BS EN 777-1:2009 pdf download

BS EN 777-1:2009 pdf download.Multi-burner gas-fired overhead radiant tube heater systems for non- domestic use Part 1: System D- – Safety.
3.3.3
volume flow rate (V)
V
volume of gas consumed by the appliance in unit time dunng continuous operation
NOTE Th volume 110w rats Is eipresssd in mi/h. 11mm. dm3/h or dm3?s (EN 437:2003).
3.3.4
mass flow rat.
M
mass of gas consumed by the appliance in unit tine dunng continuous operation
NOTE Th. mass flow rate is eiipressed in kg/h org/h [EN 43720031.
3.3,5
flam. stability
characteristic of flames wtlch remain on the burner ports or in the flame reception zone intended by the construction
3.3.6
flame lift
total or partial lifting of the base of the flame away from the burner port or me flame reception zone provided by the design
Flame lift may cause the flame to blow out, i.e. extinction of the air-gas mixture.
3.3.7
light-back
entry of a flame Into the body of the burner
3.3.8
light-back at the injector
ignition of the gas at the injector, either as a result of light-back into the burner or by me propagation of a flame outside the burner
3.3.9
sootirig
phenomenon appearing duflng Incomplete combustion and characterized by deposits of soot on the surfaces or parts en contact with the combustion products or with the flame
3.3.10
yellow tipping
yelloWing of the tip of the blue cone of an aerated flame
3.3i1
purge
forced introduction of air through the combustion chamber and flue passages ii order to displace any ren’eaming fuel/air mixture andlor products of combustion
a) pro-purge: the purge which takes place between the start signal and the energizing of the ignition device
b) post-purge: the purge which takes place immediately following shut-down
3.3.12
first safety time2
interval between the Ignition burner valve, start gas valve or main gas valve, as applicable. being energized and the ignition burner valve, start gas valve or main gas valve, as applicable, being deenergized if the flame detector signals the absence of a flame at the end of this interval
3.3.13
second safety time
where there is a first safety time applicable to either an ignition burner or start gas flame only, the second safety time is the interval between the main gas valve being energized and the main gas valve being de-energized if the flame detector signals the absence of a flame at the end of this interval
3.3.14
extinction safety time
time which elapses between the moment when the supennsed fleme is extinguished and the moment when the automatic burner control system .‘iitiates shut-down of the burner by removing power to the automatic gas shut-off valves
3.3.15
stan gas flame
flame established at the start-gas rate either at the main burner or at a separate ignition burner
3.3.16
running condition of the system
condition in which the burner is ii normal operation under the supervision of the programming unit and its flame detector device
3.3.17
controlled shutdown
process by which the power to the gas shut-off valve(s) is removed immediately. e.g. as a result of the action of a controlling function
3.3.18
safety shut-down
process which is effected immediately folloMng the response of a safety control or sensor or the detection of a fault in the burner control system and which puts the burner unit out of operation by immediately removing the power to the gas shut.off valve(s) and the Ignition device
3.3.19
non-volatile lock-out
safely shut-down condition of the burner unit, such that a restart can only be accomplished by a manual reset of the burner unit and by no other means
3.3.20
volatile lock-out
safely shut-down condition of the burner unit, such that a restart can only be accomplished by either the manual reset of the burner unit, or a failure of the mains electncal supply and Its subsequent restoration
33.21
spark restoration
process by which, following the loss of the flame si9nal. the ignition device will be switched on again without the total interruption of the gas supply.