Valve Certification and Marking: CE, ATEX, SIL, and PED Requirements

Industrial valves used in process plants are subject to a range of certification and marking requirements from regulatory authorities, industry standards bodies, and customer engineering specifications. These certifications provide assurance that valves meet defined safety, performance, and quality requirements and help ensure regulatory compliance for the facilities in which they are installed. Understanding the key certifications and marking requirements applicable to industrial valves helps engineers specify and procure compliant equipment.

CE Marking and the Pressure Equipment Directive

The CE mark indicates that a product meets all applicable European Union requirements and can be freely placed on the EU market. For industrial valves, the most relevant EU directive is the Pressure Equipment Directive (PED 2014/68/EU), which establishes essential safety requirements for pressure vessels, piping, and pressure accessories (including valves) with a maximum allowable pressure above 0.5 bar. Valves are classified into categories (I through IV) based on the fluid group (Group 1 for hazardous fluids, Group 2 for others), pipe size, and pressure rating, with higher categories requiring more rigorous conformity assessment by a Notified Body.

• PED Category I: lowest risk, manufacturer self-declaration

• PED Category II: quality system or design examination by a Notified Body

• PED Category III/IV: highest risk fluids or large high-pressure valves, full quality assurance

• Valves below 25 mm nominal bore or below 0.5 bar may be exempt from PED requirements

• CE marking must be accompanied by a Declaration of Conformity and technical file

ATEX Certification for Explosive Atmospheres

ATEX (Atmospheres Explosibles) is the EU directive governing equipment and protective systems for use in potentially explosive atmospheres. For valves, ATEX is relevant primarily for electric actuators, solenoid coils, and positioners installed in hazardous area locations where flammable gases, vapors, or dusts may be present. ATEX equipment is classified by equipment group (I for mining, II for surface industries), category (1, 2, or 3, indicating the level of protection), gas group (IIA, IIB, IIC), and temperature class (T1 through T6). The IECEx scheme provides equivalent certification recognized globally outside the EU.

SIL Certification for Safety Instrumented Systems

Safety Integrity Level (SIL) certification is required for valves and actuator assemblies used in safety instrumented functions (SIFs) that form part of a safety instrumented system (SIS). SIL levels (SIL 1 through SIL 4) indicate the probability of failure on demand (PFD) of the safety function. Valves used in SIS applications must have SIL-rated failure mode data (lambda D, lambda S, systematic capability) assessed per IEC 61508 and certified by an independent functional safety assessment body. SIL certification does not certify a specific valve or actuator in isolation but certifies that the failure data and systematic design are adequate for use in SIL-rated functions.

Manufacturer Marking Requirements

Beyond regulatory certifications, most valve standards require specific marking on the valve body for identification and traceability. ASME B16.34 requires the manufacturer's name or trademark, pressure class, nominal pipe size, material designation, and flow direction arrow (where applicable). API 6D additionally requires the API monogram, pressure class, bore size, and serial number. Special service markings such as NACE (sour service), cryogenic (LT), fire-safe (FS), and low-emission (LE) are added to indicate compliance with specific supplementary requirements. These markings must be permanent (cast, stamped, or stenciled) and legible throughout the valve's service life.