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Standard(s)- (year and edition):1 a2 N4 s1 v, v& ^
IEC 60601-1:1988 Ed.2 Am1+Am2 1 c2 m, U; h; A# z' V& m$ ESub clause(s): 0 q( F- t, {9 {
Sheet n°: DSH-4129 Q( o8 n D. i' {' t5 c2 T3 e+ ~
Subject: Detection of fault& C. R5 f" X' p8 F( ~
Key words: SFC, detection, fault/ w T8 Q; V2 v' z7 E6 ^+ L( C8 Y
Confirmed by CTL at its 39th meeting, in Cologne* Z% E: @4 S# p+ |0 ?
Question:. A6 B! `3 @8 `. O, O c
Shall a fault which remains undetected be considered a NORMAL CONDITION (NC) or a ; s. o3 S, z4 a% ]7 `: |' ISINGLE FAULT CONDITION (SFC)? ' M7 w! j) `% L8 I s2 jIf every fault is considered as SFC, regardless of whether it is detected or not, the & v8 @" Y+ C( k/ _8 [# Kconsequence will be that there is no protection required against situations where an - X1 R) K0 U' N9 b+ O: I9 ]undetected first fault is followed by a second fault which may cause a SAFETY HAZARD.' ~% I% E, Y- J- y* S% r( }
Decision: 2 P0 X5 i2 |, t" I, W! j+ j4 zIf a fault is not detected (for example by periodic inspection, maintenance, auto test, etc....), it: \- e1 {6 M2 t% d) Z
shall not be considered as a SINGLE FAULT CONDITION.4 G* s3 H& i0 Q# q2 v( Q* i
Time periodicity for the detection of fault depends on the risk analysis, `% T2 ?! z3 m; }3 {4 S
. a6 w u2 W2 p[attach]77096[/attach] # g8 h# {2 O3 @: }- {( F( t ?1 k4 M* ?( S
DSH 4120 p! B }: e+ Z0 ~3 s; N# D2 r5 x; ~- G