Deep-set venting gauge hatch

  • The Series 4000 Marsh Hawk TRV offers tank access combined with pressure and vacuum relief in a deep-set design.
  • Situating valve seats below the tank roof permits latent heat from the product to keep the seals ice-free.

Reliable, bubble-tight sealing

  • The Series 4000 has class-leading seal performance as compared to any other premium or economy venting gauge hatch currently available.
  • Improved sealing performance eliminates flutter and periodic small-scale venting which can cause frost closure in competitor top-mount hatches.

Variety of pressure settings

  • The Series 4000 Marsh Hawk pressure relief is adjustable between 2 ozsi and 16 ozsi in 2 ozsi increments.
  • The optional double-weight spring allows relief pressure between 18 and 32 ozsi, in 2 ozsi increments.
  • 1 ozsi increments optionally available.
  • Vacuum relief is fixed at 0.4 ozsi.

Suitable for Sour Service

  • The Series 4000 is ready for Sour Service out of the box with FKM (Viton) seals and stainless springs.
  • For more adverse applications, alternative seal and spring materials are available, along with hard anodization or fusion-bond epoxy coatings.


Function Venting Gauge Hatch
Temperature Range (FKM) - 26°C to 204°C [-15°F to 400°F]
Temperature Range (FEPM) -9°C to 230°C [16°F to 446°F]
Temperature Range (FFKM) -18°C to 320°C [0°F to 600°F]
Pressure Relief Type Direct-acting, Spring-loaded
Pressure Relief Range 2 to 32 ozsi
Vacuum Relief Range 0.4 ozsi fixed
Tank Connection 8” API (Fig 1 API 12F)

Related Documents


Download Brochure

Vent Sizing Chart

Download Vent Sizing Charts

A guide to venting upstream tanks

Download TB-1217-TV

Installation Instructions

Download Instructions

Mounting and Riser considerations

Download Mounting Guide

Ordering Information

Standard Series 4000 Marsh Hawk configurations are stocked ready to ship. Other configurations are typically assemble-to-order and available in under two weeks.

Please refer to the chart in the brochure PDF.

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