Check Valve vs Non-Return Valve

Quick Answer

Check valve and non-return valve (NRV) are two names for the same device. Both refer to a valve that permits flow in one direction and automatically prevents reverse flow. The term “check valve” is standard in American (ASME/API) practice; “non-return valve” is common in British and European (BS/EN) standards and in marine/offshore terminology.

Details

The function is identical: a closure element (disc, flap, ball, or piston) opens under forward flow pressure and closes when flow stops or reverses. There is no design or functional difference between a valve labeled “check” and one labeled “non-return.” The distinction is purely terminological and regional.

American usage. ASME, API, and most North American specifications use “check valve.” Standards include API 594 (wafer and dual plate), API 6D (pipeline check valves), and BS 1868 (flanged swing check, widely adopted in API projects).

British/European usage. BS and EN standards often use “non-return valve” or abbreviate it as NRV. The terms appear interchangeably in international EPC projects, particularly those with UK-based engineering contractors.

Comparison Table

Aspect	Check Valve	Non-Return Valve (NRV)
Function	Prevents backflow	Prevents backflow
Design	Swing, piston, dual plate, ball, tilting disc	Same types
Regional usage	USA, API/ASME standards	UK, Europe, marine, offshore
Standards	API 594, API 6D, BS 1868	BS 1868, BS 5160, EN 12334
P&ID symbol	Same	Same
Abbreviation	CV or CHV	NRV
Functional difference	None	None

Common Check Valve Types

Regardless of the name used, the following types exist:

• Swing check: single disc on a hinge pin; low pressure drop; best for steady flow. Standard: BS 1868.
• Dual plate (wafer): two spring-loaded semicircular plates; compact; fast closure. Standard: API 594.
• Piston check (lift check): piston or ball lifts off seat; suited for vertical lines and high-pressure service.
• Tilting disc: disc tilts on an offset pivot; balances low pressure drop with fast closure.
• Nozzle check (axial): spring-loaded disc in a streamlined body; lowest pressure drop and fastest closure. Used in compressor discharge.

Pro Tip

When writing requisitions or datasheets for international projects, use both terms in the description (e.g., “check valve / non-return valve”) to avoid confusion between American and European suppliers. On P&IDs, the symbol is universal regardless of the name used.

For detailed specifications on swing and dual plate designs, see the guide to check valve types and standards.

Read the full guide to valve types