Positioning and number of detectors

Một phần của tài liệu Bsi bs en 14637 2007 (2008) (Trang 39 - 45)

A.3.2.1 For hold-open and release of individual self-closing fire/smoke door assemblies by detectors monitoring the door

If ceiling-mounted detectors are required, they should be installed directly below the ceiling surface above the clear door opening (see Figure A.1.a)). The horizontal distance of the detectors from the wall in which the door opening to be protected is located should be at least 0,5 m and not more than 2,5 m.

In the case of a suspended ceiling, detectors should either be installed on the load-bearing ceiling (see Figure A.1.c)) or on the suspended ceiling in this area where, in the event of a fire, a major concentration of smoke is first likely to occur. Suspended ceilings with a fire protection classification (see Figure A.1.b)) are generally impermeable so that smoke spreads along their bottom surface; decorative suspended ceilings can be smoke-permeable (see Figure A.1.c)) or smoke-impermeable (see Figure A.1.b)). Estimation should be made on site (see CEN/TS 54-14). The positioning of the detectors depends on the estimation of the smoke permeability.

The selection of the number and type of detectors is related to the distance between the top edge of the clear door opening and the ceiling, as shown in Figure A.2 and Figure A.3.

In order to determine the requisite number of detectors, it is assumed that a detector covers an area of 16 m2. In the case of opening widths in excess of 4,0 m, therefore, further detectors or detector pairs may be necessary in order to cover the entire opening width.

As a general rule, at least one ceiling-mounted detector should be installed in each of the two rooms bordering on the opening to be protected, i.e. a pair of detectors is required, and at least one lintel-mounted detector should be installed above the edge of the clear opening on one side of the lintel.

On external doors no detectors are required on the outside of the building.

If, on both sides of said opening, the underside of the ceiling is not more than 1,0 m above the top edge of the opening to be protected, lintel-mounted detectors are not necessary.

If the clear opening is not wider than 3,0 m, and if it is closed by a swing door, it will be sufficient to install just one lintel-mounted detector instead of two ceiling-mounted detectors. In the case of rebated double leaf swing doors, this lintel-mounted detector should be mounted above the active leaf. In the case of double leaf swing

doors with plain meeting stiles, one lintel-mounted detector above each door leaf or ceiling-mounted detectors should be used.

Where a lintel-mounted detector is installed, this should be at a position directly on the wall above the clear door opening at a height of no more than 0,1 m above the bottom edge of the lintel.

Detectors suspended from the ceiling (pendant detectors) and detectors that are fixed to cantilevers so that the distance of the detector axis from the wall is greater than approximately the diameter of the detector base (cantilever detectors), and other detectors installed in other areas not named, are not taken into consideration for the requisite number of detectors for an application.

If the distance between the suspended ceiling and the top of the clear height of the door is >5 m, the relevant ceiling-mounted detectors should be replaced by detectors that are mounted on cantilevers of 0,5 m length and at least 3,5 m above the top of the clear opening of the door.

Dimensions in metres

h > 1,0 h > 1,0

h 1,0

a) Without a suspended ceiling

b) With an impermeable suspended ceiling

c) With a permeable suspended ceiling

Key

Smoke detector

Figure A.1 — Ceiling types and critical dimensions

Dimensions in metres

1 2

4 3

h 2 0,1

B

B

A

A 2,0

0,5

0,5 2,0

a1

1

a1

a2 a2

b1 b2

h

A - A B - B

b1; b2

Key

1 Room 1 3 Clear height

2 Room 2 4 Clear width

Line Ceiling height above bottom

edge of lintel Installation area (b = b1 or b2)

Requisite minimum number of detectors a

1 h1 and/or h2 > 1,0 m a1 and a2 and b Two ceiling-mounted detectors and one lintel-

mounted detector

2 h1 and h2 ≤ 1,0 m a1 and a2 Two ceiling-mounted

detectors 3 as line 2, but swing door with

clear width up to 3,0 m b One lintel-mounted detector

or two ceiling-mounted detectors

a Depending on the clear width of a door, in the cases described by line 1 and line 2, a greater number of detectors may be necessary (see Figure A.3).

Figure A.2 — Installation area in accordance with A.3.2.1

Distance between ceiling and top edge of the clear opening to be safeguarded, on one or

both sides of the opening > 1 m?

Opening to be closed by a

swing door?

Clear opening width

< 4 m?

Four ceiling- mounted and two

lintel-mounted detectors

Four ceiling- mounted detectors

Two ceiling- mounted detectors

One lintel-mounted detector or two ceiling-mounted

detectors Two ceiling-

mounted detectors and one lintel-mounted

detector

Yes No

No Yes

No Yes

No Yes

Yes Clear No

opening width

< 4 m?

Clear opening width

< 3 m?

_

_

_ _

Figure A.3 — Flow chart to determine the requisite number of detectors A.3.2.2 For hold-open and release of self-closing fire/smoke door assemblies by detectors connected to the FDAS of the building

The FDAS of the building should conform to the applicable parts of EN 54.

The division of the building into detection and alarm zones should satisfy the requirements of the fire alarm response strategy (see CEN/TS 54-14:2004, 5.6).

All detectors should be selected and positioned in accordance with CEN/TS 54-14:2004, 6.4 and 6.5. The numbers of detectors required depends on the volume of the rooms.

NOTE 1 Attention is drawn to the national and/or local regulations for the selection, positioning and number of detectors in a place and users' obligations there under.

NOTE 2 According to EN 54-1:1996, Figure 1, and further defined in EN 54-13, the hold-open devices of hold-open systems are regarded as “Automatic fire protection equipment (H)”.

The activation of the fire protection function of a hold-open system connected to the FDAS of a building (with the FDAS providing the release signal for connected hold-open devices) should be able to be achieved by either:

a) hold-open devices being triggered directly by the FDAS (see Figure A.4); or

b) control unit of the hold-open system being driven by the information coming from the FDAS (see Figure A.5).

(see EN 54-13:2005, B.4).

Power supply unit D

Fire alarm device(s)

C

Control and indicating equipment

B Fire

detector(s) A

Power supply equipment

L

Fire alarm routeing equipment

E

Fire alarm receiving station

F Fault warning

routeing equipment J

Fault warning receiving station

K

Control for automatic fire protection equipment

G

Automatic fire protection equipment H

Hold-open device(s) C

Manual call point(s)

D

FDAS in accordance with EN 54-1

Electrically controlled hold-open system in accordance with EN 14637

Figure A.4 — Typical electrically controlled hold-open system with release of connected hold-open devices triggered directly by the FDAS (see A.3.2.2 a))

Control unit B Manual control(s)

E

Fire/smoke detector(s) A

Fire/smoke detector A

Power supply unit D

Interface

Control for automatic fire protection equipment

G

Door position sensor(s) G

Remote indicating device(s) H

Manual reset F Stand-by power supply

J

Fire alarm device(s)

C

Control and indicating equipment

B Fire

detector(s) A

Power supply equipment

L

Fire alarm routeing equipment

E

Fire alarm receiving station

F Fault warning

routeing equipment J

Fault warning receiving station

K

Automatic fire protection equipment

H

Hold-open device(s) C

Manual call point(s)

D

FDAS in accordance with EN 54-1

Electrically controlled hold-open system in accordance with EN 14637

NOTE The dotted lines linking various components indicate the optional components that can be included in the electrically controlled hold-open system.

Figure A.2 — Typical electrically controlled hold-open system with release of connected hold-open devices by the control unit of the hold-open system driven by the information coming from the FDAS

(see A.3.2.2 b))

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