EP1440242B1 - Smoke protection for rooms - Google Patents

Abstract

The fire smoke disperser has a by-pass flow generated around a building by an axial ventilator (2) using flaps (3.1) which are self closing and which open under a predetermined overpressure in the escape path. Compression springs keep the flaps closed until a set overpressure to provide an independent self regulating action. An Independent claim is also included for a method of keeping building escape routes smoke free using the ventilator system.

Description

The invention relates to a method and a device for the smoke-free escape and escape routes, taking into account allowable pressure differences in the air in adjacent corridors and stairwells with an overpressure system.

The smoke-free maintenance of necessary stairwells is an important prerequisite to allow an evacuation of people and a fire-fighting fire. Stairways and corridors are not fire rooms. Possible fire areas, on the other hand, are the adjoining units of use such as apartments, offices and the like. Machine smoke extraction always generates a negative pressure in the occupied space. This can cause fire smoke to be sucked into the stairwell or corridor from the utility units and make the escape route impassable. Using natural smoke extraction via smoke and heat exhaust systems increases the risk that the system will become ineffective with cooling smoke. The treatment of escape and rescue routes should therefore always be done in conjunction with a supply air fan in order to achieve an overpressure in the escape route with respect to the usage unit and thus to prevent the ingress of smoke into the escape route.

In case of fire, the pressure difference at adjacent standard doors of about 2m ² surface must not exceed an atmospheric pressure of 50 Pa, since the maximum permitted door opening force is 100 N. Otherwise, there is a risk that the door in case of fire by slender or disabled people is no longer open.

Basically, smoke protection pressure systems are to be distinguished for the prevention of a smoke entrance as well as rinsing plants. While pressure equipment has the task of completely preventing the ingress of smoke, a rinsing system is intended to dilute and remove penetrating flue gases.

In the following, essentially only printing plants are considered.
The system must generate a controlled overpressure in the escape route in case of closed doors. The overpressure can prevent the ingress of smoke as long as all doors are closed. If a door opens, pressure equalization takes place in less than a second, as the pressure drop propagates at the speed of sound. At this moment it must be ensured that the open door cross-section is flowed through at a sufficient speed. Depending on whether a corridor, a lock or the usage unit is connected, this required speed is between 0.75 and 2 m / s. In order to ensure the flow through the open doors, it is necessary that flow from the use units are available.
For the overpressure system, therefore, there is a requirement that in less than a second of the volume flow, which is only required to cover the leakage, it must switch over to the rated volumetric flow in order to achieve sufficient speeds in the open door.

• V= k x b x h 1,5 in m³/s mit
• V = Volumenstrom
• k: Faktor, der die Temperaturdifferenz berücksichtigt:
• k = 1,5 wenn sich ein Flur anschließt;
• k = 1,8 wenn sich eine Nutzungseinheit anschließt
• b: Türbreite in m
• h: Türhöhe in m

For the design applies:
According to the pattern high-rise guideline applicable in Germany, the volume flow for the door flow must be set according to the following equation:

• V = kxbxh 1.5 in m ³ / s with
• V = volumetric flow
• k: Factor taking into account the temperature difference:
• k = 1.5 if a corridor adjoins;
• k = 1.8 if a usage unit joins
• b: door width in m
• h: door height in m

• Bemessungsvolumenstrom = Volumenstrom für die Tür-Durchströmung + Leckagevolumenstrom über Undichtigkeitsstellen

This results for the dimensioning of the pressure system:

• Rated volumetric flow = volume flow for the door flow + leakage volume flow via leaks

For a common flushing system, according to the pattern high-rise guideline applicable in Germany, the volume flow for the door flow rate is 10,000 m ³ / h, correspondingly more for large staircases.

From DE 198 41 540 A1 a safety staircase is known in which in each lock an overflow opening, which are provided with valve flaps, is mounted above the door and which is ventilated by means of fan with overpressure at a predeterminable volume flow.
The document EP 0 995 955 A2 proposes a similarly functioning overpressure flap between a stairwell and a downstream room for maintaining the constant pressure in the staircase.
Nothing has been reported about the necessary extremely short reaction times, but both institutions seem to be very sluggish.

