Introduction
If you’ve ever looked closely at a ball valve—whether on a water line, irrigation system, or air compressor—you’ve probably seen the marking “600 WOG” stamped right on the body. But what does it actually mean?
While it might seem like a minor detail, this little marking tells you a lot about what that valve can handle—and what it absolutely can’t.
In this article, we’ll break down the meaning of “600 WOG,” including:
- What “WOG” stands for
- What the number 600 actually represents
- What types of media and systems this rating applies to
- Why you should never use a 600 WOG valve in a steam system
- How it compares to other ratings like WSP and CWP
Whether you’re specifying valves for an industrial system or just replacing a shutoff under your kitchen sink, this guide will help you understand the meaning—and the limits—of a 600 WOG valve.
1. What Does “600 WOG” Mean on a Ball Valve?
The term “600 WOG” stamped on a ball valve is shorthand for:
- 600 PSI (pounds per square inch)
- WOG = Water, Oil, Gas
This means the valve is rated to safely operate at 600 PSI of pressure when used with non-corrosive liquid or gaseous media, under standard (ambient) temperature conditions.
Important: WOG ratings do not apply to steam or high-temperature applications. We’ll explain why later.
This marking is a quick way for manufacturers and engineers to communicate the maximum non-shock pressure capacity for common utility fluids.
2. Interpreting the Pressure Rating: What Is “600”?
The “600” in a 600 WOG valve doesn’t just look technical—it actually means the valve has been tested and rated to withstand up to 600 PSI (pounds per square inch) of pressure in non-shock, ambient temperature conditions.
But what exactly does that mean in practical terms?
600 PSI = Working Pressure, Not Burst Pressure
-
- The number refers to the maximum working pressure, not the point at which the valve will break.
- Valves are typically tested well above this value to ensure safety margins.
- A 600 WOG valve is expected to function safely and reliably at or below 600 PSI when used with water, oil, or gas at room temperature (~73°F or 23°C).
️ Temperature Affects Pressure Tolerance
- The 600 PSI rating assumes the valve is used under standard temperature conditions.
- At higher temperatures, most materials (especially plastics and soft seats) become weaker, and pressure tolerance drops.
- This is why WOG valves are not suitable for steam or high-temp oil unless explicitly certified otherwise.
️ Industry Standards That Define “600 WOG”
Most 600 WOG ratings follow standards like:
- ASME B16.34: Valves – Flanged, Threaded, and Welding End
- MSS SP-110: Ball Valves Threaded, Socket-Welding, Solder Joint, Grooved, and Flared Ends
- API 598 / ANSI standards for pressure testing and leak limits
These provide the guidelines for testing and marking, so you can trust the rating if the valve is from a reputable manufacturer.
Summary
✅ “600” means safe working pressure at 600 PSI
❌ It does not mean the valve can withstand steam or high-temperature gas
Always check for WSP rating if your system involves elevated temperatures or steam
3. What Systems Are 600 WOG Valves Suitable For?
A 600 WOG rating tells you that a valve is strong enough to handle up to 600 PSI—but only for certain types of fluids and under specific conditions. Let’s break down where you can (and can’t) use these valves safely.
✅ Suitable Systems for 600 WOG Valves
These are the types of systems where 600 WOG valves are commonly and safely used:
- Cold or ambient temperature water systems
e.g., municipal lines, residential shut-offs, irrigation - Non-corrosive oil systems
e.g., hydraulic circuits, lubrication systems - Low-pressure compressed air lines
e.g., HVAC, small compressors (when manufacturer allows) - Fuel lines (diesel, kerosene)
Only if compatible with valve materials and rated accordingly
In these cases, 600 PSI is more than sufficient for typical pressures, which usually range from 50–200 PSI in domestic and light industrial use.
⚠️ Use with Caution or Check Specs
Some systems might be compatible—but only if the valve is specifically approved:
- Hot water (over 200°F / 93°C)
→ Some WOG valves allow this, some don’t. Temperature rating matters. - Compressed air
→ Not all WOG valves are tested for air; check for bubble-tight certification. - Chemical media
→ Only use if material compatibility is confirmed (especially for seals and seats)
❌ Not Suitable For
600 WOG valves should not be used in the following systems:
- Steam lines (use WSP-rated valves instead)
- Boilers or autoclaves
- High-temperature oil systems (above 250°F)
- Corrosive chemical lines unless chemically compatible
- Food-grade or sanitary systems (unless certified)
Table: Suitable vs Unsuitable Systems for 600 WOG Valves
| Media / System | Suitable? | Notes |
|---|---|---|
| Cold Water | ✅ | Ideal application |
| Hot Water (<200°F) | ✅ | Check temperature rating |
| Compressed Air | ⚠️ | Manufacturer-specific approval needed |
| Fuel / Lubricating Oil | ✅ | Confirm seal material compatibility |
| Steam | ❌ | Never use WOG valve for steam; use WSP-rated instead |
| Sanitary Systems | ❌ | Requires NSF or FDA approval |
Summary
600 WOG valves are versatile and durable—but only when used with the right fluid under the right conditions. Misusing them (e.g., with steam) can lead to failure, leakage, or dangerous pressure events.
