Five Common Principles of Building Fire Safety

Fire safety is essential for life safety and property protection in the built environment. It is among the top priorities of many building codes used by jurisdictions around the world to regulate the design, construction, and safe use of buildings and the built environment. It is also important to recognize that safeguarding against the risk of fire, fire itself, and the effects of fire in the modern built environment is multifaceted. The regulation of fire safety can be complicated by regional issues that include construction practices, cultural traditions, and regulatory priorities and enforcement. Despite the complexity of our world, the general principles and fire dynamics do not change, therefore, principles supporting fire safety in the design and use of buildings remain useful as well.

Today’s building envelope serves many functions. It must resist relevant structural and environmental loads, enclose space, and provide shelter from weather to name a few. As with all building systems, fire safety of building envelopes is an important consideration in their design, construction, and operation.

In context of building science, the building envelope separates interior and exterior environments by providing four control functions: a water control layer, an air control layer, a vapor control layer, and a thermal control layer. The building envelope also helps provide fire safety when its different elements comply with fire safety provisions of the building codes such as resistance to ignition, limitations on vertical and horizontal flame propagation, and requirements for fire-resistance-rated construction among others.

Common Principles

The International Fire Safety Standards: Common Principles (IFSS-CP) are intended to provide a consistent high-level framework that addresses fire safety in every stage of the building life cycle (Design, Construction, Use, Alteration/Renovation, Demolition).

It is important to note that each of the Common Principles both supports, and is supported by, the other principles. Building and fire codes must include requirements that support all Common Principles because fire safety can be impacted when any of the principles is either absent or inadequately addressed.

Prevention aims to safeguard against fire outbreak and/or limit the effects of fire in order to protect life safety, prevent building damage, and protect building operations. The principle of Prevention addresses natural and manmade causes of fire. Specific Prevention considerations vary with the stage of the Building’s Life Cycle; for example, design considerations include the identification of a building’s intended use and occupant behaviors. Construction considerations include requirements for construction site ‘hot work’ especially when near combustible materials that are either already installed or stored at the jobsite.

Detection and Communication is needed for the early discovery of fire and alerting of the occupants and fire services. The main goal of this principle is to ensure communication among all relevant stakeholders and communication between the various systems. Should a fire occur, the necessary automatic detection and alerting of occupants and relevant agencies needs to be in place and operational.

Occupant Protection focuses on providing a building’s occupants with means to safely avoid and escape from the effects of fire and smoke to a safe location. Key elements of this principle include ensuring adequate time and opportunity to reach places of safety, or refuge areas through the use of egress pathways, fire safety systems, and other strategies intended to provide for escape or rescue of occupants.

Containment covers the limiting of fire spread and its consequences to as small an area as possible. There are many strategies that can be used throughout the building life cycle that fall within the scope of containment. Examples of Containment strategies include: compartmentation, smoke control, automatic sprinkler systems, structural fire protection, fire-resistant construction, and construction material characteristics.

Extinguishment is focused on the suppression of fire and the protection of the surrounding environment. Although installed suppression and control systems should be capable of controlling the fire (per the Containment principle), the action of Extinguishment falls to the fire services. With smaller fires, Extinguishment can be exercised by building occupants, however, doing so is not recommended due to the risk of injury and death.

The Common Principles and Alignment with Codes and Standards

The International Building Code® (IBC) and International Fire Code® (IFC) are highly correlated examples within the International Code Council (ICC) family of model codes used to regulate the fire safety of buildings. The multiple, interrelated layers of prescriptive and performance requirements strongly support the Five Common Principles. The fire safety provided by these codes largely comes in the Design and Alteration/Renovation stages of the building life cycle. However, requirements regarding the service and maintenance of buildings also influence the Operational or Use stage.

The scope of the IBC (2021 Ed., Section 101.2) includes construction, alteration repair, use and occupancy, equipment, maintenance, and demolition of buildings. Its purpose (2021 Ed., Section 101.3) is to establish minimum design and performance requirements to provide a reasonable level of safety for both occupants and for fire and emergency services during emergency operations.

