Every developer, business and mall owner, homeowner, and anyone who owns a building has to factor in building safety and fire resistance during construction. Although there are several ways to ensure a fire does not start, in the unlikely event that it does, you need a plan to evacuate the inhabitants of a building safely. Passive fire protection comes in to help contain a fire and save people’s lives when a fire breaks out. Despite its name, PFP is constantly working to keep people safe. Read on to learn more.
What is Passive Fire Protection?
Also known as built fire protection, passive fire protection involves creating structures that contain a fire and aid in evacuation during construction. Developers include special structures that help contain fire and smoke so buildings nearby are not affected.
Several structures integrate into a building to ensure the fire does not spread, and people evacuate safely. For instance, a developer can create small manageable spaces to ensure that fire and smoke do not spread from one room to the next. They can also reinforce the partition beams and columns that hold a building to protect it from collapsing.
Components of Passive Fire Protection
PFP addresses four main areas:
Structural Fire Protection
Any building should withstand damage from fire for long enough to allow the evacuation to occur. Engineers, therefore, guard the structural components that hold a building, such as the joint systems, the beams and columns, to ensure they are strong enough to withstand a fire for extended periods. They use intumescent fireproofing, which involves adding a coating of fireproof material on the structural steel that holds a building in place.
The fireproof material can be sprayed on the steel, as is the case of intumescent paint, or applied as a film around the structure. When a fire breaks out, the fireproof material expands to create an additional protective layer that prevents the fire from bringing down a building. With this layer, it will take more time for a fire to weaken steel.
Compartmentation
Compartmentation involves dividing a building into small manageable spaces to prevent the spread of a fire. It also involves the use of firewalls and partitions, fire and smoke barriers, and the use of fire-resistant materials.
Barriers and partitions in different rooms contain walls, ceilings and floors made of fire-rated materials such as concrete, masonry, or gypsum. With these barriers, fire does not spread from one room to the next. Fire-rated walls merge into fire-rated ceilings and even extend to concealed spaces to ensure complete protection.
Besides using fire-rated materials, the walls are structurally stable to ensure that even if a building collapses on one side of the wall, the fire will still not spread. These walls ensure that evacuation routes are safe. Firefighters will have sufficient time to evacuate people with proper maintenance of these fire-rated walls, ceilings, and floors.
Fire Doors and Windows
Openings can be the only source of fire spreading with fire-rated walls, ceilings, and floors. To ensure that does not happen, passive fire protection requires that doors and windows are made of fire-rated materials. The glass and the framing for doors and windows undergo testing during and after assembly to ensure they are strong enough to withstand fire damage for extended periods. PFP also requires the installation of fire and smoke dampers in duct systems.
Fire doors offer a safe escape route. These doors feature cold smoke seals and intumescent strips that resist the spread of fire and passage of smoke.
Fire Stopping
In some instances, a fire might spread beyond fire barriers. If, for example, a plumber leaves a hidden hole in the fire and smoke barrier, such a hold can cause a fire problem. As such, membrane penetrations need sealing or protection through fire stopping to ensure that fire barriers are not ineffective. Fire stopping involves the inspection of walls, ceilings, floors, doors and windows for any gaps and openings that technicians may have left.
During their maintenance, repairs, and installation of different devices and fittings, technicians may leave cavities on walls, ceilings, and floors; These cavities create a loophole that allows fire and smoke to spread throughout a building. Filling these cavities with fire-resistant materials is part of fire-stopping.
Fire stopping is one of the most crucial strategies in passive fire protection. Most of these membrane penetrations are in concealed spaces; without a keen eye, they are almost impossible to notice. Therefore, a fire risk survey from a specialist comes in handy to keep a building safe.
Other Areas
Other passive fire protection strategies include perimeter fire barriers, cable coating, and fire-rated joint systems. Wires and cables need protection as they can be a source of fire spreading. Using fire-retardant materials to coat these cables adds a layer of protection to a building. Further, the perimeter of the exterior curtain wall and floor also needs protection with fire-rated materials.
