# Comparison of ASME B16.34 and API 600 Standards

## Introduction

When it comes to industrial valve standards, two commonly referenced specifications are ASME B16.34 and API 600. While both standards address valve design and manufacturing, they serve different purposes and have distinct requirements. This article explores the key differences between these two important standards in the valve industry.

## Scope and Application

ASME B16.34

ASME B16.34 is a comprehensive standard that covers the design, materials, dimensions, testing, and inspection requirements for valves with flanged, threaded, and welding end connections. It applies to a wide range of valve types including gate, globe, check, ball, and butterfly valves.

API 600

API 600 specifically focuses on bolted bonnet steel gate valves for petroleum and natural gas industries. It provides more detailed requirements for gate valves used in refinery and pipeline applications, including additional testing and material specifications beyond what ASME B16.34 requires.

## Pressure-Temperature Ratings

ASME B16.34 Pressure Classes

The standard defines pressure classes from 150 to 4500, with corresponding temperature ratings for various materials. It provides detailed tables showing maximum allowable working pressures at different temperatures.

API 600 Pressure Classes

API 600 typically references ASME pressure classes but adds specific requirements for gate valves. The standard emphasizes suitability for high-pressure and high-temperature applications common in oil and gas operations.

## Material Requirements

ASME B16.34 Materials

The standard lists acceptable materials for valve bodies, bonnets, and trim components. It references ASME material specifications and provides guidance on material selection based on service conditions.

API 600 Materials

API 600 has more stringent material requirements, particularly for critical components. It specifies minimum wall thicknesses, stem diameters, and material grades suitable for harsh oilfield environments.

## Testing Requirements

ASME B16.34 Testing

The standard requires shell tests, seat tests, and backseat tests. Test pressures are based on the pressure class and temperature rating of the valve.

API 600 Testing

In addition to ASME requirements, API 600 mandates more rigorous testing including extended duration shell tests, high-pressure seat tests, and optional fire testing for API 6FA compliance.

## Design Features

ASME B16.34 Design

The standard provides general design requirements for various valve types but allows more flexibility in specific design features.

API 600 Design

API 600 specifies detailed design requirements for gate valves including minimum stem diameters, bonnet bolting requirements, and pressure seal designs for high-pressure applications.

## Conclusion

While ASME B16.34 provides broad requirements applicable to many valve types, API 600 offers specialized specifications for steel gate valves in petroleum service. Many API 600 valves also comply with ASME B16.34, but API 600 includes additional requirements that make valves more suitable for demanding oil and gas applications. Understanding the differences between these standards helps engineers select the appropriate specification for their specific application needs.