When exploring the use of environmentally safe hydraulic fluids, one quickly observes that not all environmentally safe fluids or the companies that promote them are the same. It seems almost every oil company has some type of “environmentally safe” oil. One must read the fine print to understand what they were really selling.

Because there is no standard for environmentally preferable fluids, many different types of products claim to be environmentally safe. For the most part, they fall into four major classes of products:

  • Inherently biodegradable products are those that will break down “some day” and the time to do so is usually measured in years. The environmentally safe aspect is that they are made from either food grade oil or highly refined petroleum-based fluids and contain no heavy metals in the additives. While not truly biodegradable, they can have reduced toxicity.
  • USDA H1 “food grade” lubricants that are designated for use in food processing plants. They are designed for light duty applications where the fluid does not come in contact with food. Food grade oils are typically impractical for severe marine applications. In addition, they are toxic; in fact an entire batch of food must be discarded in the event of contact with the lubricant. Finally, they are petroleum-based and therefore environmentally persistent (inherently biodegradable or non-biodegradable) meaning they will be toxic to marine life for long periods of time.
  1. Readily biodegradable products such as vegetable-based fluids break down into safe, environmentally compatible components (CO2 and H2O) by more than 90% in 28 days or less. They are also non-toxic so they don’t kill marine life. They typically are designed for low operating temperatures (less that 220°F).
  2. Synthetic products usually offer enhanced performance as compared to vegetable or petroleum products. Some can be readily biodegradable and non-toxic and can withstand operating temperatures over 400°F.

History paints a picture

Historically, vegetable-based fluids had not exhibited sufficient performance for most hydraulic applications. There were several reasons for this.

Fluid formulations — Traditionally, a lubricant is compounded from petroleum-based oil and a variety of performance chemistries. Early pioneers in the vegetable-based lubricant market used the same chemistry that was used for petroleum lubricants in vegetable based-oils. It was a great idea, but it didn’t work. The characteristics of vegetable oils are vastly different than those of petroleum oils. Vegetable oils had to be formulated for their individual strengths and limitations. Today, there are several vegetable-based products on the market. They offer good performance and a fair price. While all vegetable-based lubricants have temperature limitations, there are some that are better than others. One should check with their lubricant supplier to determine their maximum and minimum operating temperatures. While most vegetable-based lubricants have a maximum operating temperature of 140°F, there are some that offer protection as high as 220°F. Similarly, most vegetable-based lubricants offer good performance to 30°F, yet there are some that flow below –30°F.

Fluid choice — Even the highest performing bio-based fluids have operating limitations in terms of temperature and life expectancy. Using a bio-based fluid in an application higher than 220°F (and as low as 160°F for some fluids) will cause premature and possibly catastrophic equipment failure. There are numerous cases in which using a vegetable-based fluid in the wrong application was a major contributor to the failure. In extreme high temperatures and environmentally sensitive applications, readily biodegradable synthetic fluids should be utilized.

Fluid care — Traditional bio-based fluids offer unique performance characteristics; however they require special care to maximize their useful life. While water is the enemy of all lubricants, most bio-based fluids are more susceptible to hydrolytic breakdown, the result of which can be acid formation. These acids can attack seals, increase wea,r and accelerate fluid aging. Proper filtering will prolong the useful life of these fluids.

Pile drivers lead the way

There are many examples of successful long-term users of environmentally safe fluids. They have had to adapt over time to maximize the utility of the fluids. One example is American Piledriving Equipment Company (APE). For the past 20 years, APE has lead the piledriving industry toward environmental responsibility by exclusively utilizing vegetable-based hydraulic fluids. These biodegradable and non-toxic oils cost more than conventional petroleum-based fluids, but in the long term, save operators thousand of dollars by reducing fines, oil clean-up costs, and downtime. In addition, using agriculturally based products has helped the environment because it breaks down quickly in the environment (readily biodegradable), does not hurt wildlife (non-toxic), and reduces dependence on petroleum, a nonrenewable resource. Finally, using vegetable-based hydraulic fluids has improved the performance of vibro-hammers because of its excellent lubricating properties.

In April of 1989, John White, now the President of APE, developed a vibro-hammer that was smaller in size, yet could perform as well as much larger hammers. As a result of its smaller size, stronger innovative components such as tungsten were required. These hammers were used to help Boeing Corp. protect existing structures from earthquake damage. They soon found their way into Prudhoe Bay, one of the most pristine environments in the world. The environmental regulations in Prudhoe Bay are extremely strict with fines amounting to $20,000 per square foot of oil spill. Any jobsite — and in particular a pile driving site — is susceptible to oil leaks and spills and the risk of fine was too great. In fact, one option, to lay protective mats down over the entire working area was evaluated but was deemed impractical.

About this time, there were several initiatives in Europe to utilize vegetable oil as a base fluid for lubricants. Scandinavian loggers were evaluating the use of rapeseed oil for chain oils while the Swiss were experimenting with vegetable-base two cycle oils for outboard motors. APE began to explore the use of vegetable oil as the base for a hydraulic fluid and found it to be quite possible.

In mid-1992, APE made the decision to move to vegetable oil in all their equipment. There were several obstacles to overcome, however. First, was the performance of the fluid. Early vegetable-based products did not offer long-term protection for heavy-duty applications. They broke down rapidly at the temperature of a working vibro-hammer and had to be changed out more frequently than conventional petroleum products. APE needed to address the cooling system and sump size of the oil. Secondly, because there was limited supply of vegetable oils, if a contractor lost oil it would be difficult to locate a supply of appropriate product. To overcome this, APE installed a backup gravity feed reservoir that allowed the operator to refill his unit by simply pulling a lever. With these obstacles taken care of, APE went system wide with environmentally safe vegetable hydraulic fluids.

The fluid worked well, but still had a few limitations such as cold temperature performance, rust potential, and availability. However, in 1998, newer formulations were able to improve upon these limitations. In fact, with the improvements to the fluids, the APE hammers are able to run cooler, extending the life both of the hammer and the hydraulic fluid. Since then, APE has expanded the use of vegetable-based, biodegradable products to include diesel fuel, grease, gear oil and others.