The LWF Blog

Fire Engineering for Healthcare Premises – Examples of Fire-Engineered Healthcare – Part 70

January 24, 2022 1:22 pm

LWF’s blog series for healthcare professionals aims to give information on best practice of fire safety in hospitals and other healthcare premises. In part 69 of Fire Engineering for Healthcare Premises, LWF looked at how fire engineering was used in the integration of an atrium into a teaching hospital. In part 70, we discuss the example given in HTM 05-03 of structural fire engineering used in a state-of-the-art hospital facility.

The proposed hospital facility in this example was procured through the Private Finance Initiative (PFI), which is a method of financing public sector projects through the private sector. The hospital was to have a high ratio of operating theatres to ward space. The floor area of 12,000 mwas spread over 11 floors and also included an underground basement car park.

HTM 81 required that the building was constructed of 120 minute fire resistant materials, but fire-engineered analysis on the potential types of fire and temperatures that might result allowed a reduction in fire resistance to 60 minutes.

It was necessary for the hospital to have strict controls on vibrations, as it can effect surgical equipment such as microscopes, MRI equipment and other imaging instruments, operating procedures, and patient comfort. This required the use of a relatively deep composite slab, which uses Multideck 60, supporting a 150 mm deep composite slab in general areas and 300 mm deep in operating theatre areas. This provision was made to reduce the vibration sensitivity below the required level of perception.

Benefits of the construction form, i.e. a deep composite slab could be realised within the overall fire strategy. The composite slab achieved greater fire resistance than required for fire safety purposes, which brings inherent benefits to life safety and property protection.

Further benefits were realised when the steel frame was assessed using scoping calculations taken from the Steel Construction Institute’s SCI P288 and BRE’s Digest 462. The frame was also assessed using Vulcan, a finite element program developed at University of Sheffield.

The assessments undertaken indicated that the steel frame performance was enhanced due to its make-up. The slab itself would remain relatively cool which effectively insulates the reinforcement from fire damage.

The structural assessment meant it could be demonstrated that the beams framing into columns were fire protected, however combinations of intermediate beams were unprotected.

In Part 71 of LWF’s blog series, LWF will look at the integration of non-compliant design elements in a hospital build.  In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.

Lawrence Webster Forrest has been working with their clients for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact LWF on freephone 0800 410 1130.

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