Since this post was originally written, Feature Pack 2 has been released and some clarification is needed around Part L2 2021 reporting. While the BRUKL table descriptions changed between the 2013 and 2021 regulations, the current implementation in VE still applies a single‑room distinction when assigning SFP values to Columns B and D for Part L2 2021.
As a result, systems serving more than one room may now appear outside Column D, which is expected behaviour under the current logic. This post has been updated below to reflect that.
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Hi everyone,
A few users have raised questions about how local Specific Fan Power (SFP) values are reported in the BRUKL table when using ApacheSim method. After a detailed review, it’s clear that while the BRUKL codes and mapping remain unchanged between the 2013 and 2021 regulations, the intent behind columns D and E has shifted.
For the 2013 regulations, both columns D and E required the system to serve a single room or zone (and, for D, to include heat recovery). Our software explicitly checked for these conditions, which sometimes frustrated users, especially when a system serving multiple rooms couldn’t be checked against the more lenient standard in column D, and instead failed against the stricter standard in column B. Where Column D reporting is specifically required, the system must be configured such that each room is served by its own dedicated ventilation system. This can be achieved by creating separate system instances so that each system serves a single room.
With the 2021 regulations, the wording of the BRUKL table descriptions changed compared to 2013, which led to questions around how Columns D and E should be interpreted. However, under the current Part L2 2021 implementation in VE, a single‑room distinction is still applied when assigning SFP values to the table. As a result, systems serving more than one room are treated as multi‑zone for reporting purposes.
In the meantime, we recommend focusing on accurately modelling your building and services to ensure the overall pass/fail assessment reflects the current design. Please avoid modifying your services solely to influence which column an SFP appears in.
SBEM method
We also reached out to the SBEM helpline to see how SBEM method handles the reporting to the table and they wrote back saying SBEM can't model 4 of those options on the table and specifically that they can’t do Column B or D so all "Mechanical Supply" SFP’s are checked under Column E.
For Reference here are the inputs required by SBEM.exe to report SFP's in each column using SBEM method.
SFP limits vs Notional Building
It is also important to emphasise that the "Standard Value" for each column on the BRUKL does not represent the Notional Building you are being compared against in the Actual Vs Notional simulation.
The Notional Building is defined in the NCM Modelling Guide and you can view the Notional Building properties like the SFP's used in the simulation by switching to the Notional Building view and selecting Tabular Space Data (or Apache Systems).
