Cromwell House Hospital, Epsom

The project went through two architects. The first architect drew all his drawings by hand which required us to redraw sections of them into CAD to meet our needs. The second architect produced CAD drawings which improved coordination of our documents. We also carried out our own site survey of the building and the systems in them and were able to feed back to the architect areas where the drawings did not reflect the detail that we requited for our design. The contractor was appointed at final design stages so we had the benefit of discussing products and construction methodology before we completed our design.

This is an existing building undergoing alterations where two blocks (hospital and dementia) are combined into one building. The building has a Type 7 alarm system with residential sprinkler system. The main problem in this building was the bedroom doors were not smoke rated. The bedroom doors are required to be smoke rated (with no closures) to achieve compliance with C/AS3. Client did not wish to upgrade the existing bedroom doors as it was a costly exercise. Various options were considered which is to replace the existing bedroom doors or ANARP compliance with retaining existing bedroom door or alternative fire safety features to make the building compliant

We prepared the fire engineering design using the first principles verification method VM2 and a full fire protection design for the sprinkler and alarm system as well as the emergency lighting design.
Being a small hospital the owners and management team were keen to be involved in all aspects of the design and make sure that we understood the patients needs and requirements. This suited our collaborative approach because we find the best solutions often come from discussing ideas with a diverse range of people. Early on we met with the hospital manager to learn about dementia patients and she suggested that we attend a trial evacuation so that we could see for ourselves how the patients respond to alarms. The hospital was unusual in that an alarm sounded throughout the building, not just at the nurse stations. At the end of the trial evacuation we were able to discuss with the nurses and carers the best way to move patients.

From a designers perspective this was a valuable experience because it enabled us to compare the prescribed fire safety rules with what actually happens in reality. The Verification Method rules were found to be slightly on the conservative side compared to reality which was comforting. Early evacuation modelling comparing egress time with smoke build up showed that we could not demonstrate that people could escape safely. We went through a number of iterations with the client looking at fire rating additional walls to reduce firecell sizes and introducing passive smoke venting to reduce the smoke buildup. What appeared to be an ideal solution from a fire engineering perspective was not necessarily suitable from a buildability or user perspective. It was not a straight forward matter to fire rate walls or install vents in occupied areas and adding additional doors posed security and safety risks for the patients.

Team

Michael James – Fire Engineering Design
Sajeesh Nair – Fire Engineering Design
Wayne Joseph – Fire Protection Design
Clive Revie: Emergency lighting report

Consultants

Client and Project Manager: Cromwell Hospital
Project Manager: Peter Hodgson
Architect: Architectural Design Associates