Shand & Jurs 9420X Series Emergency Vent and Manhole Cover

For atmospheric tank operators, refinery engineers, terminal designers, and EHS leaders responsible for fire-case overpressure protection on storage tanks needing both emergency relief and gas-tight personnel access, the Shand & Jurs 9420X Series provides high-capacity emergency venting and a tank-entry manway in a single device.

Unlike conventional emergency vents, where the cover can be dislodged during a relief event or require manual resetting afterward, the 9420X uses a limited-lift hinged pallet design: the cover lifts only as far as the relief requires, then automatically reseats when pressure subsides, eliminating manual reset and loss-of-cover risk.

The 94200 is the standard model with a weight-loaded cover and conventional pallet seal. The 94201 incorporates the optional Expanda-Seal™ diaphragm, which increases sealing force as pressure approaches the relief setting and reduces fugitive vapor losses during normal operation while delivering full emergency relief capacity when required.

Sized per API 2000 fire-case methodology and supported by Shand & Jurs WinSize EZ-Flow software, the 9420X covers 16″, 20″, 24″, 30″, and 36″ nominal sizes with ANSI Class 150, API 650 roof manhole, and EN PN16 flange drilling. For pressure-and-vacuum emergency service see the 94225; for higher-pressure spring-loaded service see the 94250.

Features

Pallet lifts only as far as the relief event requires and automatically reseats when pressure subsides, eliminating manual reset and loss-of-cover risk.

Same hinged cover delivers fire-case overpressure relief and gas-tight personnel access for inspection through one tank-roof opening.

Diaphragm seal increases sealing force as pressure approaches the relief setting, reducing fugitive vapor losses during normal operation.

Sizes 16″, 20″, 24″, 30″, 36″ with ANSI 150 RF, API 650 roof manhole, and EN PN16 flange drilling for global installations.

Body and pallet options span aluminum, carbon steel, and 316 stainless steel; FEP, FKM, and NBR diaphragm options across stored product chemistries.

CE for ordinary EU service and ATEX II 1 G Ex h IIB T1–T6 Ga for hazardous-area installations available on specified configurations.

Applications

Atmospheric Petroleum Storage: Fixed-roof tanks storing crude, refined products, and intermediates needing fire-case overpressure relief beyond conservation-vent capacity.
Chemical & Petrochemical Storage: Flammable and combustible chemical tanks where fire codes call for emergency venting plus safe interior access for cleaning and inspection.
Terminals & Tank Farms: Multi-tank facilities needing both fire-case overpressure protection and routine interior access for API 653 tank inspections without service interruption.
Refinery Process Storage: Process intermediate and finished-product atmospheric tanks subject to fire-impingement scenarios per API 2000 Annex A wetted-surface analysis.
Wastewater Digesters: Anaerobic digester covers needing emergency overpressure relief and gas-tight personnel access for biogas storage applications.
Fugitive-Emission-Sensitive Service: Sites needing low vapor losses during normal operation (94201 with Expanda-Seal™) paired with full fire-case emergency relief capacity.

Specifications

Parameter

Specification

Models

94200 (weight-loaded standard) | 94201 (Expanda-Seal™ low-leakage)

Function

Emergency overpressure relief and tank-entry manway access

Operating Condition

Normally closed, weight-loaded gravity-hinged cover

Nominal Sizes

16″, 20″, 24″, 30″, 36″ (ANSI 150); 20″ &24″ (API 650 roof manhole); 20″ available with 24″ flange

Flange Standards

ANSI Class 150 RF; API 650 roof manhole; EN PN16; UL 142 drilling

Minimum Pressure (Aluminum Pallet)

0.865 oz/in² (16″–24″); 1.1 oz/in² (30″–36″)

Minimum Pressure (CS / SS Pallet)

1.6 oz/in² (16″); 1.5 oz/in² (20″–36″)

Standard Maximum Pressure

8.0 oz/in² (16″ and 20″); 6.0 oz/in² (24″–36″); higher settings available

Body &Pallet Materials

Aluminum, Carbon Steel, or 316 Stainless Steel

Diaphragm Materials

FEP (Fluorinated Ethylene Propylene), FKM (Fluoroelastomer), or NBR (Nitrile-Butadiene)

Diaphragm Seat (94201)

Aluminum or 316 Stainless Steel

Temperature — Aluminum

−65°F to 250°F (−54°C to 121°C)

