diff --git a/pt100/pt100.tex b/pt100/pt100.tex
index 4ef2022..90b0797 100644
--- a/pt100/pt100.tex
+++ b/pt100/pt100.tex
@@ -807,7 +807,8 @@ in figure \ref{fig:dubsim}.
 \clearpage
 \subsection{Derived Component : The PT100 Circuit}
 The PT100 circuit again, can now be treated as a component in its own right, and has two failure modes, 
-{\textbf{OUT\_OF\_RANGE}} and {\textbf{FLOATING}}. It can now be represented as a PLD see figure \ref{fig:pt100_doublef}.
+{\textbf{OUT\_OF\_RANGE}} and {\textbf{FLOATING}}. 
+It can now be represented as a PLD see figure \ref{fig:pt100_doublef}.
 
 \begin{figure}[h]
  \centering
@@ -819,6 +820,13 @@ The PT100 circuit again, can now be treated as a component in its own right, and
 
 \subsection{Statistics}
 
+%%
+%% Need to talk abou the `detection time'
+%% or `Safety Relevant Validation Time' ref can book
+%% EN61508 gives detection calculations to reduce
+%% statistical impacts of failures.
+%%
+
 If we consider the failure modes to be statistically independent we can calculate
 the FIT values for all the failures. The failure mode of concern, the undetectable {\textbf{FLOATING}} condition
 requires that resistors $R_1$ and $R_2$ fail. We can multiply the MTTF