The documents DE 198 56 193 A1; DE 199 37 530 A1 and DE 199 37 532 A1 report rinsing systems with roof vents, which have a motorized setting device. Such smoke vents are susceptible to interference and maintenance; they require electronic or electrical assemblies with some probability of failure, have long response times and are weather dependent.

From the document DE 198 49 863 A1, a spring-loaded fire damper for a ventilation duct is still known. In the case of fire, a melting element should melt and then bring the flap from a rest position into an irreversible closed position.

Finally, DE 199 19 701 A1 discloses an overpressure flap which can be opened by air pressure, which receives a restoring moment via weights.

Previous controllable systems have a relatively unreliable and sluggish or weather dependent component arrangement with too high failure probability.

It is therefore an object of the invention to propose an improved method and apparatus which can guarantee a fast and weather independent steady state response of the system in less than a second.

The problem is solved according to the invention by the features of claims 1 and 9. Further developments of the invention are described in the dependent claims.

In a generic overpressure system, the solution according to the invention comprises a fan with Nachleitapparat and stabilizer and adjustable at a standstill blades integrated in a housing within a pressure device; in the centrally arranged housing, a drivable axial fan is installed centrally and a bypass with at least one self-closing flap is arranged around this housing. The bypass can also be arranged in another version of the invention in the vicinity of the overpressure apparatus, if from there there is a backflow possibility of the air to the suction side of the fan.

As a fan, a kennel-stabilized axial fan with electric drive is used. The characteristic curve stabilization prevents the typical demolition area in axial fans in the left part of the characteristic curve. This selection allows use in parallel operation.

The bypass has a preferably even number symmetrical individual flaps with preferably mutually perpendicular axes of rotation, wherein the flaps are designed so that they allow a bypass flow around the axial fan in the open state and the maximum pressure drop of the bypass flow in the pressure apparatus at the same size as the required overpressure in the Escape route is located and the flow-effective Areas of the flaps are designed in a certain ratio to the housing cross-sectional area.
Thus, a lightweight system with symmetrical flows and designs is proposed, a prerequisite for a quickly reacting self-regulating smoke control system and low maintenance.

The flap system is designed so that the opening or closing of the flaps by air force moments or by means of a mechanical train-pressure spring system is possible, the torque curve decreases in dependence on the increasing flap opening angle, and a stable operating point (intersection) of the course of Spring moments with the decreasing air force moments above 50 degrees, preferably formed at about 55 - 80 degrees flap opening angle.

When using multiple flaps, these preferably have mutually perpendicular axes of rotation; for even-numbered bypass flaps, the axes are positively connected; All flaps should have a direction of rotation in the same direction for the sake of simplicity and due to more favorable flow conditions. This makes it easier to set and calculate the moments and make the device simple.
Preferably, the axes of rotation of the flaps by means of bevel gears, preferably gears, positively connected.

The method for the smoke-free, in particular escape and rescue routes, taking into account allowable pressure differences of the air in adjacent corridors and stairwells with an overpressure system, therefore provides that a, preferably central housing in the pressure apparatus, with an axial flow through a bypass self-closing system of flaps is generated, it being ensured that the flaps open under the effect of a pre-definable overpressure in the escape route and release the bypass.
Thus, the smoke control system regulates automatically and continuously without external sensors or measuring devices.

The method also provides that the necessary moments for opening the flaps are adjusted so that the pressure forces or air forces of the flow in the bypass sufficient and the moments for closing the flaps are provided by a mechanical tension or compression spring system, said Intersection of both torque curves so determines the maximum adjusting opening area of the flaps, creating an automatically immediately acting control system as a result of pressure changes in the escape route, which opens with a reaction time corresponding to the max. Escape route height or escape route length (usually staircase), taking into account the speed of sound and closing with a reaction time proportional to the mass moment of inertia / restoring torque of the spring system of the flaps works.

