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’.
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| 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.
