Common errors in fire compartmentation
Fire compartmentation is a decisive aspect in the design and execution of any building project. Its correct implementation requires the decisions adopted during the design phase to be applied consistently throughout construction and over the building’s entire service life.
In practice, many compliance failures do not stem from a single obvious error, but rather from partial decisions, unreviewed modifications or a lack of coordination between the different parties involved. This article reviews the most common errors in fire compartmentation and the technical guidelines for preventing them.
What will you learn in this article?
- What fire compartmentation is and why it is essential for building safety
- Regulations applicable to fire compartmentation in Spain
- The main errors in fire compartmentation
- How to prevent errors in fire compartmentation
What is fire compartmentation and why is it essential for building safety?
Fire compartmentation is the planned arrangement of construction elements and closure systems that divide a building into independent areas with regard to fire and smoke. Each of these areas must maintain specific performance levels for a defined period, in accordance with the requirements applicable to the project.
A fire compartment should not be understood as a simple physical division between spaces. It is a complete enclosure made up of vertical partitions, floor slabs, communication openings, service penetrations and construction interfaces. All these points must perform consistently to ensure that the boundary maintains its function in the event of a fire.
The purpose of compartmentation: limiting the spread of fire and smoke
The main objective of fire compartmentation is to contain the fire within the area where it originates and prevent it from spreading prematurely to other parts of the building. To achieve this, separating elements must prevent the passage of flames and hot gases and, where required, reduce heat transfer to the unexposed side.
Limiting internal fire spread provides sufficient time for occupant evacuation, the activation of fire protection systems and the intervention of emergency services.
Smoke is also part of this strategy. During a fire, hot gases can move rapidly through open-plan areas, suspended ceilings, service shafts, vertical openings or connections between floors. For this reason, the compartmentation strategy must be coordinated with the smoke control solutions provided in the building, particularly in high-volume or high-occupancy premises.
Difference between compartmentation, fire sectors and passive fire protection
Fire compartmentation is the design criterion used to define how a building is divided in order to limit internal fire spread. It is based on an analysis of the building use, architectural layout, occupancy, activities undertaken and risk conditions in each area.
A fire sector is the practical application of that compartmentation strategy. It is created through fire compartments bounded by construction elements capable of performing under fire conditions. Each compartment must be properly sealed along all of its boundaries, including locations with doors, access panels, ducts, services or movable systems.
Passive fire protection includes the systems and elements that maintain this separation without requiring manual intervention during an emergency. These include fire-resisting enclosures, fire doors, penetration seals, linear joints, protected ducts and fire curtains.
Regulations applicable to fire compartmentation in Spain and fire protection regulations
The regulations applicable to fire compartmentation vary according to the use, activity and configuration of the premises. This framework determines issues such as the area of fire compartments, the fire resistance of their bounding elements, the treatment of high-risk areas and the protection measures associated with each case.
CTE DB-SI for non-industrial buildings
The Fire Safety Basic Document of the Spanish Technical Building Code establishes fire safety requirements applicable to non-industrial buildings and is based on a clear principle: “the risk of fire spreading within the building shall be limited.” Based on this requirement, section SI 1 sets out the conditions for compartmentation into fire sectors, the fire resistance of separating elements and the characteristics of certain connections between compartments.
RSCIEI for industrial establishments
The Fire Safety Regulations for Industrial Establishments, approved by Royal Decree 164/2025, regulate fire safety conditions in this type of activity. In its definition of passive protection, the regulation states that its purpose includes “preventing or delaying its spread,” directly linking construction requirements to the containment of fire within the industrial establishment.
RIPCI and its relationship with fire protection systems
The Regulations on Fire Protection Installations, approved by Royal Decree 513/2017, regulate the design, installation, maintenance and inspection of the equipment, systems and components that form part of active fire protection. Its scope includes, among others, detection and alarm systems, water supplies, extinguishing systems, signage and certain systems associated with smoke and heat control.
Why is it an error to apply regulations that do not correspond to the building’s actual use?
Applying regulations unrelated to the actual use of a property can lead to incorrect criteria regarding the area of fire compartments, the fire resistance of separating elements or the required protection measures. Classification cannot be based solely on the building’s general designation, as a single complex may contain activities with different risk conditions.
A property with offices, production areas, storage facilities, goods dispatch zones and customer service areas does not present a single fire scenario. Each zone has a specific activity, a defined fire load, expected occupancy and a particular relationship with evacuation routes. Compartmentation must respond to this functional distribution.
Main errors in fire compartmentation
Errors in fire compartmentation occur when any of the elements that bound a compartment fails to maintain its intended performance against fire and smoke. The continuity of the compartment depends on walls, floor slabs, doors, seals, services, suspended ceilings and construction interfaces.
