Instruction sheet for BA385-IIB and BA385-IIC
Intrinsically safe Sounders
1. INTRODUCTION
The BA385-IIB and BA385-IIC are second generation ATEX certified
intrinsically safe sounders which produce a loud warning signal in a
hazardous area. Thirty two different first stage alarm sounds can be
selected by internal switches and each one can be externally changed to
a second or third stage alarm sound. The IIB model, which may be used
with gases in groups IIA and IIB, has slightly more output than the IIC
model which may be used with gases in all groups.
2. DESCRIPTION
Fig 1 shows a simplified block diagram of a BA385 sounder. The device
operates immediately power is applied to terminals 1 and 4 which are
duplicated to allow a second sounder to be connected in parallel, or for an
end of line monitoring resistor to be installed. The output tone is defined
by the position of the five internal switches and this tone can be changed
to a second or third stage alarm tone by connecting terminal 2 or 3 to 0V.
The tone generator is crystal controlled to ensure that when two sounders
are started at the same time their output tones remain synchronised.
3. SUPPLY VOLTAGE
For hazardous area installations, BA385 sounders must be powered from
a certified Zener barrier or galvanic isolator that will supply between 8 and
28V between terminals 1 and 4. Sounders may be tested or used in safe
areas without a Zener barrier or galvanic isolator, but at supply voltages
above 16V the internal current limit will function and the audio output will
be reduced. Direct connection to supplies up to 30V of either polarity will
not damage the sounder, but it is recommended that sounders are not
operated continuously with a direct supply greater than 16V.
Fig 1 Simplified block diagram
4. INTRINSIC SAFETY CERTIFICATION
4.1 ATEX certificate
Both the BA385-IIB and the BA385-IIC sounders comply with EN50 014 &
EN50 020 and they have been issued with EC-Type Examination
Certificates BAS00ATEX1180 and 1181. This confirms
compliance with
the European ATEX Directive 94/9/EC for Group II, Category 1G
equipment. The sounders carry the Community Mark and subject to local
codes of practice, may be installed in any of the European Economic Area
(EEA) member countries. i.e. Austria, Belgium, Denmark, Finland,
France, Germany, Greece, Ireland, Italy, Luxembourg, Norway, The
Netherlands, Portugal, Spain, Sweden and the United Kingdom. ATEX
certificates are also accepted in Iceland, Liechtenstein, Switzerland and
in the Czech Republic. This instruction sheet describes installations
which conform with BS EN60079:Part14:1997 Electrical Installation in
Hazardous Areas. When designing systems for installation outside the
UK, the local Code of Practice should be consulted.
BA385 sounders employ good engineering practice to minimise the risk of
injury to installers and users.
4.2 Zones, Gas Groups and T rating
The BA385-IIB sounder has been certified EEx ia IIB T4 and the
BA385-IIC model EEx ia IIC T4. When connected to approved Zener
barriers or galvanic isolators they may be installed in:
Zone 0
explosive gas air mixture
continuously present.
Zone 1
explosive gas air mixture likely to occur in normal
operation.
Zone 2
explosive gas air mixture not likely to occur, and if it
does, it will only exist for a short time.
Be used with gases in groups:
Model BA385-IIB Model BA385-IIC
Group
A
propane
yes
yes
Group
B
ethylene
yes
yes
Group
C
hydrogen
no
yes
Having a temperature classification of:
T1
450ºC
T2
300ºC
T3
200ºC
T4
135ºC
Although certified intrinsically safe at ambient temperatures between –40
and +60ºC the operating temperature range of both sounders is –20 to
+60ºC.
The BA385-IIB and BA385-IIC sounders are CE
marked to show compliance with the European
Explosive Atmospheres Directive 94/9/EC and the
European EMC Directive 89/336/EEC
BEKA associates Ltd, Old Charlton Road, Hitchin, Herts. UK SG5 2DA. Tel: +44 (0)1462 438301 www.beka.co.uk
