THE LEVEL of discontent between end users and skid builders has become quite disturbing. Some end users think skid builders are arrogant, don’t follow specs, don’t understand their problems, and don’t meet their standards. Meanwhile, skid builders think many users are unrealistically demanding, don’t precisely define their needs, and are too reliant on third-party contractors. It all seems to come down to a failure to communicate. Fortunately, there are some common-sense remedies to these conflicts.
So, what is a “skid” exactly? In general, a skid is a self-contained system shipped to a process plant on an integral platform. It contains instrumentation, controls, reactor vessels, valves, pumps, piping and all the necessary equipment to perform a specific task, such as waste remediation, pH neutralization, mixing, pumping, metering, compressor control, etc. Skid builders tend to be specialists in certain areas. They also run the gamut from extremely cooperative to very difficult to get along with.
Winter of Discontent
Ian Drazin, electrical and instrumentation supervisor at Potlach Corp., a supplier of potash fertilizers in North Las Vegas, Nev., is very upset with the quality of skid-built equipment. “My company recently purchased seven chemical skids and they have been nothing but a major problem,” he reports. “Problems include motor failures and pulsing positive displacement pump flows being measured by incorrectly specified flow transmitters. Where was the engineering? Did they ever field test their design?”
Drazin also is unhappy that the equipment wasn’t built to spec. “None of our corporate electrical standards were followed,” he adds.
So why buy skid-mounted equipment in the first place? “I have the expertise in my department to build any system I wish,” he says. “The problem is limited man-hours. We simply have too many other items on our plate that will directly affect machine run-time if we don’t work on them first. There isn’t enough time left over to devote to building our own skid system. Therefore, we turn to third-party suppliers.”
Gary D. Jacobson, P.E., a project manager at Boston-based CH2M Hill, says, “My latest problem is from two different vendors for automatic pH neutralization and polymer mixing and injection. Though the systems generally do the job for which they were purchased, the equipment supplied doesn’t meet the desired configuration and standards. Our clients sometimes want the system to conform to their standard for PLCs or operator interfaces, and the vendors either refuse or don’t provide what they have accepted an order for. Skid vendors have completely ignored comments to submitted drawings and documentation, or have agreed to incorporate comments, but then didn’t do so.”
Some other end users would only comment anonymously. One reported, “I wouldn’t want to leave the impression that we are unable to manage the vendors. Although, in this case, I guess we can’t apparently, but neither can anyone else.”
FIGURE 1: PILOT SKID
This entire computer-controlled skid mounted pilot plant for polymer research arrives on a skid from Unitel Technologies.
Richard Neff, president of skid builder Irrigation Craft, in Ft. Lauderdale, Fla., also agrees. “Skid builders often are incapable of building custom systems,” he says. “They lack the knowledge and engineering skills to correctly understand the specifications and intelligently communicate with the specifying engineers. They bid a low price, and then they resent having to provide what the specifications require.”
Jacobson summed up his discontent this way: “I’m looking forward to the skid manufacturer on my last project coming forward to propose on my next project, at which time I will do my job as the owner’s engineer and disqualify them from consideration.”
A Failure to Communicate
Warren Searles, president of HydroTec Systems, a skid builder of waste and water treatment systems in Rockton, Ill, says problems often originate with the end user/owner, and a lack of communication from the owner to its vendors. “We provided a system involving several large pressure vessels, each fitted with a control harness of valves and sensors,” he explains. “The control is held together with an Allen Bradley controller and network.” The entire system wasn’t coordinated as an entity, but was put together on site. The results are not pretty. “Once installed and started, the system functions, but not as desired by the owners, the operating management, and the operators,” adds Searles.