I will come back to the main topic of safety valves and their installation, but firstly for those that have just completed their calendar financial year, I am sure you will have found yourself in a similar predicament to myself with that strange article we in sales call ‘the accountant’.

During a visit to our UK office before I set off for a business trip to North America, our accountant wanted to run through some points from the previous year. From my travels it appears that most in the industry had 2011 down as ‘not too bad’ however, like most accountants ours wanted to show me spreadsheet after spreadsheet.

I was a little fortunate as he was not feeling too good on the day due to constipation. When he started on his spreadsheets after a third break, and still not feeling so good, I gave him a pencil and told him to work it out. We both felt a little better after that!

So, with this being gasworld’s safety issue, I thought I should write a bit about the subject and in particular, safety valves. These are installed in systems and piping to ensure they protect the pressure containing components from pressure increases that could result in damage to plant, equipment or personnel. Pressure can increase as a result of temperature changes, the filling of the vessels, equipment failure, operator error, or contaminants in the system.

During normal operation, safety valves will start to open at their set point and close bubble tight at a lower pressure. The following are some day-to-day headings that may assist in minimising safety issues in the field:

  • Correct installation – Ensure the discharging medium does not remain in the safety valve chamber, that can result in valve freezing.
  • Size correctly – Over-sizing a valve will reduce valve life.
  • Piping pressure drop – Poorly designed and wrongly sized piping can increase the pressure drop between the vessel and the valve inlet; the pressure drop should be limited to a maximum 3%.
  • Pre-installation of safety valves – Before use on your equipment, why re-test cleaned and tested valves that will possibly introduce contaminants; 99% of safety valve issues are the result of contamination.
  • Installation – Ensure pipelines are cleaned to remove all debris before the safety valve is installed; don’t use the safety valve to catch debris.
  • Rework – Don’t have valves re-set at shops that are not certified and who don’t have approved instructions; this works against national standards.
  • Regulator set pressure points – In bulk vessel installations, ensure the safety valve closing point has a higher re-seat pressure than that of the maximum pressure generated by the pressure build-up valve; or else the safety valve may never feel like closing.
  • Trailer safety valves – Issues can arise as a result of the continuous vibration from the road and worn components can result in valves sticking, continuous developments will enhance valve life.
    Finally, with the correct valve, installation and operation, your plant and valves will operate safely for many years. Most users now install safety valves for increased periods and industrial gas companies are extending safety valve life.

Together, we can create a safer working environment for all – and the considerable cost savings are something that the accountants will like too!

Published On: May 4th, 2012 / Categories: Company /