4. 600 WOG vs WSP: What’s the Difference?
At a glance, WOG and WSP may seem like similar pressure ratings—but they refer to very different use cases. Confusing them can result in using the wrong valve for a high-risk system like steam. Let’s clear up the difference.
WOG: Water, Oil, Gas
- WOG stands for Water, Oil, and Gas
- Refers to the maximum non-shock working pressure for non-corrosive liquid or gas media
- Rated at ambient temperature (typically 73°F / 23°C)
- Applies to systems like potable water, compressed air, hydraulic oil, etc.
WOG is the most common rating found on general-purpose ball valves.
WSP: Working Steam Pressure
- WSP stands for Working Steam Pressure
- Indicates how much pressure a valve can safely handle when exposed to steam
- Requires higher temperature resistance and special seat materials (often metal-seated or TFM/PTFE blends)
- Typically tested at 250°F+ or even up to 450°F, depending on valve design
⚠️ Steam is more dangerous than cold fluids due to thermal expansion and energy density—WOG valves are not designed to handle that.
Common Misconception
Just because a valve is rated at 600 PSI WOG doesn’t mean it can handle 600 PSI of steam.
- A valve may have a WOG rating of 600 PSI
- But a much lower WSP rating—or none at all
If there’s no WSP rating, assume it should not be used for steam.
Summary
| Feature | WOG | WSP |
|---|---|---|
| Full Form | Water, Oil, Gas | Working Steam Pressure |
| Media Type | Non-corrosive liquids/gases | Steam / high-temp vapor |
| Temperature Basis | ~73°F (23°C) | ≥250°F (121°C) |
| Valve Type | Soft-seated, general ball valve | Steam-rated or metal-seated valve |
| Typical Application | Plumbing, HVAC, oil | Boilers, autoclaves, sterilizers |
To sum it up:
Use WOG-rated valves for water, oil, gas at normal temps.
Use WSP-rated valves for steam—always.
5. Common Valve Ratings: WOG, WSP, and CWP
When selecting a valve, you might come across a mix of abbreviations—WOG, WSP, and CWP—each indicating a different kind of pressure rating. Understanding how they relate to one another is essential to choosing the right valve for your system.
Let’s break them down.
WOG – Water, Oil, Gas
- Maximum non-shock working pressure at ambient temperature (~73°F / 23°C)
- Applies to liquids and gases that aren’t corrosive or hazardous
- Not suitable for steam or high-temp fluid applications
- Example: A valve labeled “600 WOG” can handle 600 PSI water, oil, or gas at standard temp
WSP – Working Steam Pressure
- Maximum working steam pressure
- Rated at higher temperatures (typically 250°F or more)
- Applies to saturated steam, and sometimes superheated steam in industrial systems
- Requires high-temp-resistant body and seals
CWP – Cold Working Pressure
- Sometimes used interchangeably with WOG
- Often found on flanged valves or European-rated valves
- Indicates maximum pressure at ambient temperature, like WOG
- More common in mechanical/HVAC system specifications
Table: Valve Pressure Ratings Overview
| Rating Type | Full Name | Applies To | Temp Limit | Common Systems |
|---|---|---|---|---|
| WOG | Water, Oil, Gas | Non-shock liquids/gas | ~73°F (23°C) | Plumbing, HVAC, irrigation |
| WSP | Working Steam Pressure | Saturated steam | 250°F (121°C)+ | Boilers, autoclaves, sterilizers |
| CWP | Cold Working Pressure | Cold water/gas | ~100°F (38°C) | HVAC, commercial water distribution |
Key Takeaway
While these abbreviations may seem similar, their differences can determine whether a valve fails or functions safely:
- WOG ≈ CWP: For general cold water/oil/gas use
- WSP: Required for any steam application
Always match the valve rating to your media, temperature, and pressure environment.
6. Examples of 600 WOG Valve Applications
Now that you know what 600 WOG means, let’s look at where these valves are actually used in the real world. From household plumbing to light industrial systems, 600 WOG valves are a go-to option for many low- to medium-pressure applications.
Residential Applications
- Main water shutoff valves
Most homes have ball valves rated at 600 WOG for main supply lines. - Irrigation systems
Used to isolate water lines going to sprinkler heads or garden faucets. - Water heater inlet/outlet shutoffs
For cold side shutoff—verify temperature rating if using on the hot side.
