Safety - Severity & Risk

Question 1

Frequent

Answer 1

Rate - PS > 1 x 10-3
Real-world: more than 10 events per year
Can only pair with Sev Class 4 (C)
1, 2 , 3 sev would result in an A

Question 2

Probable

Answer 2

Likely to occur several times a year
Rate 1x10-3 >ps 1x10-4
1-10 events per year
Can only pair with sev class 4
Sev 1/2 =A ..unacceptable
Sev 3 = B undesirable

Question 3

Occasional

Answer 3

Likely to occur once a year
1x10-4 > ps 1 x 10-5
Between 1 and 10 years
Sev 3 = class C
Sev 4 = class D
(Not sev 1 or 2)

Question 4

Remote

Answer 4

Unlikely to occur in a year
1x10-5 > ps 1x 10-6
1 in 10 years
Can pair with a Sev 3 = class D
And sev 4 = D

Question 5

Improbable

Answer 5

Very unlikely in a year
1 x 10-6 > 1 x 10-7
1 in 100 years
Can pair with sev’s 2,3,4(class d) not 1

Question 6

Extremely improbable

Answer 6

Almost impossible but still assessed
Ps 1x10-7
1 in 1,000 years
Any sev always a D