BS EN 777-4:2009 pdf free download – Multi-burner gas-fired overhead radiant tu be heater systems for non- d omestic use Part 4: System H一Safety.
b) indicator lights are used their purpose shall be clearly and permanently identified on the system, or on the plate or label required by 8.1.2. The indicator lighting circuitry shall be so designed and arranged that:
1) it indicates when a supervised flame is present and, in the case of a supervised ignition burner, it also indicates when the main burner is in operation;
2) any failure arising in the indicator lighting circuitry shall either not affect the operation of any safety device or prevent the operation of the system.
5.1.8 Electrical equipment
The electrical equipment of the system shall be so designed and constructed as to obviate hazards of electrical origin and shall comply with the requirements of EN 60335-2-102:2006 which cover such hazards.
If the system is fitted with electronic components or electronic systems providing a safety function, these shall comply with the relevant requirements of EN 298:2003 with regard to electromagnetic compatibility immunity levels.
If the manufacturer specifies the nature of the electrical protection of the system on the data plate, this specification shall comply with EN 60529:1992:
a) to give the degree of personal protection against contact with dangerous electrical components inside the system case;
b) to give the degree of electrical protection, inside the system case, against harmful actions due to water penetration.
5.1.9 Operational safety in the event of fluctuation, interruption and restoration of the auxiliary energy
Interruption and subsequent restoration of the electricity supply at any time during the starting up or operation of the system shall result in continued safe operation, volatile lock-out, non-volatile lock-out, or safety shut-down followed by automatic recycling.
Interruption and subsequent restoration of the electricity supply shall not override any “lock-out” condition except where the system is intended to be reset by means of switching off and on the electricity supply to the system (e.g. volatile lock-out). Such re-setting shall only be possible if any interruption and subsequent restoration of the electricity supply cannot give rise to a hazardous system condition.
NOTE Requirements relating to the continued and safe operation of the system in the event of normal and abnormal fluctuation of auxiliary energy is specified in 6.6.1 d.
5.1.10 Motors and fans
The direction of rotation of motors and fans shall be clearly marked.
Belt drivers, where used, shall be so designed or positioned as to afford protection to the operator.
Means shall be provided to facilitate adjustment of belt tension. Access to such means shall be possible only with the use of commonly available tools.
Motors and fans shall be mounted in such a way as to minimize noise and vibration. Lubrication points, if provided, shall be readily accessible.