The fire-resistive construction method will involve the designing and construction of fire resisting elements such as firewalls, fire barriers, fire partitions, smoke barriers, and smoke partition. The purpose of these components is to restrict the spread of fires between building units. Firewalls should be continuous from the foundation to the building roof, and it should have sufficient stability to resist the collapsing if the construction on either side collapse.
Firewalls used to separate a structure into multiple units, which reduce the severity and consequences of fires by limiting the fire in one area and prevent the spreading of the fires to other structures area. Fire barriers and partitions are interior walls used to sub-divide the portion of a building that concealed by firewalls into smaller areas. Fire barriers and walls will be supported by the adjacent structure.
They will prevent the heat flows within the area concealed by firewalls, which gives the residents sufficient time to evacuate. The purpose of using smoke barriers is to restrict the smoke movement and fires. Similarly, smoke partitions used to limit the movements of smoke but not necessarily to prevent the spread of fire.
Fire-resisting elements will significantly reduce the impact of fire on a building. Fire-resistive construction of a structure will restrict the fire, which reduces the property damage. Moreover, it is providing occupants with sufficient time to leave the structure by containing the fire in one area and not allowing it to spread.
Fire-resisting elements should have a specific resistance rating, and it should be tested to verify this property. Fire-resistance rating is the duration at which a building element, component, or assembly maintains the ability to confine a fire, continues to perform a given structural function, or both.
The rating will be different according to structure importance. It can range from 2 hours for storage facilities and factories to 4 hours for high hazard facilities. IBC code (international building specification) provides a table showing the required fire resistance for different groups of structures.
Firewalls usually are thicker than typical walls. Also, it is designed to remain stable even if the adjacent structures collapse. the designer of firewalls shall ensure the following points:
- Other forces affecting the wall include the collapse of an adjacent roof structure or adjoining buildings.
- Effects of the thermal expansion of the adjacent structural steel or the wall itself.
- It should be designed as a non-loadbearing member. It should carry its own weight only. however, the structural framing within a tied firewall can be loadbearing.
Figure 2 (no firewall)
Figure 3 (firewall)