The intended use
The intended use
The basis for a safe and healthy use
You can read it in almost every manual: a description of the intended use of the product or the machine. It is a description that every technical writer must treat very carefully, because it sets the liability of a manufacturer and affects the further contents of the manual. I will elaborate this in this blog.
The intended use according to the Machinery Directive
The importance of accurately describing the intended use can best be explained on the basis of the Machinery Directive (2006/42/EC). The Machinery Directive describes the intended use as follows: the use of machinery in accordance with the information provided in the instructions for use*.
The Machinery Directive demands to include a description of the intended use of a machine in the operating instructions. The intended use is associated with performing a risk assessment, which is also required by the Machinery Directive. On performing a risk assessment, the Machinery Directive (in Annex II) notices the following:
The manufacturer of machinery or his authorised representative must ensure that a risk assessment is carried out in order to determine the health and safety requirements which apply to the machinery. The machinery must then be designed and constructed taking into account the results of the risk assessment.
By the iterative process of risk assessment and risk reduction referred to above, the manufacturer or his authorised representative shall:
- determine the limits of the machinery, which include the intended use and any reasonably foreseeable misuse thereof,
- identify the hazards that can be generated by the machinery and the associated hazardous situations,
- estimate the risks, taking into account the severity of the possible injury or damage to health and the probability of its occurrence,
- evaluate the risks, with a view to determining whether risk reduction is required, in accordance with the objective of this Directive,
- eliminate the hazards or reduce the risks associated with these hazards by application of protective measures, in the order of priority established in section 1.1.2(b).
When conducting a risk assessment for a machine, any hidden hazards and the risks involved with these hazards are examined. If it is determined that a particular risk is of such an extent that possible injury may occur or that general health is affected, mitigation measures must be taken.
In BS-EN-ISO 12100 is described how a risk assessment can be conducted. This standard also describes a method for taking mitigation measures, called the “three-step method”. According to the three-step method, which is also made compulsory by the Machinery Directive (in slightly different words), there is the following hierarchy of mitigation measures:
- Eliminate risk through an inherently safe design.
- Reduce risk through shielding.
- Inform users about residual risks.
Information about residual risks can be provided at the source (on the machine) and/or in accompanying documents, as in the operating instructions. As the above article from the Machinery Directive describes, the Directive considers it necessary to reduce those risks that fall within the operating limits of the machine. The operating limits can be set by determining what the manufacturer’s intended use is; in other words, the intended use! The description of the intended use determines which instructions are given in the rest of the manual. For example, is a cooling system only used for cooling certain medications, than only this specific procedure needs to be described.
Reasonably foreseeable misuse
In addition to a description of the intended use, the Machinery Directive also demands to include information about the reasonably foreseeable misuse. This is described in the following article:
The contents of the instructions must cover not only the intended use of the machinery but also take into account any reasonably foreseeable misuse thereof.
Some examples of reasonably foreseeable misuse are for example using a barbecue indoors or using an aggressive detergent in an environment where food is processed.
If the reasonably foreseeable incorrect use is not carefully described, it may affect a manufacturer’s liability. The fact is that Directive 85/374/EEC regarding liability for defective products holds a producer liable for defective products. In determining whether a product is defective, all circumstances are taken into account, including “the reasonably foreseeable use of the product”.
Figure 1. Reasonably foreseeable misuse?
Reasonably unforeseeable use
Describing the reasonably unforeseeable use falls outside the liability of a manufacturer and outside the legislative framework; the manufacturer has no legal responsibility for describing them. The images below (Daams, 2011) show some examples of unforeseeable use. Obviously, it is always debatable what predictable human behaviour is and what is not. For instance, a cat in a microwave, is this reasonably foreseeable misuse or unforeseeable use?
Figure 2. Reasonably unforeseeable use
* The 82079-1:2012 Gives the following definition for intended use: exhaustive range of functions or foreseen applications defined and designed by the supplier of the product