ASCO 551 553 Solenoid Valves (Spool) 3/2 NC, ¼”-1/2” Stainless Steel (30 Pilots) – Hazardous Area Valve Ex d, Ex ia

ASCO 551 553 – Pilot Operated or Air Operated Spool Solenoid Valves For Hazardous Areas & Potentially Explosive Atmospheres
ASCO 551 553 hazardous area solenoid valves are pilot operated or air operated spool type valves suitable for hazardous areas installation with international classifications including ATEX, UL, CSA and other local approvals on request.
3/2 Way Solenoid Valve
NC – Normally Closed Valve
NO – Normally Open Valve
Via ASCO Numatics FASTSHIP and SAMEDAY Express Delivery Service we are able to deliver 2,000+ ASCO valves from stock direct to you.
T&D are an Authorised UK Distributor for ASCO Numatics, part of Emerson Industrial Automation.
ASCO 551 553 SOLENOID VALVES
- The ASCO monostable spool valves in conformity with IEC 61508 Standard (2010 route 2H version) have TÜV (551 series) and EXIDA (551-553 series) certified with integrity levels: SIL 2 for HFT = 0 / SIL 3 for HFT = 1
- Series 551 versions according to ATEX 94/9/EC, for zones 0, 1 and 2 and series 553 air-operated versions for zones 1 and 2
- All the exhaust ports of this spool valve are connectable, providing better environmental protection, particularly recommended for sensitive areas such as clean rooms, and applications in the pharmaceutical and food processing sectors
- The solenoid valve offers environmental protection against the ingress of liquids, dusts or any other foreign matter (environmentally-protected construction)
- The solenoid valves satisfy all relevant EC Directives
Differential Pressure : 2 – 10, 4 bar [1 bar = 100kPA]
Flow (Qv at 6 bar): 1/4 = 860 l/min (ANR)
1/2 = 3000 l/min
Fluids | Temperature Range (TS) | Valve Seal Materials |
air, inert gas, filtered | -40°C to +60°C | VMQ (silicone) + PUR Polyurethane |
ASCO 551 553 – valve FLUID CONTACT COMPATIBILITY
ASCO 551 553 Solenoid Valve | Air Operated (Series 551-553) | CNOMO Solenoid (Pilot) Interface (Series 551) |
Body, end covers | Stainless Steel, AISI 316L | Stainless Steel, AISI 316L |
Spool Valve Internal Parts | Stainless Steel, POM | Stainless Steel, POM |
Seals | NBR | NBR |
Pilot Internal Parts | – | Size 30 (E06.05.80N) |
ASCO 551-553 solenoid valves are available with NAMUR interface. NAMUR, translated from the German acronym to StandardiSation Association for Measurement and Control in Chemical Industries, is the specification for a standard interface between pneumatic actuators, solenoid valves and directional control valves.
ASCO 551 553 – valve ELECTRICAL CHARACTERISTICS
Valve Coil Insulation Class : F
Electrical Safety : IEC 335
Standard Valve Voltages : DC (=) 24V – 48V ; LISC : 12…24V
AC (~) 24V – 48V – 115V – 230V/50Hz; other voltages and 60Hz are available on request
ASCO 551 553 – VALVE SPECIFICATIONS – AIR OPERATED
Pipe size | Orifice size | Flow coefficient kV | Operating pressure differential (bar) | Prefix option | ASCO Catalogue number | |||
(mm) | (m3/h) | (i/min) | Min | Max (PS) | ||||
air (*) | ||||||||
~ | = | |||||||
Air pilot operated – spring return (monostable) | ||||||||
1/4 | 6 | 0.75 | 12.5 | 2 | 10 | 10 | – | ASCO *551A113 |
1/2 | 13 | 2.49 | 41.5 | 2 | 10 | 10 | – | ASCO *553A113 |
Air pilot operated and return (bistable) | ||||||||
1/4 | 6 | 0.75 | 12.5 | 2 | 10 | 10 | – | ASCO *551A114 |
1/2 | 13 | 2.49 | 41.5 | 2 | 10 | 10 | – | ASCO *553A114 |
ASCO 551 553 – VALVE SPECIFICATIONS – CNOMO SOlenoid PILOT OPERATED
Pipe size | Orifice size | Flow coefficient kV | Operating pressure differential (bar) | Power level ~/= | ASCO Catalogue number | |||
(mm) | (m3/h) | (i/min) | Min | Max (PS) | ||||
air (*) | ||||||||
~ | = | |||||||
Solenoid air pilot operated – spring return (monostable) | ||||||||
1/4 | 6 | 0.75 | 12.5 | 2 | 10 | 10 | BP | ASCO *551A213 |
1/4 | 6 | 0.75 | 12.5 | 2 | – | 8 | LP | ASCO *551B213 |
Solenoid air pilot operated and return (bistable) | ||||||||
1/4 | 6 | 0.75 | 12.5 | 2 | 10 | 10 | BP | ASCO *551A214 |
1/4 | 6 | 0.75 | 12.5 | 2 | – | 8 | LP | ASCO *551B214 |
*Select 8 for NPT ANSI 1.20.3 or select G for ISO G (228/1)
ASCO 551 553 – VALVE OPTIONS
- Mounting on aluminium supply rail, 1/4 or 1/2
- Other pipe threads are available on request
ASCO SOLENOID VALVES – ATEX, IEC EX & NEMA hazardous area CERTIFIED

ASCO Solenoid Valves For Hazardous Area Oil, Gas & Petrochem Industries (ATEX & IECEx) – call T&D for sales, technical and specification support on all ASCO valves.
Image : Energy Reality - A Project of Post Carbon Institute.
Hazardous Area Certification
ATEX (Zone 1 Zone 2), IEC Ex, NEMA (Div 1 Div 2) & Explosion Protection
➡ Did you know? T&D supply ATEX hazardous area certified Analytic Gas Heated Hoses.
➡ Did you know? T&D distribute Hazardous Area Instrumentation Equipment as Approved Vendors to global oil and gas operators and their EPC’s.