Designing for fire safety

Approaches

Destruction of whole cities by fire may have been common in the past, but it is not the case nowadays – although our cities and buildings have grown considerably in size. Fire safety is a standard part of building design process. For some building types and occupancies it is a mandatory part with high importance.

Prescriptive approach

Setting requirements in terms of fire characteristics of building parts and materials is now the traditional way of securing a certain level of fire safety. The requirements may often originate from experience and have been implemented as a consequence of past disastrous fire cases.

Performance-based approach

Over the past few decades we can see a rapid development in a new way of building design – a valuable set of scientific tools called Fire Safety Engineering.
This method may be the only possible way to construct very large and special buildings. Elements of this approach are often used in conjunction with traditional prescriptive way – for example modelling of evacuation and smoke spread.

Although predictions of fire growth and smoke movement are made using the anticipated building content and building use, they do not usually take into account two facts:

The building structure may give out heat and contribute to fire,
The building structure may emit significant amount of toxic smoke and gases.

Hence it should be assumed that only building structures which do not release heat and smoke can be used if this approach has been applied during the building design.

Given the fact that fire – and human reaction to it – is a disaster and hard to predict phenomenon, it is beneficial to have certain level of robustness and reliability as part of the building design.

Safety margins are used in every aspect of building design and there is no reason why they should not exist in assumptions and procedures aimed at saving human lives.

Fire protection

Building parts are often expected to provide a certain level of resistance to fire in terms of load-bearing capacity, integrity, insulation, and other criteria. ROCKWOOL stone wool insulation provides a stable and reliable protection against heat due to its inherent properties. Some elements of building construction may be self-sufficient in this respect, e.g. brick walls or concrete elements.

Other elements may require additional protection for insulation against heat, for the sealing against cracks and gaps and compensating for deformations – which all affect building parts during fire.

Lightweight structural elements containing combustible parts covered by thin surface layers may prove to comply with fire safety requirements for a period of time, but it is important to know the role of such subtle surface layers during installation and use of the building during its lifetime.

In general, two ways of fire protection are used in building practice:

1. Passive fire protection

These systems are considered a traditional and proven way to protect people, property and businesses from fire. Once installed, they are on guard against fire growth without a need for power or water supplies. They usually require minimum or no maintenance during the lifetime of a building.

ROCKWOOL stone wool insulation is a long-time proven and reliable part of a wide range of passive fire protection systems in building elements, building and technological equipment, marine and other transport applications.

2. Active fire protection

To further enhance protection against fire, new technologies have been developed during past decades with a specific goal – to reduce the risk of fire spread in buildings. These include smoke detection and smoke control systems, automatic sprinkler systems, oxygen reduction systems, systems to facilitate evacuation, and others. Being effective tools to reduce risk of a big fire, these systems usually require energy or water supplies, and careful maintenance and operation during their lifetimes.

Both active and passive fire protection systems fulfill their specific roles in fire safety design and may together provide a high level of safety in all stages of fire growth – from small local fires to long-term disastrous fires in their fully developed stages.

Using ROCKWOOL products in fire protection results in negligible contribution to fire and smoke, effective insulation up to very high temperatures, and compensation against cracks, gaps, and deformations of the structural parts, as well as a high degree of immunity against losing fire safety properties should damages to surface layers and coverings occur.