Sensing Pressure in Fire Suppression Systems
Welcome to “The Pressure to be Perfect” blog from AdVanced Sensor that discusses pressure measurements that are made every second of our lives and without our knowledge. This blogs discuss the many applications and industries that use pressure sensors to measure flow, force, and pressure.
Take this somewhat common circumstance. With all companies, safety is always a priority. So most of us engineers have been annoyed by the monthly fire drill. You know…you are working diligently on your latest development program and then suddenly the nearly ear drum rupturing sound of the fire alarm catapults your from your seat and out to the freezing cold everyone marches; aligned in single file. This got me thinking about pressure measurements in fire systems.
Notably there are three basic solutions to mitigating fire in buildings. Passive, Pressurization, Exhaust and Opposed Airflow The pressurization method is employed in high-rise construction to pressurize stair enclosures and provide zoned smoke control; see diagram at right with a fire source on the second floor. Once the fire is detected, fans are energized creating positive pressurization (yellow) of the stairwell; this pressure is a higher pressure than the floor areas that empty into the stairwell. This higher pressure pushes smoke back into the floor space and does not allow smoke to enter the stairwell area. Secondarily, zoned smoke control utilizes “Negative Pressure” to pull smoke out of the area of fire origin to a vent by opening exhaust dampers into the primary exhaust shaft and eventually out the building. Both the positive and negative pressures are controlled by variable speed fans and are fed signals from differential pressure sensors that are located within the stairwell and exhaust shaft