Technical Bulletin April 2018


We understand that the Welsh and Scottish Governments are currently in the process of revising the specifications of their Notional buildings, in their respective NCM Modelling Guides, in order to adopt modifications similar to those adopted in England’s Notional building in iSBEM_v5.4.a with respect to district heating.

As a result, please be advised that the BRE have received MHCLG’s approval to release a new version of the iSBEM software, iSBEM_v5.4.b, which implements those revised Notional specifications, on Friday 6th April 2018.

Please note that iSBEM_v5.4.b will maintain the same purposes of analysis offered by iSBEM_v5.4.a (released on 20th November 2017).

Inferred u-values for EPC calculations

I have received feedback from assessors that they often find it difficult to decide which of the Building Regulation items they should be selecting from the libraries in the software.  What I am hearing is that there are often more than one, usually similar but sometimes dissimilar values to pick from.  If this is causing you concern, particularly with the currently elevated interest in EPC ratings due to the MEES requirements, this might be good time to remind you that the inference options in the software are there to help you when you cannot source reliable information yourself.  Of course in the case of Building Regulations, the original requirements are all available to download from government websites, so as long as you can include your source document in your records in case of audit, you can enter the evidence as you have found it in the documents that were in force when the building was built.

This is true all the way back to the 1965 Building Regulations when the thermal requirements were set out in Part F rather than Part L.  The other difference in 1965 was that the Thermal Transmittance values, u-values, were expressed in units of British Thermal Units/hour/square foot/degree Fahrenheit. So, there is a word of caution to be given if the age of the building does take you to the 1965 Regulations. 

The reason for bringing this to your attention is that the units are explained in one paragraph of Part F before the thermal transmittance values are given in another.  The u-values are simply presented as numbers, 0.25 for roofs and floors and 0.3 for walls, so there is a risk that you would take these numbers as being 0.25 or 0.3 W/m2K.

In fact they should be converted to W/m2K, giving values of approximately 1.4 and 1.7 respectively. I hope that this is helpful and will reduce the risk of errors in the era of MEES.
The Energy Performance of Buildings (England and Wales) (Amendment) Regulations 2018

This amendment was laid before Parliament on 15th March 2018 and came into force on 6th April 2018.  The amendment can be accessed here:

This amendment reduces the Landmark fee by 28p.  I am not proposing to alter our fee structure in response to this.  We try to stick to round numbers in our fee structure, for simplicity.  Sometimes we have had to round up to do this and sometimes round down.  If Landmark increase their fee by pennies at the next amendment, we will keep our fee constant, effectively reducing price but with no change for you. 

Air Conditioning Inspection Reports

We have had a few queries recently concerning confirming correct operation of air conditioning equipment when it is difficult to access temperature or pressure gauges. Could I draw your attention to the ACIR convention AC CL 1.3, giving guidance on this which can be found here.
Andrew Geens
Head of CIBSE Certification