Electromagnetic fields

Re: Electromagnetic fields

Just a point of clarification on the info below. The date for the EMF Directive to be transposed into UK law has been put back to 2012.

Here's the text of something we published in HSW recently:

EMF stands for Electromagnetic Fields, also known as non-ionising radiations. EMF's are produced by numerous pieces of electrical equipment, such as mobile phones or computer screens, at levels which are not considered harmful for human beings. However, the absence of risk is less clear for more powerful EMF emitters potentially including broadband masts, Magnetic Resonance Imaging (MRI) equipment, and industrial microwave ovens and welding machinery. These powerful EMF emitting equipments are the specific target of the EMF European Directive, the third of four "physical agents" Directives (the others cover vibration, noise and optical radiation -this last is currently under development). Member States originally had until 30 April 2008 to implement the EMFs Directive, but the European Commission has just announced that states will now have until 2012 to bring in the relevant regulations.
The Directive is intended to protect employees from the short-term effects of EMF which include both thermal and electrical effects on the body. When they eventually come in, the regulations will apply to all work activities where employees are exposed to risks from electromagnetic fields, whether from machinery or from any neighbouring antennae or broadband emitters.
Every employer in the UK will have to conduct a mandatory risk assessment for their premises. Where they use equipment that produces a high level of EMF employers will have to measure and calculate EMF strengths to which the personnel and public are exposed.
They will then have to eliminate or reduce, as much as possible, the risk of exposure to employees. Where risk cannot be eliminated, they will have to implement measures to ensure the risk of exposure falls below "exposure limit value. Where an employee has been exposed, the employer will have to investigatethe exposure and arrange a medical examination for the employee.

Louis Wustemann | 13:16 04.02.2008| Report this answer as unsuitable

Re: Electromagnetic fields

Does the attached help

Electro Magnetic Field (EMF) Legislation


These notes are compiled following attending a presentation given by TWI North at Middlesbrough on 26 April 2007.
The presentation was given by Geoff Melton (Arc welding TWI consultant).

Background
The EU Physical Agents (Electromagnetic Fields) Directive 2004/04/EC becomes law in the UK in April 2008. It is part of an ongoing package of Directives such as the Noise Directive, Vibration Directive, etc aimed at improving workers health. This particular Directive aims to limit workers exposure to EMFs.

Electromagnetic fields are generated when high electric currents flow through cables. Typical examples of this are Resistance Welding, Arc welding, Induction welding and heating and Magnetic particle inspection.

The effect of EMFs is to create an electric current flow in the human body which is believed could cause an effect to the brain and/or central nervous system. The limits do not apply to the body extremities (arms, legs) but do apply to the head and torso. There is no medical evidence of a long-term affect on the body of EMF exposure and as such this Directive acts from a precautionary view.

It is not possible to measure the electric currents flowing through the human body and so measurements of the electromagnetic field are made and work has been done to calculate exposure limits for both the public at large and for workers using equipments that generate EMFs. It is to be noted that the limits used in the Directive (ICNIRP guidelines) were calculated some time ago and more recent work has concluded that higher limits are acceptable.

The Directive stipulates three activities that must be performed:

Article 4 - Determine the exposure and assess the risk
Article 5 - Actions needed if limits are exceeded
Article 6 - Provide workers with information and training

Measurements of equipment therefore need to be taken. However, it is to be noted that:

The higher the current the greater the electro magnetic field
The lower the frequency of the current the higher the field strength
The field strength falls rapidly as the distance from the source increases.
Time exposure is irrelevant as the effect of EMF is instantaneous.








There are some draft standards which define the requirements of the Directive:

pr EN 50445 Product standard for welding equipment
pr EN 50444 Product standard for arc welding equipment
pr EN 50505 Product standard for resistance welding equipment
pr EN 50499 Determination of workers exposure to EMF

As yet these do not appear to be available on the BSI web site.

There appears to be no standards written, or exposure limits defined, for Magnetic Particle Inspection. TWI are due to carry out surveys on the various MPI techniques (Probes, electromagnetic yoke, fixed installations both current flow and magnetic flow).

There is an ongoing debate about this Directive in terms of exposure from medical MRI scanners as the currently defined limits would mean that they could no longer be used.




Stuart Livingstone
30 April 2007

stuart.livingstone | 14:22 25.01.2008| Report this answer as unsuitable