Net2
AN1090
Advice on using access control with fire doors
Fire escape doors
- How to identify a fire escape
Fire doors in common areas should be marked with
regulatory signs. These show a white figure running
against a green background, often accompanied
by the words 'Fire exit' or 'Exit' and a white direction
arrow. Where a door is the only way out of a room, it
should be treated as an escape route.
- Egress through a fire escape door
A person must be able to open a fire escape door in the event of an emergency. This is normally through
a handle which directly opens the lock. In buildings such as theatres where there are large numbers of
occupants, the usual method is by using a crash bar which mechanically pulls open the locking bolts.
Where access control equipment is fitted to a fire escape door which includes an overriding mechanical
release, there are no extra considerations.
Where a fire escape door has an electric lock, you must ensure that there is a 'fail safe' way of opening the
door in the event of an emergency. Electronic equipment is more vulnerable to fire damage and potential
failure, than mechanical locking.
- Fail safe opening of fire doors
The first step is to use a 'fail open' release for the door. This type of device requires power to lock; it is
therefore unlocked when no electricity is supplied. Magnetic locks are normally fail open.
The next step is to have a 'fail safe' method of cutting the power to the lock to ensure the lock releases in
an emergency. In the event that the access control does not work, there must be an emergency override. In
most commercial premises, this is provided by a break glass switch fitted on the 12V lock supply line.
Break glass switches are widely available in green and white. Red must not be used as this can be confused
with the fire alarm system.
In premises where large numbers of people may have to exit at once, doors will almost certainly be released
by an interface with the fire alarm system. (FIB. Fire Interface Board). In most cases a local override at each
door will also be required.
It is possible to link the access control systems to the fire alarm panel. Net2 can send 'Open door' commands
to specific doors on receipt of the alarm signal. While building owners often specify this, it is NOT a 'fail safe'
method of opening the doors as it relies on the access control system being fully functional. A local release
method will also be required.
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Net2
AN1090
- Responsibilities
The installer should be able to discuss these with the client and to provide information on wiring details as
necessary. However the end user, or their architect or other consultant, is responsible for defining the fire
escape routes and what the requirements of the local fire officer are, as these will vary from authority to
authority.
- Security issues
Where doors are released in the event of a fire alarm the security provided by the access control system may
be nullified. A break glass unit used in an unauthorised manner will leave the door unlocked. Where high
security is required, consideration should be given to using locks, door contacts or break glass units that are
linked to a monitoring system. Net2 can provide this facility.
- Fail open locks - additional notes
It is also important that the locks used on a fire exit should not jam under side pressure before the door
is unlocked. A person can be pushing on a door in panic while operating the mechanical release or break
glass switch causing side pressure on the door. This is particularly likely where a number of people arrive
at the door in seconds in an emergency. Many electric motorised bolts, solenoid bolts and some electric
releases will jam in this situation. Models are available that have been designed, tested and proven to open
in these circumstances. Always get the manufacturer's details regarding this. Maglocks are inherently safe
in this regard although be wary of cheap models that can stick over time due to residual magnetism in the
armature.
- Wiring Break glass units and fire alarm interfaces
Where a fire escape door is opened by electronic means, you must ensure that the door can also be opened
in case of a failure of the electronic control. The most common method is to fit a break glass switch that
breaks the 12V supply cable to the lock.
The door may also be released by a fire alarm system. This is most commonly done through a Fire Interface
Board, (FIB) provided by the alarm installer. The FIB provides a switching position from where other systems
can be controlled by the fire alarm system. A normally open relay, held closed by the fire system will drop in
the event of a fire and break the 12V feed to the lock.
Where the escape doors are opened by Net2 , a local break glass switch will also be required. The wiring
details for these are shown in a later section.
For Paxton compact products, the 12V wire (Yellow) from the reader to the lock is wired through the break
glass switch or relay.
Note that local requirements of fire officers vary throughout the country. For example, in some London
boroughs a double pole break glass switch is required. This breaks both of the 0V and 12V wires going to
the lock.
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Net2
AN1090
Wiring a Break Glass
PLACE SERIAL
NUMBER
123456
LABEL
HERE
0889
Po w e r
0V
Re l ay 1
http://paxton.info/107
+12V
Re l ay 2
Net2 classic
Re d 1 2 V d c
Reader 2
Re d LED
Am b e r LED
Dat a/ D0
Data
Ke y p a d 1
Load
Gr e e n LED
0V out
Cl o ck / D 1
Clock/D1
Media Detect
Me d i a D e t e c t
Re a d e r 1
Data/D0
Ca u t i o n : Fo r 1 2 V d . c r e a d e r s o n l y. Fo r co r r e ct
co n n e ct i o n o f o l d 5 V r e a d e r s r e f e r t o
i n st r u ct i o n s
Amber LED
0 V ou t
Keypad 2
Red LED
Green LED
Lo a d
Dat a
Cl o ck
Red 12V dc
2
White/O rang e
3
Orang e
4
Ne t w o r k
1
Green
CAT5 ca b l e co d i n g
White/Green
I nput s
Clock
Screen or spare cores from
network cable
T
The Exit button must NOT be used to act as an emergency Break Glass.
This function relies on a fully working ACU using a 'push to make' circuit.
A failure in any part of the circuit due to the fire itself could stop the lock
being released and is therefore not 'fail safe' as required.
Similarly, a fail secure lock is not permitted, as lock power cannot be guaranteed during all emergencies.
Break glass
A break glass should be fitted, in conjunction with a fail
open release to all fire doors to ensure a reliable egress
method in the event of an alarm.
Maglock
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Net2
AN1090
Wiring a Fire Interface Board (FIB) with Break Glass
Re d 1 2 V d c
Re d LED
Am b e r LED
+12V
Po w e r
Reader 2
Net2 classic
http://paxton.info/107
PLACE SERIAL
NUMBER
123456
LABEL
HERE
Re l ay 2
0889
0V
Re l ay 1
Dat a/ D0
Ke y p a d 1
Data
Gr e e n LED
Media Detect
0V out
Load
Cl o ck / D 1
Re a d e r 1
Clock/D1
Ca u t i o n : Fo r 1 2 V d . c r e a d e r s o n l y. Fo r co r r e ct
co n n e ct i o n o f o l d 5 V r e a d e r s r e f e r t o
i n st r u ct i o n s
Amber LED
Green LED
Me d i a D e t e c t
Keypad 2
Red LED
Data/D0
0 V ou t
Red 12V dc
Lo a d
Dat a
Cl o ck
A 24V supply from the Fire Interface
Board (FIB) maintains a closed relay
(NO/COM) circuit. This is a Fail Safe
circuit as the loss of the signal will drop
the relay and release the door.
Clock
2
White/O rang e
3
Orang e
4
Ne t w o r k
1
Green
CAT5 ca b l e co d i n g
White/Green
I nput s
Screen or spare cores from
network cable
T
NO
COM
NC
In the event of a fire, the FIB or Break Glass
will override the Net2 ACU by cutting the 12V
power to the Lock.
Break glass
Maglock
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