Computational Fluid Dynamics Modelling for 80 Pall Mall

Home to the Government’s War Office in the 19th Century, 80 Pall Mall has undergone varied incarnations since first being constructed for the 3rd Duke of Schomberg in the 1690s. Its original façade was re-built when, along with neighbouring properties, it was converted into offices in the 1950s. It has now been completely refurbished again, with a total strip out and re-build of the accommodation and
retention of the Grade II listed façade. FDS Consult was appointed to advise on a sympathetic approach to fire designing the scheme, using the team’s innovative thinking and experience to justify a non-code based strategy by use of computational fluid dynamics modelling, minimise costs and enable one of the tenants to create the striking office environment they wanted.

The building comprises basement, ground floor and five further floors, all of which is used as office accommodation. The original brief was to fire design the building as a shell but, after a tenant secured the basement, ground and first floor levels, the internal layout of these storeys changed, affecting
the fire design.

The original proposal for the office building shell was to compartment each floor by ensuring that all services were fire stopped. While this plan remained in place for levels 2-5, the tenant’s proposal for the ground and first floors was to introduce glass-fronted meetings rooms around the periphery of each floor leading to an open atrium with a central, open staircase. FDS Consult’s expert team was able to help the
client deliver this vision by:

  • Introducing fire curtains linked to the smoke detection and fire alarm system to achieve compartmentation of the meeting rooms in the event of a fire, maintaining the floor sub-division.
  • Using CFD (Computational Fluid Dynamics) modelling to justify the extended travel distances created by the central staircase.

Other challenges lay in the original layout of the building, including an original staircase that was narrower than the code demanded and a light well on one side of the structure which did not meet current standards. FDS Consult’s creative approach to fire design not only enabled the team to overcome these obstacles but even ensured that they were used to best advantage to minimise modifications
to the building. FDS Consult’s innovative approach allowed the team to:

  • Justify the lightwell thanks to the compartmentation of the building.
  • Omit dedicated smoke vents from the basement area by arguing that the light well provided similar conditions to an upper storey.
  • Justify the narrow staircase thanks to the compartmentation, fire detection systems and calculation of evacuation times which demonstrated that it would take just 30 additional seconds for the anticipated occupancy loads to be evacuated.
  • Maximise rental incomes by saving useable floor space thanks to justification of reduced staircase width.

Thanks to FDS Consult’s innovative approach, the scheme achieved cost savings of £500,000 and a key tenant was able to create an impactful office space that reflects the high status of their Pall Mall address.

“The project was a great success for our client. From a project management perspective its good to compile a team where the dynamics seem to fit into place. Incorporating FDS Consult’s support was very useful and it gave us the backing to speak knowledgeably about the constraints, risks and opportunities, giving us insight to deal with concepts which allowed for the lower floor plates to be addressed at a greater density. The reports FDS Consult provided were concise, but detailed enough to achieve client buy-in and give us the ammunition we need to argue a good well thought out fire strategy, with the openess of AIS as our Approved Inspector, the fire issues were wrapped up efficiently without compromise to the scheme apartments.”
Buro Four

Type of project:Refurbishment
Client:Gracemark & Permira
Architect:Latitude & Pringle Brandan
Project Management:Buro Four



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