Heat and smoke vent

The flue is an essential element for preventive fire protection and the protection of persons. During a fire, mostly heat, smoke and hot gases. Contrary to previous approaches, the smoke exhaust from the heat vent is to be distinguished. He directs smoke produced in a fire, from the interior of a building from the outside.

If for reasons of fire resistance of buildings is also the heat exhaust of interest, additional measures must be taken in general to the flue. Because the combustion process boosts thermal effect. These thermals means that the products of combustion (flue gases) as so-called Plume rise and form a smoke layer below the basement ceiling and the roof.

The objectives in the use of smoke exhaust system are manifold. They are used for example to people to keep escape routes smoke emission or time- limited smoke-free or to allow firefighters the fire attack.

Mechanical and natural systems

We distinguish mechanical and natural ventilation systems: Automated systems lead from the combustion products have fans. In natural systems, the combustion products through openings reach ( roof or wall openings ) or windows safely to the outside.

Both types of systems have in common that without inflowing air is no effective removal of harmful gases. The slipstream can be realized through openings in the exterior walls or fans. Here, it is usually required that inflowing air eddying ( impulsarm ), ie with low flow rates (<1 m / s) introduced. For mechanical ventilation systems is particularly important to ensure that the produced by the vacuum suction is not too high in the room and the door opening forces ( in the escape routes ), including the effect of the door closer does not exceed the limit of 100N.

A smoke control areas to be protected is generally achieved only by special smoke control pressure systems (RDA ) systems in conjunction with smoke extraction systems.

Smoke extraction and combined smoke and heat extraction

In general, a distinction is made between smoke extraction devices ( orifices ) (RA ) systems and smoke and heat ventilation systems (RWA ). Protection target and mode of action must be specified in the building permit with a valid fire detection or the corresponding special building regulations. Prüfsachverständige or expert shall verify that the requirements with the assembled state.

SHE systems are listed as requiring inspection predominantly safety-related systems in accordance with the inspection regulations of the countries in the valid Bauregelliste 2013. If required as a protection objective a low-smoke layer height, then calculate this example DIN 18232-2:2007-11 (national ) or DIN 18232-5:2012-5 ( mach ) or shall be demonstrated with special engineering methods (Smoke simulation).

The smoke control systems shall be installed according to applicable components Bauregelliste over regulated building with approved or marked ( CE marking with DIN EN 12101-1 to -10 detection). Performance shall be submitted in testing at the moment.

The specific hydraulic conditions at the object and in systems engineering must be considered in the design, dimensioning, Zoning and control of the systems.

Release of the system

The plants can be manually and / or automatically triggered by fire detectors or thermal trigger or by a fire alarm system. The triggering of smoke control systems shall be possible by hand ( smoke or thermal detectors ) can also be made depending on the requirements of the protection target by automatic trigger. Manual release are attached to a secure, easily accessible location usually on walls and require in case of fire, the smashing glass. In general, a control point on the ground floor and on the top of the stairs is required ever. Thermal detectors can be designed as a glass vessel, and are usually the individual RWA device ( NRWG ) to ordered. Smoke detector with optical sensors are for example mounted at the top of stairwells and release smoke at the RA system from.

The state of the system must be clearly identifiable and specific knowledge about the course of the fire if necessary, from this be able to modify (RESET) at a central location or to the trigger points for the fire department.

Also, during a power failure, the RWA-/RA-Anlage must remain functional. This can be accomplished with electrical systems through a safety power supply, directly in the Control Center. For pressure gas powered equipment, the system must fail secured by compressed gas cylinders or central compressed air systems as RWA - pressure air tank or special compressed gas cylinders (CO2), are supplied.

During the emergency release existing ventilation switches may not work ( priority control ). It may be permitted to waive the secured cable laying, if, in case of fire, the system is at an early stage and safely opened or operated by suitable smoke detectors that monitor the entire range of cable route and this operation can be maintained over the required operating time (possibly locking device ). The failure or a fault in the system are to be able to register in time to take appropriate action before an alarm event.

Legal framework

The layout and design of smoke exhaust devices of stairwells sets the valid state building code, MBO or a special construction ( VStättV ) that currently usually depending on special construction with a geometric free area of ​​the flue opening of at least 1.0 m at the top. Special features are possibly to be observed in building permits and to the valid fire protection concepts or certificates for fire protection for each property.

Standardization

In the context of European harmonization, the standard series EN 12101 applies ( expands the German DIN 18232 ). Due to the relevant harmonized product standards, the products may be marketed under the Construction Products Directive and CE marking:

• EN 12101-1: Smoke and heat control systems - Part 1 Specification for smoke barriers
• EN 12101-2: Smoke and heat control systems - Part 2: Specification for natural smoke and heat exhaust ventilators
• EN 12101-3: Smoke and heat control systems - Part 3: Specification for powered smoke exhaust ventilators
• EN 12101-7: Smoke and heat control systems - Part 7: Smoke extraction ducts
• EN 12101-8: Smoke and heat control systems - Part 8: Smoke control dampers
• EN 12101-9: Smoke and heat control systems - Part 9: Control panels
• EN 12101-10: Smoke and heat control systems - Part 10 power supply

The classification of these products from the results of fire resistance tests (temperature / time) is based on the standard series EN 13,501th

The configuration of smoke and heat exhaust ventilation systems is carried out with

• Building Services
• Fire protection