SIRAI – Solenoid Valves (WRAS Approved)


Solenoid Valves

Solenoid Valves

SIRAI solenoid valves provide effective flow control of water, air, inert gases, refrigerant gas, steam and non-aggressive fluids – the strong compact valve body and technical specification provide reduced overall dimensions, reduced installation times and reduced maintenance for process instrumentation in non-hazardous location applications.

Solenoid valves are available in 2/2 or 3/2 normally closed, normally open or universal service types plus proportional control and latching versions for low power absorption applications – WRAS approved 2-way and 3-way SIRAI solenoid valves are available.


General Purpose Solenoid Valves

SIRAI Solenoid Valves

SIRAI Solenoid Valves

Typical applications for SIRAI valves:

  • Liquid and gas dosage
  • Gas flow rate regulation – blowers, diaphragm pumps, venturi meters
  • Vacuum regulation for medical electronic or cosmetic treatment equipments
  • Flow rate regulation of spray nozzles for small cooling systems

Standard Voltages

  • DC 12-24V
  • AC 24V/50Hz – 110V/50Hz (120V/60Hz) – 230V/50Hz (+10% -15%); 50/60Hz

Ambient Temperatures

  • -10°C +60°C (class “A” and “F”), -10°C +80°C (class “H”)

Standard brass body solenoid valves are available with gas female threaded ports (ISO 228) for sub-base mounting or NPT connections – stainless steel, nickel plated brass, aluminium and PP solenoid valves also available.

💡 Did You Know: Flow Rate – the flow rate of a valve is indicated by the flow factor Kv, which represents the quantity of water, expressed in m /h, that flows through the solenoid valve with a pressure drop of 1 bar and a temperature between 5°C and 30°C (Standard VDI/VDE 2173).

  • VDI/VDE 2173 Fluidic Characteristic Quantities Of Control Valves & Their Determination

Micro Solenoid Valves

SIRAI - Micro Solenoid Valves

SIRAI – Micro Solenoid Valves

SIRAI micro solenoid valves are specified for limited space applications demanding a compact valve with small size, low power, control components – micro solenoid valves control a variety of non-aggressive liquid and gaseous fluids and can be disassembled for cleaning and maintenance. Micro solenoid valves are available in 2/2 or 3/2 normally closed, open or universal service versions plus proportional control and latching type. Customised valves can be produced with materials and performance specification to meet specific application requirements.

Solenoid Valves With Latching Coils

Where general service solenoid valves have a power absorption which exceeds the process application requirement a latching coil can be installed to the valve. The bi-stable control limits power consumption to the valve switching phase – the combined action of electric winding and permanent magnet ensures the solenoid valve switches from the open to closed position (or vice versa) by means of a simple pulse in a few milliseconds.

 💡 Did You Know? Power Absorption – power absorption indicates the power during inrush and holding for AC (VA) and the ‘cold’ absorbed power for DC (W). These power absorptions are measured by energising the solenoid coil at nominal voltage at an ambient temperature of 20°C.

Solenoid Valves For Refrigerant Gas 

The extreme volatility of refrigerating gases necessitates modified solenoid valves and specialised sealing systems must be used. SIRAI valves integral with HNBR (Hydrogenated Nitrile Butadiene‎) are proven to shut-off and control flow of common refrigerant gases. T&D can provide expert technical advice and sales support for the specification of solenoid valves to provide safe refrigerant gas flow control and also refrigerant gas detection.

Pinch Solenoid Valves

Solenoid Valves - SIRAI Pinch Valves

Solenoid Valves – SIRAI Pinch Valves

The operating principle of Pinch solenoid valves differs from general service type valves – the pinching device is moved by a solenoid operator and shuts-off the fluid by pinching or releasing a tubing in soft silicon. The fluid can flow in either direction with a high rate of flow, without turbulence or “dead spaces”.

Pinch solenoid valves control all the fluids that are compatible with the tubing material, protecting them from all contamination, including temperature changes – extensively used in chemical, pharmaceutical, food, medical and analyser applications.

Pinch solenoid valves are available in 2/2 or 3/2 (2-way and 3-way) configurations with normally closed or normally open options – compact version and latching models are also available.

