This British Standard specifies the installation requirements for direct and indirect gas-fired forced convection air heaters for space heating that are designed for commercial or industrial applications and to which The Gas Appliances (Safety) Regulations 1995 [1] apply.
This British Standard applies to the installation and maintenance of appliances that are designed to utilize gases of Group H of the 2nd family (e.g. natural gas), gases of Group P of the 3rd family (e.g. propane) as well as gases of Group B of the 3rd family (e.g. butane) when supplied under the conditions of the third family pressure couple (see BSEN437:2003+A1:2009).
NOTE1 This British Standard does not specifically cover LPG/air for which additional requirements might be necessary.
This British Standard applies to the installation of direct gas-fired air heaters within the scope of BSEN525:2009 and to indirect gas-fired forced convection air heaters within the scope of BSEN621:2009, BSEN1020:2009 and, where appropriate, BSEN1196:1998. These standards cover air heaters having a net heat input not exceeding 300kW. This standard also applies to the installation of direct gas-fired air heaters within the scope of BS5990:2006 and to indirect gas-fired forced convection air heaters within the scope of BS5991:1998. These standards cover air heaters having a gross heat input greater than 330kW but not exceeding 2MW (1.8MW net).
NOTE2 For the purposes of this British Standard, installation includes design, inspection and commissioning. It is recognized that each of the tasks can be performed at the same time by different persons.
NOTE3 The ratio of gross to net heat input is approximately 1.11:1 for Group H (natural gas), 1.09:1 for Group P (propane) and 1.08:1 for Group B (butane).
NOTE4 The ventilation rates in cm2/kW of heat input given in this British Standard are based on the net calorific value.
This British Standard also applies to air heaters designed to supply make-up air, door curtain heaters, transportable air heaters and heat exchange modules (i.e. air heaters without a main air movement fan) where such heat exchange modules are used in environmental non-process applications such as air handling units. It also covers installation of heaters in areas where petroleum or other flammable heavier-than-air vapours can be present (see 5.1.2).
It does not include the safety requirements for installation where flammable dusts, toxic gases or flammable lighter-than-air gases might be present in significant quantities.
NOTE5 In such cases it is important that liaison takes place with the Health and Safety Executive.
This British Standard does not apply to the installation of air heaters to which The Gas Appliances (Safety) Regulations 1995 [1] apply, or that are designed for the sole use in domestic premises.