Flame and Fire Resistance Assessment Projects

Assessment of fire resistance of timber fire doors in large blocks of flats, London

My client, a letting agency, required an inspection of a sample of flat entrance doors to establish if they possessed the required half hour fire resistance etc. It was understood that a general fire risk assessment for the builidng had previously been undertaken and the risk assessor had correctly indicated that the flat entrance doors may not have the required fire performance.

There were 280 flats in the 1930’s complex (perhaps the largest of its kind in London) and the initial inspection involved a detailed examination of the doors, frames and door hardware for four flats (three were flush and one was panelled). Some of the contexts involved large corridor travel distances and it was vital that the flat entrance doors would not put other tenants at risk should there be a fire in a flat. The inspection involved consideration of factors such as type, thickness and condition of door, suitabilty of door frame, type and robustness of hinges, efficacy of latch, condition of letter plates and other openings, self-closing device, performance seals, above-door construction compatibility, etc. The doors appeared on first sight to be hollow with plywood faces, perhaps with a paper honeycomb core, but this would need to be confirmed by exploratory tests. Assuming they needed replacement with new fire door leafs, practical recommendations were made on the work needed to obtain requisite fire resistance and smoke seaing properties. A check list of relevant factors was prepared and research was also undertaken on current and old guidance on fire doors.

Client: PW Lettings

Advice on flame spread behaviour of ceramic mosaics.

The client, an importer of high quality ceramic mosaics, sought guidance on the amount of fire test information needed for marketing and safety purposes. The small ceramic tesseraie were bonded onto a flexible plastic mesh and the composite would then be bonded to walls, floors or ceilings. The surface spread of flame behaviour was likely to be very good owing to the non-combustible nature of the stone and marble tesserai used, but I identified that it would be necessary to find out how the grout and the plastic supporting mesh behave as heat was conducted thorough the tesserai to the substrate –  stability and flame spread properties could be established in the BS 476 Part 7 Surface spread of flame test needed to satisfy building regulations, and one question was ‘How many tests and which fire tests were necessary bearing in mind the different variables in the composite?’ The various British and European fire test methods were explained, the likely fire behaviour was discussed, and a strategy agreed for gaining acceptance of the product that would lead to minimum product development costs.

Client: Finemosaics (www.finemosaics.co.uk)

4hr sandwich panel fire wall for Iron Mountain document storage warehouse

I was asked to give expert advice on a proposed fire wall 24m high by 80m wide in a 200m long document storage warehouse. The fire wall was of unusual design as it comprised two independent cantilever walls each possessing 4hr fire resistance through the use of 4hr rated structural sandwich panels with steel faces and non-combustible rockwool cores fixed to rolled steel I-section cantilever columns. I gave advice in several areas: scrutinising and commenting on the test laboratory’s fire resistance test report; researching the FM and NFPA221 guidance on fire walls; making calculations of incident thermal radiation intensity arising from flames above the top of the fire wall and commenting on the effect this would have on the adjoining roof; quantifying the magnitude of thermal bow in the 24m high cantilever columns; commenting on details of supporting fire resisting roller shutters from the sandwich panels; and preparing a fire safety strategy for the design of the fire wall.
Client: Lysander and Associates, Guildford and Toorc Consulting, acting for Iron Mountain – Son of Belvedere


Arbed Construction System

I made a review of documentation on the assessment of fire resistance of Arbed AF composite concrete/steel columns incorporating steel I-sections and reinforcing bars. The assessment was for use in the United Kingdom.

Client: Arbed Recherches, Luxembourg

Assessment of Eurobond 200mm thick PIR-cored sandwich panel assembly spanning 6m horizontally as an external wall and providing one hour fire resistance from the inside

Because of the small size specimen used in the standard furnace fire resistance test (3m by 3m in UK furnaces) it is necessary for a qualified fire engineer to make an assessment for end-use applications appreciably larger than the size tested. It is vital to take account of increased thermal bowing (which can be and was calculated) and increased dead load which is transferred to the unexposed steel face assembly after delamination of the fire exposed face. Both these effects are capable of causing loss of fire integrity in the unexposed steel face, and are both difficult to predict, thus requiring professional engineering judgment.

The performance of a fire separating paneled wall is governed by the integrity and insulation criteria for the unexposed face of the wall. Some factors affecting these performance criteria include:

  • Panel support method
  • Thickness of panel core
  • Density of core
  • Overlap of steel joint in panel edge
  • Span of panel
  • Thickness of steel faces
  • Number, diameter and type of panel-end fastenings
  • Location of panel fasteners relative to panel ends

I made the assessment using the results of two fire resistance tests on the PIR-cored panels together with the results of an ad hoc fire test on a 10m by 9m assembly of sandwich panels which had rock wool cores, and was able to show that one hour fire resistance was possible, subject to several conditions.

Client: Advanced Thermal Composites Ltd, Burtonwood, Cheshire.


Buildings using Sodra prefabricated fire resisting timber floor units.

Sodra is a major manufacturer in Sweden of timber floors for houses and wishes to market in the UK. The unique construction with the ceiling mounted on joists independent of the structural floor joists gives high levels of sound insulation. The floor has been subjected to a fire resistance test in the accredited laboratories of the Swedish National Testing and Research Institute (SP) in Boras. I reviewed the test data and test reports supplied and, after consideration of all the relevant parameters, I made a detailed assessment showing that the floor, if tested in the UK, would be expected to achieve the required fire resistance (at least 60 minutes for stability, integrity and insulation in teh BS 476 fire test). This meant that the client did not need to have an expensive retest.

Client: Sodra Building Systems AB, Skogssudden, SE-351 89, Vaxjo, Sweden

Assessment of proposed Class Relaxation.

Client: Scottish Development Department, Edinburgh.

Beacon House, West Byfleet.

Preparing Letter of Assessment of fire resistance of lift loading doors.

Client: Gordon & Allkins Partnership, Epsom, 1989

Large aluminium framed Georgian wired glass screen.

Assessment of fire resistance.

Client: Areal System, Thirsk, 1989.

Lift landing doors.

Assessment of French fire resistance report.

Client: Manor Lifts Ltd, Liverpool, 1989

Town Centre Development, Walsall.

Assessment of fire resistance of floor slab incorporating an expansion joint.

Client: Alan Brough Associates, Derby

Unknown project in Rugby.

Assessment of fire resistance of double swing doors manufactured by Messrs Leaderflush.

Client: Rugby Borough Council, 1978