In chapter 13 of The Hydraulic Maintenance Handbook I discuss in detail the elimination of problems by engineering them out. An obvious example of this strategy is, if a hydraulic system has tapered thread adapters, their replacement with a more reliable type of connector eliminates the possibility of recurring leaks. Job done. And if an oil to water heat exchanger isn’t used, water can never contaminate the hydraulic fluid. Or if a suction strainer is discarded, it can never clog and destroy the pump. And so on.

Importantly, none of the above types of modifications can be regarded as a ‘significant change’ to the machine. This is important to be aware of because in some jurisdictions, if a component is added, removed or substituted with one of a different type, and the result is deemed to be a ‘significant change’ to the machine, the party who made the change incurs the same compliance requirements and corresponding liabilities as the original designer or manufacturer of the machine.

For example, the European Machinery Directive 2006/42 EC obligates any party making a ‘significant change’ to a machine to consider the risks involved as if it was a new machine. And that party can be regarded as a manufacturer, with the requirement to comply with regulatory standards for health and safety, etc.

Loosely defined, a ‘significant change’ is one that introduces a new hazard or increases the risk of an existing hazard. Modifications which increase power, result in a functional change or alter a safety circuit are examples of the types of changes that can increase risk or introduce new hazards.

Take note, that even for the average owner or maintenance practitioner, who is not normally in the business of modifying hydraulic circuits, this issue is still very much relevant. Screwing in a relief valve so that its setting is above the manufacturer’s recommendation increases the power output of the circuit or sub-circuit. And on an older machine, if an obsolete counterbalance valve cartridge is replaced with a different make and model, this constitutes a change to a safety circuit.

The point here being, some maintenance and repair actions can have implications that go beyond the mandate to get the machine up and running or keeping it that way. Which means not being aware of these legal implications can be a costly mistake. And to discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, get “Six Costly Mistakes Most Hydraulics Users Make… And How You Can Avoid Them!” available for FREE download here.