Storage Tank Protection
Tank Safety Valve Manufacturer
BCST Valve manufactures tank safety valves for pressure relief, vacuum protection, emergency venting and controlled tank breathing. These devices help protect atmospheric and low-pressure storage tanks during normal operation and credible upset conditions.
Our tank safety valve range includes pressure vacuum relief valves, emergency vents, vacuum relief valves, flame-arresting vents and pressure relief manhole covers.
- Normal pressure and vacuum breathing
- Emergency pressure and vacuum relief
- Weight-loaded and spring-loaded designs
- Flame-arresting configurations for suitable applications
- Project-specific materials, settings and connections
Pressure Protection
Relieves vapor when tank pressure reaches the specified condition.
Vacuum Protection
Admits air or inert gas when excessive vacuum begins to develop.
Emergency Venting
Provides additional capacity during specified abnormal conditions.
Factory Verification
Functional and setting checks within the agreed inspection scope.
Product Collection
Tank Safety Valve Types
Select the protection function according to the tank design limits, operating conditions and credible emergency scenarios.
Pressure Vacuum Relief Valve
Controls pressure and vacuum during normal filling, withdrawal and thermal breathing.
- Pressure and vacuum protection
- Weight or spring loading
- End-of-line installation
Emergency Pressure Vent
Provides additional pressure-relief capacity when normal tank breathing equipment cannot pass the required emergency flow.
- High-capacity pressure relief
- Weight or spring-loaded cover
- Tank-top installation
Emergency Pressure Vacuum Vent
Provides emergency pressure relief and rapid intake protection through separate operating elements.
- Emergency pressure relief
- Emergency vacuum intake
- Combined tank protection
Vacuum Relief Valve
Admits air or inert gas when tank vacuum reaches the specified opening condition.
- Vacuum-only protection
- Direct or connected inlet
- Low-pressure tank service
Flame-Arresting Tank Vent
Combines the specified venting function with a flame-arresting element for a suitable application.
- Pressure and vacuum options
- Integrated flame-arresting element
- Application assessment required
Emergency Relief Manhole Cover
A large-area relief device designed to provide emergency venting and tank access in one assembly.
- Large relief opening
- Pressure-only or pressure vacuum options
- Selected sizes from DN450 to DN750
Product Comparison
Select the Appropriate Tank Safety Device
Normal breathing and emergency venting are different duties. The complete tank protection system should be evaluated for both.
| Safety Device | Pressure Relief | Vacuum Relief | Typical Duty | Key Selection Factor |
|---|---|---|---|---|
| Pressure Vacuum Relief Valve | Yes | Yes | Normal tank breathing | Filling, withdrawal and thermal flow |
| Emergency Pressure Vent | Yes | No | Emergency pressure relief | Emergency outbreathing capacity |
| Emergency Pressure Vacuum Vent | Yes | Yes | Emergency pressure and vacuum protection | Upset scenario and required capacity |
| Vacuum Relief Valve | No | Yes | Normal or dedicated vacuum protection | Withdrawal and cooling conditions |
| Flame-Arresting Tank Vent | Model dependent | Model dependent | Venting with flame protection | Gas group and flame scenario |
| Emergency Relief Manhole | Yes | Optional | Large-capacity emergency venting | Relief area and opening setting |
Protection Strategy
Normal Breathing and Emergency Relief
A storage tank may require separate devices for normal operation and emergency conditions. Each device should be selected for its intended duty.
- A pressure vacuum valve handles routine filling, withdrawal and thermal breathing.
- An emergency vent remains closed during normal operating conditions.
- The emergency vent opens when pressure reaches its specified emergency setting.
- A vacuum relief valve admits replacement gas when excessive vacuum develops.
- Each device reseats as tank conditions return toward its operating range.
- The combined capacity must protect the tank under the defined scenarios.
Tank Design Limits
All settings must remain within allowable pressure and vacuum limits.
Required Capacity
Normal and emergency venting duties must be calculated separately.
Stored Medium
Material and seal selections must suit the liquid and vapor.
Installation System
Screens, piping and flame elements affect available capacity.
Risk Review
Tank Conditions That Require Protection
Selection should consider normal operation and all credible abnormal conditions identified by the project team.
Product Filling
Incoming liquid displaces vapor and increases pressure inside the storage tank.
Product Withdrawal
Outgoing liquid creates an empty volume that must be replaced by air or inert gas.
Thermal Breathing
Changes in ambient or process temperature can expand or contract the tank vapor space.
External Fire Exposure
Heat input can rapidly increase vapor generation and emergency outbreathing demand.
Steam Condensation
Rapid condensation after steaming can produce a severe vacuum inside the tank.
Equipment Malfunction
Control failure, blocked venting or abnormal process flow can create an upset condition.
Technical Reference
Typical Tank Safety Valve Configurations
The following information summarizes selected catalog configurations. Final settings and sizes require engineering confirmation.
| Configuration | Typical Size Range | Catalog Setting Reference | Function |
|---|---|---|---|
| Normal Pressure Vacuum Vent | DN50 to DN250 | Project or catalog setting | Normal tank breathing |
| Pressure Relief and Intake Manhole | DN500 to DN600 | +1961 Pa / -392 Pa reference | Emergency pressure and vacuum protection |
| Pressure Relief Manhole Cover | DN450 to DN750 | Project-specific setting | Emergency pressure relief |
| Flame-Arresting Relief Manhole | Model dependent | Project-specific setting | Emergency venting with flame protection |
| Vacuum Relief Valve | DN50 to DN250 | -295 Pa or -392 Pa reference | Dedicated vacuum protection |
| Custom Tank Safety Valve | Project dependent | Specified by purchaser | Special tank protection requirements |
Available Sizes
Size and Capacity Selection
Connection size alone does not confirm adequate protection. Valve capacity must be evaluated at the specified opening condition.
