A building is a complex structure especially when considering a fire. The aim of passive fire protection is to prevent a fire spreading through the building. This has several benefits, the first and most important is that it ensures the safety of people in the building and allows them to escape from a fire uninjured. The other benefit is that it confines the damage caused by a fire, so that instead of the entire building being destroyed or damaged, the destruction is confined to a small area. This can be the difference between a business carrying on with a little disruption and not being able to trade until new premises can be found.
Passive fire protection is achieved by compartmentation where the interior of the building is divided into fire proof boxes and if a fire occurs it stays inside the box. A new building, built to current standards, should have no issues. However as soon as any alterations are carried out there is the possibility that this compartmentation can be compromised.
The purpose of a passive survey is to find the areas where the compartmentation within the building has been damaged and recommend ways to repair the damage.
Where the extent of the compartmentation in a building is unknown whether this is due to the age of the building or because the original plans and specifications have been lost, a passive survey can identify the lines of compartmentation and identify any work needed to maintain or bring back the appropriate protection.