Views: 0 Author: J-VALVES Publish Time: 2026-05-28 Origin: Site
When selecting the J-VALVES DN700 PN63 WCB Globe Valve for high-temperature working conditions, engineers and procurement teams often face a key question: Should the valve comply with API 600, ASME B16.34, or both?
There is no simple answer. Though both standards regulate the design of industrial valves, they serve fundamentally different purposes. Selecting an inappropriate standard may lead to the following issues:
Safety hazards under high-temperature and high-pressure conditions
Non-compliance during project audits
Extra costs caused by over-specification
Premature valve failure in critical working scenarios
This guide elaborates on the differences between API 600 and ASME B16.34, focusing specifically on large-diameter globe valves (DN700 / 28 inches) made of WCB carbon steel, with a pressure rating of PN63 (equivalent to Class 400) and intended for high-temperature service.
ASME B16.34 Valves — Flanged, Threaded, and Welding End is widely recognized as the core universal standard for industrial valves, laying down basic specifications followed by nearly all valve manufacturers.
Feature | Description |
Scope | Covers all valve types: gate, globe, ball, butterfly, check and plug valves |
Material Coverage | Carbon steel, alloy steel, stainless steel and non-ferrous metals |
Pressure Classes | Class 150 to Class 2500 |
Primary Focus | Pressure-temperature ratings, minimum wall thickness and overall dimensions |
Application | Power generation, chemical processing and general industrial sectors |
Testing | Basic hydrostatic shell test (1.5 times the Maximum Allowable Working Pressure) and seat test (1.1 times the Maximum Allowable Working Pressure) |
ASME B16.34 sets the minimum requirements, ensuring valves are safe, interchangeable and suitable for conventional pressure service.
Issued by the American Petroleum Institute, API 600 is a specialized standard exclusively for steel gate valves used in critical applications of the oil, gas and refining industries.
Feature | Description |
Scope | Steel gate valves only |
Material Coverage | High-grade steels including WCB, WC6, WC9, CF8 and CF8M |
Pressure Classes | Class 150 to Class 2500 |
Primary Focus | Heavy-duty structure, corrosion allowance and fire-safe design |
Application | Oil & gas industry, refining, petrochemical industry and critical isolation services |
Testing | Extended shell test (duration over 5 minutes), zero-leakage seat test and API 607 fire resistance test |
API 600 is formulated on the basis of ASME B16.34. It adopts the pressure-temperature ratings of ASME B16.34 while imposing stricter requirements as follows:
Wall thickness: 20% to 30% thicker than the minimum value specified in ASME B16.34
Bonnet design: Bolted bonnet is mandatory
Seat design: Metal-to-metal seating is required; soft seats are not permitted
Non-Destructive Testing (NDT): 100% radiographic testing (RT) for valve bodies
Fire resistance: Mandatory compliance with API 607
Note for Globe Valves: API 600 applies solely to gate valves. For globe valves such as the DN700 PN63 WCB model, the applicable API standard is API 623 for globe valves instead of API 600. Even so, API 600 requirements are still widely referenced as a quality benchmark in many procurement specifications.