Passive Fire Protection in Building Design
PFP starts from the design phase of a building. Developers need to consider the compliance requirements in their operating region and the industry standards that govern PFP. The environmental conditions in an area determine the materials and methods a contractor employs in PFP.
The designer, the architect and the engineer are responsible for creating a building plan that includes PFP elements. Such a design must include:
- Detailed plans showing the size and position of ducts, cables, and pipes going through fire-rated floors, walls, and ceilings
- The specifications of the fire engineer are in the building plans
- The space around penetrating membranes in walls, floors, and ceilings
- The placement of passive fire protection elements
- Details on the specific materials to be used on different parts of the building for fire protection
Compliance requirements vary from one region to the next. The building plan must incorporate all the elements required to get approval for construction.
Fire-Resistant Construction Materials
Here are common fire-resistant materials to use to meet PFP guidelines:
Brick
Bricks pass through a fire kiln during their manufacture. As such, they are already resistant to fire. The thickness of a wall and the nature of the mortar used to hold the bricks together will determine the fire rating. Bricks can withstand a fire for four hours or even longer.
Gypsum
Also referred to as drywall, a gypsum board allows a building to get an excellent fire-resistant finish inside. The board consists of gypsum sandwiched between two paper sheets. Gypsum contains additives that improve its fire-resistant qualities, giving it an excellent fire-resistant rating. The sheet of paper covering the outer side of the gypsum does not cause the fire to spread as it burns slowly.
In its core, the gypsum board has chemically combined water. In a fire outbreak, the core releases the water as steam to ensure the fire does not spread through the gypsum board. A building may contain several gypsum boards, creating multiple layers for adequate passive fire protection.
Stucco
Stucco is a decorative plaster material. It features Portland cement, line, and lime, which make it resistant to fire when used on buildings. The material is durable and can cover any material, including wood and bricks. Two or three coats of stucco are added on top of metal mesh reinforcement. Adding a 1-inch layer of stucco protects a building for at least an hour, allowing time for evacuation.
Stucco can also be used on roof eaves. It covers the eaves to create an appealing and fire-resistant finish when added.
Concrete
Concrete is noncombustible and has low thermal conductivity. As such, it will take a few hours before it catches fire and its structural integrity is compromised. It resists fire better than steel and can even be used to protect steel from fire.
To create fire barriers, the type and amount of aggregate used matter. For instance, treated aggregate resists fire better than natural aggregate. As such, fire engineers prefer certain types of aggregate to others. In the case of natural aggregates, their moisture can expand when they heat, causing them to compact, which can cause damage.
Concrete can be used on roofs. Thanks to its fire-resistance qualities, concrete can protect a building if sparks from a wildfire fall on the roof. Today, contractors use Insulating Concrete Form (ICF), which consists of concrete covered with polystyrene panels on two sides to form a wall.
Fire-Resistant Glass
Windows bring light into a building but can also be a fire hazard. The standard window will break from the intense heat from a nearby fire, and this can cause flames and smoke to spread to nearby rooms. Besides breaking from a fire inside the building, fires outside can ignite curtains and other items in a home without the necessary passive fire protection strategies.
Fire-resistant windows can keep a building safe and allow time for evacuation and fire-fighting. These windows will take at least twice the time it takes for standard windows to break. For instance, a dual-paned glass will break in phases – the first layer breaks, and then it takes some more heating for the second layer to break. Another option is tempered glass, which is treated to be at least four times stronger than standard glass.
Some buildings may feature glass blocks as part of PFP. These blocks may not offer visibility, but they are light and resist fire. There are also wired glass options and tempered glasses with metal mesh reinforcement.
Benefits and Advantages of Passive Fire Protection
PFP offers several advantages to building owners and inhabitants. These include:
- The measures will contain the fire in one room to allow safe evacuation. The rate at which a fire spreads determines how destructive it is. A fire will spread fast when it catches flammable materials, when ventilation is poor, and when heat builds up quickly in a small room. With compartmentation, the rate at which a fire spreads is limited, thanks to fire-rated walls, ceilings, and floors. These elements ensure people have enough time to leave the building and for firefighters to respond. For all building owners, the welfare of people should be a priority, and PFP ensures that happens.
