Prescriptive codes and fire service experience

I RESPOND to the article, Building barriers, by Dr Jim Marsden in the June edition. I have no doubt this will spark much debate in the industry.

In the article, Dr Marsden raises many pertinent issues which essentially revolve around the question: Is the guidance contained in the prescriptive codes sufficient for non-code compliant buildings? An equally valid question may be: Is the guidance in the prescriptive codes too onerous for some properly fire engineered buildings?

Under a number of different headings, he discusses the issues from the perspective of a fire service officer. Most of the comments and observations are perfectly valid, but I would like to make a number of points.

Firstly, the use of computational fluid dynamic (CFD) analysis is, as he identifies, a useful tool in predicting smoke movement around a building, and some software is better than others for combustion modelling. However, when carrying out a CFD study for, say, an extended corridor design, it is absolutely essential that sensitivity studies are undertaken.

This picks up on a number of matters raised in his discussion of fire dynamics, such that the sensitivity is usually based on a range of studies, from at least no ventilation through to 100% glazing failure, with a sensitivity of 50% failure thrown in for good measure. The studies are also usually performed up to the point of intervention of the fire crews, rather than just for evacuation (to satisfy Section B5 of Approved Document B). This has the desired effect of demonstrating the resilience of the design as it stands and, if required, can be compared to a typical code-compliant design.

From my experience, while the aim to satisfy the functional requirements of the Building Regulations requires the design to be no less satisfactory than a code-compliant design, in actual fact the engineered solution significantly outperforms a code-compliant design (and is usually expected to by the regulators).

When this information is pre-sented to the fire authority, I wonder how much information is actually passed on to operational crews and if the crews really understand the impact, from an operational perspective, of the use of firefighting shafts integrated with fire engineering within buildings. I know that fire safety officers do, but I am becoming increasingly concerned that there is a ‘dumbing down’ of technical fire safety within a number of authorities.

Having seen an increased number of firefighter deaths over recent years, I also wonder if all the hard work done by organisations like Essex and Cheshire fire and rescue services and the Fire Service College towards the end of the 1990s in improving firefighting techniques has been wasted.

I am of the opinion that while operational crews might find this kind of information dull, it could actually be used to inform them about certain design parameters which, in turn, could lead to adopting appropriate firefighting techniques, such as gas cooling, within such engineered buildings, so that they are not caught out as Dr Marsden describes.

He makes excellent points on the use of façade design on buildings below 30m, which should be considered more by the risk management plans of the fire and rescue service perhaps when assessing risk. He also identifies a clear distinction between sprinkler-protected buildings and non-sprinklered buildings, yet the prescriptive codes make no allowance for this.

In conclusion, Dr Marsden has sparked a much-needed debate about the performance of some of the prescriptive codes, and he offers some interesting alternatives to the traditional concept. Also, I fundamentally agree that the fire and rescue service is the organisation to represent UK plc in early design discussions for complex fire engineered buildings – but sadly too few fire and rescue authorities have appropriately qualified experienced staff to come to the table.

Chris Hughes BEng (Hons), CEng, MIFireE, GEI Associate, Bodycote warringtonfire Consulting

The views expressed above are those of the author and do not necessarily represent the views of Bodycote warringtonfire Consulting

Passive protection during construction

IN A recent report to the Ministerial team in Communities and Local Government, the Practitioners’ Forum and the Business and Community Safety Forum made some valid points on the fire risks of timber-framed buildings during construction, and called on the Government to urgently review Building Regulations. However, the report perhaps exceeds its brief by questioning an ‘apparent systematic failure of passive fire protection’ – implying this for even completed timber-framed buildings.

There has already been con-siderable research undertaken as part of the TF2000 project into medium-rise timber-framed buildings, backed by the Government and supported by research into the quality of installation of passive fire protection by the Association for Specialist Fire Protection and the Passive Fire Protection Federation. This latter work led to a best practice guide published in 2003 – see http://www.pfpf.org.uk/ – but not all the recommendations have been implemented.

Buildings under construction are likely to be vulnerable to greater fire spread than when finished, and the Construction (Design and Management) Regulations 2007 sets out requirements to ensure that duty-holders plan and manage health and safety at all stages of construction projects. However, fire safety in buildings is determined on interacting measures which are only fully functional when the building is completed. Individual measures, whatever they are, can only be judged when all the elements are in place and operational.

Poor installation by trades in the construction sector that have no specialist fire product training is a major concern for anyone in the fire protection industry. The fire industry has addressed this issue by establishing independently audited, third-party certification schemes for installers. These address some of the concerns expressed by the Practitioners’ Forum, but until they are mandatory there will always be problems with fire protection measures being unknowingly compromised.

David Sugden
Chairman, Passive Fire Protection Federation