️ Light Industrial / Commercial Use
- Lubrication oil circuits
Where low-pressure non-corrosive oil is distributed to machinery. - Air compressor shut-off valves
In low-to-medium PSI compressed air lines (verify compatibility with air). - Cooling water loops
In manufacturing or HVAC systems, for routing chilled or process water.
Emergency Isolation / Maintenance Lines
- Bypass valves
Used temporarily to isolate sections for repair without shutting down an entire system. - Test ports / drain valves
Installed in accessible locations for flushing or pressure testing.
⚠️ Where NOT to Use 600 WOG Valves
Let’s be crystal clear—600 WOG valves are not safe for everything:
| System Type | Safe to Use? | Reason |
|---|---|---|
| Steam heating lines | ❌ | Needs WSP rating; WOG not high-temp certified |
| Superheated water systems | ❌ | Exceeds temp rating; could cause seal failure |
| Chemical processing lines | ⚠️ | Depends on media and valve material compatibility |
| Potable food/beverage | ❌ | Needs NSF/ANSI or FDA-grade approval |
Summary
A 600 WOG valve is extremely versatile, but only when used within its rated pressure and temperature limits.
Use them for:
- Water
- Oil
- Air (if certified)
- Non-hazardous media
Avoid them for:
- Steam
- Chemical process
- High-temp or sanitary use
7. FAQs: Understanding 600 WOG
Still have questions about 600 WOG? You’re not alone. Here are answers to some of the most common user queries we’ve found across Google, Reddit, and industry forums.
Is 600 WOG the same as 600 PSI?
Yes—600 refers to 600 PSI of working pressure under non-shock conditions at ambient temperature.
It’s not burst pressure or pressure at elevated temperature.
Can I use a 600 WOG valve for steam?
No.
WOG valves are not tested or approved for steam, which operates at much higher temperatures.
Use a WSP-rated valve for any system involving saturated or superheated steam.
What’s the difference between WOG and CWP?
They’re very similar and often used interchangeably:
- WOG = Water, Oil, Gas
- CWP = Cold Working Pressure
Both refer to non-shock pressures at ambient temperature.
Why do some 600 WOG valves fail on compressed air?
Not all WOG valves are rated for gas-tight sealing.
Compressed air systems may require valves tested for bubble-tight shutoff or leakage class compliance.
Check the valve’s air rating or spec sheet.
Can I use 600 WOG valves for hot water?
Yes, with caution.
Many can handle hot water up to 180–200°F, but check the temperature limit in the product specs.
WOG only covers pressure, not temperature.
Are all 600 WOG valves the same?
No.
Different manufacturers use different materials and designs.
Some may include higher temp seals, others may be basic brass with Teflon seats.
Always compare detailed specs—not just the WOG rating.
Does WOG mean the valve is suitable for oil?
Yes, in general.
But confirm oil type (diesel, hydraulic, mineral, etc.) and check chemical compatibility with seals and body.
Is WOG rating tested or just theoretical?
Reputable manufacturers test valves according to ASME, ANSI, or MSS standards, usually with hydrostatic testing.
Avoid unbranded or unverified valves that only show WOG ratings without test reports.
Summary
WOG is a helpful starting point—but it’s not the full story.
Always check the operating temperature, media type, and manufacturer certifications before installing a valve based solely on “600 WOG”.
8. Conclusion: What 600 WOG Really Tells You
The “600 WOG” marking stamped onto a valve may seem like a small detail—but it holds critical information about how and where that valve can be safely used.
To recap:
- 600 means the valve is rated for 600 PSI working pressure
- WOG stands for Water, Oil, and Gas—not steam
- This rating applies to non-shock, ambient temperature systems
- WOG ≠ WSP. If you’re working with steam, you need a steam-rated (WSP) valve
- Always check for manufacturer-specific temperature, media, and air compatibility
Understanding what these markings mean helps you avoid overuse, failure, or even system hazards—and ensures you’re choosing the right valve for the job.
✅ Safe Use Summary
| Condition | Use 600 WOG Valve? | Alternative Needed? |
|---|---|---|
| Cold water or oil | ✅ | No |
| Hot water (<200°F) | ⚠️ | Confirm with specs |
| Steam | ❌ | Use WSP-rated valve |
| Air lines | ⚠️ | Check for leak-tight or air rating |
| Sanitary or chemical systems | ❌ | Use certified or chemical-rated valve |
Looking for the Right Valve?
At XHVAL, we specialize in designing and manufacturing high-performance ball valves for every kind of application—from WOG-rated general use to WSP and CWP-rated solutions for steam, high pressure, and specialty media.
→ Browse XHVAL Ball Valves by Pressure Class
→ Contact Us for Technical Support or Custom Requirements
Let our experts help you choose the right valve, for the right system, with the right rating.