What is a fire compartmentation survey?
The purpose of a compartmentation survey is to prevent the spread of fire, smoke and gases that can form within the building once a fire has started. Compartmentation surveys also includes identifying any high-risk areas or high value areas of the building and recommending compartmentation if necessary. (Guidance on this can be found In Approved Document B – Volume 2 Section). Having compartmentation will help occupants with their means of escape enabling them to escape without the risk of smoke inhalation or further harm that may cause risk to life while escaping the building.
I residential buildings these surveys are known as a Type 2 or a Type 4 fire risk assessment. Type 1, 2, 3, and 4 are types of fire risk assessments (FRAs) for residential properties. The type of assessment required depends on the level of risk and the results of the previous assessment.
Type 2 fire risk assessment (common parts, destructive)
A type 2 fire risk assessment is normally only recommended when a type 1 fire risk assessment indicates that there may be serious structural flaws within a building, which may increase the risk of fire spreading.
Unlike a type 1 assessment which is non-destructive in nature, a type 2 fire risk assessment involves destructive sampling. It may call for a contractor to open up parts of the building, and then return them to their original condition once the assessment is complete.
Due to the type 2 fire risk assessment being destructive, it is usually carried out when the property is vacant.
Type 4 fire risk assessment (common parts and flats, destructive)
A type 4 fire risk assessment is one of the most comprehensive fire risk assessment types, and can be destructive. It will involve a contractor creating openings for inspections to be carried out on certain fire stopping points within the premises. The contractor will then repair any damage.
Because of the destructive nature of a type 4 fire risk assessment, it is best carried out when the property is vacant. In reality, these types of fire risk assessment are usually only suggested in situations where serious defects are detected in common parts of a building and individual dwellings.
Pre-Event
- A Risk Assessment including the assessment of fire doors as these form a principal feature of fire compartmentation, it is also recommended to define the compartmentation strategy if not known.
- A Visual Inspection on current compartmentation already in place, this involves looking at fire doors, floors, walls, roof / ceiling and floor voids, basements, risers and shafts. This can be carried out in a non-destructive visual manner or intrusive due to the nature of the assessment sometimes an intrusive method will need to be used to correctly assess the materials or identify breaches.
- Action plan that highlights any failures within the compartmentation and include the location of the failings
Will there be any damage caused to the structure?
Guidance and Regulations
The British standard for fire compartmentation stems from legislation in the Building Regulations Act 2010, the Fire Safety Act 2021 and the Building Safety Act 2022.
Approved Document B – Volume 2 Buildings other then dwellings
B3 Section 8: Compartmentation/sprinklers
8.1 All of the following should be provided as compartment walls and compartment floors and should have, as a minimum, the fire resistance given in Appendix B, Table B3.
8.2 A wall common to two or more buildings should be a compartment wall.
8.3 Parts of a building occupied mainly for different purposes should be separated from one another by compartment walls and/or compartment floors. Compartmentation is not needed if one of the different purposes is ancillary to the other.
8.4 Effective compartmentation relies on both of the following. a. Fire resistance should be continuous at the join between elements forming a compartment. b. Any openings between two compartments should not reduce the fire resistance.
8.5 The lowest floor in a building does not need to be a compartment floor.