MEDC XB15 User Manual
Page 6
These units also have the following approvals:
Main Harmonics (AC) to EN61000-6-3:2007 / IEC61000-3-2:2006
Conducted Emissions (DC) to EN61000-6-3:2007
Radiated Field Immunity (DC and AC) to EN61000-6-2:2005 / IEC61000-4-3:2002 + A1:2002
Electrical Fast Transients/Bursts (DC and AC) to EN61000-6-2:2005 / IEC61000-4-4:2004
Surge Immunity (DC and AC) to EN61000-6-2:2005 / IEC61000-4-5:1995 + A1:2000
Dips and Interruptions (AC) to EN61000-6-2:2005 / IEC61000-4-11:2004
Ingress protection (IP66 & 67) to BS EN 60598-1:1997
7.0 FUNCTIONAL SAFETY
Introduction
The XB15 beacon has been designed for use in potentially explosive atmospheres and harsh environmental
conditions. The glass reinforced polyester enclosures are suitable for use offshore or onshore, where light weight
combined with corrosion resistance is required.
The safety function of the beacon is to provide an intermittent spherical visual warning light when the correct
voltage is applied to the unit. The DC versions of the beacon are designed to operate on a supply voltage tolerance
of +/- 20%; the AC versions of the beacon are designed to operate on a supply voltage tolerance of +/- 10%.
The telephone initiate versions of the beacon are not included in this safety manual.
Under No fault (Normal) Operating conditions the XB15 beacon will provide a spherical visual warning light when
required by the system.
Under fault conditions the failure mode of the beacon is a failure to provide a spherical visual warning light. For the
failure rate associated with this failure mode please refer to the table below.
Assessment of Functional Safety
This beacon is intended for use in a safety system conforming to the requirements of IEC61508.
Sira Test & certification Ltd has conducted a Failure Modes Effect and Diagnostic Analysis (FMEDA) of the DC
version of XB15 Xenon beacon against the requirements of IEC 61508-2 using a Proof Test Interval of 8760hrs.
The DC version of the beacon was considered to be the worst case.
The results are shown below and are based on Route 1
H .
The beacon is classed as a Type B device
06/14
© MEDC 2014
XB15 XENON BEACON
Safety Function of XB15 Xenon Beacon:
‘To provide a spherical visual warning light when required’
Architectural constraints:
Type B
HFT=0
SFF =
74.65%
Proof Test Interval
=8760Hrs
[4]
MTTR = 8 Hrs
[4]
SIL 1
Random hardware failures:
λ
DD
= 1.12E-05
λ
DU
= 6.62E-06
λ
SD
= 4.84E-06
λ
SU
= 3.43E-06
Probability of failure on demand:
PFD
AVG
=2.92E-02
(Low Demand Mode)
SIL 1
Probability of Dangerous failure
on safety function:
PFH = 6.62E-06
(High Demand Mode)
SIL 1
Hardware safety integrity
compliance
Route 1
H
Systematic safety integrity
compliance
Route 1
S
Systematic Capability
SC 2 (Ref to 56A24816B)
Overall SIL-capability achieved
SIL 1 (Low Demand)
SIL 1 (High Demand)
a
r
t
s
n
o
c
l
a
ur
t
ec
ti
h
c
r
A
B
N
O
EN
X
5
1
B
X
5
1
B
X
f
o
n
o
it
c
un
F
y
etty
f
Sa
‘
a
w
wa
l
ua
s
is
v
l
a
ca
ic
rri
e
h
p
ss
a
e
dde
id
v
o
rro
p
o
TTo
:
s
t
n
i
a
B
e
p
y
T
0
=
T
F
H
=
F
SF
%
5
6
.
4
7
e
T
f
o
o
r
P
H
0
6
7
8
=
=
R
T
T
M
v
N
O
C
EA
B
:
n
o
c
ea
B
n
o
n
e
X
5
d’
rred
ir
u
eq
rreq
n
e
h
w
wh
t
h
g
iig
lli
g
n
in
n
rrn
’
ed
l
a
v
er
t
n
I
t
es
s
r
H
]
4
[
s
r
H
8
=
]
4
[
1
L
SI
f
e
r
a
w
d
r
a
h
m
o
d
n
a
R
y
e
ur
li
a
fa
f
o
y
ty
il
i
b
a
b
o
r
P
e
g
n
a
D
f
o
y
ty
il
i
b
a
b
o
r
P
:
n
o
it
c
n
u
f
y
etty
fe
a
s
n
o
p
e
t
n
i
y
etty
fe
a
s
e
r
a
w
d
r
a
H
e
c
n
a
il
p
m
o
c
p
t
n
i
y
etty
fe
a
s
c
it
a
m
e
t
s
Sy
e
c
n
a
il
p
m
o
c
ti
li
b
a
p
a
C
c
it
a
m
e
t
s
Sy
:
es
ur
li
a
f
λ
DD
E
2
1
.
1
=
-05
λ
U
D
E
2
6
.
6
=
-06
:
d
n
a
m
e
d
n
o
e
D
F
P
VG
A
E
2
9
.
2
=
-02
e)
d
o
M
d
n
a
m
e
D
w
o
L
(
e
r
u
li
a
fa
us
o
rro
e
E
2
6
.
6
=
H
F
P
-06
)
e
d
o
M
d
n
a
m
e
D
h
g
i
H
(
y
ty
i
r
eg
y
tty
i
r
eg
t
y
tty
λ
D
S
E
4
8
.
4
=
-06
λ
U
S
E
3
4
.
3
=
-06
1
L
SI
1
L
SI
1
e
ut
o
R
H
1
e
ut
o
Ro
S
)
B
6
1
8
4
2
A
6
5
o
t
f
e
R
(
2
SC
)
d
D
w
L
(
1
L
SI
L
SI
ll
a
r
e
v
O
-
ti
li
b
a
p
a
c
ed
v
e
i
h
c
a
y
ty
)
d
n
a
m
e
D
w
o
L
(
1
L
SI
)
d
n
a
m
e
D
h
g
i
H
(
1
L
SI