“Safety Exit”: The Life Timer in Buildings

Imagine this: You’re dealing with urgent work in a stylish office, enjoying a hearty breakfast at a homestay with your loved one, or visiting an exhibition in a historic building with your family. Suddenly, you hear piercing alarm sounds, and at this moment, you and everyone around you are thrown into endless panic. You follow others rushing toward the “safety exit,” “evacuation route,” or “emergency exit.” What I want to tell you today is the importance of specific exit routes to everyone’s life support system.

Chapter 1: Time is Life – The Underestimated Time Gap

When we watch dangerous scenes in movies, have we ever put ourselves in the scene and thought: hearing the alarm → reacting mentally → taking action to evacuate, which is a linear behavior, and it would take only a short time for us? But in reality, when danger really occurs, we will be at a loss, and our minds may even go blank. Studies tell us a key figure: 2 minutes and 38 seconds. This is not the time to run to a safe area, but the average time from perceiving danger to actually starting effective action: cognitive delay, confirming information, looking for companions, and overcoming initial hesitation.

But this is just the beginning. Imagine:

• An elderly person with limited mobility living in a high-rise building.
• A student who is awakened from a nap at school, panicking and at a loss.
• A mother in a shopping mall carrying shopping bags and pushing a stroller.
• People in an office building who lose their way due to thick smoke and toxic gases.
• Parents in a building looking for their lost children.
• A crowd in a stairwell panicking and falling.

The superposition of all these “realistic factors” will lengthen the safe evacuation time by 140% or even more. In the face of disasters, acknowledging the time redundancy and ensuring that the available time is greater than the required time is the guarantee of life safety. According to specifications such as Germany’s DIN 18095 and Britain’s BS 9999, it is mandatory that the fire resistance rating of evacuation routes must far exceed the theoretically calculated time, with a safety time reserve of at least 50% or even 100%. Especially for special places like hospitals, the fire resistance rating of evacuation routes is 120 minutes. This means that even if part of the main structure of the building collapses, this life passage must stand independently like Noah’s Ark, striving for every second of life for the most vulnerable.

Chapter 2: The Dual Souls of Safety Exits – Escape and Rescue

A safety exit is not just a simple “exit.” It is a life support system that incorporates the elaborate design of professionals and has a dual mission:

Escape Route:

This is the core mission. It is a pre-set, protected, and continuous path (horizontal corridors + vertical stairs/ramps), ensuring that people at any location in the building can reach the final safe point (usually a designated assembly area outside the building) by their own strength.

Rescue Route:

An equally important mission. This path is also a battlefield channel for firefighters to charge forward in the opposite direction! Imagine: when the crowd is rushing out, firefighters equipped with heavy gear need to quickly and safely break into the core of the fire to extinguish the fire and conduct in-depth search and rescue. If the stairwell is blocked by debris, engulfed by thick smoke, or becomes ineffective due to structural problems, not only will the people inside be trapped, but the rescue forces outside will also be blocked – forming a fatal “island effect.” Therefore, a good safety exit directly affects the efficiency of fire-fighting tactics and the safety of rescue personnel themselves.

Chapter 3: Building the “Passive Fire Protection System” – The Core of Safety Exit Composition

Different from the Active Fire Protection, which includes detection, sprinkler, and smoke prevention systems, the core function of the Passive Fire Protection is that without external energy or manual intervention, through the inherent properties of building materials, components, and structural design itself, it can actively delay the spread of fire and smoke when a fire occurs, protect key parts of the building, and strive for crucial “golden time” for personnel evacuation and fire rescue.

Compartmentation：
The passive fire protection system uses the highest-grade Class A fire-resistant materials such as firewalls, fire-resistant floor slabs, and fire-resistant ceilings to divide the building into independent fire compartments. Its core function is to restrict the fire to the ignition unit (such as a room or a floor) under certain conditions, preventing the fire from spreading and causing heavy casualties and losses.

Protecting Lifeline Facilities:
In order to ensure that the positive pressure air supply system (+20-30 Pa) continuously injects fresh air into the safety exit and blocks the infiltration of external toxic smoke, the integrity of the structure itself must be guaranteed. Sealing through holes (gaps in cable pipes and air ducts) and cooperating with the self-closing function of fire doors can significantly slow down the spread speed of fatal smoke. Key systems such as smoke exhaust ducts are equipped with fire sleeves or wrapped with fire-resistant materials to ensure their continuous operation in a fire.

Structural Fire Protection:
In a fire, if the load-bearing structures (steel, beams, floor slabs) far from the safety exit lose their load-bearing function prematurely (insufficient fire resistance rating R), it may cause collapse in local or connected areas. If this destroys the safety exit or deforms and blocks it, making it impassable, it will lead to irreversible consequences. Therefore, the fire resistance performance of the overall structure of the building is also a guarantee for the safety exit, reducing structural damage to the building after the disaster and lowering reconstruction costs. Fire-resistant materials and fire-resistant panels are used on the supporting structures to improve their load-bearing fire resistance rating.

How long does this “passive fire protection system” need to last?
Answer: It depends on the usage scenario: A street corner cafe? It may only need partition walls and fire doors with a fire resistance limit of 30 minutes. A large comprehensive hospital? Its core evacuation staircase walls, floors, and fire door systems may need to reach 120 minutes!

Chapter 4: Illuminating the Escape Route – The Morality and Laws of Design

Life is the most precious thing in the world, so fire safety cannot rely solely on recommendations; it must have mandatory requirements. For example, the European Accessibility Directive (2010/48/EU) stipulates that true safety must cover every part of the building.

Physical Access:

• The Width of Life: To meet the needs of people with limited mobility, such as wheelchair users and those on rescue stretchers, for normal passage, the width of the passage must be at least ≥90cm, and in practice, it needs to be wider.
• Safe Corners: To reduce the risk of stepping empty and collision during a panic escape, high-visibility warning signs need to be set at the corners of stairs and passages.
• Safety Support: The escape route is not always smooth, and there are usually injured people and people with limited mobility. Therefore, the slope, handrails, and space must be strictly regulated in the design to provide support for escapees.
• Dark Navigation: Pave a bright route for the visually impaired, and design a tactile paving system (with convex point spacing ≤50mm) linked with high-brightness emergency lighting.

Cognitive Access:

• Clear Signage: Use universal images, high-contrast colors, and concise text to ensure quick understanding of information, reducing the time spent thinking and thus saving escape time.
• Refuge Floors/Safe Zones: Super high-rise buildings are very spectacular, but they face more severe tests in the face of fire. Setting up refuge floors with independent fire and smoke protection provides a temporary safe haven for people who cannot evacuate immediately (such as people on the top floor and critically ill patients).
• Controlled Use of Elevators: Under strict fire and smoke protection and firemen’s control, specific elevators are allowed to be used for evacuating people with limited mobility, which is a key part of the escape route in complex buildings (such as hospitals and nursing homes).

Conclusion: Safety – The Timer of Life

After saying all this, what I actually want to tell everyone is: A safety exit is not just a sign stuck on the wall, nor is it that ordinary-looking door in the corridor. Though it may seem unattractive, monotonous, and less convenient or comfortable to walk through than an elevator, and people usually don’t pay much attention to it, everyone must remember its essence (the route and direction).

A reliable safety exit is a timer that extends life safety. It uses the most rational rules, the strongest materials and structures, and the most inclusive design to resist the most primitive fear of disasters. It acknowledges human weaknesses (delayed reaction, panic) and reserves life for the most vulnerable. It requires investment today, only to exchange for hope at some unknown moment in the future.