Product Overview
The THINKTANK TT-YA42H / YA802Y Series is a spring-loaded safety relief valve designed for overpressure protection of high-pressure liquid process equipment and transmission pipelines.
The series is suitable for petroleum, chemical and other compatible liquid media at operating temperatures up to 200°C.
The TT-YA42H covers nominal pressure ratings of PN160, PN250 and PN400, while the TT-YA802Y provides a higher-pressure PN600 configuration.
Both models automatically relieve excessive system pressure and help protect pressure-containing equipment and piping from conditions exceeding the specified pressure limit.
Model Selection
TT-YA42H
The TT-YA42H is designed for high-pressure liquid-service applications with:
- Nominal Pressure: PN160 / PN250 / PN400
- Nominal Size: DN10–DN32
- Applicable Media: Petroleum, chemical and other compatible liquids
- Maximum Operating Temperature: ≤200°C
The dimensional data shows a flanged process connection arrangement together with an Rc threaded outlet connection.
TT-YA802Y
The TT-YA802Y is the higher-pressure configuration listed for:
- Nominal Pressure: PN600
- Nominal Sizes: DN15 / DN25
- Applicable Media: Petroleum, chemical and other compatible liquids
- Maximum Operating Temperature: ≤200°C
Its listed connection dimensions differ from the TT-YA42H and should therefore be treated as a separate configuration during piping design.
Quick Specifications
| Parameter | Specification |
|---|---|
| Model | TT-YA42H / TT-YA802Y |
| Product Type | High-Pressure Safety Relief Valve |
| Operating Principle | Spring-Loaded |
| Applicable Media | Petroleum, chemical and other liquids |
| Maximum Operating Temperature | ≤200°C |
| TT-YA42H Pressure Rating | PN160 / PN250 / PN400 |
| TT-YA42H Size Range | DN10–DN32 |
| TT-YA802Y Pressure Rating | PN600 |
| TT-YA802Y Sizes | DN15 / DN25 |
| Application | Equipment and liquid transmission piping |
| Function | Automatic Overpressure Protection |
| Manufacturer | THINKTANK |
How It Works
The TT-YA42H / YA802Y operates using a spring-loaded pressure relief principle.
During normal operation, spring force keeps the valve disc seated and the valve closed.
When the pressure of the protected liquid system reaches the specified set pressure, the hydraulic force acting on the disc overcomes the spring force and causes the valve to open.
Liquid is discharged through the valve outlet, reducing pressure in the protected equipment or pipeline.
As system pressure decreases to the required reseating condition, spring force moves the disc back toward the seat and the valve closes automatically.
High-Pressure Liquid Service
The TT-YA42H / YA802Y Series is intended for applications where both the liquid medium and relatively high system pressure must be considered during safety valve selection.
The listed nominal pressure classes extend from PN160 to PN600, depending on model.
For this type of application, valve selection should not be based only on the nominal pipe size or pressure rating. The following factors have a direct influence on valve selection and relieving capacity:
- Set pressure
- Operating pressure
- Required relieving capacity
- Fluid density
- Fluid viscosity
- Operating and relieving temperature
- Back pressure
- Connection configuration
The actual allowable set-pressure range should be confirmed for the selected valve configuration.
Typical Applications
The TT-YA42H / YA802Y Series can be considered for:
- Petroleum liquid transmission pipelines
- Chemical liquid process piping
- High-pressure liquid systems
- Process equipment
- Pressure-containing equipment
- High-pressure transfer systems
- Packaged process equipment
- Skid-mounted liquid process systems
Final valve selection should consider the actual liquid properties, set pressure, operating conditions, required relief capacity and piping configuration.