• Alle Türen sind geschlossen.
  Zur Erzielung des gewünschten vorbestimmbaren Überdrucks wird nur soviel Luft in den Druckraum (Fluchtweg) gebracht, wie zur Deckung bauseitiger Leckagen erforderlich ist.
  Die Bypass-Klappen sind in diesem Betriebszustand offen.
• Eine Tür ist geöffnet.
  Sofern aus den nachgeschalteten Räumen eine Abströmung erfolgen kann, führt der Druckabfall zu einem sofortigen Schließen der Klappen und der offene Türquerschnitt wird nun in Richtung Brandraum durchströmt.
• Einsatz in Spülanlagen.
  Im oberen Teil des Treppenhauses wird eine Abströmfläche bereitgestellt. Die gesicherte Abströmung kann allerdings im Betriebsfall durch die Gebäudeumströmung oder durch direkten Windeinfluss stark beeinträchtigt werden, mit der Folge eines zu hohen Druckaufbaus und damit nicht mehr zu öffnender Türen.
  Die Bypassklappen innerhalb des Gerätes stellen sicher, dass dieser Zustand nicht eintreten kann.

The system can thus automatically regulate the following operating states:

• All doors are closed.
  To achieve the desired pre-definable pressure only as much air is brought into the pressure chamber (escape route), as is required to cover leaks on site.
  The bypass flaps are open in this operating state.
• A door is open.
  If an outflow can occur from the downstream rooms, the pressure drop leads to an immediate closing of the flaps and the open door cross-section is now flowed through in the direction of the fire room.
• Use in flushing systems.
  In the upper part of the staircase, an outflow surface is provided. However, in the case of operation, the protected outflow can be severely impaired by the flow around the building or by the direct influence of wind, resulting in excessive pressure build-up and therefore no longer openable doors.
  The bypass flaps inside the unit ensure that this condition can not occur.

The benefits of the system are obvious. All reactions of the plant take place automatically. Additional transducers, pressure regulators, actuators, clamping and transfer points for the overpressure system as required in the prior art can be omitted. This means minimizing possible failure components and reducing default probabilities.

Fig. 1

die Vorderansicht eines Überdruckapparates gemäß der Erfindung;

Fig. 2

einen simplifizierten Längsschnitt durch einen Apparat gemäß Fig. 1 mit Darstellung der Wirkung eines Ventilators bei geschlossenem Bypass;

Fig. 3

einen simplifizierten Längsschnitt durch einen Apparat gemäß Fig. 1 mit Darstellung der Wirkung eines Ventilators bei geöffnetem Bypass;

Fig. 4

eine Momentendarstellung der Luftkräfte und Federkräfte über verschiedenen Öffnungswinkeln der Klappen des Bypass;

Fig. 5

eine typische Fluchtweg / Treppenhausanordnung mit nachgeschalteten Brandräumen und einer Überdruck-Rauchfreihaltungsanlage;

Fig. 6

perspektivische Draufsicht auf eine reale Ausführung eines Überdruckapparates.

With reference to a drawing, the problems and solutions and advantages of the invention are shown in more detail ..
Show it

Fig. 1

the front view of an overpressure apparatus according to the invention;

Fig. 2

a simplified longitudinal section through an apparatus of Figure 1 showing the effect of a fan with the bypass closed.

Fig. 3

a simplified longitudinal section through an apparatus of Figure 1 showing the effect of a fan with open bypass.

Fig. 4

a momentary view of the air forces and spring forces over different opening angles of the valves of the bypass;

Fig. 5

a typical escape route / stairwell arrangement with downstream fire areas and an overpressure smoke evacuation system;

Fig. 6

Perspective top view of a real version of an overpressure apparatus.

Like reference numerals in the following description refer to identical or functionally identical parts.

Overview of FIGS. 1 -3 and 5.
Within the box unit / pressure apparatus 1, both the supply air fan 2 in a centric housing and via a spring mechanism 6 automatically acting pressure relief valves 3, 3.1 arranged. These flaps open automatically when the pressure exceeds the target value and create a bypass 4 to the suction side of the fan. 2
Fig. 1 shows 4 symmetrically arranged around the housing with the fan flaps 3.1, which together form the bypass system 3. Each flap 3.1 has a rotary or pivot axis 3.2, to which it is opened in the same direction by the bypass flow 4 or the prevailing air forces and moments in short-circuit against the restoring moments of the spring system 6 (FIG. 3) or by spring forces or moments by means the spring system 6 is reset (Fig.2).

