# Comparison of ASME B16.34 and API 600 Standards for Valve Design

## Introduction

When it comes to valve design and manufacturing, two standards stand out as the most commonly referenced in the industry: ASME B16.34 and API 600. While both standards provide guidelines for valve construction, they serve different purposes and have distinct requirements. This article explores the key differences between these two important standards.

## Overview of ASME B16.34

The ASME B16.34 standard, published by the American Society of Mechanical Engineers, is a comprehensive document that covers:

– Pressure-temperature ratings
– Dimensions
– Materials
– Testing requirements
– Marking requirements

This standard applies to valves of various types including gate, globe, check, ball, and butterfly valves, with flanged, threaded, and welding end connections.

## Overview of API 600

API 600, developed by the American Petroleum Institute, is specifically focused on bolted bonnet steel gate valves for petroleum and natural gas industries. Key aspects include:

– Design requirements
– Material specifications
– Testing procedures
– Inspection criteria
– Documentation requirements

## Key Differences Between the Standards

### Scope and Application

ASME B16.34 has a broader scope, covering multiple valve types across various industries. API 600 is more specialized, focusing specifically on steel gate valves for hydrocarbon service.

### Pressure-Temperature Ratings

While both standards provide pressure-temperature ratings, ASME B16.34 offers more comprehensive tables covering a wider range of materials and temperature conditions.

### Material Requirements

API 600 has more stringent material requirements, particularly for components in contact with the fluid. It specifies additional requirements for materials used in sour service (H2S-containing environments).

### Testing Requirements

Both standards require pressure testing, but API 600 includes more rigorous testing protocols, including:

– Extended shell test duration
– Additional seat leakage tests
– Optional supplementary tests for critical applications

### Quality Control

API 600 mandates more comprehensive quality control measures, including:

– More detailed inspection requirements
– Stricter documentation
– Additional certification requirements

## Choosing Between the Standards

The choice between ASME B16.34 and API 600 depends on several factors:

– Industry requirements (API 600 is typically required for oil and gas applications)
– Valve type (API 600 is gate valve specific)
– Operating conditions (API 600 is preferred for more severe services)
– Customer specifications

## Conclusion

While ASME B16.34 and API 600 both provide valuable guidance for valve design, they serve different purposes in the industry. ASME B16.34 offers a more general framework applicable to various valve types, while API 600 provides specialized requirements for critical applications in the petroleum industry. Understanding these differences is crucial for engineers, specifiers, and purchasers when selecting valves for specific applications.