Criterion | ASME B16.34 | API 600 |
Scope | All valve types (gate, globe, ball, butterfly, check, plug) | Steel gate valves only |
Purpose | Basic safety assurance and part interchangeability | Superior reliability for critical service |
Wall Thickness | Minimum thickness for pressure containment | Increased thickness (with 20%-30% corrosion allowance) |
Bonnet Design | Screwed, bolted or welded bonnets are all acceptable | Bolted bonnet only |
Seat Type | Flexible options (soft seat or metal seat) | Metal-to-metal seat only (13Cr, Stellite) |
Stem Diameter | Standard size | Reinforced design (larger size, higher tensile strength) |
Material Range | Wide selection (cast iron, steel, brass, stainless steel, etc.) | Restricted to high-grade steels |
NDT Requirements | Optional unless otherwise specified by purchasers | 100% radiographic testing for body and bonnet; magnetic particle inspection for stem |
Post-Weld Heat Treatment (PWHT) | Not mandatory | Mandatory for alloy steels |
Shell Test Duration | 1-2 minutes | 5 minutes |
Seat Test Acceptance | Minor leakage allowed (≤ 1 drop per minute) | Zero visible leakage |
Fire-Safe Testing | Optional | Mandatory (comply with API 607) |
Operational Cycling Test | Not required | 5 to 10 full open-close cycles |
Material Traceability | Basic certification | Heat batch certificates + serial number tracking |
Documentation | Type A test certificate | Type B Certificate of Conformance |
Weight | Lighter | Heavier (due to thicker walls) |
Cost | Lower | Higher (typically 15%-40% price premium) |
Target Industries | HVAC, water treatment and general industries | Oil & gas, refining and petrochemical industries |
Service Life | Standard service life | Extended service life (over 10 years under harsh conditions) |
Aspect | ASME B16.34 | API 600 |
Design Approach | Prioritize practical performance and basic functions | Adopt fail-safe design concept |
Safety Margin | Minimum acceptable safety margin | Enhanced safety margin for high-risk applications |
Maintenance | Standard maintenance cycle | Less frequent maintenance thanks to robust structure |
Failure Consequence | Acceptable for non-critical working conditions | Risks minimized for safety-critical applications |
Parameter | Value | Explanation |
DN700 | Nominal diameter: 700 mm (28 inches) | Large-bore valve for high-flow applications |
PN63 | Nominal pressure: 63 bar | Approximately equivalent to ANSI Class 400 |
WCB | ASTM A216 WCB | Cast carbon steel (max. 0.25% carbon; tensile strength ≥ 60,000 psi) |
Globe Valve | Linear motion valve | Designed for flow throttling and regulation |
High-Temperature Service | Generally above 400°C (752°F) | Requires special material selection |
API 600 does not cover globe valves and is only applicable to steel gate valves.
For the DN700 PN63 WCB Globe Valve, the applicable standards are listed below:
Standard | Applicability | Role |
ASME B16.34 | Fully applicable | Primary design standard for pressure ratings, dimensions and materials |
API 623 | Fully applicable | Specialized standard for globe valves (for oil & gas applications) |
API 600 | Not directly applicable | May be referenced as a quality benchmark, not a mandatory compliance standard |
ASME B16.10 | Fully applicable | Governs face-to-face dimensions |
ASME B16.5 | Fully applicable | Governs flange dimensions |
If a procurement document requires a globe valve to comply with API 600, the requirement is technically infeasible. The correct specification methods are as follows:
Take ASME B16.34 as the basic design standard.
Refer to API 623 if enhanced performance is required for globe valves.
Adopt requirements similar to API 600 (thicker walls, NDT, fire-safe design) for critical working conditions.
Temperature | MAWP (PN63 / Class 400) | Notes |
-29°C to 38°C (-20°F to 100°F) | 63 bar (913 psi) | Full pressure rating maintained |
200°C (392°F) | Approx. 58 bar (841 psi) | Slight pressure derating |
400°C (752°F) | Approx. 49 bar (710 psi) | Obvious strength reduction |
425°C (797°F) | Approx. 46 bar (667 psi) | Maximum recommended temperature for WCB |
Above 425°C (797°F) | Not recommended | Use WC6, WC9 or C5 alloy steel instead |
Factor | ASME B16.34 Approach | Enhanced Approach (API 600-like) |
Material | WCB is acceptable up to 425°C | Adopt WC6 for service above 400°C |
Wall Thickness | Minimum thickness per ASME B16.34 | Add corrosion allowance to resist thermal cycling |
Bonnet Gasket | Standard spiral wound gasket | High-performance graphite gasket for superior thermal stability |
Packing | Standard PTFE/graphite packing | High-temperature graphite packing with live loading |
Seat Design | Flexible seat structure | Metal-to-metal seat with Stellite hardfacing |
Thermal Expansion | Basic thermal expansion control | Optimized clearance design for stem and bonnet |
Cycling Durability | Standard durability | Reinforced structure for frequent thermal cycling |
Scenario | Valve complying solely with B16.34 | Enhanced valve (API 600-like requirements) |
Initial Cost | Lower (approx. $15,000 - $25,000) | Higher (approx. $20,000 - $35,000) |
Wall Thickness | 45 mm (minimum value) | 55 - 60 mm (with allowance) |
Expected Service Life | 5 - 8 years | 10 - 15 years |
Maintenance | Annual inspection | Bi-annual inspection |
Leakage Risk | Moderate | Low |
Unplanned Downtime | Higher probability | Lower probability |
Total Cost of Ownership | Higher long-term cost | Lower long-term cost |
Application | Recommended Standard | Rationale |
General industrial steam system | ASME B16.34 | Cost-effective with adequate safety margin |
Critical steam service in power plants | ASME B16.34 + API 623-like enhancements | Higher reliability is required |
Process isolation in refineries | ASME B16.34 + API 623 | Meet oil & gas industry specifications |
High-temperature service in petrochemical plants | ASME B16.34 + API 623 + fire-safe design | Strict safety requirements |
Offshore platforms | ASME B16.34 + API 623 + NORSOK | Harsh operating environment and stringent regulations |
Nuclear facilities | ASME Section III (not B16.34) | Special standards for nuclear applications |
Please confirm the following points before finalizing valve specifications:
What medium will the valve control? (Steam, hydrocarbon or chemical fluid?)