The opening force of the bypass flaps 3.1 is applied by an overpressure in the stairwell / escape route 5 (FIG. 5). This is opposed by a spring system 6 with a closing force / restoring force or torque. About the variation of the spring force by changing e.g. the preload length or other parameters known to those skilled in the art, the pressure differential at which the flaps are opened can be adjusted. With the flaps open, a portion of the air flow 4 circulates within the apparatus in this embodiment of the invention.

When the overpressure drops due to opening doors 7, the spring system 6 effects an immediate closing movement of the flaps 3. The ventilator 2 now conveys the rated volumetric flow V in order to maintain the predeterminable overpressure.

By the overpressure apparatus 1, a controlled overpressure of e.g. 50 Pa built up. The constant pressure is controlled by self-acting pressure relief valves 3.1 within the pressure apparatus that provide when exceeding the allowable pressure difference bypass surfaces 3 to the suction side of the device.

The control of the system is carried out, for example, smoke detectors 11, which are arranged outside each access door in the hallway or the lock 9 of the downstream rooms / offices 10 outside the protected area. Doors to Staircase 5 and the lock 9 must be self-closing and at least fire-retardant.

When smoke detection of the smoke detector 11, the smoke protection printing system, the pressure device 1 is put into operation. At the same time signal horns and freewheel door closer can be activated on the doors 7. Each floor E represents a detector line. In the floor affected by the fire, windows 13 are automatically opened via an actuator. The outflow can also be made via a standard L90 shaft, to which smoke extraction flaps are connected in toto.

• Schaltschrank 15, optische Rauchschalter 11, Alarmhupen-Blitzleuchten-Kombination 12, Freilauf-Türschließer, Wetterschutzgitter-Jalousieklappen-Kombination 14 für Luftzufuhr zum Ventilator 2, Stellantrieb (für Fenster oder Entrauchungsklappe 13).

Only if a Abströmmöglichkeit from the fire room 10 or from intermediate units is given, it can be ensured that when the stairwell doors 7 open a flow in the direction of fire room can be done.
The equipment further typically includes:

• Control cabinet 15, optical smoke switch 11, alarm horn / flashing light combination 12, free-wheeling door closer, weather protection grille / shutter combination 14 for air supply to fan 2, actuator (for window or smoke extraction flap 13).

4 shows the torque curve in various functional situations of the printing system.
Shown are six different courses of moments M in Ncm and a working line of the system according to the invention in addition to different air force moments with closed bypass, respectively above the opening angle α in degrees from 0 - 90 degrees.

• ___ Öffnungsmoment "Tür zu", frei ansaugend (220 Pa Druck)
• -------■ Öffnungsmoment frei ausblasend saugseitig (70 - 80 Pa)
• -------Δ Öffnungsmoment frei ausblasend saugseitig (200 Pa)
• -------× Öffnungsmoment frei ansaugend druckseitig, Bypass offen
• -------* Öffnungsmoment mit Saugleitung, druckseitig geschlossen
• -------• Öffnungsmoment mit Saugleitung; Bypass offen
• -------□ Arbeitslinie
• 1■ Luftkraftmoment (50 Pa)
• 2■ Luftkraftmoment (100 Pa)
• 3■ Luftkraftmoment (150 Pa)
• 4■ Luftkraftmoment (200 Pa)

Legend to FIG. 4:

• ___ opening moment "door closed", freely aspirated (220 Pa pressure)
• ------- ■ Opening torque free blowing on suction side (70 - 80 Pa)
• ------- Δ Opening moment free blowing on suction side (200 Pa)
• ------- × Opening torque freely suctioning pressure side, bypass open
• ------- * Opening torque with suction line, closed on the pressure side
• ------- • Opening moment with suction line; Bypass open
• ------- □ working line
• 1 ■ Air force moment (50 Pa)
• 2 ■ Air force moment (100 Pa)
• 3 ■ Air force moment (150 Pa)
• 4 ■ Air force moment (200 Pa)

Due to the expert design of the apparatus with bypass, clear intersections of the working line with all torque curves / opening moments result.

