How Pressurized Stairwells Keep You Safe

Picture this: You wake up with a start to the sound of crackling flames and the screech of an alarm. A nearby apartment room has caught fire, and you need to get out before it spreads to the rest of the building. You go through the motions; grab the keys, check the door knob, keep low to the ground. You head to the stairs and make your way outside to safety. 

In modern high-rise buildings, staircases are designed to protect you in the case of a fire. Staircases have a higher fire rating than the rest of the building, which means the stairs aren’t as likely to catch fire. Additionally, stair pressurization systems utilize clean air from outside to push smoke (which naturally rises) back onto the floors. This helps to make sure the smoke doesn’t fill up the stairwell so residents can breathe easier as they are making their way outside. 

Stairwell pressurization systems are made up of three main components: 

1. Fan/stairwell controller
2. Differential pressure transmitter
3. Damper actuator

The fan for the stair pressurization system doesn’t need to run all the time. That would waste energy and increase building costs. Running the fan continuously may also result in overpressurization (excessive positive pressure) on the fire exit door, preventing the door from opening. Therefore, the fan needs to be notified when to turn on in case of emergency. 

When the fire alarm activates, a signal which starts the system is sent out, turning on the fan and differential pressure transmitter. The fan brings in fresh air from outside, while the transmitter monitors the differential pressure inside the stairwell and relays information to the damper so that it knows to remove excess air. These devices working together keep fresh air pumping into the building and the stairwell clear of smoke.

Series MSX Magnesense® Differential Pressure Transmitter

The Dwyer® Series MSX Magnesense® differential pressure transmitter has the high accuracy pressure measurement required for exacting control. It uses air flow and velocity measurement to provide a linear pressure or velocity output and eliminates the need for different instrumentation by using the square root capability for calculating flow. Additionally, this product can be used to notify both a local alarm and control system via dual voltage and current output signals. 

When it’s critical, it has to be Dwyer.

In addition to allowing for a safe exit from the building, the pressurized staircase also helps provide a path clear of smoke for firefighters when they arrive. Dwyer® products are used in many critical applications around the globe, in many different industries. From building control to medical applications, Dwyer® products play a vital role in keeping people safe.

If you have any questions about selecting products for your application, the Dwyer Applications Engineers are available to assist by phone at (219) 879-8868 x6402, or by email at