151-Reliability and Maintenance Procedure / 748
R
eliabilit
y
and Maintenance
P
rocedure
BOS-PRD-2601.900401
Criticality analysis applied to equipment and component as listed and structured based on:
x
Hazard type and Hazard severity;
x
Severity for failure based on function/use/redundancy/hazards.
De
f
ined hazard t
y
pe
s
:
x
Hazardous situations: hazards regarding ship’s safety, crew safety and environment protection.
x
Hazards regarding the ship’s specific mission (anchor handling, towing, dynamic positioning, cargo,
and fuel transfer, bulk and liquid product handling, etc.).
Level o
f
Hazard
s
everit
y
(
C
riticalit
y
)
:
Use of the following scale for quoting the severity of a hazard:
1. Critical;
2. Severe;
3. Marginal;
4. Negligible.
E
q
uipment de
f
inition:
Type of component/equipment/functions/systems:
1: Component, belonging to a piece of equipment;
2: Equipment;
3: Structural element.
S
everit
y
o
f
e
q
uipment
f
ailure:
Criticality analysis on equipment taking into account:
1. Hazards types;
2. Severity levels defined for the function/system to which the equipment belongs;
3. Use of the equipment.
E
q
uipment u
s
e:
The emergency use of equipment as required by SOLAS and vessel consumer distribution from
EMERGENCY SWITCHBOARD.
1: Continuous;
2: Intermittent;
3: Rare;
4: Emergency.
Detection o
f
f
ailure
,
redundanc
y
and availabilit
y
:
1: No detection;
2: Detected by an alarm;
3: Detected on use.
Further con
s
ideration
s
:
a) Time taken to repair after failure detection and isolation of the failed equipment;
b) Stand-by equipment put in service after failure detection and isolation of the failed equipment;
c) Number and availability of stand-by equipment according to the considered mode of ship operation
or considered function;
d) Description of the stand-by equipment (redundancy).
C
oncluding Anal
ys
i
s
:
The severity level of equipment failure (criticality) downgraded in the following conditions:
a) Reduced by one level if the time to repair was considered as acceptable or if the stand-by equipment
could ensure the function;
b) Reduced by two levels if two stand-by equipment could ensure the function;
c) Where one equipment (redundancy) is intended to be used in case of emergency, the severity level
of hazards is automatically set to “1”, (Critical) - even if a stand-by equipment is available or in use.
Version CR(BOS-PRD-10.900401). Original date: 28/05/2012. Version date: 31/12/2014.Valid version only on QMS site. Uncontrolled document when printed
Procedure prepared by: BOS Technical Manager. Approved by: BOS Technical Manager. Validated by: BOS Quality Representative.
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