From 2e2d7492d7be5e68db1892408e88dfc378aa4bba Mon Sep 17 00:00:00 2001
From: Robin Clark <r.clark@energytechnologycontrol.com>
Date: Fri, 11 Feb 2011 10:41:41 +0000
Subject: [PATCH] morning edit

---
 mybib.bib         | 20 ++++++++++++++------
 survey/survey.tex | 25 +++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/mybib.bib b/mybib.bib
index 8255810..7a2eb1e 100644
--- a/mybib.bib
+++ b/mybib.bib
@@ -271,24 +271,32 @@
  howpublished = "http://www.cmis.bton.ac.uk/research/vmg/papers/",
   year =         "2007"
 }
+
+@MISC{en161,
+  author =       "E N Standard",
+  title =        "EN161:2007 Automatic shutoff valves for gas burners and gas appliances"
+ howpublished = "British standards Institution http://www.bsigroup.com/",
+  year =         "2003"
+}
+
 @MISC{en298,
   author =       "E N Standard",
-  title =        "Gas Burner Controllers with forced draft",
- howpublished = "EN298",
+  title =        "EN298:2003 Gas Burner Controllers with forced draft",
+ howpublished = "British standards Institution http://www.bsigroup.com/",
   year =         "2003"
 }
 
 @MISC{en60730,
   author =       "E N Standard",
-  title =        "Automatic Electrical controls for household and similar use",
- howpublished = "EN60730",
+  title =        "EN60730: Automatic Electrical controls for household and similar use",
+ howpublished = "British standards Institution http://www.bsigroup.com/",
   year =         "1994"
 }
 
 @MISC{en61508,
   author =       "E N Standard",
-  title =        "Functional safety of electrical/electronic/programmable electronic safety related systems",
- howpublished = "EN61508",
+  title =        "EN61508:2002 Functional safety of electrical/electronic/programmable electronic safety related systems",
+ howpublished = "British standards Institution http://www.bsigroup.com/",
   year =         "2002"
 }
 
diff --git a/survey/survey.tex b/survey/survey.tex
index 22ff302..1e6c8a7 100644
--- a/survey/survey.tex
+++ b/survey/survey.tex
@@ -58,6 +58,31 @@ slowly when voltage too low
 
 \section {Four Current Failure Mode Analysis Methodologies}
 
+\subsection{Working Example: Gas Valve Proving}
+For each methodology outlined in the following sections,
+an example will be provided using an industiral safeguard
+used in the combustion industry. This example is 
+the arrangement of three valves~\cite{en161} to the gas supply to the burner.
+The first two valves in the chain are emergency shutdown valves.
+These are mains (line voltage) powered devices, that
+raise the valve opening against a strong spring. If the 
+power is removed, they snap shut. The third valve
+regulates the flow of fuel into the burner.
+Between valve 1 and 2 there is a length of pipe,
+of a given volume. 
+
+
+At start up 
+this is tested, by opening valve
+2 and checking the pressure reading is ambient pressure.
+
+Valve 2 is then closed and valve 1 is opened
+allowing gas to enter the volume.
+At start up gas is allowed to enter the first valve and presurises
+the space between it and valve 2. The pressure is monitored for a given time
+to ensure that valves 1 and  2 are not leaking.
+
+
 \subsection { FTA }
 
 \glossary{name={FTA},description={Fault Tree Analysis}}