# The Oil Heaters (Safety) Regulations 1977, Paragraph 4


After the end of the tests specified in paragraphs 2 and 3 of this Schedule the draught shall be stopped and the heater allowed to burn for 15 minutes. During this 15 minute period no flame shall appear outside the heater.

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Source: https://www.legislation.gov.uk/uksi/1977/167/schedule/3/paragraph/4 (the official version)
Page: https://openlegislation.uk/oil-heaters-safety-regulations-1977/schedule-3/paragraph-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.