Types 98L and 98H
TYPE BODY MATERIAL
Cast Iron WCC Steel, CF8M Stainless steel
98L 1/4, 1/2, 3/4, 1 NPT
1/4 through 1 NPT, NPS 1/2 through 1 /
DN 15 through 25, SWE, CL150 RF,
CL300 RF, PN16/25/40 RF
98H 1/4, 1/2, 3/4, 1, 1-1/2,
2 NPT
1/4 through 2 NPT,
NPS 1/2 through 2 / DN 15 through 50,
SWE, CL150 RF, CL300 RF,
PN 16/25/40 RF
98HM – – – – 1/2, 3/4, 1, 1-1/2, 2 NPT
REGULATOR BODY SIZE BODY AND SPRING
CASE MATERIALS
MAXIMUM INLET
PRESSURE(3)
psig bar
Type 98L All Sizes
Cast Iron
Steel
Stainless Steel
60
125
125
4.1
8.6
8.6
Type 98H All Sizes
Cast Iron
Steel
Stainless Steel
300
300
300
20.7
20.7
20.7
Type 98HM All Sizes Steel
Stainless Steel
300
300
20.7
20.7
BODY SIZE XT FD FL Km NPS DN
1/4 – – – –
0.78 0.50
0.91 0.83
1/2 15 0.83 0.69
3/4 and 1 20 and 25 0.88 0.77
1-1/2 and 2 40 and 50 0.92 0.85
MATERIAL TEMPERATURE RANGE
Nitrile (NBR) -40 to 180°F / -40 to 82°C
Neoprene (CR) -40 to 180°F / -40 to 82°C
Fluorocarbon (FKM)(5) 0 to 300°F / -18 to 149°C
Limited to 200°F / 93°C for hot water
Ethylenepropylene (EPDM)(5) -40 to 275°F / -40 to 135°C
Perfluoroelastomer (FFKM)(5) 0 to 425°F / -18 to 218°C
PTFE Diaphragm protector -40 to 400°F / -40 to 207°C
MATERIAL TEMPERATURE RANGE
Cast iron(6) -40 to 406°F / -40 to 207°C
WCC Steel -20 to 450°F / -29 to 232°C
CF8M Stainless steel -40 to 450°F / -40 to 232°C
Available Constructions
Type 98L: Direct-operated low-pressure
backpressure regulator/relief valve with internal
pressure registration and standard adjusting screw
for 2 to 38 psig / 0.14 to 2.6 bar set pressure range
Type 98H: Direct-operated high-pressure
backpressure regulator/relief valve with internal
pressure registration and standard adjusting screw
for 5 to 200 psig / 0.34 to 13.8 bar set pressure range
Type 98HM: Direct-operated high-pressure
backpressure regulator/relief valve with external
pressure registration and standard adjusting screw
for 5 to 275 psig / 0.34 to 19.0 bar set pressure range
Body Sizes and End Connection Styles
Maximum Cold Working Pressures of Body Size
and Materials(1)(2)
Flow Coefficient
C1
: 35
IEC Sizing Coefficients
Relief Pressure Ranges
See Tables 1 and 2
Shutoff Classification Per ANSI/FCI 70-3-2004
Metal Seats: Class IV
Polytetrafluoroethylene (PTFE): Class IV
Elastomer Seats: Class VI
Temperature Capabilities for Elastomer Parts(1)(4)
Temperature Capabilities for Metal Parts(1)(4)
Type 98HM Sensing Line Connection
NPS 1/2, 1-1/2 or 2 / DN 15, 40 or 50 Body: 1/8 NPT
NPS 3/4 or 1 / DN 20 or 25 Body: 1/4 NPT
Pressure Registration
Types 98L and 98H: Internal
Type 98HM: External
Options
• Handwheel or tee handle for Types 98L and 98H
• Tapped spring case vent for Types 98L, 98H
and 98HM
• Seal washer to permit spring case pressure
loading for Types 98L, 98H and 98HM
Approximate Weights
Type 98L
NPS 1/4 Body: 6 lbs / 3 kg
NPS 1/2 / DN 15 Body: 13 lbs / 6 kg
NPS 3/4 / DN 20 Body: 30 lbs / 14 kg
NPS 1 / DN 25 Body: 30 lbs / 14 kg
Type 98H
NPS 1/4 Body: 7 lbs / 4 kg
NPS 1/2 / DN 15 Body: 7 lbs / 2 kg
NPS 3/4 / DN 20 Body: 16 lbs / 7 kg
NPS 1 / DN 25 Body: 16 lbs / 7 kg
NPS 1-1/2 / DN 40 Body: 55 lbs / 25 kg
NPS 2 / DN 50 Body: 55 lbs / 25 kg
Type 98HM
NPS 1/2 / DN 15 Body: 8 lbs / 4 kg
NPS 3/4 or 1 / DN 20 or 25 Body: 20 lbs / 9 kg
NPS 1-1/2 or 2 / DN 40 or 50 Body: 73 lbs / 33 kg
1. The pressure/temperature limits in this instruction manual or any applicable standard limitation should not be exceeded.
2. Temperature and/or the body end connection may decrease these maximum pressures.
3. Maximum inlet pressure equals set pressure plus buildup.
4. Pressure and/or the body end connection may decrease these maximum temperatures.
5. Not for use on steam service.
6. Not available for Type 98HM.
Specifications
This section lists the specifications for the Types 98L and 98H. Factory specifications are stamped on the
nameplate fastened on the regulator at the factory.
Type 98HM Backpressure/Relief Valve
TO UPSTREAM
SENSING LINE
October 2008 Type 98HM
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
COMP
A6925
3
Types 98L and 98H
The Type 98HM can be used for backpressure or
relief applications in liquid, gas or steam service.
The Type 98HM features a sensing line connection
for sensing pressure externally from the regulator.
The Type 98HM is a direct-operated, spring-to-close
regulator and requires no external power to operate.
A seal washer for the set screw can be included when
applications require pressure loading of the spring
case (not available on NPS 1-1/2 and 2 / DN 40 and
50 bodies).
Note
Using a Type 98HM as a relief valve
does not exclude the installation of an
ASME certified full flow relief valve as
specified by local codes and regulations
or system design.
Principle of Operation
Relief or backpressure valves respond to changes in
upstream pressure. Pressure changes register under
the diaphragm (see Figure 2) through a registration
hole in the valve body (through upstream sensing
line connection for Type 98HM). When the pressure
increases beyond the spring setting, the diaphragm
pressure overcomes the spring compression. This
causes the valve plug to move away from the orifice.
The flow line through the valve is open and excess
pressure is vented. When upstream pressure drops
back to normal, the valve resumes its closed position.
TYPE 98H
(ALSO TYPICAL OF TYPE 98L)
TYPE 98HM
INLET PRESSURE
OUTLET PRESSURE
ATMOSPHERIC PRESSURE
Figure 2. 98 Series Operational Schematics
Installation
▲ WARNING
Personal injury or system damage may
result if this relief valve/backpressure
regulator is installed where service
conditions could exceed the limits
given on the Specifications section
or regulator nameplate. Installations
should be adequately protected from
physical damage.
Overpressuring any portion of this
equipment may cause equipment
damage, leaks in the relief valve/
backpressure regulator, or personal
injury due to bursting of pressurecontaining parts. System operation
within the limits shown in the
Specifications section (page 2) does
not eliminate the possibility of damage
from external sources or debris in the
pipeline. The relief valve/backpressure
regulator should be inspected for
damage regularly and after any
overpressure condition
