7
EN-DFA Series
North America
Only
Burn Time Rating
▲
WARNING
Temperature sensors must be used with
this product if there is a potential for
stabilized burning inside the arrestor.
Additional external safety equipment
is required to ensure appropriate
corrective measures are taken within
30 seconds to protect the system if an
abnormal temperature is detected. Never
disconnect or remove these devices in
active process systems.
All Model EN-DFA detonation flame arrestors are rated
for short time burning, t
BT
not to exceed one minute in
accordance with EN ISO 16852:2016. This burn time
was determined at atmospheric pressure. If there are
operating conditions which can lead to a stabilized
burning event, additional safety measures are
required. Depending on the operating conditions, the
devices shall be equipped with temperature sensors
on one or both sides of the flame arrestor element.
These temperature sensors are installed into the
system in such a way that they trigger the initiation of
measures for the elimination of the stabilized burning
(for example, emergency functions like switching-
off the system, inerting or similar). These measures
must occur within half of the time for which the flame
arrestor is short-time burn proof (0.5 x t
BT
). See Figure
4 for warning labels showing burn rating, t
BT
. This
requires that measures must be able to be taken within
30 seconds.
Threaded instrumentation ports, with standard 3/4 NPT
threads, are integrated into each end section. Other
instrumentation port thread sizes can be requested.
If the user requests the addition of temperature
sensors by Emerson, they will either be installed and
shipped threaded into the appropriate instrumentation
ports in the flame arrestor end sections or shipped
separately with the flame arrestor. To install the
temperature sensors that have been shipped
separately, simply remove any protective packaging
from the temperature sensors and thread the
temperature sensors into the appropriate threaded
instrumentation ports on the flame arrestor end
sections making sure to follow temperature sensor
manufacturer’s instructions, particularly for wiring.
In the case where only one temperature sensor was
requested from Emerson, the flame arrestor will be
marked with a flow arrow to indicate flow direction
and the temperature sensor will be installed on the
downstream or unprotected (“hot”) side of the flame
arrestor. This is the side of the flame arrestor closest
to the source of ignition. If the temperature sensor is
shipped separately, the user shall be responsible for
Table 8.
Torque Values for Flat Face Connection Flange (Steel Only)
NOMINAL PIPE DIAMETER
NUMBER OF BOLTS
BOLT DIAMETER
TORQUE
In.
mm
Ft-lb
N•m
1
4
0.50
12.70
14
18.98
1-1/4
4
0.50
12.70
16
21.69
1-1/2
4
0.50
12.70
18
24.41
2
4
0.63
16.00
32
43.39
2-1/2
4
0.63
16.00
43
58.30
3
4
0.63
16.00
47
63.72
3-1/2
8
0.63
16.00
26
35.25
4
8
0.63
16.00
32
43.39
6
8
0.75
19.05
49
66.44
8
8
0.75
19.05
68
92.20
10
12
0.88
22.4
69
93.55
12
12
0.88
22.4
98
132.9
Assumptions: Use of SAE grade 5 bolts or studs or stronger
No lubricant
Elastomer < 70 Durometer Shore A
Notes: If lubricant is used on bolts, apply torque reduction factor listed in Lubricant Table. For best results hardened steel washers should be used on all cast flange bolted connections.
Table 9.
Torque Correction Factors for Common Lubricants Applied on Connection Fasteners
DESCRIPTION
COEFFICIENT OF FRICTION
MULTIPLY TORQUE VALUE IN TABLE 8 BY
Machine Oil
f = 0.15
0.75
API SA2 Grease
f = 0.12
0.60
Nickel-based Lubricant
f = 0.11
0.55
Copper-based Lubricant
f = 0.10
0.50
Molydisulfide Based Lubricating Paste
f = 0.06
0.30
