diff --git a/submission_thesis/CH2_FMEA/copy.tex b/submission_thesis/CH2_FMEA/copy.tex
index 75b4003..ed45d8f 100644
--- a/submission_thesis/CH2_FMEA/copy.tex
+++ b/submission_thesis/CH2_FMEA/copy.tex
@@ -28,16 +28,15 @@ The four main current FMEA variants are described and we  develop %conclude by d
 the concepts
 that underlie the usage and philosophy of FMEA.
 %
-We return to the overall process of FMEA
-and model it using UML. 
+We return to the overall process of FMEA and model it using UML. 
 %
-By using UML %we define 
-relationships between the FMEA data objects 
-are defined. % at the start of this chapter.
+By using UML  
+the entities needed to implement FMEA 
+are defined.  
 %
 The act
 of defining relationships between the data objects
-in FMEA raise questions about the nature of the process
+in FMEA raises questions about the nature of the process
 and allows us to analytically discuss its strengths and weaknesses.
 
 
@@ -1222,6 +1221,14 @@ FMEDA is a modern extension of FMEA, in that it recognises the effect of
 self checking features on safety, and provides detailed recommendations for computer/software architecture. 
 %
 %
+%
+FMEDA is the fundamental methodology of the  statistical (safety integrity level)
+type standards (EN61508/IOC5108).
+The end result of an EN61508 analysis is an % provides a statistical 
+overall `level~of~safety' known as a Safety Integrity level (SIL), for an installed system.
+%
+It has a simple final result, a Safety Integrity Level (SIL) from 1 to 4 (where 4 is safest).
+%
 These SIL levels are broadly linked to the concept of an 
 acceptance of given probabilities of dangerous 
 failures against time, as shown in table~\ref{tbl:sil_levels}.
@@ -1229,24 +1236,14 @@ failures against time, as shown in table~\ref{tbl:sil_levels}.
 The philosophy behind this is that is recognised that no system can have a perfect
 safety integrity, but risk and criticality can be matched to acceptable,
 or realistic levels of risk.
-%
-FMEDA is the fundamental methodology of the  statistical (safety integrity level)
-type standards (EN61508/IOC5108).
-The end result of an EN61508 analysis is an % provides a statistical 
-overall `level~of~safety' known as a Safety Integrity level (SIL), for a system.
-%
-It has a simple final result, a Safety Integrity Level (SIL) from 1 to 4 (where 4 is safest).
-%
 %There are currently four SIL `levels', one to four, with four being the highest level. 
 %
-It allows diagnostic mitigation for self checking circuitry. 
 %
-
 SIL levels are intended to
 classify the statistical safety of installed  plant: 
 salesmen’s terms such as a `SIL~3~sensor' or other `device' given a SIL level, are meaningless.
 %
-SIL analysis is concerned with `safety~loops', not individual modules. 
+SIL analysis is concerned with `safety~loops', not individual modules, sensors, computing devices or actuators. 
 %
 In control engineering terms, the safety~loop is the complete
 path from sensors to signal~processing to actuators for a given function
@@ -1265,9 +1262,11 @@ In EN61508 terminology, a safety~loop is known as a Safety Instrumented Function
 %
 FMEDA requires %does force 
 the analyst to consider all hardware components in a system
-by requiring that an MTTF value is assigned for each base component failure~mode; 
+and requires that an MTTF value is assigned for each {\bc} {\fm}; 
 the MTTF may be statistically mitigated (improved)
-if it can be shown that self-checking will detect its failure modes.
+if it can be shown that self-checking measures will not only detect it within the SIF, but
+also react in a safe way.
+That is that the SIF can recognise that it has a fault condition and can take appropriate action.
 %
 The MTTF value for each component {\fm} is denoted using the symbol `$\lambda$'.
 %