# The Gas Appliances (Safety) Regulations 1992, Paragraph 3.4.4


Independent flueless domestic heating appliances and flueless instantaneous water heaters must not cause, in the room or space concerned, a carbon monoxide concentration likely to present a danger to the health of persons exposed, bearing in mind the foreseeable duration of their exposure.

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Source: https://www.legislation.gov.uk/uksi/1992/711/schedule/3/paragraph/3.4.4 (the official version)
Page: https://openlegislation.uk/gas-appliances-safety-regulations-1992/schedule-3/paragraph-3.4.4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.