How the LPS engine is validated.
A lightning protection design is a document you sign. So the numbers behind it cannot be a black box. Here is exactly how the Voltbench engine is checked — the standard it implements, the independent worked examples it reproduces, and the trace it prints so you can re-check any figure yourself.
Three layers, not one claim
Correctness is the whole product, so it is checked three independent ways.
Every coefficient cites its clause
Each factor — the kc current-division values, ki and km, the earth-electrode length curve, the protection angle — is a resolved value pinned page-by-page to IEC 62305-3 Ed. 3.0:2024, with the clause printed next to it. Not transcribed from a blog; read from the standard.
Reproduces published worked examples
The engine is run against independent worked designs from established guides and peer-reviewed papers, figure by figure. Where a result differs, the reason is understood and documented — usually because Voltbench takes the more conservative reading (see below).
The working is on the report
Every report prints the calculation trace: the formula, the substituted values, the result, and the clause. You never take a number on faith — you check it against the standard the same way you would a colleague's hand calculation.
The independent sources it reconciles against
The two liability-critical outputs — the separation distance and the earth-electrode sizing — are each reproduced from more than one independent published source.
Sources, for reference: W. J. Furse & Co (ABB), A Guide to BS EN 62305, 3rd ed.; DEHN, Lightning Protection Guide, 3rd ed.; A. Kern, O. Beierl, W. Zischank, “Calculation of the Separation Distance according to IEC 62305-3”, ICLP 2009; nVent/ERICO, IEC 62305 Separation Distances. Voltbench reproduces the method and prints its own figures; it does not republish these documents or the standard's tables.
The air-termination layout: measured, not reconciled
The design proposes where the rods go, and no published guide has a worked example to check that against. So it is held to a different standard, and this page says which.
What this does not claim: the layout is a proposal, measured against the roof you described. Nothing on the roof is an input, so no route is taken around a chiller, a parapet or a vent, and no quantity or fixing schedule is produced. The engineer moves any of it — the figure is what an alternative should be judged against, not a substitute for judging one.
When Voltbench and a guide differ, it is on purpose
A couple of published examples round a value down where the standard's spacing would be slightly exceeded, or assume an even current split where the earthing arrangement does not guarantee one. In those places Voltbench takes the conservative reading and discloses it on the report — so a difference from an old guide is a documented engineering choice, never a silent one. The current edition (2024) also changed two coefficients from the 2006/2011 guides; those are implemented to the 2024 standard.
See the trace for yourself
The sample report shows the full working on one fixed building — every resolved coefficient, its clause, and the calculation trace. Read it, then run your own design.
Voltbench is a calculation aid for qualified electrical engineers. Its outputs support, and do not replace, the professional judgement of a licensed engineer of record, who remains responsible for the design and its verification against the governing standard.