Last edited 30 Jan 2019

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Soft landings and design for performance

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Design for Performance (DfP) is referenced by the 2018 update of the Soft Landings Framework. This article explains what it is and its objective to close the energy gap.

Design for Performance (DfP) aims to change the way we design new commercial office developments in the UK and end the culture of satisfying theoretical energy efficiency metrics. DfP instead targets performance outcomes, using a process which commits a signatory from the outset to achieving a specific base building an energy rating, verified by measurement.

Unlike the energy used by tenants for their lighting and IT, a base building energy rating can be secured by a developer with support from supply side stakeholders. Because it represents the operational energy efficiency of the property asset, the base building rating is a metric of interest to investors targeting lower carbon portfolios and, notably, to potential tenants, because it can be associated with building quality, reflecting the reality that a better rating will be the result where a building is better designed, better constructed, better commissioned and better maintained and operated. At present, the UK commercial office market targets compliance with Building Regulations and EPC ratings: energy efficiency endeavours currently focus on design and technology that improve predicted performance. DfP requires a relentless focus on performance outcomes, with specific activities required at each Soft Landings Phase, as follows.

Contents

[edit] Phase 1: Inception and briefing

The essential starting point is for the building developer to set a base building energy target and commit to design, construct and commission the premises to operate at the target level. Written notice of the target must be provided to all consultants and contractors involved. All parties must commit to allowing the operational performance to be measured and disclosed after 12 months of full occupation.

[edit] Phase 2: Design

The building services consultant must undertake simulation of the building including its HVAC system and controls to predict actual base building energy use and establish measurable monthly subsystem targets. The design and simulation must be subjected to an independent review by an approved expert as part of the Soft Landings reality-checking process. Changes arising from the review should be consolidated into the final design package.

[edit] Phase 3: Construction

During the construction phase, it is important to keep the simulation model and Description of Operations up to date with any significant design changes and ensure achievement of the target is not compromised by value engineering. The draft Description of Operations should be made available to tenderers for the controls engineering.

[edit] Phase 4: Pre-handover

A key objective should be for the implemented controls to be consistent with the simulation model of the final design and the revised Description of Operations. The building services consultant should have effective oversight of tenant fit-outs, including veto of proposals which would stop the target rating being achieved.

[edit] Phase 5: Initial aftercare

Extended commissioning, monitoring and intensive post-occupancy fine-tuning should include tracking the rating using a mix of actual and forecast energy use for the first 12 months of operation. These activities must be built into the remit of the building services consultant, control engineers, managing agents and facilities managers, and reinforced by performance-based maintenance contracts, linked to achievement of the target rating.

[edit] Phase 6: Extended aftercare and POE

The contractor should retain enough control during the first year of occupation to ensure the FM team can deliver the target performance in year 1. The FM team can then be expected to continue to achieve it in subsequent years. Contractual retentions might be placed on the builder and mechanical contractor based on energy-rating performance i.e. performance failure could be treated as a defect.

The end-of-period independent formal assessment of the base building rating would then have to be completed prior to contractual release. Typically, the landlord should provide tenants with annual updates of the base building rating for the duration of their leases.

[edit] Conclusions

The Design for Performance process fits hand-in-glove with the philosophy of the Soft Landings Framework. It provides a proven way to achieve a measurable operational energy performance target.

A fully-fledged DfP Scheme is under development with a view to its launch in 2019. A Guide to DfP and Soft Landings is expected to be published by BSRIA later this year.


This article was written by Robert Cohen, Technical Director, Verco, and published by BSRIA in January 2019 at https://www.bsria.co.uk/news/article/soft-landings-and-design-for-performance/

--BSRIA