What Are The Main Types Of Suppression Systems?
There are six main types of fire suppression systems that are installed based on the nature of the industry. 1. The Wet Sprinkler System Wet sprinkler suppression systems are an…
is essential is because of the time it provides for evacuation and rescue operations. In the event of a fire, occupants on higher floors may have limited means of escape. Fireproofing in high rise buildings that use fireproofing materials and techniques can delay the spread of flames, allowing more time for people to evacuate safely and for emergency responders to reach the affected areas.
According to the 2021 International Building Code, a high-rise building is any structure with an inhabited floor more than 75 feet above the lowest level of fire department vehicle access. Due to their height, high-rise buildings present unique challenges for emergency services. Issues such as evacuating occupants, getting responders and equipment to the affected floor, suppressing the blaze, ventilating the building, and maintaining communication with the command center all make these situations particularly difficult to manage.
Fireproofing in high rise buildings present unique challenges. Unlike low-rise buildings, high rise structures have limited evacuation options and are more susceptible to rapid flame spread. Fireproofing in high rise buildings plays a crucial role in protecting the lives of the occupants and preventing the loss of property.
The regulations require fire-resistant structures to ensure structural safety, compartmentalization, safe egress, and protection of gaps in construction. They also mandate the use of materials with low flame spread and smoke development, as well as an additional stairwell and dedicated elevators for emergency services.
According to the fire code, active protection devices must be in place, including automatic sprinkler systems, standpipe systems, extinguishers, alarms, smoke control systems, smoke and heat vents, department connections, pumps with outage protection, and standby or emergency power sources.
Type I and II buildings utilize noncombustible materials for most parts of their structure, though there are some cases where exceptions apply.
Type III buildings are characterized by walls made of flame-resistant material and the interior components can be made of any material allowed by the code. Wood framing and sheathing that has been treated to make it flame retardant is permissible in exterior walls with a rating of 2 hours or less.
Type IV construction involves the use of building elements such as mass timber or noncombustible materials that have a flame-resistance rating.
Type V construction is one in which the materials used for structural components, external walls, and internal walls are allowed as per the code.
The necessity to provide passive protection in high rise buildings became apparent after the tragedy of 9/11. Subsequently, the International Code Council’s Board of Directors formed an adhoc committee – the Terrorism Resistant Building (TRB) committee – to review and suggest revisions to the building code to reinforce the construction of buildings in order to make them more resistant to terrorist attacks. It could be debatable whether the building code should be amended in this regard, nevertheless, the task group did create and propose tougher standards for high-rise edifices.
The TRB’s suggestions which were adopted in the 2009 International Building Code to regulate High-Rise Buildings (Section 403) included:
• An elevated demand for SFRM protection for structures more than 420 feet from a fire department vehicle access, plus more attention to inspection.
• A separation of close-by exit stairways.
• A necessity for impact resistance for key escape shafts for safety.
• An extra exit stairway for the evacuation of building occupants.
• An additional five service elevators for use by first responders during fires.
Aside from the regulations in Section 403 of the International Building Code, there are other criteria in the code that must be fulfilled for materials to be granted flame-resistant ratings, regardless of the height of the building. The section of the code on Flame-Resistance Ratings of Structural Members (704) has specific rules that must be followed when installing SFRM. These include:
1.The implementation of the SFRM (Sprayed Fire-Resistive Material) must be in accordance with the list, taking into consideration but not limited to the least layer thickness and dry density of the material, the way of application, the state of the substrate surface, and the utilization of bonding adhesives, sealants, reinforcing or other components
2. SFRM installation must comply with the manufacturer’s instructions.
3. The substrate to receive the SFRM must be free of dirt, oil, grease, release agents, loose scale, and other conditions that prevent adhesion.
4. When applied over primers, paint or encapsulants other than those specified in the listing, the steel substrate shall meet certain dimensional requirements and minimum bond strength requirements.
5. The temperature minimum during and after the SFRM application.
6. The SFRM that has been dried shall not exhibit cracks, holes, delamination, or any exposure of the substrate.
The Chapter 25 of the IBC contains requirements for the use of gypsum board. According to the ASTMC 1396, “Standard Specification of Gypsum Board”, Type X gypsum board is frequently used in flameresistance-rated construction.
In accordance with the provisions of Section 1705.15 of the IBC, special inspections of SFRM, and IFRM (Intumescent flame-resistant materials) are required during and after installation. Special inspections of SFRM are performed in accordance with the detailed provisions contained within the section. This section provides information on the surface preparation, temperature requirements in advance of and after application, and thickness, density, and bond strength measurements.
In accordance with AWCI 12-B ‘Standard Practice for the Testing and Inspection of Field Applied Thin-Film Intumescent Materials; An Annotated Guide’, special inspections of IFRM are required to be conducted in accordance with Section 1705.16. These items do not relate to the methods of application, but they are critical in ensuring the products are installed properly.
Intumescent coatings, which are epoxy-based, paint-like mixtures, can be applied to a primed steel surface. When exposed to high temperatures, these coatings swell to many times their original size, forming an insulating layer that prevents the steel from succumbing to the heat.
These coatings can grant protection up to four hours. Intumescent coatings are an effective way to maintain an architecturally pleasing structure while also meeting code rating requirements.
Unfortunately, intumescent coatings are costly, costing several times more than other spray-applied systems. The price of intumescent coatings increases with an increased fire rating. These coatings are usually only used on exposed steel. It is common to have a combination of systems in one member, such as spray-applied fibrous systems on the hidden parts and intumescent coatings on the exposed parts.
The primary differences in high-rise building protection, as discussed in this article, involve the additional passive and active measures required. The fireproofing process is similar to that of other buildings, though longer rating periods are necessary due to the challenges of evacuation and suppression in tall structures.
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