Data Sheet

Bulletin 71.4:MR108
2
Specications
The Specications section on this page provides the ratings and other specications for the Type MR108. The
following information is stamped on the nameplate fastened on the regulator at the factory: type; body size;
maximum inlet, outlet and differential pressure; maximum pressure above setpoint; maximum casing pressure;
maximum temperature; spring range; cage type; and trim and diaphragm material.
BodySizesandEndConnectionStyles
See Table 1
ShutoffClassicationperANSI/FCI70-3-2004
Class VI (Soft Seat)
MaximumInlet,OutletandEmergency
CasingPressure
(1)
See Table 5
BackpressureControlRanges
5 to 300 psig / 0.34 to 20.7 bar; See Table 2
ConstructionMaterials
See Table 3
MaximumSetpoint
 Low-PressureActuator:35 psig / 2.4 bar
High-PressureActuator:
Nitrile (NBR) and Ethylene Propylene (EPDM)
Diaphragm: 300 psig / 20.7 bar
Fluorocarbon (FKM) Diaphragm: 150 psig / 10.3 bar
MaximumDifferentialPressures
Low-PressureActuator:70 psig / 4.8 bar
High-PressureActuator:400 psig / 27.6 bar or
maximum inlet pressure, whichever is lower
MaximumPressureOverSetpointtoAvoidInternal
PartsDamage
(1)
Low-PressureActuator:20 psig / 1.4 bar
High-PressureActuator: 120 psig / 8.3 bar
FlowandSizingCoefcients
See Table 4
C
v
Coefcients
See Tables 6 and 7
Capacities
See Tables 8 through 11
TemperatureCapabilities
(1)
 Nitrile(NBR):-20 to 180°F / -29 to 82°C
Fluorocarbon(FKM): 20 to 250°F / -7 to 121°C
(2)
EthylenePropylene(EPDM): -20 to 225°F /
-29 to 107°C
(3)
PressureRegistration
External
UpstreamControlLineConnectionSize
1/2 NPT
SpringCaseVent
Type Y602-12
Pressure-LoadedSpringCaseVentConnection
1/2 NPT
ApproximateWeights
 ForTypeMR108withLow-PressureActuator
NPS 1 / DN 25: 88 lbs / 40 kg
NPS 2 / DN 50: 118 lbs / 54 kg
NPS 3 / DN 80: 167 lbs / 76 kg
NPS 4 / DN 100: 176 lbs / 80 kg
ForTypeMR108withHigh-PressureActuator
NPS 1 / DN 25: 78 lbs / 35 kg
NPS 2 / DN 50: 107 lbs / 49 kg
NPS 3 / DN 80: 156 lbs / 71 kg
NPS 4 / DN 100: 166 lbs / 75 kg
Options
• Inlet Pressure Gauge Tap on Body
• Pressure-Loaded Actuator
• Drain Valve
• NACE Construction
• Bleed Valve (For High-Pressure Actuator only)
• Ethylene Propylene (EPDM) Elastomer Trim Parts
1. The pressure/temperature limits in this Bulletin or any applicable standard limitation should not be exceeded.
2. Fluorocarbon (FKM) is limited to 200°F / 93°C in hot water.
3. Ethylene Propylene (EPDM) is limited to 20 to 225°F / -7 to 107°C when used with Low Pressure Actuator.
Table 1. Body Sizes and End Connection Styles
BODYMATERIAL
ENDCONNECTIONSTYLE
NPS1and2/DN25and50BodySizes NPS3and4/DN80and100BodySizes
Cast Iron NPT, CL125 FF or CL250 RF CL125 FF or CL250 RF
WCC Steel
(1)(2)
NPT, CL150 RF, CL300 RF, CL600 RF or PN 16/25/40 RF CL150 RF, CL300 RF, CL600 RF or PN 16 RF
CF8M Stainless steel
(1)(2)
NPT, CL150 RF, CL300 RF, CL600 RF or PN 16/25/40 RF CL150 RF, CL300 RF, CL600 RF or PN 16 RF
CF3M Stainless steel
(1)(2)
NPT, CL150 RF, CL300 RF, CL600 RF or PN 16/25/40 RF CL150 RF, CL300 RF, CL600 RF or PN 16 RF
1. Optional NACE construction available.
2. Constructions meet API 614 requirements.