What is the maximum operating temperature? (Is WCB suitable, or is WC6 required?)
Is the valve used for isolation or flow throttling? (Globe valves are mainly for throttling)
What are the consequences of valve failure? (Safety risks, environmental pollution or economic losses?)
Are there applicable regulatory standards? (API, NORSOK, ASME Section III, etc.?)
What is the expected service life? (5 years or 20 years?)
Is fire-safe design required? (Compliance with API 607?)
What level of NDT is acceptable? (Visual inspection only, or 100% radiographic testing?)
For J-VALVES DN700 PN63 WCB Globe Valves used in high-temperature service:
ASME B16.34 is a mandatory standard, serving as the fundamental rule for valve design, pressure ratings and dimensions.
API 600 is not directly applicable, as it only regulates gate valves. Select API 623 for globe valves if enhanced performance is needed.
The differences between standards are prominent for critical applications: thicker walls improve safety margins; stricter NDT reduces failure risks; metal-to-metal seats deliver better performance at high temperatures; fire-safe design may be a statutory requirement.
For service temperatures above 400°C: upgrade material from WCB to WC6 or WC9 alloy steel; adopt requirements similar to API 600 (even for globe valves); select high-performance packing and gasket materials.
Cost vs. Risk Analysis: A 15%-40% cost premium for enhanced specifications is reasonable in the following cases: the loss caused by valve failure far exceeds the valve cost (common for DN700 large-bore valves); safety is the top priority; unplanned production downtime is unacceptable.
For DN700 PN63 WCB Globe Valves in high-temperature service:
Take ASME B16.34 as the basic standard, and apply API 600-like enhancements including thicker walls, full NDT and metal seats. Upgrade to WC6 material if the operating temperature exceeds 400°C. Refer to API 623 when compliance with oil & gas industry requirements is needed.
Q1: Can a globe valve obtain API 600 certification?
A: No. API 600 applies exclusively to steel gate valves. Globe valves shall comply with ASME B16.34, and API 623 can be adopted optionally.
Q2: Is ASME B16.34 sufficient for high-temperature steam service?
A: It is applicable to general industrial steam service up to 425°C. Enhanced specifications are recommended for critical applications or temperatures above 425°C.
Q3: Which standard is equivalent to API 600 for globe valves?
A: API 623 Globe Valves — Bolted Bonnet is the counterpart standard for globe valves.
Q4: Why does API 600-compliant valve cost more?
A: Higher material consumption for thicker walls, mandatory NDT, extended testing procedures, fire-safe requirements and stricter quality control all lead to higher costs.
Q5: Can a gate valve comply with both ASME B16.34 and API 600?
A: Yes. Most high-quality gate valves meet both standards.
Q6: What problems will occur if WCB is used above 425°C?
A: WCB will suffer obvious strength degradation and graphitization risk. Use WC6 (max. 540°C) or WC9 (max. 565°C) instead.
Q7: Is PN63 equal to Class 400?
A: PN63 is roughly equivalent to ANSI Class 400. Always check the official pressure-temperature rating table for verification.
Q8: What is the typical lead time for a DN700 PN63 globe valve?
A: 16 to 24 weeks for standard B16.34 products; 20 to 30 weeks for valves with enhanced specifications.
J-VALVES is a leading manufacturer of industrial valves for critical applications. Our DN700 PN63 WCB Globe Valves are engineered to surpass industry standards, delivering reliable performance in the most demanding high-temperature working conditions.
If you have any questions, please contact our engineering team for a free valve specification review.
