The Law on the use of Faraday Cages in Public Establishments

“Evil communications corrupt good manners” – Charles Dickens

Internet Law and Regulation

9 August 2016 by Alban O'Callaghan, Trainee Solicitor
The Law on the use of Faraday Cages in Public Establishments

Introduction

A publican in East Sussex, England recently installed a material in the walls of his premises which had the effect of preventing patrons from using their smartphones while inside. The material, comprised of silver foil and fine copper mesh, causes the phone’s signal to be blocked from passing through the wall, thereby rendering them inoperable. The reason behind this move, according to the pubs owner, was to encourage his patrons to interact with one another as opposed to retreating into their smartphones. While novel in its inception, this technology is not new. It has been part of everyday life for the better part of the last century and a half and is technically referred to as a Faraday cage. This article seeks to clarify the legality of its use in public establishments, such as pubs and restaurants, and the legal ramifications of doing so.

A Faraday Cage: What Is It?

Invented by the English scientist Michael Faraday in 1836, a Faraday cage is essentially an enclosure made of conductive material, often fine metal mesh or perforated sheet metal. The electric charges within this material cause electromagnetic radiation from around the cage’s exterior to be distributed in a way that cancels out the electromagnetic radiation that is within the cage. Thus the cage effectively prevents external electromagnetic radiation from entering the interior. The effect of this is that transmission or reception of radio waves is blocked by the cage, rendering the inside of the cage free from radioactive waves – a virtual “dead spot”.

What Does It Do?

Provided that the material is of the requisite thickness, the cage will prevent electromagnetic interference from passing through it. A common use for this is in the case of microwave ovens where the window is covered in this material in order to contain the electromagnetic energy within the oven, while protecting the exterior from the radiation. Other examples are in the case of elevators and cable cars which are made of metallic conducting frames. This material prevents electromagnetic radiation from entering inside the elevator, causing mobile phones and radios to stop working. However, the most common example of one of these cages in operation would be aeroplanes and cars which are designed to protect the interior from a lightning strike. This is done by the electric charge of the lightning bolt being caused to redistribute around the fuselage rather than penetrating the interior.

What Is The Legality Of It?

Faraday cages are legal for many domestic purposes, such as those outlined above. However, conflict can arise when any apparatus of this nature has the effect of unlawfully interfering or actively jamming radio waves or wireless telegraphy. “Wireless technology” has been defined under section 2 of the Broadcasting and Wireless Technology Act 1988 as “the emitting and receiving…over paths which are not provided by any material substance constructed or arranged for that purpose, of electric, magnetic or electromagnetic energy of a frequency not exceeding 3 million megahertz, whether or not such energy serves the conveying (whether they are actually received or not) of communications, sounds, signs, visual images or signals, or the actuation or control of machinery or apparatus.” It is therefore arguable that smartphone signals constitute wireless technology for the purposes of this legislation.

Under section 7 of the Wireless Telegraphy Act 1972, the sale, let, hire, import or manufacture of apparatus that has the purpose interfering with wireless telegraphy is prohibited. Section 2 of S.I. No. 66 / 2011 somewhat practically defines “wireless technology interference apparatus” as any apparatus for wireless telegraphy that is designed to cause interference. The offence carries a maximum penalty of €5,000 upon summary conviction and €250,000 upon conviction on indictment pursuant to section 10 of the Wireless Telegraphy Act 1972 (as amended by the Broadcasting and Telegraphy Act 1988 and Broadcasting Act 2009).

Conclusion

It has been argued that the installation of a Faraday cage in a public establishment does not actually jam a wireless signal i.e. it does not actively emit radio frequency signal that causes other radio signals from being received and therefore is not illegal. To do so would most certainly constitute an offence under Irish law. The ambiguity arises due to the fact that the cage does not actively emit such signals but instead acts as a stationary filter. It is therefore prima facie not illegal under Irish law to install a cage of this nature on a premises. However, section 7 of the 1972 Act does provide grounds on which its legality may be challenged.

© Alban O’Callaghan, McKeever Solicitors, 9th August 2016

This article is a general review of the law on the subject and is not intended to be a complete statement of the law. Specific legal advice must be sought on a case by case basis. For further information, please contact Alban O’Callaghan or Patrick Kelly.

Key Contacts

Patrick A. Kelly
Partner

IFSC, Dublin
Paddy is the current Managing Partner at McKeever Solicitors. He is admitted to practice in Ireland and England & Wales, and is a CEDR Accredited Mediator.

T: +353 (0) 1 670 2990

F: +353 (0) 1 670 2988

E: pkelly@mckr.ie

Alban O'Callaghan
Trainee Solicitor

IFSC, Dublin
Alban holds a Masters in Law from University College Dublin and is due to complete his solicitor training in 2017. His background is in the commercial banking sector.

T: +353 (0) 1 670 2990

F: +353 (0) 1 670 2988

E: aocallaghan@mckr.ie