IEC 62305-2:2024 Risk Assessment Software
Lumex is cloud lightning risk assessment software for IEC 62305: Voltrace, which runs the full IEC 62305-2:2024 method and computes your lightning risk against the tolerable limit, plus the frequency of damage to internal systems, from the standard's own coefficients, traceable to every input, and turns the result into a branded, audit-ready report. It is purpose-built risk assessment software for the current 2024 third edition, in the browser, for your whole team.
Lumex is software for the IEC 62305-2:2024 lightning risk assessment. It runs the full IEC 62305-2 risk method in the browser: you model the structure, its surroundings and the services connected to it, and the engine resolves your lightning risk against the tolerable limit, plus the frequency of damage to internal systems, building it from all nine risk components straight from the standard's coefficients.
It is built on the published current 2024 third edition, adopted nationally across most of the world, so the method behind every number is the one an auditor or authority cites today. New to the standard itself? Start with what IEC 62305 is, then read on for what the software does.
One risk R, plus a frequency of damage F
IEC 62305-2:2024 combines injury to people and loss from fire into a single risk R, judged against the tolerable risk RT, for which clause 7.3 NOTE 1 gives 10⁻⁵/yr as a representative value and your jurisdiction may set its own. Alongside it sits a separate frequency of damage F for the availability of internal electrical and electronic systems, judged against its own tolerable frequency of damage FT. Every verdict traces back to the clause behind it.
R · vs RT
One combined risk R
Touch and step voltages, plus fire after a strike. The 2024 edition combines injury to people and loss from fire into this single risk R, held to the strictest tolerable line.
F · vs FT
Frequency of damage F
How often a strike disrupts the availability of internal electrical and electronic systems, judged against a tolerable frequency of damage FT. The concern for data centres and control rooms.
NSG · strike-point density
Ground strike-point density
The 2024 edition drives the dangerous-event rate from a ground strike-point density NSG, replacing the older flash density NG, because one flash can strike the ground at several points.
TWS · IEC 62793
Thunderstorm warning systems
The 2024 edition recognises thunderstorm warning systems, per IEC 62793, as a measure that lowers the probability of harm to people during the window of greatest exposure.
Nine 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 |
|---|---|---|
| RAT | Direct flash to the structure causing touch and step voltages inside it, and outside within 3 m of a down conductor | R |
| RAD | Direct flash to a person exposed on the structure | R |
| RB | Direct flash to the structure causing dangerous sparking and fire | R |
| RC | Direct flash to the structure causing internal system failure (LEMP) | R, F |
| RM | Nearby flash inducing failure of internal systems | R, F |
| RU | Flash to a connected line causing touch voltage indoors | R |
| RV | Flash to a connected line causing fire or explosion via the service | R |
| RW | Flash to a connected line causing internal system failure | R, F |
| RZ | Flash near a connected line inducing internal system failure | R, F |
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)
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
How many strikes per year that area can expect. NSG is the local ground strike-point density (the 2024 edition's measure, in events / km² / yr, replacing the older flash density); CD is the location factor.
Probability of damage (Annex B)
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)
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
Each component is N times P times L. Sum them into the risk R and compare it to RT; the frequency components sum into F and compare to FT, for a clear pass or fail.
A real IEC 62305 engine, not an estimator
Lumex computes the assessment in full and shows its working, then turns it into the document you file.
The full risk computation
Collection areas, dangerous-event rates, damage probabilities and loss factors, computed from the IEC 62305-2 coefficients and rolled into all nine risk components, with your lightning risk judged against the tolerable limit and the frequency of damage to internal systems assessed alongside it. See how a risk is calculated.
Traceable to every input
Each result carries the full coefficient trace behind it, so the number your engineer signs can be defended clause by clause, never an opaque black box. More on traceable risk assessment.
Branded, audit-ready reports
One assessment produces a PDF with the structure model, methodology, per-zone results and a sign-off block, with your firm's branding on Enterprise. See what makes an audit-ready report.
The whole team, and every review date
Team workspaces where a project holds many sites, each with its own zones, report, revision history and review date. Periodic inspection reports per IEC 62305-3 are coming soon.
Why not a spreadsheet or a desktop tool
A spreadsheet hides its assumptions and drifts out of step with the standard. A desktop tool ties the work to one machine and one licence. Software in the browser removes both, and ends the assessment in a report you can file, not a raw grid of numbers.
| What the assessment needs | Spreadsheet or desktop tool | Lumex |
|---|---|---|
| The current 2024 third edition | Drifts out of step with the standard | IEC 62305-2:2024 built in |
| The working behind every number | Assumptions buried in cell formulas | A full coefficient trace, there to check |
| National rules for your country | Adjusted by hand, if at all | Jurisdiction profiles apply national departures |
| Protection that brings the risk within limits | Trial and error | The smallest set of measures, recommended for you |
| Answers about a figure | Look it up in the standard | Lumi explains it from the assessment's own trace |
| A record of who changed what | No revision history or audit trail | Every change recorded, end to end |
| A deliverable you can file | A raw grid of numbers | A standard-cited, auditor-ready report |
| Nothing to install | Tied to one desktop | In the browser, on any machine |
Who runs IEC 62305 assessments in Lumex
The software is built around how an IEC 62305 assessment actually gets done, in-house or for clients.
