I. Means of Protection (MOP) Definition
Means of protection (MOPs) are also known as “levels of protection” (LOP) and “safeguards”. A MOP is a physical part, system or instruction that can help reduce the likelihood of unacceptable risks (e.g. pain, death, or property damage). Some product safety standards (e.g. IEC 60601-1) define a MOP as a way to reduce unacceptable risk due to electrical shock hazards.
A means of protection can be used for all types of separation between hazardous and non-hazardous areas and all kinds of product hazards. A MOP can be a single element or set of elements applied to the electrical equipment, installation or user. It can even be a learned or directed behaviour for reducing the unacceptable risk of harm.
II. MOP Categories
MOPs can be used to reduce the likelihood of unacceptable risks associated with several hazard types.
#1. Means of protection against electrical shock
This category of means of protection against electrical shock consists of the following elements:
- solid insulation such as basic, supplemental, double and/or reinforced insulation.
- spacing between hazardous and non-hazardous areas
- protective earth connections
- components (e.g. safety interlocks and impedances)
- barriers and enclosures to prevent access to hazardous areas
- warning markings on hazardous areas
- installation instructions
- personal protective equipment such as gloves resistant to dangerous voltages.
#2. MOPs against radiation hazards
The MOPs against radiation (ionising and non-ionising) hazards include:
- screening of radiation sources
- safety interlocks to prevent access to hazardous areas
- components that can help limit radiation hazards
- warning markings on radiation areas
- installation instructions
- personal protective equipment such as safety spectacles.
#3. Means of protection against mechanical hazards
This type of MOPs includes elements, such as:
- pressure-relief valves
- barriers
- safety interlocks
- rounding of sharp edges and corners
- warnings on suitable areas
- installation instructions
- personal protective gear such as face shields or impact-resistant goggles)
#4. MOPs against biological hazards
MOPs against biological hazards include the use of biocompatible materials according to ISO 10993, warnings on potentially hazardous areas and personal protective equipment such as special clothing.
#5. MOPs against thermal hazards
The likelihood of heat and fire hazards can be reduced by:
- insulating potential ignition sources (e.g. bad contacts or short circuits) from combustible parts
- using materials with appropriate flammability
- incorporating components like overcurrent protection devices or thermal cutoffs.
- placing warnings on hazardous areas
- providing installation instructions
- recommending the use of personal protective equipment such as gloves.
#6. MOPs against chemical hazards
A means of protection against chemical hazards may include one or several of the following elements:
- warnings on areas associated with chemical hazards
- installation instructions
- separation and sealing of parts with dangerous substances
- personal protective equipment (e.g. chemical-resistant goggles or gloves)
#7. Means of protection against information hazards.
This last category of MOPs consists of user manuals, safety symbols and cautionary warnings, and other safety information.
