This standard specifies the requirements and test methods for the construction, safety, marking and rational use of energy of open fronted gas-fired independent space heaters with and without a fan to assist with the transportation of flue gases. Although the fan may be mounted outdoors, this standard only covers appliances where the body of the appliance is indoors. This standard applies to types B11AS, B11BS, B14AS and B14BS (commonly referred to in this standard as type B1 appliances) open fronted gas-fired independent space heating appliances: - that incorporate an atmospheric burner; - that are connected directly to an open flue (see Figure 1), or to a