Fire Safety Engineering for last-mile logistics

One of the main applications of the Performance-Based approach in the fire safety field is evaluating the fire resistance of structures, especially in fire prevention projects for steelwork buildings. In this article on Fire Safety Engineering, we will see how FSE helps support the development of fire protection systems in the context of last-mile logistics building projects. We will delve into topics such as ventilation systems sizing and defining fire scenarios considering how the Heat Release Rate (HRR) changes depending on the installation of sprinkler systems.

1. FSE for steelwork buildings

The rapid expansion of e-commerce has contributed to accelerating the development of last-mile logistics. More and more frequently, new buildings mainly made of steelwork are constructed to store large quantities of goods. Thanks to its potential and the use of CFD simulation models, Fire Safety Engineering makes it possible to develop fire prevention projects as alternative solutions. Logistics centers are highly challenging environments due to the high density of stored material and the presence of advanced systems for active fire control and, consequently, a very sophisticated fire prevention strategy.

2. How to evaluate the fire resistance of structures

One of the main steps in designing fire protection systems for steelwork buildings is evaluating the fire resistance of structures. For this to happen, it is necessary to define the loads of the structure considering the thermal contribution due to a possible fire. The natural fire curve (t-T curve) determination is one of the most relevant features of the FSE application. The t-T curve represents the evolution of hot gas temperature on structural elements over time. Thanks to this data, the structural engineer can assess the load-bearing capacity of the building from a static point of view in case of fire.

3. Sizing the ventilation systems using FSE

Smoke and heat disposal systems inside a building can be of two types: natural or mechanical. Conformal solution sizing is developed by applying UNI 9494 1 and 2. When the floor area of the building under analysis is outside the scope of the UNI 9494 reference standard, sizing can be done through the Performance-Based approach. In this case, the ventilation system sizing is made through an alternative solution. The development of sizing through an alternative solution requires a strict definition of fire scenarios: the goals are to safeguard human life and maintain livable conditions when the rescue teams arrive.

4. Sprinkler systems: why they are important

The reference standard requires a fire control or mitigation system to be in place in high-fire load environments. The purpose is to minimize horizontal spread, reducing the probability that ignited material may ignite nearby materials. Among the various active fire control systems, sprinkler systems are the ones to fulfill this function. In buildings hosting last-mile logistics centers, the typically installed sprinkler systems are of the ESFR type.

5. The Heat Release Rate (HRR)

One of the main aspects of designing fire protection systems using a Performance-Based approach is the fire characterization through a proper choice of the Heat Release Curve or HRR. You can choose the Heat Release Curve on the basis of experimental data or according to references from the technical literature. The HRR curve allows you to consider the presence of active fire control systems.

6. Conclusions

Fire Safety Engineering plays a crucial role in fire prevention projects for steelwork buildings, which today are more common due to the increase in last-mile logistics. The Performance-Based approach allows fire safety projects to be developed as alternative solutions, meeting the needs of increasingly challenging contexts and ensuring the desired levels of safety.