With the fast-moving pace of technology and innovation, valuable information that should be passed on to fellow industry professionals is often glossed over today. While shortcuts or quick ways to get by can reflect well on short-term budgets, they show a lack of experience and overall understanding of what makes a system viable for the long haul.
As I travel for my job, the sites and valve stations I visit always intrigue me. They either impress me with their engineering brilliance or cause me to shake my head and wonder how they were ever approved, let alone built.
Based on this experience, the following list (in no particular order of importance) outlines 10 common red flags that should make you question what else has been short-circuited that will lead to more maintenance and costly repairs involving valve chambers.
1. Bolts that are too long.
We were always taught that only one or two threads should protrude past the nut once the joint is tight. I assumed that this was to reduce the risk of damage or corrosion—or even to prevent the bolt from finding your shin as you walk past it—but it also makes economic sense. Why buy a bolt longer than you need? Typically, bolts are too long because somebody did not have time to calculate the correct length or that individual simply did not care what the end result would look like. Bottom line: It is lazy engineering.
2. Valve chambers where the control valve has no way of being isolated.
While valve chambers and isolating valves take up valuable real estate, it is important to allow enough space for personnel to work on the valve when maintenance is required. If gate valves are considered too long, at least install butterfly valves, which take up hardly any space at all. Always bear in mind that, for the operators who have to work on these stations, the easier they are to work on, the greater the chance that maintenance tasks will be done effectively.
3. Installations with no pressure gauges or provisions to temporarily install one.
Some utilities like to have calibrated test gauges that they move from site to site. These facilities typically are good at providing connections for their site personnel to access, but what about those installations that don’t even have fittings? It always amazes me that someone is expected to set a valve with no provision to be able to see the actual pressures right at the valve. Even with supervisory control and data acquisition (SCADA) and telemetry capabilities, someone at some point will stand next to a valve and need to see what the pressure is.
4. Too little space.
When you have gone through a lot of trouble to install a valve station, probably involving excavation work, concrete, etc., don’t try to save a couple of dollars by making it as small as possible. I am not a big person, but I have been in valve chambers that I considered tight. To expect a couple of guys to fit into these areas and perform even basic maintenance would be very tough. Remember: Tools can get quite long, so allowances must be made so bolts can be loosened. More space is always better than too little space, and it allows you to add equipment later.
5. Valve chambers with no piping allowances for the removal of the main components.
Most of the time, installers understand that you cannot bolt everything together in a concrete chamber without having some type of coupling to allow for component removal at some point in the future. If all the components are bolted tightly with no clearances, getting them apart will be nearly impossible. Whether they are grooved-type couplings, flange adapters or pipe couplings, they are necessary. Sometime in the future it may be necessary to remove a part, and, while that is typically not the concern of the installation contractor, it should be a concern to the owner and engineer. It is still shocking to see so many installations without any allowance at all.
6. Concentric reducers on horizontal lines.
This might seem like nitpicking, but this is a valid issue. Eccentric reducers keep the top of the pipeline at the same level, which means that air pockets are less likely to form. Concentric reducers are for vertical lines. In some applications, an eccentric reducer may not be available or even necessary, but this issue usually comes down to cost: Concentric reducers are less expensive, so if a contractor can get away with them, he will.
7. Valve chambers that have no allowance for drainage.
All chambers get wet. Even during valve startup when air is being bled out of bonnets, water will end up on the floor at some point. Anyone who has been in the industry for any length of time has seen a flooded valve pit, but there is really no excuse for it (unless, of course, the entire area is flooded, in which case you have bigger issues). If a daylight drain cannot be installed, then use a simple sump pump, assuming there is power. In cases where there is no power, a float valve with an ejector will efficiently keep a chamber dry.
8. No allowances to get rid of air.
Pressure-reducing valves are great at producing air. As pressure drops, air comes out of suspension and is transferred into the pipelines, which will cause issues downstream of the valve. A simple air-release valve will get rid of any air that may be present and will prevent problems downstream. An air-release valve upstream of a control valve is also effective because air in pilot lines can cause instability. Why not get rid of air before it ever reaches the valve?