A

accumulation
pressure increase over the maximum allowable working pressure of the vessel allowed during discharge through the pressure-relief device
more details
actual flow capacity
actual flow capacity is the flowing capacity determined by measurement
more details
adjusted set pressure
vacuum or gauge pressure at which under test stand conditions (atmospheric back pressure) valves commence to lift
more details
ambient air
normal atmosphere surrounding the equipment and protection system
more details
ambient temperature
temperature of the air or other medium where the equipment is to be used (IEV 826-01-04) (IEC 60204-32:1998) Note: For the application of the Directive 94/9/EC only air is considered
more details
annular flame arresting unit
flame arresting unit consisting of annular crimped ribbons
more details
atmospheric conditions
atmospheric conditions are pressures from 80 kPa till 110 kPa and temperatures from -20°C up to 60°C
more details
atmospheric discharge
release of vapors and gases from pressure-relieving and depressurizing devices to the atmosphere
more details

B

back pressure
back pressure is the gauge pressure existing at the outlet side during blowing
more details
bi-directional flame arrester
a flame arrester which prevents flame transmission from both sides
more details
blow down
difference between set pressure and reseating pressures, normally stated as a percentage of set pressure
more details
bottom outlet valve
emergency valve at the tank bottom to shut immediately in case of downstream piping rupture
more details

C

check valve
valve, that prevents backflow against flow direction
more details
coating
protective painting with defined layer-thickness
more details
combustion air
air required to combust the flare gases
more details
component
component means any item essential to the safe functioning of Equipment and Protective System but with no autonomous function
more details
conventional pressure-relief valve
spring-loaded pressure-relief valve whose operational characteristics are directly affected by changes in the back pressure
more details

D

deflagration
explosion propagating at subsonic velocity (EN 1127-1:1997)
more details
deflagration flame arrester
a flame arrester designed to prevent the transmission of a deflagration. It can be end-of-line or in-line
more details
design pressure (common design)
pressure, together with the design temperature, used to determine the minimum permissible thickness or physical characteristic of each component, as determined by the design rules of the pressure-design code
more details