PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

D559T1-8M-1Valve,safety Relief

Circor Aerospace, Inc. Dba Circor Aerospace Inc · NSN 4820-01-443-9866 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-01-443-9866 — this item is cataloged by the U.S. Government under National Stock Number 4820-01-443-9866. Primary manufacturer part number: D559T1-8M-1.
Features
  • Valve,safety Relief — FSC 4820
  • Material: STEEL COMP 316 BODY
  • Connection Style: PLAIN (PIPE) FIRST END
  • Maximum Operating Temp: 250.0 FAHRENHEIT SINGLE RESPONSE DEGF
  • Style Designator: STRAIGHT THRU
  • Disk Loading Method: SPRING
  • Valve Operation Method: AUTOMATIC
  • Minimum Operating Temp: -40.0 FAHRENHEIT DEGF
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
  • Applications requiring Steel Comp 316 Body construction
General Description

The Valve,safety Relief, cataloged under National Stock Number 4820-01-443-9866, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Circor Aerospace, Inc. Dba Circor Aerospace Inc. Government technical data includes 14 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 5 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4820-01-443-9866
Primary Part NumberD559T1-8M-1
Item NameValve,safety Relief
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerCircor Aerospace, Inc. Dba Circor Aerospace Inc
StatusACTIVE
MaterialSTEEL COMP 316 BODY
Connection StylePLAIN (PIPE) FIRST END
Maximum Operating Temp250.0 FAHRENHEIT SINGLE RESPONSE DEGF
Style DesignatorSTRAIGHT THRU
Disk Loading MethodSPRING
Valve Operation MethodAUTOMATIC
Minimum Operating Temp-40.0 FAHRENHEIT DEGF
Furnished Items and Quantity1 DEFLECTOR CAP
Operating Pressure200.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS
Opening Pressure Setting1.0 POUNDS PER SQUARE INCH LBS
Thread Series DesignatorNPT FIRST END
Thread DirectionRIGHT-HAND FIRST END
Nominal Thread Size1.000 INCHES FIRST END IN
Connection TypeTHREADED EXTERNAL PIPE FIRST END
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 12
5940-00-143-4780MS25036-108 INTERCHANGEABLE
Terminal,lug
Sae International Dba Sae International
4320-00-585-77704875 INTERCHANGEABLE
Pump Unit,centrifugal
E C Schleyer Pump Co Inc
5940-00-617-24302-34161-1 INTERCHANGEABLE
Terminal,lug
Te Connectivity Corporation
3040-00-671-1582487-5 INTERCHANGEABLE
Gearshaft,worm Wheel
Mas Components & Coatings, Llc Dba Mas Components & Coatings Llc
5330-01-037-87734875-5 INTERCHANGEABLE
Packing
Coffin Turbo Pump Inc
5120-01-073-6240GS15913-1 INTERCHANGEABLE
Inserter,bearing and Bushing
Hamilton Sundstrand Corporation Dba Collins Aerospace
5961-01-100-3465 INTERCHANGEABLE
Mounting Kit
5340-01-141-5484 INTERCHANGEABLE
Hardware Kit,electronic Equipmen
5915-01-204-10771603976 INTERCHANGEABLE
Filter,low Pass
Lockheed Martin Corporation Div Rms - Mitchel Field
4820-01-259-87774875-G503 INTERCHANGEABLE
Valve,safety Relief
Howell Laboratories Inc Dba Howell Laboratories Inc
Cross-Reference Index
Part NumberManufacturer
4875 Howell Laboratories Inc Dba Howell Laboratories Inc (USA)
D559T1-8M-1 PRIMARY Circor Aerospace, Inc. Dba Circor Aerospace Inc (USA)
4875-G501 Howell Laboratories Inc Dba Howell Laboratories Inc (USA)
4870 ITEM 67 Howell Laboratories Inc Dba Howell Laboratories Inc (USA)
4875C-G501 Howell Laboratories Inc Dba Howell Laboratories Inc (USA)
Related Parts
5940-00-143-4780INTERCHANGEABLE
TERMINAL,LUG
MS25036-108
4320-00-585-7770INTERCHANGEABLE
PUMP UNIT,CENTRIFUGAL
4875
5940-00-617-2430INTERCHANGEABLE
TERMINAL,LUG
2-34161-1
3040-00-671-1582INTERCHANGEABLE
GEARSHAFT,WORM WHEEL
487-5
5330-01-037-8773INTERCHANGEABLE
PACKING
4875-5
5120-01-073-6240INTERCHANGEABLE
INSERTER,BEARING AND BUSHING
GS15913-1
5961-01-100-3465INTERCHANGEABLE
MOUNTING KIT
5340-01-141-5484INTERCHANGEABLE
HARDWARE KIT,ELECTRONIC EQUIPMEN
5915-01-204-1077INTERCHANGEABLE
FILTER,LOW PASS
1603976
4820-01-259-8777INTERCHANGEABLE
VALVE,SAFETY RELIEF
4875-G503
2540-01-397-8646INTERCHANGEABLE
LATCH,DOOR,VEHICULAR
4875
2530-01-420-5572INTERCHANGEABLE
HUB,WHEEL,VEHICULAR

Frequently Asked Questions

What is NSN 4820-01-443-9866?

NSN 4820-01-443-9866 is a Valve,safety Relief, manufactured by Circor Aerospace, Inc. Dba Circor Aerospace Inc, classified under FSC 4820 (No Item Name Available). Status: active.

What are the part numbers for NSN 4820-01-443-9866?

NSN 4820-01-443-9866 has 5 cross-referenced part numbers: 4875 (Howell Laboratories Inc Dba Howell Laboratories Inc), D559T1-8M-1 (Circor Aerospace, Inc. Dba Circor Aerospace Inc), 4875-G501 (Howell Laboratories Inc Dba Howell Laboratories Inc), 4870 ITEM 67 (Howell Laboratories Inc Dba Howell Laboratories Inc), 4875C-G501 (Howell Laboratories Inc Dba Howell Laboratories Inc).

What NSN replaces 4820-01-443-9866?

There are 12 known substitutes for 4820-01-443-9866: 5940-00-143-4780, 4320-00-585-7770, 5940-00-617-2430 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of D559T1-8M-1?

Key specifications for D559T1-8M-1: Material: STEEL COMP 316 BODY; Connection Style: PLAIN (PIPE) FIRST END; Maximum Operating Temp: 250.0 FAHRENHEIT SINGLE RESPONSE DEGF; Style Designator: STRAIGHT THRU. 15 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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