BS EN 777-2:2009 pdf free download – Multi-burner gas-fired overhead radiant tu be heater systems for non-domestic use Part 2: System E一Safety.
5.1.1.2 Category II
5.1.1.2.1 Categories of systems designed for use with gases of the first and second families
Adjustment of the gas rate with, if necessary, a change of injector, restrictor or regulator.
Adjustment of the gas rate of the ignition burner, either by using an adjuster or by a change of injector or restrictor and, if necessary, a change of the complete ignition burner or of some of its parts.
Putting the regulator out of service under the conditions of 5.2.6.
Putting the gas rate adjuster(s) out of service under the conditions of 5.2.1 and 5.2.2 if applicable.
The adjustments or component changes are only acceptable when converting from a gas of the first
family to a gas of the second family or vice versa.
5.1.1.2.2 Categories of systems designed for use with gases of the second and third families
Adjustment of the gas rate with, if necessary, a change of injector, restrictor or regulator.
Adjustment of the gas rate of the ignition burner, either by using an adjuster or by a change of injector or restrictor and if necessary, a change of the complete ignition burner or of some of its parts.
Putting the regulator out of service under the conditions of 5.2.6.
Putting the gas rate adjuster(s) out of service under the conditions given in 5.2.1 and 5.2.2 if applicable. The adjustments or component changes are only acceptable when:
a) converting from a gas of the second family to a gas of the third family or vice versa;
b) converting from one butane/propane pressure couple to another (e.g. 28-30/37 mbar to
50/67 mbar).
5.1.1.3 Category Ill
Category Ill systems admitted in certain countries are given in Annex A (see A.3.2.3).
5.1.2 Materials and method of construction
The quality and thickness of materials used in the construction of a system including its POCED shall be:
a) such that the construction and performance characteristics are not altered so as to affect the safe operation of the system in normal conditions of use and of maintenance by the user;
b) such as to ensure a reasonable operating life.
In particular, when the system is installed according to the manufacturer’s instructions, all the components shall withstand the mechanical, chemical and thermal conditions to which they may be subjected when used in a manner which can be reasonably foreseen.
Copper shall not be used for gas carrying parts where the temperature is likely to exceed 100 °C. Asbestos or materials containing asbestos shall not be used.
Solder that has a melting point between 450 °C after application shall not be used for gas carrying parts.
5.1.3 Accessibility for maintenance and use
Components and controls shall be arranged such that any adjustment, maintenance or exchange is easy without removing the radiant tube from the installed position. Where necessary, access doors or removable panels shall be provided.
Parts that are intended to be removable for maintenance or cleaning shall be readily accessible, shall be simple to assemble correctly and difficult to assemble incorrectly. Such parts shall be difficult to assemble incorrectly where incorrect assembly would create a hazardous condition or result in damage to the system and its controls.
Parts of the system which are not intended to be removed by the user and for which removal would affect safety shall be capable of removal only with the aid of tools.