Passive Systems
Passive fire protection (PFP), despite its name, is always at work.
Based on compartmentation of fire and preventing collapse through structural fire resistance, when properly installed and maintained, your building’s passive fire protection can save lives and assets, and the building itself.
Structural fire protection
Structural fire protection guards essential structural components (such as structural steel and joint systems) from the effects of fire.
This is accomplished with a fireproofing material (spray-on thin-film intumescents, endothermic materials like gypsum-based plasters and cementitious products, mineral wool wraps and insulation, and fireproofing cladding) or building the structure out of concrete products.
“When structural fire protection is designed and applied properly, the building’s structural integrity should be maintained when it’s exposed to fire.”
Compartmentation
Fire barriers, firewalls, fire partitions, and smoke barriers are all included in compartmentation.
Fire barriers include fire-rated walls, floors, and ceilings (often made of concrete, combination wood, gypsum, or masonry). These barriers are used to limit the spread of fire in a building and allow safe egress. Walls extend from a fire-rated floor to the fire-rated ceiling above, and continue into concealed spaces for full protection.
“These walls are built structurally stable, so even if there is collapse of a building on either side of the wall, the wall will remain standing,” .
The importance of properly maintained fire barriers. “Rated walls and floors protect evacuation routes from fire and smoke migration,” adding that the window of evacuation time is maximized when the barriers effectively contain the fire.
Opening protection
Fire doors and windows are installed in an opening of a fire barrier to maintain its fire resistance. Doors, builders’ hardware, and frames work together to form an effective smoke and fire barrier.
Fire-rated glazing/glass and framing are tested as a complete assembly that maintains the protection of the fire barrier. Additionally, fire and smoke dampers (often used in duct systems) are considered “opening protection” and complete the fire barrier where air ducts penetrate fire-rated and/or smoke-resistant assemblies.
Firestopping materials
These materials are used to limit fire spread through penetrations in a fire barrier. “It’s not uncommon to see a fire barrier penetrated during a minor building alteration, and then the penetrating item isn't protected by firestopping,can leave hidden holes in the barriers as they perform their services.
If the penetration isn’t properly sealed and protected with an appropriate fire-stop system, the fire barrier is rendered less effective, and fire will spread beyond the compartment of origin.
Other areas of PFP that warrant mentioning are cable coating (the application of fire retardants to wire and cable), joint systems (which include changes in direction between fire-separating elements and the spaces surrounded by those elements), and perimeter fire barriers (which deal with the perimeter of the floor and the exterior curtainwall).
While passive fire protection can successfully prevent the spread of fire, it’s important to note that most professionals recommend redundancy in fire protection.
In other words, a fire-sprinkler system, alarms and detection systems, and occupant education, in conjunction with passive fire-protection systems, are a safer, more balanced approach to protecting your building and the people inside.
Codes and Testing/Certification
A potentially complicated aspect of PFP is the bevy of codes and regulations involving each component of a fire-protection system. It’s vital to understand that a particular product (a window, for instance) isn’t fire-rated in and of itself - it’s rated only when it’s installed properly and used in a fire-rated assembly or tested system.
unless you’re missing your building’s construction documents, knowing what’s required (and where) isn’t difficult. “On construction documents, fire-resistance-rated walls are indicated adding that the life-safety drawings included with construction documents make it clear where you need fire-rated components.
Products within PFP systems are tested and certified to standards written by accredited organizations