Overview

This document provides detailed pressure and temperature ratings for ASTM A126 cast iron valves, specifically focusing on ANSI Class 125 and Class 250 ratings for various valve sizes and classes.

Pressure/Temperature Ratings

The ratings are given for saturated steam, liquid, gas, and steam applications, with pressure values expressed in both PSI and bar, and temperature in °F and °C. The document includes data for valve sizes ranging from 1 inch to 24 inches, categorized under ANSI Classes 125 and 250.

Valve Classes and Sizes

• Class B valves cover sizes 1" to 12" and 14" to 24".
• Class A valves cover sizes 1" to 12".

Specific notes indicate that bronze signals apply to Class 150 ANSI for sizes 1 inch through 12 inches, and bronze signals apply to Class 300 ANSI for sizes 1 inch through 8 inches.

Material and Standards

The valves conform to ASTM A126 standards and must meet the requirements of ASME B16.43-1991 standards, including end welding, threading, and flange-valve extraction information.

Service Temperature and Pressure Data

Tables provide detailed pressure ratings at various temperatures for different valve types and service conditions. Temperatures range from approximately -20°F (-29°C) up to 550°F (288°C), with corresponding pressure ratings decreasing as temperature increases.

Examples of pressure ratings include:

• At 100°F (38°C), Class 125 valves have pressure ratings around 150 PSI (10.3 bar).
• At 450°F (232°C), pressure ratings drop significantly, e.g., to approximately 50 PSI (3.4 bar).

Key Parameters and Limitations

• Pressure ratings vary by valve size, class, and temperature.
• Bronze valves have specific size and class applicability.
• Pressure ratings for saturated steam are distinctly noted.
• Tables include working pressures for various valve materials and configurations.

Recommendations and Best Practices

• Ensure valve selection matches the pressure and temperature requirements of the application.
• Adhere to ASME and ASTM standards for installation and operation.
• Consider material compatibility and service conditions when selecting valve class and size.

Summary of Tables

The tables provide comprehensive data for engineers and technicians to determine appropriate valve ratings under different operating conditions, ensuring safety and compliance with industry standards.