Fire safety requirements in the IBC are structured in a manner that begins with the establishment of classifications for occupancy and construction type. Occupancy classifications group together similar uses of buildings. Construction type classifications establish minimum criteria for the primary building elements (structural frame, interior and exterior walls, floors, and roofs). Virtually all other requirements and limitations are influenced by one or both of these classifications. Table 1 provides examples of where the Common Principles of fire safety are supported by provisions and requirements of the IBC.

Table 1: Examples of IBC provisions and associated fire safety principles
IFSS Common Principle	IBC Topics	IBC Chapters
Prevention	Combustible / noncombustible materials Construction Type classification Interior finish requirements Thermal barriers and ignition barriers Ignition resistance Surface burning characteristics Flame propagation Construction fire safety Inspection / Special Inspection	6, 7, 8, 14, 15, 17, 26, 33
Detection and Communication	Fire protection and life safety systems Smoke detection	9
Occupant Protection	Occupancy classification Construction Type classification Means of Egress Thermal barriers Smoke barriers and smoke control	3, 6, 7, 9, 10, 14, 26
Containment	Fire resistant assemblies Fire walls, fire barriers, fire partitions Fire doors Thermal barriers Fireblocking and firestopping Surface burning characteristics Flame propagation Inspection / Special Inspection	6, 7, 14, 17, 26
Extinguishment	Automatic sprinkler systems Fire department connections Portable fire extinguishers	9

The IFC (2021 Ed., Section 101.2) regulates structures and the immediate premises. It establishes safeguards regarding fire, explosion, hazardous conditions, fire protection systems, and the safety of fire and emergency services during emergency operations. The IFC is similar to the IBC is that the IFC’s purpose (2021 Ed., Section 101.3) is to establish minimum requirements that provide a reasonable level of life safety and property protection, and the safety of fire and emergency services during emergency operations. The IFC is also different than the IBC in that many of its provisions apply to a building after it has received a certificate of occupancy. The provisions of the IFC include requirements that address each of the Common Principles but with an emphasis on specific hazards (materials and building uses), fire protection and life safety systems, furnishings, and features for fire service operations.

The Common Principles and Combustible Materials in the Building Envelope

The use of combustible building envelope materials in commercial and residential construction has seen continuing growth and acceptance based on improved performance, innovative construction practices and methods, and the benefits provided by lightweight, durable, and often multifunctional materials for insulating, waterproofing, air sealing, and many other construction purposes. Uses of combustible materials in the building envelope have become essential contributors to energy-efficient designs, and strategies.

Both IBC and IFC contain provisions regulating combustible materials and their uses. Combustible materials must comply with rigorous fire performance requirements for both the material itself (e.g., surface burning characteristics) and for specific end uses (e.g., roof assemblies, exterior wall assemblies, and fire-resistance-rated construction) in addition to other general limitations and permissions. Provisions governing uses and installation of these materials are found throughout the IBC, and often contain references back to Chapters 6, 7, 8, 14, 15 and 26 or specific sections within those chapters. The sections below discuss a few more specific examples of how IBC provisions for plastics demonstrate support for each Common Principle.

Prevention

Responsible, code-compliant use of combustible materials, including allowable uses in noncombustible construction, support fire Prevention as much as the use of noncombustible or minimally combustible materials from many perspectives. For example, IBC Section 602 specifies that construction Types I and II shall consist of noncombustible materials. However, Section 603 permits a list of combustible materials, including foam plastics, and uses of combustible materials in Types I and II construction when they meet the applicable code requirements; for example, foam plastics are permitted when they meet the requirements Chapter 26.

Other fire safety provisions for foam plastic insulation that support fire Prevention are contained in IBC Section 2603. The thermal barrier required by Section 2603.4 provides, among other things, protection against ignition. For exterior wall assemblies, Section 2603.5.7 requires NFPA 268 testing to limit ignition from radiant heat sources (i.e., from an adjacent building fire).

Section 1405 of the IBC has a similar requirement, with some specific exceptions, for NFPA 268 testing when combustible exterior wall coverings are used in Types I through IV construction.

