IEC 62305 in Germany
Germany runs the same IEC 62305-2 method as everywhere else, with one recorded departure that changes the arithmetic: the fire provisions reduction factor r_p is 1 for all cases.
Germany applies the IEC 62305-2 risk method unchanged, with one recorded departure that changes the numbers: the fire provisions reduction factor rp is 1 for all cases.
The standard itself says so. IEC 62305-2:2024 carries a list of differing practices in its foreword, at printed p.9, and the German entry records that rp = 1 applies for all cases. That is not a national annex bolted onto the side of the standard, and it is not folklore passed around a design office. It is published in the same document as the method.
This page explains what rp is, where it enters the calculation, what holding it at 1 does to a result, and what else the same entry records. Everything here cites the clause, equation or table it comes from, because a parameter rule you cannot trace is a parameter rule you cannot defend in a review.
Which publication governs in Germany
Germany reaches IEC 62305 the way the rest of Europe does. CENELEC adopts the international standard as EN IEC 62305, and the national body publishes that European text under a German reference. So a German specification may name the international number, the European number or the national one, and in each case the technical content is the IEC 62305 content.
The naming is worth getting right on a document. The current series is IEC 62305 and its adoptions carry the IEC number in their designation, as in EN IEC 62305. A bare EN 62305 refers to the superseded 2011 series and is not the standard a current assessment is built to. If a specification you have been handed says EN 62305 without the IEC, that is a question to raise before you calculate, not a typo to silently correct.
None of this changes the method. The reference number tells you which national publication governs; the differing practices list tells you what that country changes. For Germany the answer to the first is the European adoption, and to the second it is rp. For the wider picture of how adoption works, see IEC 62305 around the world.
What rp is and where it enters
A lower case reduction factor from Table B.5, multiplying into two probabilities. Knowing which two is what tells you where the German rule bites.
The selection
rp is the reduction factor that credits whatever is in place to limit what a fire costs. Table B.5 runs from 1, no provisions, down to 0,2 where an automatic extinguishing installation or a comparable provision is present. Selecting a value below 1 is what claims credit for those provisions.
Into PB
PB is the probability of physical damage, dangerous sparking, from a flash to the structure. Equation (B.4) forms it from PS (Table B.4), PLPS (Table B.3), rf (Table B.6) and rp. PB drives the risk component RB.
Into PV
PV is the probability that a flash onto a connected line does physical damage. Equation (B.11) forms it from PEB, PLD, PTWS, CLD, rf and rp. PV drives the risk component RV.
rp and rf are lower case reduction factors, deliberately not written as RP or RF. The upper case R names belong to the risk components, and there is no risk component called RF. Keeping the case right in a report is not pedantry, it is what stops a reviewer reading a factor as a risk.
What holding rp at 1 does to a result
Because rp multiplies into PB and PV, fixing it at 1 leaves both probabilities at their unreduced value. The two fire related components RB and RV are therefore higher than the same building would produce under a plain IEC baseline calculation that selected a value below 1, and the total risk R rises with them.
The size of the difference is the size of the credit that was being claimed. A building with no fire provisions selects rp = 1 anyway, so the German rule changes nothing for it. A building with an automatic extinguishing installation selecting rp = 0,2 would, in a jurisdiction that allows the reduction, cut the rp contribution to PB and PV to a fifth. In Germany it does not. Between those two ends, the effect scales with the value the engineer would otherwise have selected.
The decision that can flip is whether protection is needed at all. The verdict in IEC 62305-2 is a comparison of the computed risk against the tolerable value. A building sitting just below the line on a baseline calculation, carried there by the fire provisions credit, sits above it once that credit is removed. So the departure is not a rounding detail. It can be the difference between a report that says no protection is required and one that specifies a lightning protection system.
What the rule does not do is make fire provisions pointless. Extinguishing installations still do what they are installed to do, and they remain governed by whatever fire regulation applies to the building. The departure is about how the risk arithmetic treats them. Reading it as advice not to install them would be a serious misreading.
What else the same entry records
The German entry at printed p.9 has three parts, and Lumex applies all three. Each one is printed on the report with its citation, so a reviewer can tell a regulator's rule from a modelling choice.
rp = 1 for all cases
Modelled and applied to the figures. Selecting the German jurisdiction forces every Table B.5 selection to 1, and the report prints the departure with its citation so a reviewer can tell a regulator's rule from a modelling choice.
PTWS = 1 for six components
The same entry records PTWS = 1 for RB, RC, RM, RV, RW and RZ, and Lumex applies it to exactly that list. Equations (B.4), (B.5) and (B.6) carry no PTWS term, so naming RB, RC and RM is arithmetically inert; the effect lands on RV, RW and RZ. The entry names none of RAT, RAD or RU, so those three are left alone. Greece forces the same factor without that limit.
Highest Table C.2 values
The entry also records the highest values of Table C.2 for LF1 and LF2. Under the German jurisdiction each loss class takes its published maximum, 0,2 for very high loss down to 0,02 for low loss, so a German assessment cannot sit at the bottom of a band the regulator reads from the top.
Setting these out one by one is deliberate. A tool that silently claims a departure it does not apply produces a report a reviewer cannot trust, and the two failure directions are equally bad: a missing departure understates the risk, a claimed but unapplied one misrepresents the provenance of the figures. So each departure is named on the report with the clause it comes from, and where one is not modelled we say so on the page rather than leave it to be assumed.
RT is representative, not fixed by the standard
It is common to see the tolerable risk quoted as though IEC 62305-2 fixes it. It does not. 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.
For Germany the standard records no national RT, so an assessment uses the representative value unless a project specification, a regulator or the authority having jurisdiction names another. That is a judgement to make and record at the start of a project, with whoever is entitled to make it, rather than a number to assume. It is also why a tool should resolve the tolerable value from the jurisdiction rather than carry it as a constant in the code.
Related reading
For how national adoption works generally, and which designation applies in other markets, see IEC 62305 around the world. For the method the German rule modifies, read the IEC 62305-2 risk assessment, and for the arithmetic itself see how IEC 62305 risk is calculated.
Three other national departures are set out in their own pages: IEC 62305 in Greece, where PTWS is 1 for all cases rather than for a named list of components, IEC 62305 in Italy, where RL1 and RL2 are compared with the tolerable risk separately, and Annex D and Annex E in national practice, which covers the Netherlands and South Africa.
Select the jurisdiction before you compute
In Lumex the jurisdiction is an input, not an afterthought. Selecting Germany applies the rp rule to every Table B.5 selection before the calculation runs, so the figures in the report are the German figures rather than baseline figures with a note attached. The report then prints the departure and its citation, and names the parts of the German entry that are not yet modelled, so a reviewer can see exactly which rules produced the numbers in front of them. See the Lumex platform.
Questions answered
Does Germany use IEC 62305?
What is r_p in IEC 62305-2?
What does r_p = 1 change in a German assessment?
Does this mean fire protection provisions are pointless in Germany?
Are there other German departures in IEC 62305-2:2024?
Is the tolerable risk different in Germany?
Lumex computes the IEC 62305-2 method 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 Lumex assessment states the jurisdiction it was computed under and the values that applied.