Fig. 6 shows a concrete embodiment of the overpressure apparatus 1 with fan 2 in the central housing as it is available for smoke-free escape routes 5.
The bypass 3 is composed of four flaps 3.1 around the housing. The flaps 3.1 pivot about the axes 3.2, the synchronization is ensured by bevel gears 3.3. Thus, the spring 6, adjusted in their effect / resilience for the flaps 3.1 by choosing a suitable length and tensile force on eg variable usable wire thicknesses of a coil spring, at each opening angle of the flaps in operation, they are connected via guide slots 3.4 with the flaps 3.1.

Claims (10)

1. Device system for keeping escape and rescue routes free of smoke, taking into account permissible pressure differences in the air in adjoining corridors and stairwells, having an excess pressure unit, which comprises a fan with a control apparatus and stabiliser and rotating blades which are adjustable when stationary, integrated into a housing, characterised in that, within an excess pressure apparatus (1), an actuatable axial fan (2) is installed centrally in the centrally disposed housing and a bypass with at least one flap (3) which is capable of closing automatically is disposed around this housing or in the vicinity of the excess pressure apparatus with a return flow option for the air to the suction side of the fan.
2. Device system according to claim 1, characterised in that the bypass comprises an even-numbered quantity of symmetrical individual flaps (3.1) with axes of rotation (3.2), the flaps being configured such that they make possible a bypass flow (4) around the axial fan (2) in the opened state and the maximum pressure loss of the bypass flow in the excess pressure apparatus has the same value as the required excess pressure in the escape route (5) and the flow-effective surfaces of the flaps (3) are configured in a specific ratio to the flow-effective cross-sectional surface of the housing.
3. Device system according to claim 1 or 2, characterised in that the ratio of the flow-effective cross-sectional surface of the housing to the flow-effective bypass surface is ≥ 1.4, preferably 1.6 to 2.1, and the ratio of housing length to housing height is ≥ 1.1, preferably 1.15 to 1.3.
4. Device system according to one of the preceding claims, characterised in that the flap system is configured such that opening or closing of the flaps is made possible by air-force moments or by means of a mechanical tension-compression spring system, the moment curve reducing as a function of the increasing flap opening angle, and a stable operating point (intersection) of the curve of the spring moments being formed with decreasing air-force moments above 50 degrees, preferably at approx. 55 - 80 degrees, flap opening angle (α).
5. Device system according to one of the preceding claims, characterised in that axes of rotation of the even-numbered bypass flaps, which are at right angles to each other, are connected in a form-fitting manner.
6. Device system according to claim 5, characterised in that the axes of rotation of the flaps can be connected in a form-fitting manner by means of bevel wheels.
7. Device system according to one of the preceding claims, characterised in that all the flaps are designed for a same-direction pivot direction.
8. Device system according to one of the preceding claims, characterised in that, in the case of a horizontal arrangement of the excess pressure unit, the bypass flaps have a weight-compensated configuration.
9. Method for keeping escape and rescue routes free of smoke, taking into account permissible pressure differences in the air in adjoining corridors and stairwells, having an excess pressure apparatus with an axial fan in a housing, characterised in that, around the housing with the axial fan (2) or in the vicinity of the excess pressure apparatus with a return flow option for the air to the suction side of the fan, a bypass flow (4) is produced by means of a system of flaps (3) which is capable of closing automatically, it being ensured that the flaps (3) open under the effect of a predeterminable excess pressure in the escape route (5) and release the bypass (4).
10. Method according to claim 9, characterised in that the moments for opening the flaps are adjusted such that the pressure forces or air-forces of the flow in the bypass (4) are adequate and the moments for closing the flaps are provided by a mechanical tension or compression spring system (6), the intersection of both moment curves thus determining the maximum arising opening surface of the flaps, as a result of which an automatically directly acting control system is produced as a result of pressure changes in the escape route, which operates, when opening, with a reaction time corresponding to the maximum escape route height or escape route length, taking into account the speed of sound, and, when closing, with a reaction time proportional to the mass moment of inertia/return moment of the spring system of the flaps.

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