Occupant Protection

The safe movement of occupants in accordance with the Occupant Protection fire safety principle requires time for egress. The thermal barrier required by Section 2603.4 to separate foam plastic insulation from interior spaces provides a minimum of 15-minutes before the insulation could potentially contribute to room fire growth. This 15-minute protection provides time for occupants to escape a fire that has started in a compartment such as an interior room. Compliance of foam plastic assemblies with other IBC provisions for interior finishes (Chapter 8) and fire-resistance-ratings (Chapters 7 and 26) help provide that means of egress and areas of refuge continue to allow for occupants to escape or to refuge during emergency evacuations.

IBC Chapter 5, Chapter 9, and Chapter 14 also contain several references to the use of a thermal barrier to separate combustible materials from interior spaces.

Containment

Many IBC provisions for combustible materials support the Containment principle of fire safety They include: maximum allowable surface burning characteristics of materials and interior finishes, ignition resistance and flame propagation of exterior wall assemblies, and fire-resistance-ratings of various constructions and assemblies.

All plastic and polymeric materials are subject to limitations. One example is surface burning characteristics, defined as flame spread index and smoke developed index as tested in accordance with ASTM E84 or UL 723. Limits imposed on flame spread index and smoke developed index are prescribed in either the code text or by a referenced standard. Examples where the IBC requires ASTM E84 / UL 723 testing for specific materials include:

• Water-resistive barriers – 1402.5 (Exception 2.2)
• Metal Composite Metal (MCM) panels – 1406.9, 1406.10.1
• High-Pressure Decorative Exterior-Grade Compact Laminate (HPL) panels – 1408.9, 1408.10.1
• Foam plastic insulation – 2603.3, 2604.2.4, 2603.5.4

Other IBC provisions that manage the spread of fire include exterior wall assembly requirements discussed above under the Prevention fire safety principle. Requirements that manage the spread of fire by limiting ignition and flame propagation of exterior wall assemblies of Types I through IV construction are found in Chapters 14 and 26. The requirements include fire performance testing of the exterior wall covering or the complete wall assembly. Ignition resulting from radiant heat from an adjacent building fire is managed by Section 1405.1.1.1 with NFPA 268 testing and prescribed limits on tolerable incident radiant heat energy related to fire separation distance. The potential for an exterior wall assembly design and composition to contribute to vertical and lateral flame propagation is regulated through requirements to test and comply with NFPA 285.

Other examples of IBC fire safety provisions managing fire spread through prescribed requirements and fire performance tests include:

• Chapter 7 – Various provisions for fire walls, barriers, and partitions, smoke barriers and partitions, fireblocking and draftstopping in concealed spaces, and fire resistance testing, calculations, ratings, and openings in rated assemblies.
• Section 803 – Interior wall and ceiling finish requirements based on occupancy and classification based on testing in accordance with ASTM E84 / UL 723, NFPA 286, or NFPA 265.
• Section 1505 – Roof assembly fire classification based on testing in accordance with ASTM E108 / UL 790.

In Summary

The need for fire safety in the built environment crosses all political, cultural, and jurisdictional boundaries. Fortunately, there are broadly applicable Common Principles for fire safety identified by the International Fire Safety Standard Coalition (IFSS). When implemented to guide comprehensive requirements of building and fire codes, such as the IBC and IFC, these Common Principles provide for robust and sustainable fire safety throughout the building life cycle. IBC requirements for building design and building materials are an important example demonstrating how each of the IFSS Common Principles for fire safety are included and addressed by code for the regulation of buildings. This includes the many uses of plastic building materials, and assemblies containing them, supporting fire safety today and beyond.

1 IFSS. International Fire Safety Standards: Common Principles, 1st Ed.; International Fire Safety Standards Coalition; Geneva, Switzerland, 2020; ISBN 978-1-78321-384-9; https://ifsscoalition.files.wordpress.com/2021/12/d4d39-ifss-cp-1st-edition.pdf (accessed January 16, 2023).