Electrical consultants
Run the risk assessment as part of a wider electrical design. See the consultants workflow.
MEP design firms
Fold lightning protection into building-services design and deliverables. See the MEP workflow.
LPS installers & auditors
Produce and sign the assessment, with a review date on each site. See the installer and auditor workflow.
Where Lumex fits the standard series
Lumex runs the IEC 62305-2:2024 risk assessment and reports the protection level your design must meet. The Part 3 layout is yours to draw and a competent person's to sign. Final responsibility for every result rests with the signing engineer, and Lumex does not replace professional judgement or the published standard. Lumex is an independent product and is not affiliated with or endorsed by the IEC; the coefficient values shown here are illustrative, and the authoritative tables are defined in IEC 62305, available from the IEC. Lumex also runs NFPA 780-2026 and AS 1768:2021, each by its own method.
General principles
Lightning parameters & damage model that underpin Lumex's terminology and LPL definitions, the shared basis the other three parts build on.
Risk management
The full procedure Voltrace implements: the risk R and frequency of damage F, all nine components, every annex coefficient.
Physical damage & life
LPS classes, and the Annex D (D.7.2.2) inspection guidance behind each assessment's review date. Inspection reports are coming soon.
Electronic systems
SPD coordination and LEMP-protection factors feed the PSPD and PM inputs, which decide how far surge protection lowers the risk to internal systems.
Why "on the 2024 third edition" matters
IEC 62305 was rewritten in 2024 for the first time in fourteen years. Most spreadsheets, templates and older tools still run the 2010 maths. Lumex is built on the published third edition (2024), adopted nationally across most of the world, so the report you file matches the standard an auditor cites today.
First edition
The four parts of IEC 62305 first brought lightning protection under one risk-based framework.
Second edition
A refined risk model, and the edition most legacy spreadsheets and Word templates still encode today.
Third edition
A full technical revision across all four parts, published in September and October 2024. The edition Lumex computes.
What the third edition changed. The 2024 revision moved to a ground strike-point density (NSG) in place of the older flash density, brought injury to people and loss from fire into a single combined risk view, added a frequency-of-damage measure for the availability of internal systems, and recognised thunderstorm warning systems (per IEC 62793) as a way to reduce risk. Lumex tracks these changes, so your assessment reflects current practice rather than the 2010 method.
The risk R fails. One upgrade makes it pass
An illustrative data centre, assessed clause by clause. The same maths Lumex runs on every project, with the verdict you can defend.
The building & inputs
Bhiwadi data centre
Illustrative example · Zone Z2 · Rajasthan
The verdict, traced
As built · Class III LPS
R = 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
R = 4.8 × 10⁻⁶
within RT 1.0 × 10⁻⁵
Every figure here is computed by Voltrace™, not estimated, straight from IEC 62305-2:2024. Run the same trace on your own building in minutes.
Get startedWhat goes into the document you sign
One assessment produces a full report and a short one, both citing IEC 62305-2:2024 throughout. The full report carries the structure model, the methodology, the results zone by zone, the protection recommended and a sign-off block, with the calculation trace behind each figure.
Where a national rule applies, the report prints the jurisdiction, every departure applied and the citation for each, so a reviewer can tell a regulator's rule from a software error. On Enterprise, every PDF carries your logo and colours. See what makes an audit-ready report.
Periodic inspection reports
Once the protection is installed, it has to be inspected over its life. Periodic inspection reports for IEC 62305-2:2024 are in development and not yet available. Today every assessment carries a review date, with an email reminder a month before it falls due.
Lumi speeds the routine. Voltrace still owns every number
You just saw that trace, computed clause by clause. Lumi works around Voltrace 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 the risk R, with the maths shown for each.
IEC 62305-2:2024 in Lumex, questions answered
What is IEC 62305 software?
Is Lumex a full IEC 62305-2:2024 engine or a simplified calculator?
How is IEC 62305 software better than a spreadsheet?
Does the software work to IEC 62305 or EN IEC 62305?
Can I export an audit-ready report from the software?
Does the software use AI to calculate the risk?
Working to a different standard?
Each standard runs by its own method, and a figure from one is never mixed with another. Compare all three.
Lumex computes the method of the standard you choose, IEC 62305-2:2024, AS 1768:2021 or NFPA 780-2026, and shows the working. It does not certify a structure. You may not issue or submit a Lumex output until a competent person, qualified where the structure is located, has reviewed the inputs and the result and signed it.
The tolerable risk in IEC 62305-2 is not a fixed constant. Clause 7.3 NOTE 1 gives RT = 1 × 10⁻⁵ per year as a representative value of tolerable risk and adds that another value may be set once the case has been investigated in detail. Printed p.12 then lets national or local regulations fix RT, the tolerable frequency of damage FT, and the Annex A, B, C and E calculation rules and parameter values. Every IEC 62305-2 assessment in Lumex states the jurisdiction it was computed under and the values that applied.
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