Flowserve NRG 16-50 - Manual (Page 5)

5
Directives and Standards
Pressure Equipment Directive (PED) 97/23/EC
Water level limiters are safety accessories as defined in the Pressure Equipment Directive (PED). The
level electrode NRG ...-50 in conjunction with level switch NRS -50 is EC type approved according
to EN 95/EN 953. These Directives state, among other things, the requirements made on limiting
systems and equipment for steam boiler plants and (pressurised) hot-water installations.
ATEX (Atmosphère Explosible)
The level electrodes NRG ...-50, NRG ...- and NRG 6-36 are simple items of electrical equipment
as specified in EN 60079- section 5.7. According to the European Directive 94/9/EC the equipment
must be equipped with approved Zener barriers if used in potentially explosive areas. Applicable in
Ex zones , (999/9/EC). The equipment does not bear an Ex marking.
The suitability of the Zener barriers is certified in a separate document.
Note that the requirements of the IEC 6508 are not met if the NRG ...-50, NRG ...-,
NRG 6-36 + Zener barriers + NRS -50 are interconnected!
VdTÜV Bulletin “Wasserstand 100” (= Water Level 100)
The level electrodes NRG -50, NRG ...- and NRG 6-36 in conjunction with the level switch
NRS -50 are type approved according to the VdTÜV Bulletin “Water Level 00”.
The VdTÜV Bulletin “Wasserstand (=Water Level) 00” specifies the requirements made on water level
control and limiting equipment for boilers.
Functional Safety acc. to IEC 61508
The level electrodes NRG ...-50 / NRG 6-36 are certified acc. to IEC 6508 only if used in
combination with level switch NRS -50.
This standard describes the functional safety of safety-related electrical/electronic/programmable
electronic systems.
The equipment combination NRG ...-50 or NRG 6-36 + NRS -50 corresponds to a type B
subsystem with Safety Integrity Level (SIL) 3.