Valve Specification Sheets: What to Include and Why

Purpose of Valve Specification Sheets

A valve specification sheet (data sheet) is the primary technical communication document between the process engineer, instrument engineer, and the valve supplier. It must completely define the valve's service conditions, performance requirements, material requirements, testing obligations, and documentation requirements. An incomplete data sheet leads to wrong equipment selection, costly change orders, and potential safety issues.

Process and Service Data

• Fluid name, composition, and phase (liquid, gas, two-phase)

• Operating temperature range: normal, minimum, and maximum

• Operating pressure range: normal, minimum, and maximum including emergency conditions

• Fluid density, viscosity, and vapor pressure at operating conditions

• Flow rate: normal, minimum, and maximum with corresponding Cv or Kv values

• Differential pressure across valve: normal, maximum, and shutoff

Valve Construction Requirements

The data sheet must specify valve type (ball, gate, globe, butterfly), end connection standard and rating, body and bonnet material, trim material and hardness, seat type (soft or metal), leakage class, packing material, and actuation method. For control valves, flow characteristic (equal percentage, linear, quick opening) and rangeability are specified. Any special requirements such as fire-safe design, cryogenic service, or fugitive emission compliance must be noted.

Testing and Documentation

• Pressure testing: shell test pressure, seat test pressure, and acceptance criteria

• NDT requirements: radiographic, ultrasonic, or magnetic particle inspection

• Material certificates: EN 10204 Type 2.2, 3.1, or 3.2 with chemical and mechanical test data

• Functional testing: actuator operation, torque measurement, position indicator accuracy

• Fugitive emission test: reference to ISO 15848 or API 622 class required

• Third-party inspection hold and witness points as required by project

Common Omissions and Mistakes

Frequent data sheet errors include missing fluid properties (viscosity, vapor pressure), unspecified packing type, missing fugitive emission requirements, unspecified CV characteristic, and ambiguous testing instructions. Reviewers should verify that all fields are completed with project-specific data rather than copied template values. Supplier deviations from the data sheet must be flagged for engineering review and approval before order placement.