Guideline PPE Exposed to the thermal effects of an electric fault arc

Guideline for the selection of personal protective equipment when exposed to the thermal effects of an electric fault arc
Each and every day electro-technical work is carried out world-wide at the risk of the occurrence of an electric fault arc either by failure or due to a technical reason.

There are different ways to protect people against the arc risks. At first the fault arc shall be prevented by technical measures such as constructions and electrical protective devices, and creating electrically safe working conditions (de-energized installations, working rules etc.).

Training and competence policy procedures have to be applied. In many case it is not possible to totally eliminate the risk that nevertheless a fault arc can occur and Personal Protective Equipment (PPE) must be selected for protecting people.

Since the first publication of these guidelines in 2001 great advances have been made.

The effects when an electric arc occurs can now be specified with more precision. We are now able to predict what arc energies have to be expected in the events of arcing faults.

Moreover it is difficult in an electric installation to predict the direction of the arc due to the magnetic field caused by the short circuit current, and the resulting movements of the arc plasma and the arc roots at different elevations of the electric arc.

But there is now an improved knowledge on these processes.

However there are different consequences of electric fault arcs: thermal effects, electric shock, noise, UV emissions, pressure, shrapnel, the consequences of physical and mental shock and toxic influences.

Standards and test methods deal only with the thermal effects. This guideline focus also only on these aspects representing the most serious risks for persons.

Thus PPE that works one hundred per cent against an electric fault arc is not possible. Rather, the consequences of an electric arc can be reduced and many times eliminated.

In the case that any work in the vicinity of an electrical installation or under live conditions is necessary, the person is generally in an area that is not approachable for the normal population.

In those cases the general technical preventive measures, e.g. plates and doors, have to be opened or even to be removed for a certain period of time, as long as any sort of aforesaid work has to be done.

As these actions are part of maintenance and repair work, hazards due to electric arcs cannot be completely eliminated for the fore-seeable future.

Additionally other workers such as operators may be in proximity with the equipment or interact in such a way which could be exposed to an electrical arc.

These risks should be included in the risk assessment, too.

In the frame of the International Section of the ISSA on Prevention of Occupational Risks due to Electricity an international working group analyzed the situation and provides new information.

This revised guideline reflects the improved knowledge since the first edition.

A complete revision was made.

As major improvement the guideline gives information for risk assessment and how to apply the standardized procedures to the real work environment.

The working group referred to experiences and the improved situation of the standardization of electric arc test methods.

Today considerations may be based on well-established testing methods for PPE for arc flash exposures that are internationally standardized and harmonized.

This guideline follows the requirements of the European Directive for Personal Protective Equipment (89/686/EEC) [1]. In the following according PPE are considered exclusively; all items of this guideline are PPE in the sense of the directive.

The document is intend to help employers to fulfil the obligations according to the Council Directive 89/391/EEC on the introduction of measures to encourage improvements in the safety and health of workers at work.

International Social Security Association
Section for Electricity, Gas and Water
c/o Berufsgenossenschaft Energie Textil Elektro Medienerzeugnisse
Gustav-Heinemann-Ufer 130, D-50968 Köln,
Germany

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