- Passive fire protection strategies protect properties and assets. Property damage is limited when these strategies contain fire and smoke in one location. As such, property owners do not have to spend money on repairs and replacements.
- PFP systems are always at work without human intervention. Unlike a fire extinguisher or a fire hose, you never have to do anything to get PFP systems to work. After installing these systems during construction, they are ready to protect occupants 24/7. The occupants of a building do not need any training besides learning the best evacuation routes. Even better, most of these systems do not need constant routine maintenance.
- With the right fire protection strategies, one can minimize company downtime. You never have to worry that fire will spread through cables and ducts, as these will have fire-resistant seals. You will have peace of mind knowing that your employees are protected, your building is safer, and so is your property.
Like active fire protection, PFP gives you peace of mind.
Challenges and Considerations in Passive Fire Protection
For a building to be fire-rated, it needs to meet the set codes and regulations. It has to be tested and certified, and this is where the challenges start. Each fire protection system component needs to meet a set of codes. For instance, a window is only fire-rated once it is installed correctly and becomes part of a fire-rated assembly. Specialists have to follow approved building plans and designs that show fire-rated components.
The National Fire Protection Association (NFPA) structures standards, codes, and regulations you must follow to create a fire-protection system. Always check out the documents they provide to see if you are in compliance before construction work begins.
Buildings and components fitted with passive fire protection systems must pass tests and be certified to industry standards. Accredited organizations such as Underwriters Laboratories Inc. and ASTM Intl. will perform tests and offer certifications based on how well components meet set standards. Ratings are as follows:
- F rating for half an hour or an hour
- T rating for temperature
- L rating for smoke penetration
- W rating for the ability to resist water leakage
You have to maintain the systems in addition to knowing the codes and regulations governing each passive fire protection component. Maintenance is more critical during building modifications. If a part of the building is to undergo plumbing modifications or be rewired, there are chances that penetrations may occur in fire barriers.
After a building modification, a specialist needs to inspect the openings, caulking, pipe penetrations, condition of the walls, and workmanship. If there are signs that workmanship affects fire-stopping components, necessary remedies must be taken.
If your building is at least ten years old, there is a high chance that penetrations are unprotected. As such, you may consider modifications to re-install the fire-stopping elements.
Frequently Asked Questions (FAQs)
How long does passive fire protection last?
Fire-rated walls, ceilings, and floors can last for several decades. However, fire-stopping elements need inspection after about three years to determine their state and whether they need replacement or repair. During a home modification, the fire-stopping elements might need replacement.
Can passive fire protection replace active fire suppression systems?
PFP systems are not a replacement for AFP systems. Instead, these two systems work hand in hand to create a comprehensive fire protection system. PFP systems can contain a fire, but you must still suppress the fire using sprinklers, fire extinguishers, and hoses.
Are there specific fire-rated materials for different fire types?
Yes. Building materials have different ratings for fire safety depending on smoke toxicity, ignition temperature, and flame spread. Most materials are rated based on their flame spread. There are three classes: I or A, II or B, and III or C. Class A has a rating of between 0 and 25, Class B has a rating of between 26 and 75, and Class C has a rating of between 76 and 200 for flame spread.
How can I identify if a building has proper passive fire protection measures in place?
The plan of a building will reveal any PFP systems installed. You can also tell the systems installed from an inspection report, which shows fire-stopping details, records of systems installed, and quality check details.
Conclusion
Passive fire protection, by itself, is not sufficient to keep a building safe. You need a blend of passive and active fire protection systems. PFP systems will contain the fire, while active systems help you fight the fire. With PFP systems, you will meet local building codes and regulations and protect people and property. As you do that, you will enjoy the peace of mind that comes with living in a safe building.
During construction, developers and building owners must consider different fire protection standards from UL Certifications and the American Society for Testing Materials, ASTM International. These two organizations, among others, create guides on ensuring complete building fire protection and rate materials based on their fire-resistance abilities. You also need to work with specialists and professionals who understand not only codes and regulations but also materials and installation methods.