TELEGRAPHS Citation and Commencement 1 These Regulations may be cited as the Wireless Telegraphy (Control of Interference from Radio-Frequency Heating Apparatus) Regulations 1971. and shall come into operation on 21st October 1972. Interpretation 2 1 In these Regulations, except so far as the contrary is provided or the context otherwise requires, the following expressions have the meanings hereby respectively assigned to them: “ the Act ” means the Wireless Telegraphy Act 1949 ; “ the British Islands ” means the area comprised by the United Kingdom, the Channel Islands, and the Isle of Man ; “ radio-frequency heating apparatus ” means apparatus, not being electro-medical apparatus, scientific apparatus, or arc-welding apparatus, which is designed to produce a heating effect by the use of radio-frequency energy and which, or any part of which, generates or is liable to generate electro-magnetic energy at frequencies of three million megahertz or less when it is in operation, and includes any switchgear or controlling apparatus forming part of or directly associated with that apparatus and any induction cables, attachment, electrodes and connecting leads used or designed to be used with that apparatus ; “ kilohertz ” has the same meaning as kilocycles per second, i.e. one thousand cycles per second ; “ megahertz ” has the same meaning as megacycles per second, i.e. one million cycles per second ; “ electric supply lines ” means electric lines for transmitting electric power to a radio-frequency heating apparatus : “ terminal voltage ” means the radio-frequency voltage present between each electric supply line terminal of a radio-frequency heating apparatus and the screening of the measuring apparatus referred to in Regulation 5 ; expressions used in Schedule 2 have the meanings respectively assigned to them in Part 1 of Schedule 2; and other expressions have the same meaning as they have in the Act. 2 The Interpretation Act 1889applies for the interpretation of these Regulations as it applies for the interpretation of an Act of Parliament. Requirements 3 When any radio-frequency heating apparatus is used in the British Islands on or after the 21st October 1972 it shall comply with the following requirements for the purposes of section 10 of the Act: a the field strength of electro-magnetic energy radiated in any direction from the apparatus, as measured and computed in accordance with Regulation 5 shall not exceed the limits specified in columns 1 and 2 of Schedule 1 at any frequency within the range from 150 kilohertz to 1000 megahertz, but if the apparatus causes undue interference with any wireless telegraphy used for the purposes of any safety of life service or for any purpose on which the safety of any person or of any vessel, aircraft or vehicle may depend, the limits specified in columns 1 and 4 of Schedule 1 shall apply, and b the terminal voltage, as measured and computed in accordance with Regulation 5 shall not exceed the limits specified in columns 1 and 3 of Schedule 1 at any frequency within the range from 150 kilohertz to 30 megahertz but if the apparatus causes undue interference with any wireless telegraphy used for the purposes of any safety of life service, or for any purpose on which the safety of any person or of any vessel, aircraft or vehicle may depend, the limits specified in columns 1 and 5 of Schedule 1 shall apply. 4 Any radio-frequency heating apparatus which obtains its electric power from any supply to which dwelling houses are not also directly connected is exempt from the provisions of Schedule 1 Columns 3 and 5 Field strength and terminal voltage measurement 5 1 For the purpose of measuring and computing the field strength of the electro-magnetic energy and the terminal voltage at frequencies exceeding 150 kilohertz but not exceeding 1000 megahertz the radio-frequency heating apparatus shall be tested by means of measuring apparatus of the description and having the physical and electrical characteristics and performance set out in British Standard 727 : 1967, Section 1, Pages 9–13. 2 The tests for field strength shall be made by the method and under the conditions set out in Part 2 of Schedule 2 and the tests for terminal voltage shall be made by the method and under the conditions set out in Part 3 of Schedule 2. 3 The said field strength and terminal voltage shall be computed as provided in Parts 2 and 3 of Schedule 2 from the readings afforded by the measuring apparatus while the radio-frequency heating apparatus is operating. Christopher Chataway Minister of Posts & Telecommunications Dated 14th October 1971