEC 62305:2024 procedure, not a simplified estimator, so every number traces back to the clause and coefficient you can defend.
Four risks, each held to its own line
IEC 62305:2024 judges four fronts on their own terms: life (R1), service (R2), heritage (R3) and economic loss (R4). Each is tested against its tolerable threshold RT, and every verdict traces back to the clause behind it.
R1 · RT = 10⁻⁵/yr
The risk to
human life
Touch and step voltages, plus fire after a strike, put people in danger. R1 holds the strictest limit of all.
R2 · RT = 10⁻³/yr
The risk to
public services
The power, water, gas and signal a community leans on. R2 measures what happens when a strike knocks them out.
R3 · RT = 10⁻⁴/yr
The risk to
cultural heritage
Historic buildings and the treasures inside cannot be rebuilt, so damage from one strike stays with us for good.
R4 · cost-benefit
The risk to
economic value
Weighed on a plain cost and benefit basis, R4 tells you whether paying for lightning protection is worth it.
Eight risk components
Every risk is the sum of components; each component = dangerous-event rate (N) × probability of damage (P) × loss factor (L).
| Comp. | Source & cause | Belongs to |
|---|---|---|
| RA | Direct flash to the structure causing touch and step voltages | R1 |
| RB | Direct flash to the structure causing dangerous sparking and fire | R1, R2, R3, R4 |
| RC | Direct flash to the structure causing internal system failure (LEMP) | R1, R2, R4 |
| RM | Nearby flash inducing failure of internal systems | R1, R2, R4 |
| RU | Flash to a connected line causing touch voltage indoors | R1, R4 |
| RV | Flash to a connected line causing fire or explosion via the service | R1, R2, R3, R4 |
| RW | Flash to a connected line causing internal system failure | R1, R2, R4 |
| RZ | Flash near a connected line inducing internal system failure | R1, R2, R4 |
From flash density to a verdict you can defend
Every component follows the same chain. Lumex carries each named number through, so you can read the trace from the first input to the final pass or fail.
Collection area (Annex A)
Ad = L·W + 2·(3H)·(L+W) + π·(3H)²
How much ground around the building attracts a strike, from its length, width and height. Adjacent and line-attracted areas (Am, Al, Ai) follow the same annex.
Dangerous-event rate
Nd = NG · Ad · CD · 10⁻⁶
How many strikes per year that area can expect. NG is the local ground flash density (flashes / km² / yr); CD is the location factor.
Probability of damage (Annex B)
PB from LPS class · PSPD from SPD coordination · PTA, PEB …
How likely a strike is to actually cause damage. Protection measures lower P. An LPS of Class I drives PB to 0.02; a coordinated Type 1 SPD set drives PSPD to 0.01.
Loss factor (Annex C)
LA, LB, LC from rp · rf · hz · LX
How much is lost if damage does happen. Fire-protection (rp), fire-risk (rf) and special-hazard (hz) factors scale the typical loss values.
Component and risk
RX = N · P · L, then R1 = Σ components, then compare to RT
Each component is N times P times L. Add the components for a risk, then compare the total to RT for a clear pass or fail.
R1 fails. One upgrade makes it pass
A real data centre, assessed clause by clause. Same inputs, same maths Lumex runs on every project, with the verdict you can defend.
The building & inputs
RPG Bhiwadi DC
Data centre · Zone Z2 · Rajasthan
The verdict, traced
As built · Class III LPS
R1 = 2.4×10⁻⁵
exceeds RT 1.0×10⁻⁵
Fix: upgrade to LPS Class II, dropping PB to 0.05.
After fix · Class II LPS
R1 = 4.8×10⁻⁶
within RT 1.0×10⁻⁵
Every figure here is computed, not estimated, straight from IEC 62305:2024. Run the same trace on your own building in minutes.
Join the waitlistAI speeds the routine. The engine still owns every number
You just saw the deterministic trace. Planned for launch, AI works around that engine to cut the busywork, with the signing engineer in control at every step.
Risk-driver analysis
Reads the completed trace and shows which component drives each risk, so you know exactly where to act.
Drafted report narrative
Turns your computed figures into clear report prose you review, edit and approve before it is filed.
Ranked mitigation options
Suggests protection upgrades and ranks them by their effect on R1 to R4, with the maths shown for each.
Early fail flags
Flags risks likely to exceed RT as you enter inputs, long before you reach the final verdict.
Where Lumex fits the standard series
General principles
Lightning parameters & damage model that underpin Lumex's terminology and LPL definitions.
Risk management
The full procedure Lumex implements: R1–R4, all eight components, every annex coefficient.
Physical damage & life
LPS classes and the §E.7 periodic-inspection report referenced by Lumex.
Electrical & electronic systems
SPD coordination and LEMP-protection factors feed the PSPD and PM inputs.
Lumex computes the IEC 62305 procedure across all four parts, but it remains an assessment tool: final responsibility for every result rests with the signing engineer, and Lumex does not replace professional judgement or the published standard.