Pressure differential system (PDS)

Pressure differential system are permanently installed devices that prevent the penetration of smoke through controlled overpressure in the areas to be protected - usually vertical escape and rescue routes (protected staircase) in high-rise buildings. Smoke control in escape and rescue routes is an important requirement for the evacuation of people and firefighting measures by the fire department over a longer period of time. The following criteria play an important role:

• The pressure gradation (pressure +) between the protected and the unprotected area with closed doors
• Maximum door opening force of ≤ 100 N
• Air flow rate of ≥ 1 m/s; ≥ 2 m/s when the doors are open, from the area to be protected via the air release path to the outside

Outside air

The outdoor air is taken directly from the outside and must be protected against the intake of smoke, flammable gases and steam. The outdoor air supply must be monitored by means of duct smoke detectors.

Air distribution

In order to minimise flow or pressure losses in the staircase, outdoor air is blown in through a shaft on several levels (e.g. every third floor) for taller buildings.

Pressure control

The pressure relief damper is a device for the release of excess compressed air from an overpressure area (staircase). This device is usually located at the top of the staircase. In pressure control mode (i.e. when the staircase doors are closed), the excess air should be discharged into the atmosphere via the pressure relief damper. Mechanically or motorised pressure controls are possible.

Air release

Features (such as shafts and facade openings) through which the hot smoke can escape from the accommodation or another area not under pressure from the building. Approved products must be used in the air release (e.g. certified smoke control dampers). Smoke can be released via the shaft in the lobby or via the facade opening, e.g. in the accommodation.

Belimo PDS pilot system for testing and demonstration purposes

Pressure differential systems are becoming increasingly important for the safety of modern buildings. Belimo is investing in an internal PDS test environment as part of its preventive fire protection system. This allows new solutions to be realistically tested and demonstrated. Both a system with a pressure relief damper (barometric damper) and a variant with a motorcontrolled pressure relief damper can be demonstrated. We focus on custom motorisation for specific dampers but also on acquiring relevant physical parameters with our sensors. Actual value signals are fed to intelligent controllers, which then regulate and control the damper actuators and the dampers. Training and practical experience are another focal point for different target groups such as public authorities, specialist planners, systemintegrators, investors or maintenance companies. The Belimo development and sales staff also use the test environment as a test facility or for training and further education.