Building Compliance vs Performance – 23rd May 2017

The CIBSE Building Simulation Group hosted a presentation on the subject of building compliance vs performance in the wake of the controversial Bath University study which asked the question “The Performance Gap: Are Modellers literate?”.

Hazim Awbi, CIBSE BSG chairperson introduced the speakers, Umer Uzair of Syntegra presenting ‘Building Compliance vs Performance, an overview’ and Tom Spurrier of Hoare Lea presenting ‘Tale of Two Cities’.

Left to Right – Umer Uzair of Syntegra & Tom Spurrier of Hoare Lea.

Tom, first to present, highlighted the key drivers behind the design of buildings today as being the regulatory compliance models that designers need to comply with.

Suggesting that there is a clear difference between ‘Compliance approach’ and ‘Performance approach’ when designing buildings, Tom outlined the key tools for each approach.  This includes SBEM and SAP calculations for compliance and more advanced methods such as Passivhaus, NABERS, Climate Based Daylight Modelling (CBDM), TM52 for comfort where Performance modelling is required.

After a brief run-through of the limitations that the regulatory compliance models have, including the ‘comparison’ nature of the calculations rather than actual, the performance tools were discussed in more detail.  Tom’s full presentation can be found here. 

Umer highlighted within his presentation that publicly available data demonstrates the gap that the majority of industry professionals know exist within the industry, including sources such as CarbonBuzz.

His presentation re-iterated the key missunderstandings relating to regulatory compliance models and the expectation of buildings to achieve similar in-use energy efficiency.

The London Plan, BREEAM and SKA ratings were discussed and their use of the regulatory compliance models highlighted.

Umer suggested that designs should include for undertaking two models, one for compliance, and the other as a full design model, reflecting the building as it will physically exist and be used, incorporating future occupancy profiles, operating hours and more accurate weather profiles.

Unregulated load also need to be included, with predictions for Vertical Transportation & data centre energy use.

Umer concluded with a summary of useful thoughts for bridging the performance gap.  These included complex energy modelling through to the correct communication and briefing with the client and maintenance teams.

Following Umer’s informative presentation, Hazim Awbi, BSG Chair (pictured above) raised the issue of the Bath University Research as a discussion topic, highlighting key failings within the research and questionnaires that modellers were requested to answer.

The presentations resulted in some interesting debate which highlighted the compliance approach delivering the quickest and lowest cost design package and the performance based package costing much more.  With clients tendering design portions for the lowest cost, then the compliance approach will continue to rule.

Presentations from this event can be found here.