Search:
DSCF which are not top failures
Explanation:
A search will be made for dangerous safety-critical failures (DSCF), which either are not linked at all or have failure effects i.e. they are not “top failures”
Note:
- A DSCF (Dangerous Safety-Critical Failure) is a failure which has a safety level (SIL/ASIL) not equal to QM (Quality Management). The function at which the DSCF is anchored is automatically defined as a safety goal (see Properties dialog „Functional Safety“).
- Top failures (TF) are failures which have causes but no effects.
Example:
Abbreviations
- ASIL = Automotive safety integrity level
- BF = Base failure of a base function
- BFn = Base function of a base structure element
- BSE = Base structure element
- Cl Prc = Classification for process characteristic
- Cl Prd = Classification for product characteristic
- Cl Req = Classification for requirement
- CM = Control method
- DA = Detection action
- DC = Diagnostic coverage
- DSCF = Dangerous safety critical failure
- Er Det = Error detection
- Er Resp = Error response
- F = Failure
- FIT = Failure in time
- Fn = Function
- FSM = Functional safety management
- IE = Inspection equipment
- LF = Latent fault
- LFM = Latent fault metric
- OC = Operating condition
- PA = Preventive action
- PE = Process element
- PFH = Probability of failure per Hour
- PMHF = Probabilistic metric for random hardware failures
- PrcC = Process characteristic
- PrdC = Product characteristic
- QM = Quality method
- QR = Quality rule
- Req = Requirement
- RMR = Risk Matrix Ranking
- RP = Reaction plan
- SE = Structure element
- SE ErDet = Structure element for error detections
- SE ErResp = Structure element for error responses
- SFF = Safe failure fraction
- SG = Safety Goal
- SIL = Safety integrity level
- SM = Organisational-SE for “safety mechanisms”
- SPF = Single point fault
- SPFM = Single point fault metric
- TF = Top failure of a top function
- TFn = Top function at root element
- TS = Test sample
- The above structure contains three system elements, each with three functions which in turn have a single failure. The functions that contain safety goals have this info in brackets in the function name.
- The aim of this Quality Rule is to detect failures, which are assigned to safety goals and have different safety levels than that of QM. Furthermore, these failures are not top failures in the failure net. Any failure not linked at all will also be found.
- In the image above, you can see which failures meet these criteria by having the following Display options active: “Functional Safety parameters” and hot-click icon “failure net”. The following icon indicates that the failure is a top failure:
. These icons indicate that it is not: 
.
Search result: 
The following failures are hits with this Quality Rule: TF2, TF3 and BF2.