Views: 860 Author: Site Editor Publish Time: 2025-09-08 Origin: Site
### Introduction: Elevators, Smoke Curtains, and Fire Curtains
In modern building design, elevators are essential for vertical transportation. However, during a fire, an elevator shaft can act like a chimney, rapidly spreading smoke and fire between floors. This creates a significant life safety hazard. To mitigate this risk while still potentially allowing for the use of elevators for firefighter access or occupant evacuation, a system involving **smoke curtains** and **fire curtains** is employed.
This system is not about the elevator itself, but about creating protected zones around elevator lobbies and hoistways to compartmentalize the building and manage the movement of smoke.
#### 1. The Problem: Elevator Shafts in a Fire
* **Stack Effect:** An elevator shaft is a vertical void. Heated smoke from a fire will naturally rise and be drawn into the shaft, spreading toxic gases and superheated air to every floor it connects to.
* **Compromised Evacuation:** Smoke inhalation is the leading cause of fire-related deaths. Smoke spreading through elevator shafts can quickly make stairwells—the primary means of evacuation—unusable.
* **Impeded Firefighting:** Firefighters need clear, smoke-free paths to access the fire floor and rescue occupants. Uncontrolled smoke spread hinders their efforts.
#### 2. The Solution: Compartmentation with Curtains
The core principle is **compartmentation**—breaking a building into smaller sections to contain fire and smoke. Smoke and fire curtains are deployed to create these barriers dynamically around elevators.
* **Fire Curtains:** These are barriers rated to withstand fire for a specific period (e.g., 1, 2, or 3 hours). They are typically made of fiberglass or other fire-resistant materials and are designed to prevent the spread of flame and radiant heat. They are often used to protect the opening of the elevator hoistway itself.
* **Smoke Curtains:** These are barriers designed primarily to contain and control the movement of smoke. They are made of a flexible, lightweight material (often fiberglass or silicone-coated fabric) and do not have a fire-resistance rating. Their goal is to create a "smoke reservoir" to keep escape routes clear.
#### 3. Key Locations for Curtains in Elevator Systems
**A. Elevator Lobby Smoke Curtains:**
* **Location:** Instated at the entrance to an elevator lobby, separating the lobby from the adjacent corridor or open floor plan.
* **Purpose:** To contain smoke within the elevator lobby area, preventing it from spreading into office spaces or corridors that serve as exit paths. This allows the elevator lobby to act as a temporary smoke reservoir.
**B. Elevator Hoistway (Shaft) Opening Fire Curtains:**
* **Location:** Installed at the perimeter of the opening where the elevator car enters each floor (the hoistway door opening).
* **Purpose:** To provide a fire-rated barrier that seals the vertical shaft when needed. If a fire breaches the elevator doors, this curtain deploys to protect the integrity of the shaft, preventing fire from entering it or from erupting out of it onto other floors.
**C. Perimeter Gap Smoke Curtains:**
* **Location:** Around the edges of the elevator car or at the floor opening.
* **Purpose:** To seal the small gaps between the moving elevator car and the hoistway wall. This prevents "piston effect," where the movement of the car can push smoke from a fire floor into other parts of the building.
#### 4. How the System Operates
The deployment of these curtains is integrated with the building's fire alarm system.
1. **Detection:** A smoke detector or heat alarm on a specific floor is activated.
2. **Signal:** The fire alarm control panel receives the signal and initiates a sequence.
3. **Deployment:** The control panel sends a signal to the release devices (e.g., fusible links, electromagnetic holders) on the affected floor(s).
* **Smoke Curtains** in the lobby of the fire floor descend, containing the smoke.
* **Fire Curtains** at the hoistway opening on the fire floor may deploy to seal the shaft.
* Curtains on other floors may also deploy preemptively to protect the shaft and safe areas.
4. **Elevator Recall:** Simultaneously, the fire alarm system triggers **Phase I Emergency Recall**, sending all elevators to the designated ground floor (or alternate safe floor) to prevent occupants from using them during the fire.
#### 5. Important Considerations and Standards
* **Firefighter Use (Phase II):** After recall, firefighters can use a special key to take control of an elevator (**Phase II Operation**) to access the fire floor. The smoke and fire curtains are critical here, as they help maintain a tenable environment in the elevator lobby for firefighters to stage their operations.
* **Occupant Evacuation Elevators (OEEs):** In very tall buildings (skyscrapers), specialized elevators are designed for evacuation during a fire. The use of smoke and fire curtains around these systems is even more critical and is governed by strict codes (e.g., ASME A17.1/CSA B44, ICC IBC).
* **Codes and Standards:** Installation must comply with local building codes and international standards like:
* **NFPA 80:** Standard for Fire Doors and Other Opening Protectives.
* **NFPA 105:** Standard for Smoke Door Assemblies and Other Opening Protectives.
* **International Building Code (IBC)**
* **Testing and Maintenance:** Like all life safety systems, these curtains require regular inspection and testing to ensure they deploy correctly in an emergency.
### Summary
The integration of **smoke curtains** and **fire curtains** with elevator systems is a sophisticated life safety strategy. It allows architects to design open, aesthetically pleasing spaces while ensuring that when a fire occurs, invisible barriers deploy to:
1. **Contain Smoke** to its area of origin.
2. **Protect the Elevator Shaft** from becoming a conduit for fire and smoke.
3. **Maintain Tenable Conditions** in escape routes and staging areas for firefighters.
4. **Enable Safe Emergency Operation** of elevators by first responders.
This system is a vital component of modern high-rise building safety, protecting both lives and property.