Failure to correctly define fire compartments from the design stage
This error occurs when fire compartments are incorporated into the project after the architectural layout and services have already been defined. At that point, service shafts, openings, suspended ceilings or service penetrations may already cross the intended boundaries between compartments.
Compartmentation is then resolved through partial details or adapted solutions during construction. The boundaries of each compartment must be identified in plans, sections and construction details to reflect their continuity across every element that forms the enclosure.
Incorrectly calculating the maximum area of fire compartments
An incorrect calculation of a compartment’s area occurs when only the floor area is considered without analysing the complete configuration of the space. Double-height areas, mezzanines, interconnected zones or adjoining rooms may form part of the same fire compartment.
Failing to consider the actual use of the building or each area
A building may have a primary use while also including rooms dedicated to different activities. An office building may contain archives, storage rooms, car parks, electrical rooms or technical spaces. Each of these areas has different occupancy conditions, fire loads and service requirements.
Ignoring the fire load in industrial or storage areas
In industrial and logistics facilities, fire load is linked to the quantity, type and distribution of combustible materials present. Cardboard, plastics, pallets, textiles, packaging, aerosols or raw materials create different risk conditions.
Storage height, racking systems, goods density and production processes also influence the development of a fire.
Installing enclosures without the appropriate fire resistance
Fire resistance does not depend solely on the visible material of an enclosure. Classification applies to the complete system, including the supporting structure, profiles, fixings, joints, dimensions and installation method.
Using poorly maintained fire curtains
Fire curtains form part of compartmentation when they automatically close an opening between fire compartments. Obstacles accumulating in the descent area, fabric deterioration, misaligned guides, electrical supply faults or the lack of functional checks may prevent the curtain from deploying fully. When the closure does not reach its fire position, the opening remains unprotected and compartment continuity is interrupted.
Leaving service penetrations unsealed
Services pass through walls and floor slabs via cable trays, pipes, ducts, electrical conduits or telecommunications systems. Each penetration creates an interruption in the separating element. The later addition of new cables or ducts may alter the original configuration of the seal.
Failing to compartment suspended ceilings, service shafts, ducts or vertical openings
Suspended ceilings, service shafts, ducts and vertical openings can allow smoke and hot gases to spread between compartments or floors when they do not maintain the continuity of the separating element.
Compromising compartmentation during refurbishment works
Refurbishment work may introduce new openings, service penetrations, cable trays, doors or internal layout changes. These actions alter the elements that bound a compartment when they penetrate or replace an existing fire-resisting solution.
Confusing reaction to fire with fire resistance
Reaction to fire indicates how a material contributes to the development of a fire. Fire resistance, on the other hand, assesses the performance of a construction element during a defined thermal exposure.
Failing to properly document installed compartmentation solutions
As-built drawings, technical data sheets, classification reports and installation details make it possible to identify how each fire compartment has been resolved. This documentation records the location of enclosures, doors, seals, joints, fire curtains and service penetrations.
When this information is unavailable, it becomes more difficult to verify which solution was installed at each point or assess the impact of a subsequent refurbishment.
How to prevent errors in fire compartmentation
Preventing errors in compartmentation is based on defining fire compartments, selecting construction systems, correctly installing critical points and controlling modifications made to the building.
Carry out a preliminary assessment of the building, activity and risks
The preliminary assessment considers the use of each room, occupancy, fire load, architectural configuration, evacuation routes and existing services. This information makes it possible to define fire compartment boundaries and the elements that pass through them.
Coordinate architecture, engineering, services and maintenance
Compartmentation affects architectural, structural and services drawings. Separating elements are related to openings, service shafts, suspended ceilings, ducts, cable trays, doors and movable systems. Coordination between disciplines helps identify construction interfaces before installation. Project details define how service penetrations, joints, opening closures and connections between compartmentation elements are resolved.
Select tested solutions appropriate to the required fire resistance rating
Compartmentation systems must be selected according to the fire resistance classification specified in the project. The technical documentation for each solution sets out its conditions of use, including the type of supporting structure, dimensions, fixings, joints, orientation and installation configuration.
In large openings or open-plan spaces, Tecnitex fire curtains form part of the compartmentation solution when their classification, dimensions and installation conditions comply with the requirements of the project.
Review compartmentation after refurbishment, extensions or changes of use
Refurbishment works may affect walls, floor slabs, doors, suspended ceilings, ducts, service shafts and service penetrations. The subsequent review assesses the modified elements and their relationship with fire compartment boundaries.
Changes of use also modify the occupancy, fire load, storage or operational conditions of a room. These changes affect the compartmentation criteria established for the building.