Data Sheet

Bulletin 71.1:MR105
8
Universal NACE Compliance
Optional materials are available for applications
handling sour gases. These constructions comply with
the recommendations of NACE International Sour
Service Standards.
The manufacturing processes and materials used
by Emerson Process Management Regulator
Technologies, Inc. assure that all products specied
for sour gas service comply with the chemical,
physical and metallurgical requirements of NACE
MR0175 and/or NACE MR0103. Customers have
the responsibility to specify correct materials.
Environmental limitations may apply and shall be
determined by the user.
Capacity Information
Air Capacities
To determine wide-open ow capacity for relief valve
sizing, use one of the following equations:
For Critical Pressure Drops
Use this equation for critical pressure drops (absolute
outlet pressure equal to one-half or less than one-half
the absolute inlet pressure).
Q = P
1(abs)
C
g
where,
Q = gas ow rate, SCFH
C
g
= gas sizing coefcient
P
1
= absolute inlet pressure, psia
For Non-Critical Pressure Drops
Use this equation for pressure drops lower than critical
(absolute outlet pressure greater than one-half of
absolute inlet pressure).
Q = C
g
P
1
SIN DEG
520
GT
3417
C
1
ΔP
P
1
Table 4. Maximum Differential Pressures
Table 5. Wide-Open Flow and IEC Sizing Coefficients
LINEAR CAGE
Body Size
Wide-Open Flow Coefcient IEC Sizing Coefcient
Line Size Equals Body Size
C
1
K
m
F
L
X
T
F
d
NPS DN C
g
C
v
1 25 463 13.7 34.0 0.81 0.90 0.73 0.36
2 50 761 22.5 33.8 0.75 0.87 0.72 0.24
3 80 997 30.5 32.7 0.78 0.88 0.68 0.22
4 100 934 27.5 34.0 0.77 0.88 0.75 0.18
QUICK OPENING CAGE
Body Size
Wide-Open Flow Coefcient IEC Sizing Coefcient
Line Size Equals Body Size
C
1
K
m
F
L
X
T
F
d
NPS DN C
g
C
v
1 25 597 17.5 34.1 0.81 0.90 0.73 0.43
2 50 1740 48.2 36.1 0.81 0.90 0.82 0.34
3 80 3540 103.1 34.4 0.76 0.87 0.75 0.32
4 100 4300 135.9 31.6 0.72 0.85 0.65 0.30
REDUCED PORT QUICK OPENING CAGE
Body Size
Wide-Open Flow Coefcient IEC Sizing Coefcient
Line Size Equals Body Size
C
1
K
m
F
L
X
T
F
d
NPS DN C
g
C
v
2 50 1570 43.8 35.9 0.81 0.90 0.72 0.36
ACTUATOR TYPE
BODY SIZE
MAXIMUM DIFFERENTIAL PRESSURE
Gas Service (Linear Cage) Liquid Service (Quick Opening Cage)
NPS DN psid bar d psid bar d
Low Pressure
1 25
400 or maximum
inlet pressure,
whichever is lower
27.6 or maximum
inlet pressure,
whichever is lower
200 13.6
2 50 200 13.6
3 80 225 15.5
4 100 225 15.5
High Pressure
1 25
400 or maximum
inlet pressure,
whichever is lower
27.6 or maximum
inlet pressure,
whichever is lower
250 17.2
2 50 200 13.6
3 80 225 15.5
4 100 250 17.2