
5
TECHNICAL DATA (continued)
Electrical Connection Through base with screw/clamp
terminals
Physical Size 5e in (143 mm) width
(See Figure 1)
Electrical Wiring Two-wire 18 AWG thermoplastic
in conduit. 18 AWG limited energy
shield cable
Weight 1 pound (45 kilograms)
Maximum detectors per
circuit (ZN-30 or ZU-35) 5 detectors
APPLICATION DATA
Flame detectors are essentially line-of-sight devices. That is, the
detector must be mounted where it can see the flame directly.
Pay particular attention to blind spots, such as intervening struc-
tural beams and columns, ducts, chutes, or belts. Any other
opaque objects or materials including heavy personnel traffic
must also be considered.
In hazards which include conveyor belts, the line-of-sight of the
detector must clear not only the belt, but a full conveyor load as
well.
Among the materials that are opaque (non-transmitting) to ultra-
violet radiation are ordinary glass and transparent plastics.
The DF-30 detector alarms after a 5-second view of a flame of
sufficient intensity and should be used in hazards where a fast
response is necessary, such as volatile material handling areas,
and where there are no other sources of ultraviolet rays which
may cause false alarms. The DF-30A responds after a 10-second
exposure to flame (at the design intensity) and can be used in
hazards where the fire is expected to develop at a slower rate.
Signal interference substances that must be considered are UV
absorbing gases and vapors. Ammonia is such a vapor, but others
of more importance in the industrial environment are toluene,
ethylene, and similar sol ents. Therefore, when considering
protection of equipment where paint is in use, be sure to con-
sider the concentrations of the sol ents present.