(Regulation 24)
1. The oil heater shall be operated in accordance with the provisions of Appendix C to the British Standard Specification of 1974 in a wind tunnel constructed and operated in accordance with the provisions of Appendix J to that Specification.
2. After the heater has been finally adjusted as specified in Appendix C to the British Standard Specification of 1974 it shall be exposed for 5 minutes to a steady frontal horizontal draught at a velocity not exceeding 8 metres per second. During this 5 minute period not more than 10 flashes of flame shall appear outside the heater, none of which shall last as long as one second or exceed 50 millimetres in length.
3. If, in the case of a heater fitted with a short drum burner, the flame is displaced during the 5 minute period specified in paragraph 2 of this Schedule so that the flame burns at the base of the heater, the heater shall be exposed to the draught specified in that paragraph for a further 30 minutes. During this further period no flame shall appear outside the heater.
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.
5. If during either of the tests specified in paragraphs 2 and 3 of this Schedule the flame is extinguished the draught shall be stopped immediately. During the following 15 minutes no flame shall appear outside the heater.