Article by Norwegian consultant and valve instructor Mr. Ingolf Fra Holmslet
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We all know that a hydrocarbon plant is built in accordance with a set of rules and regulations. As the media in the pipe system is dangerous, explosive and easily flammable, we want it to stay inside the piping. Internal leaks are tolerated to a certain degree, but we can´t tolerate external leaks out of the pipes, flanges or valves.
It is in the wind to talk about fugitive emissions so small that it sometimes is nearly impossible to stay below the limits after a few operations of the valve. The material quality of the valves is in many cases exclusive with tolerances and surface finish on the valve parts that makes the parts difficult and expensive to machine. The sum of this all makes the valves expensive.
Let us look at the madness, given the high price of these valves and the use of auxiliary equipment for these valves. On the valve body there are lubrication fittings with canals to the seats and to the stem and in many cases, the fittings are of a type and quality which in fact makes them dangerous to use. The one in the picture is also wrongly installed, these fittings may be with or without a cap. In the valve body there are normally a drain and a vent point with a plug (in some cases welded) or blind flange, making it impossible to use for maintenance or testing. It is not unusual to install instrument valves in the valve body and as we all know you should not install instrument valves in the body of API 6A or 6D valves.
And now one important question: why are some of the valve manufacturers using noncertified equipment on the outside of a major high-quality valve? In many cases there are no 3.1 certificates of the equipment, there are no tests of the fittings and certainly no test certificate. Look at the picture of the lubrication fitting. That fitting should not be used on hydrocarbon systems – it is dangerous. If injecting lubrication with high pressure, the coil spring will be compressed, and flow area will be reduced to almost nothing and in the end the check ball and spring may be blown out, which could be fatal.
The answer to my question above: to save money. I know about loss of order on fittings due to less than 1% in price difference (1 to 3 US Dollar per fitting)!
And I am not talking about comparing on equal terms. The cheapest fittings were without pressure testing and no 3.1 certificate, the expensive one (1% higher price) had full traceability, 3.1 certificate and was fully tested. I have been told by several people that auxiliary equipment doesn´t need documentation, which is nonsense. We are in many cases talking about expensive high-pressure valves, and then some manufacturers install non-certified equipment in the body, equipment that may cause major accidents to save 1% of the price of the fitting, which in fact is negligible when looking at the total price of the valve.
One of the challenges here is that the end user doesn’t specify types of fittings and they take for granted that they will receive valves with proper quality equipment installed on the valves. It should be the end user that specifies the fittings to be used and all equipment installed on the main valve should of cause be certified and tested.
To be continued….
About the Expert:
Norwegian consultant and valve instructor Mr. Ingolf Fra Holmslet writes a series of articles for Valve World.
Klyde Consultants AS