Catalog Product Range
- Normal breathing valves: selected sizes from DN50 to DN400
- Emergency pressure vents: size range varies by model
- Relief manhole covers: selected sizes from DN450 to DN750
- Flanged connection options for different projects
- Custom configurations subject to technical review
Capacity Review
- Calculate normal pressure and vacuum breathing requirements.
- Identify credible emergency pressure and vacuum scenarios.
- Confirm opening settings against tank design limits.
- Include piping, screens and flame-element resistance.
- Verify the selected valve at the required operating point.
| Design Input | Why It Matters | Required Information |
|---|---|---|
| Tank Pressure Limit | Defines the maximum safe relief setting | Maximum allowable pressure |
| Tank Vacuum Limit | Defines the maximum safe vacuum setting | Maximum allowable vacuum |
| Normal Flow | Determines breathing valve capacity | Filling, withdrawal and thermal rates |
| Emergency Flow | Determines emergency vent capacity | Applicable emergency scenario |
| Vent System Resistance | Reduces available valve capacity | Piping, screens and installed accessories |
Materials
Material Options for Different Media
Material selection should consider the stored liquid, vapor composition, operating temperature, corrosion risk and environmental exposure.
| Component | Typical Material Options |
|---|---|
| Valve Body or Cover | Aluminum alloy, carbon steel, SS304, SS304L, SS316 or SS316L |
| Pallet or Relief Disc | Stainless steel or body-compatible alloy |
| Guide Components | Stainless steel |
| Flame-Arresting Element | Stainless steel, model dependent |
| Seal | PTFE or application-specific material |
Selection Checklist
Information Required for Technical Selection
Complete operating data allows the manufacturer to review valve function, settings, capacity, materials and installation compatibility.
Tank Data
- Tank type and storage volume
- Maximum allowable pressure
- Maximum allowable vacuum
- Tank nozzle size and rating
- Tank design and operating requirements
Process Data
- Stored liquid and vapor composition
- Maximum filling rate
- Maximum withdrawal rate
- Operating and ambient temperatures
- Defined emergency scenarios
Project Requirements
- Normal and emergency settings
- Body, trim and seal materials
- Flange standard and facing
- Accessories and flame protection
- Inspection and documentation scope
Applications
Tank Safety Valve Applications
Tank safety valves support storage installations across industries where pressure, vacuum and emergency venting must be controlled.
Oil & Gas
Protection for petroleum product and hydrocarbon storage tanks.
Tank Farms
Normal and emergency venting for bulk storage terminals.
Chemical Processing
Material-compatible tank protection for chemicals and solvents.
Refineries
Tank breathing and emergency relief for refinery storage systems.
Manufacturer Quality Control
Inspection Before Delivery
The inspection scope is confirmed during order review and depends on the selected product and project requirements.
- Review the approved datasheet and product drawing.
- Verify body, internal and sealing materials.
- Inspect dimensions, connections and product markings.
- Check the specified pressure or vacuum opening condition.
- Inspect sealing and free movement of operating components.
- Review documentation and protective packing.
Installation & Maintenance
Maintain Reliable Tank Protection
Correct installation and scheduled inspection help preserve the intended settings, sealing performance and relief capacity.
Installation Guidelines
- Install each valve in its specified orientation.
- Keep tank nozzles and vent passages clean.
- Avoid transferring piping loads to valve bodies.
- Confirm that operating components move freely.
- Include backpressure in connected vent systems.
- Provide safe access for inspection and maintenance.
Maintenance Guidelines
- Inspect screens and flow passages for blockage.
- Clean pallets, covers and seating surfaces.
- Examine seals for wear or chemical damage.
- Inspect flame-arresting elements where fitted.
- Do not alter weights or springs without authorization.
- Verify operation before returning equipment to service.
Send Us Your Tank Protection Data
Provide the tank design limits, normal and emergency flow requirements, stored medium, settings and connection details. BCST Valve will review the information and recommend an appropriate tank safety valve configuration.
Frequently Asked Questions
Tank Safety Valve FAQ
Answers to common questions from tank designers, plant operators and procurement teams.
What is a tank safety valve?
Tank safety valve is a general term for equipment that protects a storage tank from excessive pressure, vacuum or emergency venting conditions.
Which tank safety valve do I need?
The answer depends on whether the duty is normal breathing, emergency pressure relief, vacuum protection, flame protection or a combination of these functions.
Does a pressure vacuum valve replace an emergency vent?
Not automatically. Normal breathing and emergency relief are different duties. Each should be evaluated against its required capacity and setting.
How is the correct size selected?
Selection uses the required normal or emergency flow, opening setting, tank design limits, vapor properties and resistance through the complete vent path.
Can I select by tank nozzle size?
No. A matching connection does not prove adequate capacity. Valve performance must be checked at the specified pressure or vacuum condition.
When is a flame-arresting device required?
It may be required when the application risk assessment identifies a flame transmission hazard. The vapor, gas group, installation and credible flame scenario must be reviewed.
Can the settings be customized?
Selected models can be reviewed for project-specific settings. The values must remain compatible with the tank limits, required capacity and device construction.
What materials are available?
Options include aluminum alloy, carbon steel, SS304, SS304L, SS316 and SS316L, subject to the selected model and stored medium.
How often should tank safety valves be inspected?
Inspection frequency depends on the medium, operating conditions, environment and site maintenance program. Moving parts and flow passages must remain clean and unobstructed.
What information is required for a quotation?
Provide tank limits, filling and withdrawal rates, emergency scenarios, stored medium, temperatures, required settings, connections and documentation requirements.
Need Help Selecting a Tank Safety Valve?
Send your tank and process data to BCST Valve for technical selection and quotation support.
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