OPW 178S Series External AST Emergency Shut-Off Valve

The OPW 178S Series External AST Shut-Off Valve is designed to shut off product flow from an aboveground storage tank, bulk loading rack or any place in the fuel supply line in the event of a fire. The 178S installs in-line on fuel supply piping. A fusible link attached to a spring-operated lever holds the poppet normally open. In the event of a fire, the fusible link melts at 160°F, allowing the spring-actuated poppet to shut off the flow of product in the fuel supply line. The 178S is available in 2″ female NPT connections.


The 82RV is designed to give thermal pressure relief to our 821 Series Solenoid Valve line. Made of all stainless steel construction with a Viton® seal, it is suitable for all petroleum products. The 82RV is precision set at the factory at 25 PSI (1.7 bar), and is field adjustable from 5 to 30 PSI (.34 to 2 bar).

Features & BenefitsOrder SpecificationReplacement PartsDownloads


  • 178S Ductile Iron Construction – valve is manufactured from a ferrous metal to resist fracturing from high temperatures.
  • Full-Bore Inside Diameter for Superior Flow Rates – maximizes flow rates in the fuel supply lines.
  • Protected Main Poppet Disc – main poppet seal is held out of the main flow stream and protected from damage due to dirt or debris in the fuel.
  • Compensator Ring on Main Poppet Carrier – ensures full seating of the main poppet for a tight seal.
  • Viton® Main Disc and Stem Seat – compatible with gasoline, diesel, kerosene, ethanol, methanol, MTBE, fuel oil, mogas, motor oil and various other blends of fuel.
  • Rated At Normal Pressure Limit of 125 psi (8.6 bar) (cold)
  • Non-Shock Pressure Limit of 200 psi (13.8 bar)
  • Temperature Limit 225° F


  • Body and Cap: ductile iron
  • Packing Nut and Stem: Stainless steel
  • Disc: Viton®
  • Stem Seat: Viton®
  • Seat ring: brass
  • Cap and Packing Nut Seals: Viton®

Ordering Specifications

Product # in. mm lbs. kg
178S-6130 2 51 5.35 2.43

For more information contact OPW Customer Service at 1-800-422-2525; International call 1-513-870-3315.


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in. mm
A 5-17/32 140
B 3-1/16 78
C 3-1/16 62

Replacement Parts

Key Part No. Description
1 H05973M Spring
2 H12070M O-ring (Viton®)
3 H7635RB Packing Nut
4 H10445M O-ring (Viton®)
5 H01344M Fusible Link Sub-Assy
6 H01505RB Pin
7 C01533RB Stem
8 H07644M Set Screw
9 H07642ZA Lever
10 H03295M Washer
11 H04035M Disc Nut
12 H12071R Disc (Viton®)
13 H10004A Disc Holder
14 H11293M Compensating Ring
15 C03144M Carrier
16 H11547DI Cap
17 H10003M Retaining Ring


Catalog Page

AST Product Configurations