General Performance Requirements
| Applicable Medium | Shell Test Pressure Ps | Seal Test Pressure Pm | Blowdown ΔP | Discharge Pressure Pp | Lift Height H |
| Steam | — | 90% Pk or the minimum reseating pressure, whichever is lower | When Pk ≤ 0.4 MPa: ΔP ≤ 0.04 MPa; when Pk > 0.4 MPa: ΔP ≤ 10% Pk | ≤ 1.03 Pk | Full-lift: ≥ 1/4 d₀; Low-lift: ≥ 1/20 d₀ |
| Air or other gases | 1.5 PN | When Pk ≤ 0.3 MPa: Pm = Pk − 0.03 MPa; when Pk > 0.3 MPa: Pm = 90% Pk | When Pk ≤ 0.2 MPa: ΔP ≤ 0.03 MPa; when Pk > 0.2 MPa: ΔP ≤ 15% Pk | ≤ 1.1 Pk | Full-lift: ≥ 1/4 d₀; Low-lift: ≥ 1/20 d₀ |
| Water or other liquids | — | When Pk ≤ 0.3 MPa: Pm = Pk − 0.06 MPa; when Pk > 0.3 MPa: Pm = 80% Pk | When Pk ≤ 0.3 MPa: ΔP ≤ 0.06 MPa; when Pk > 0.3 MPa: ΔP ≤ 20% Pk | ≤ 1.2 Pk | Full-lift: ≥ 1/4 d₀; Low-lift: ≥ 1/20 d₀ |
Notes:
- Pk = Set pressure
- d₀ = Orifice diameter
- PN = Nominal pressure
- Actual test and performance requirements shall be confirmed according to the selected valve model, project specification and applicable standard.
- For the TT-YA42H / YA802Y Series, the water or other liquids performance requirements are the relevant reference conditions.
- The supplied product data does not identify the valve as low-lift or full-lift, so the applicable lift criterion should be confirmed for the final configuration.
Dimensions – TT-YA42H
Nominal Pressure: PN160 / PN250 / PN400
| DN | B (mm) | D (mm) | Z₁–Ød | M | Orifice d₀ (mm) | K (mm) | L₁ (mm) | Rc | b (mm) | g (mm) | H Approx. (mm) |
| 10 | 95 | 105 | 4–18 | M33×3 | 10 | 88 | 117 | 3/4″ | 25 | 20 | 248 |
| 15 | 105 | 135 | 6–26 | M48×3 | 15 | 95 | 140 | 1″ | 25 | 25 | 290 |
| 20 | 135 | 200 | 6–29 | M56×3 | 20 | 145 | 170 | 1 1/2″ | 40 | 30 | 356 |
| 25 | 140 | 200 | 6–29 | M64×3 | 25 | 145 | 173 | 2″ | 40 | 38 | 440 |
| 32 | 160 | 210 | 6–29 | M64×3 | 32 | 155 | 181 | 2 1/2″ | 40 | 40 | 520 |
Dimensions – TT-YA802Y
Nominal Pressure: PN600
| DN | M | Rc | B (mm) | L₁ (mm) | H Approx. (mm) |
| 15 | 1/2″ | 1/2″ | 105 | 90 | 280 |
| 25 | 1″ | 1″ | 105 | 115 | 305 |
Dimensions are for preliminary engineering and layout reference. Final approved dimensional drawings should be confirmed before piping fabrication or installation.
Safety Relief Valve Sizing and Selection
For correct selection of the TT-YA42H / YA802Y Series, provide:
- Required model
- Process liquid
- Fluid composition
- Fluid density
- Fluid viscosity
- Set pressure
- Operating pressure
- Design pressure
- Operating temperature
- Relieving temperature
- Required relieving capacity
- Back pressure
- Required nominal pressure class
- Inlet connection
- Outlet connection
- Required materials
- Applicable project standards and certification requirements
- Installation and discharge arrangement
Because these valves are intended for high-pressure liquid applications, the actual set pressure and required relieving capacity should be verified before selecting a nominal valve size.
Engineering Support
THINKTANK supports petroleum, chemical, process equipment and high-pressure system customers with:
- High-pressure safety relief valve sizing and selection
- Liquid relieving capacity calculation
- Set-pressure configuration
- Pressure-class selection
- Material compatibility review
- Dimensional drawings
- 3D models for system integration
- Existing safety relief valve replacement evaluation
- Project-specific technical documentation
With more than 30 years of industrial valve application experience, THINKTANK can support new high-pressure liquid applications as well as technically suitable equivalent replacements for existing safety relief valves.
