Safety Manual: S70X & 80X Viewing Head - Honeywell 700 User Manual

HONEYWELL MODEL 700/800 SIGNAL PROCESSOR AND VIEWING HEAD
SAFETY MANUAL: S70X & 80X VIEWING HEAD
S702, S706, S802, AND S806
FIT FOR USE IN A LOW DEMAND SAFETY APPLICATION.
Models: S702, S702-PF, S706, S706-PF, S802, S806
Models SIL
S702 and S802 3
S706 and S806 3
System Architecture
MTTR (Mean Time to Restoration
Proof Test Interval
Fit for use in
Term
Dangerous Failure
Safety-related System
Safety Function
Proof Test
MTTR (Mean Time to
Restoration)
λ
sd
λ
su
λ
dd
λ
du
HFT
System Architecture
PFD (Average Probability
AVG
of Failure on Demand)
FIT (Failures in Time)
66-2069EP—04
HFT SFF
0 >99%
1.81 x 10
0 >99%
1.51 x 10
Table 6. Definitions.
Failure which has the potential to put the safety-related system in a hazardous or fail-to-function
state.
A system that implements the required safety functions required to achieve or maintain a safe
state and is intended to achieve on its own or with other systems the necessary safety integrity for
the required safety functions.
Defined function, which is performed by a safety-related system with the aim of achieving or
maintaining a safe state for the plant, in respect of a specified hazardous event.
Periodic test performed to detect failures in a safety-related system so that, if necessary, the
system can be restored to an "as new" condition or as close as practical to this condition.
The average duration required for restoration of operations after a failure.
Rate of safe detectable failures per one billion hours.
For example if λ = 3000, then it is estimated that there will be about 3,000 safe detectable
sd
failures during every one billion hours of operation.
For λ = 3000, this is about one safe detectable failure every 38 years.
sd
Rate of safe undetectable failures per one billion hours.
Rate of dangerous detectable failures per one billion hours.
Rate of dangerous undetectable failures per one billion hours.
Hardware Fault Tolerance
Specific configuration of hardware and software elements in a system.
Average Probability of Failure on Demand. In this case, regarding the S702, S706, S802, and
S806 viewing heads.
A unit of measurement representing one failure per billion hours. 1,000,000,000 hours is
approximately 114,155.25 years.
Product Declaration
λ
PFD
s
-10 -7
1.70 x 10
-5 -5
1.02 x 10
1oo1
8 hours
5 years
SIL 3 environment
Definition
38
λ
dd
-11 0
2.27 x 10
-11
2.27 x 10 6.90 x 10
λ
du
-10