Hatch Risers

Hatch risers are used to mount Marsh Hawk TRV units to tanks with sloped roofs. The riser accommodates the slope angle of the roof, allowing the hatch to sit in an upright orientation, while keeping the internals of the vent within the heat envelope of the tank. The risers have 8” API mounting flanges on top and bot-tom, and a canted at the standard 12:1 roof pitch.

Adapter Spools

Adapter spools are used to mount a Marsh Hawk or TVTH to a tank lacking the standard 8” API mounting pattern. The spool height accommodates fastener installation, while keeping the Marshhawk internals within the heat envelope of the tank. Common adapter spools include 8 and 12 150# ANSI, as well as the API 18” and 22” oblong bolt patterns. Custom mounting pat-terns can be accommodated, call us for more information.

Pipe-away System

The Pipe-away system provides means to capture emissions from a tank while still maintaining the pressure- and vacuum-relief characteristics of a Marsh Hawk TRV. The Pipe-away System sports a 4” 150# ANSI flange connection to pipe vapors away, in addition to a 8” API flange at the top that can accommodate a TVTH. The Pipe-away ships standard with a modified Marsh Hawk, blind 8” API flange, gaskets and tank mounting hardware.


Risers, spools and pipe-away systems are welded carbon steel, and coated with high temperature flat-black paint.

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Ordering Information


  1. Specify the 12:1 Vent Riser
  2. Specify Tank Connection (8 API Standard)

Spool Adapter

  1. Specify Spool Adapter
  2. Specify Tank Bolt Pattern (see left for typical connections)

Pipe-Away System

  1. Specify Pipe-away System
  2. The following steps are the same as ordering a Marsh Hawk
    • Specify Marsh Hawk TRV
    • Specify Pressure Release Setting (2 – 16 oz / in2)
    • Specify Seal Material
  3. Specify Pipe-away connection (4 150# ANSI Standard)

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