Environmental; Hardware Fault Tolerance; Systematic Capability; Classification - Crowcon IRmax Installation, Operating And Maintenance Instructions

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The Probability of failure on demand is the likelihood that the system will be in a failed
state at a random moment. This is synonymous with the steady state unavailability which
is given by:
Unavailability = (λ x MDT)/(1 + (λ x MDT))
which approximates to, λ x MDT for small values of λ x MDT
where λ is the failure rate and MDT is the Mean Down Time.
This is consistent with the expression for Availability given as: MTBF/(MTBF+MDT)
The failure rates used, and thus the derived availabilities are those credibly associated with
a well proven design after a suitable period of reliability growth.

8.9 Environmental

Environmental constraints:
The product shall be operated over a maximum ambient temperature range of
-40°C to +75 °C.
The product shall be stored over a maximum ambient temperature range of
-40°C to +80 °C.
The product shall be operated over a maximum ambient Relative Humidity range of
0% to +100 % Condensing.
The product has an Ingress Protection rating of IP66 according to the definitions within
standard EN60529.
The product is designed for continuous operation.

8.10 Hardware fault tolerance

The HFT is 0.

8.11 Systematic Capability

The IREX/IRmax is of Class SC2.

8.12 Classification

The IREX/IRmax is a type B component.
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