Shand & Jurs 94221 P&V Emergency Vent and Manhole Cover

For terminal operators, refinery specifiers, and digester-cover designers, the Shand & Jurs 94221 consolidates conservation venting, emergency relief, and manway access into a single tank-roof penetration for atmospheric storage tanks and fixed digester covers.

Unlike split installations that use separate P/V vents, emergency vents, and manways — multiplying leak paths, nozzle counts, and roof reinforcement — the 94221 handles all three functions at one location, with a limited-lift cover that automatically reseats after an overpressure event.

Weight-loaded pressure and vacuum pallets provide predictable routine breathing. On an excursion, the limited-lift emergency cover opens for high-capacity discharge, reseats without cover loss, and requires no manual intervention. Sizing is per API 2000 with WinSize support.

Optional Expanda-Seal technology (setpoints 1.5 oz/in² and higher) tightens sealing as operating pressure approaches setpoint, holding leakage under 0.5 SCFH at 95 percent. Available in 20-inch and 24-inch sizes with ANSI Class 150 FF, API-650, or EN1092-1 flanges.

Features

Consolidates pressure relief, vacuum relief, emergency venting, and tank access into one roof penetration, reducing nozzle count and simplifying tank-top layout.

Emergency cover opens for high-capacity discharge during overpressure events and automatically reseats without cover loss or manual reinstallation.

Diaphragm-sealed pressure and vacuum pallets maintain predictable routine breathing performance, stabilizing tank pressure across daily thermal cycles.

Available on setpoints 1.5 oz/in² and higher, holds leakage under 0.5 SCFH at 95 percent of setpoint, reducing fugitive emissions during normal operation.

Direct installation on standard API 650 tank-roof manways supports retrofit into existing roof openings without tank-top modification or reinforcement.

Service access through the integrated manway avoids unbolting separate covers, reducing downtime, confined-space preparation, and gasket-replacement cost.

Applications

Petroleum Storage: Combines routine breathing, emergency relief, and inspection access on crude, product, and intermediate tanks requiring both normal and fire-case protection.
Chemical Storage: Handles elevated-pressure and corrosive-vapor service with aluminum, carbon steel, or 316 stainless steel bodies matched to the process environment.
Tank Farms: Reduces nozzle count across large terminal installations, lowering reinforcement requirements and leak paths versus separate vent, emergency, and manway hardware.
Fire Case Protection: Limited-lift emergency cover delivers high-capacity discharge sized per API 2000 fire-case methodology, supporting engineering review and documented safety cases.
Fixed Digester Covers: Protects anaerobic digester covers against biogenic and thermal pressure events while preserving routine inspection and maintenance access through the same opening.
VOC-Regulated Tanks: Expanda-Seal option reduces continuous vapor leakage near setpoint, supporting reduced-emission operating programs at terminals and chemical sites.

Specifications

Parameter

Specification

Device Type

Combined P/V conservation vent, limited-lift emergency vent, and manhole cover

Pressure Settings

1.0 oz/in² (1.73″ W.C.) Aluminum; 1.3 oz/in² (2.25″ W.C.) Stainless Steel

Vacuum Settings

1.1 oz/in² (1.9″ W.C.)

Maximum Pressure Setting

8 oz/in² (13.84″ W.C.)

Maximum Vacuum Setting

4.0 oz/in² (6.92″ W.C.)

Emergency Relief

Limited-lift cover (automatic reseating)

Expanda-Seal Leakage

<0.5 SCFH at 95% of setpoint

Standard Leakage (Baseline)

~1.0 SCFH at 90% of setpoint

Sealing Method

Diaphragm-sealed pallets

Loading Method

Weight-loaded

Nominal Sizes

20″ and 24″

Connections

ANSI Class 150 FF; API-650; EN1092-1 available

Sizing Basis

API 2000 (WinSize / EZ-Flow support)

Body Material

Steel (normal service), Aluminum (low temperature), or 316 Stainless Steel

Pallets

Aluminum or 316 Stainless Steel

Diaphragm

FEP (standard); FKM or PFA for Expanda-Seal assemblies

Weights

Lead and Steel (standard); 316 Stainless Steel available

Hardware

316 Stainless Steel

Temperature Range

Aluminum −65°F to +250°F; Carbon Steel −20°F to +350°F; 316 SS −65°F to +350°F

Approvals / Options

API-650 mounting, stainless steel construction, alternate diaphragm materials, raised-face flange (CS/SS only), ATEX certification

2026 COST ESTIMATE

Contact Support

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

What makes the 94221 different from a conventional emergency vent?

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A conventional emergency vent lifts its cover during an overpressure event and stays open until a technician reinstalls it. The 94221 uses a limited-lift cover that opens for high-capacity discharge and then automatically reseats once pressure subsides — no cover loss, no manual intervention, no reinstallation labor. It also combines P/V conservation venting and manway access in the same penetration.

Does the 94221 meet API 2000?

Sizing follows API 2000 methodology for normal and emergency venting capacity, supported by Shand & Jurs WinSize (EZ-Flow) software. Final conformance to the site’s applicable standards is determined by the owner / operator and engineering review.

What sizes and mountings are offered?

The 94221 is available in 20″ and 24″ sizes. ANSI Class 150 FF and API-650 mounting are standard; EN1092-1 flanges are also available. API-650 mounting supports direct installation on standard tank-roof manways.

When should Expanda-Seal be specified?

Expanda-Seal is recommended where continuous vapor leakage near setpoint would carry an emissions, odor, or product-value penalty — VOC-regulated terminals, high-value product storage, and nitrogen-blanketed tanks. It is available on configurations with setpoints of 1.5 oz/in² or higher and is not available on the lowest-setpoint configurations.

Can the 94221 be used on fixed digester covers?

Yes. Wastewater digester covers subject to biogenic and thermal pressure events benefit from the combined P/V, emergency, and manway design: fewer penetrations, automatic reseat after an event, and built-in inspection access. 316 stainless steel and alternate diaphragm materials are available for aggressive biogas chemistry.

How does the 94221 interact with separate emergency vents?

Where it is installed, the 94221 is itself the emergency vent and the P/V conservation vent and the manway. On tanks that require greater fire-case capacity than the 94221 delivers, it can be paired with a higher-capacity emergency vent such as the 9420X lift-cover series; engineering design sets the combination.

Summary

With over a century of tank-safety heritage inside Cognesense, the Shand & Jurs 94221 combines P/V conservation venting, limited-lift emergency relief, and manway access in a single roof penetration, protecting atmospheric storage tanks and fixed digester covers during routine and fire-case events. The limited-lift cover automatically reseats after an overpressure event with no cover loss, while optional Expanda-Seal reduces continuous vapor leakage near setpoint. Sized per API 2000 with WinSize support, the 94221 helps terminals and chemical sites measure, monitor, and protect what matters most.

94221 P&V Emergency Vent and Manhole Cover