Temperature — Carbon Steel

−20°F to 350°F (−29°C to 177°C)

Temperature — 316 Stainless Steel

−65°F to 350°F (−54°C to 177°C)

Approvals

CE marking for ordinary EU service; ATEX II 1 G Ex h IIB T1–T6 Ga for hazardous-area service (option-dependent)

Quality System

Manufactured under an ISO 9001-certified quality system

Standards Alignment

Sized per API 2000 fire-case methodology; supports NFPA 30 emergency-venting programs; conformance determined at the site level

Sizing Tool

Shand & Jurs WinSize (EZ-Flow) software supports fire-case vapor-rate and wetted-surface calculations

2026 COST ESTIMATE

Contact Support

If you have questions not covered here, please contact the Cognesense support team for assistance.

When do I use the 94200 vs. the 94201?

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The 94200 is the standard weight-loaded model — the right choice when normal-operation fugitive losses are not a concern and a conventional pallet seal is sufficient. The 94201 adds the Expanda-Seal™ diaphragm, which increases sealing force near the relief setting to reduce vapor losses during normal breathing. Specify the 94201 where fugitive emissions matter or where VOC controls drive the design.

What sizes and flange standards are available?

Nominal sizes 16″, 20″, 24″, 30″, and 36″ on ANSI Class 150 RF flanges; 20″ and 24″ available on API 650 roof manhole; 20″ available with a 24″ flange for retrofits. EN PN16 and UL 142 drilling are also offered. Specify the flange standard at order time.

How does the limited-lift hinged design work?

The pallet is hinged and weight-loaded with a controlled lift travel. During an overpressure event the cover lifts only as far as the relief requires, vapor discharges, and the cover automatically reseats as pressure subsides — no manual reset, no risk of the cover being dislodged or lost during the event.

What materials are available?

Body and pallet options are aluminum, carbon steel, or 316 stainless steel. Diaphragm material (94200) is FEP, FKM, or NBR. The 94201 Expanda-Seal™ diaphragm seat is aluminum or 316 stainless steel. Hardware and load weights match the body alloy by default; 316 SS hardware and weights are available.

How is the 9420X sized for fire-case relief?

Sizing follows the API 2000 methodology for fire-case vapor generation rates and tank wetted-surface area. Shand & Jurs WinSize (EZ-Flow) software supports the calculation. Final selection must account for tank design pressure and any other concurrent venting paths; site-level conformance to specific overfill or fire-protection programs is the operator’s determination.

What does Expanda-Seal™ do, and is it worth the cost upgrade?

Expanda-Seal™ is a low-leakage diaphragm that increases sealing force as tank pressure approaches the relief setting, reducing fugitive vapor loss during normal breathing. The economic case depends on stored product volatility, vapor pressure, and any local VOC-emission limits. On high-volatility products it can return its cost in annual product retention per tank.

When should I specify the 94250 spring-loaded design instead?

Specify the 94250 when set pressures exceed the practical range of a weight-loaded pallet — typically above a few ounces per square inch and up to 15 PSIG. The 9420X Series is correct for ounce-per-square-inch set points typical of atmospheric tanks; the 94250 is the right answer for pressurized storage where weight-loaded designs become impractical.

When should I specify the 94225 P/V emergency vent instead?

The 9420X provides pressure relief only. Specify the 94225 P/V Emergency Vent and Manway Cover when the tank requires both fire-case pressure relief and emergency vacuum relief in a single combined device — typically on tanks that can experience both extraordinary overpressure and rapid vacuum (e.g., during high pumping rates or rapid cooldown after a fire event).

Does the 9420X provide vacuum relief?

No. The 9420X Series is a pressure-only emergency vent. For combined pressure-and-vacuum emergency relief in a single hinged cover, see the 94225 Series. For tanks needing only vacuum relief at conservation-vent levels, see the 94080 and 94100 vacuum vent series.

Does the 9420X require a separate manway, or does it serve as one?

The 9420X serves as the manway. Lift the hinged cover for personnel access during inspection and cleaning; the limited-lift hinge and retaining cable keep the cover captive. The combined function eliminates a separate manway nozzle and reduces total roof penetrations, which lowers the count of potential fugitive-emission paths on the tank.

9420X Series Emergency Vent and Manhole Cover