Coils For Solenoid Valves

Solenoid Coils For Solenoid Valves

Solenoid Coils For Solenoid Valves

An extensive range of SIRAI solenoid coils are available:

  • Encapsulated Coils – choice of power supply, materials and electrical connections
  • Linear Solenoids – galvanised steel body or with encapsulated coils, “F” class insulation and wound with a “H” class wire
  • Holding Solenoids – DC coils, external diameters ranging from 30-70mm, “F” class insulation and “H” class wound wire available with flying leads or spade terminals electrical connections
  • Locking Solenoids – provided with “F” class insulation and “H” class wound wire, built-in return spring with encapsulated coils or with stainless steel body

Dry Solenoid Valves – Total Isolation Type

Total isolation solenoid valves (DRY) combine the traditional characteristics of strength and reliability with construction suitable for the flow control of aggressive and/or non-contaminable fluids. The fluid is in contact only with the solenoid valve body and the isolation lever or isolation diaphragm; consequently the fluid is protected from any chemical contamination and/or thermic shock.

Total isolation valves are available in 2/2 or 3/2 (2-way and 3-way) normally closed, normally open or universal service versions – compact and silent type valves with latching actuators are available. In widespread serviced throughout the food, biotechnology, chemical, pharmaceutical and physiological/medical sectors.

Contact T&D to discuss flow control requirements for hazardous area solenoid valves where ATEX approved valves are required for installation in potentially explosive atmospheres. Should you require support selecting solenoid valves please call T&D to talk to our technical sales engineers.

Hazardous Area Valves

Solenoid Valves With Hazardous Area Approvals – ATEX, IECEx, INMETRO, NEPSI & GOST.

WRAS Approved Solenoid Valves

  • SIRAI L282D WRAS Approved Solenoid Valves – 2/2 Normally Open Pilot Operated
  • SIRAI L182D WRAS Approved Solenoid Valves – 2/2 Normally Closed Pilot Operated – refer to downloads opposite for specification, performance and ordering details about SIRAI WRAS Approved valves.

securing breeam credits

Flow Control Devices (One BREEAM Credit)

T&D work closely with M&E Engineering Consultants and their building services contractors writing specifications to assist in securing BREEAM credits for sustainable building projects.

Sample Specification By Thorne & Derrick

Credit and criteria is applicable to commercial areas / properties only.

Thorne & Derrick flow control devices, regulate the supply of water to each WC area or facility according to demand and therefore minimise water leaks and wastage from sanitary fittings.

The system shall include;

Installation of a sanitary supply shut off system to each toilet area within the building, controlling supply to all urinals, wash hand basins and WCs linked to a PIR movement detector such that once the washroom has been unoccupied for pre-set (but adjustable) time, the system will automatically turn the water supply ‘off’ again, thus saving water if the water systems leak, or are deliberately left on.

The unit shall incorporate a mains powered control unit operating a magnetic latch solenoid valve with programmable delay period of 10 seconds to 40 minutes.

Where combined toilet areas (for example male and female facilities) are fed from a common supply, one solenoid valve serving the core shall be installed, operating under the control of a sensor within each individual toilet area.

The solenoid valve shall be of a type that is normally closed, powered open.

Solenoid valves shall be specified to pipe diameter and / or flow rates and must be manufactured by Sirai, product range L182 brass bodied, 230v, rated up to 10 bar, (minimum pressure differential required to operate: ½”, ¾” and 1” require 0.35 bar), WRAS approved product.

To discuss your requirements regarding BREEAM credits for your project, please contact Thorne & Derrick.

T&D can also provide written specifications to achieve BREEAM Credits for Refrigerant Gas Detection.

Read Blog: BREEAM Pol 01 – Murco Refrigerant Gas Detection Products Achieve Recognition

BREEAM Pol 01 – Murco Refrigerant Gas Detection Products Achieve Recognition

Solenoid Valve Manufacturing

SIRAI are a leading European manufacturer of solenoid valves – the following selection of images demonstrate SIRAI’s commitment to advancing the development of valve technology at their modern factory using research and development, laboratory testing to a Quality Manufacturing System according to Bureau Veritas ISO 9001: 2008.

SIRAI Valves

Valve Research & Development

Manufacturing Solenoid Valves

Manufacturing Solenoid Valves

Solenoid Valve Assembly

Solenoid Valve Assembly


Solenoid Valve Testing

Solenoid Valve Testing

Vacuum Impregnating Solenoid Coils

Vacuum Impregnating Solenoid Coils

Evaluation Of Solenoid Valves

Evaluation Of Solenoid Valves


SIRAI was founded in 1946 in Milan, by Mr. Lamberto Vanti, under the name RAI (Regolatori Automatici Industriali = Automatic Industrial Controllers), initially manufacturing heating and air conditioning components, 3-pole pressure switches, electric servo-motors and motorised valves.

In 1947, the Company changed the corporate name to SIRAI. Gradually, SIRAI commenced manufacturing pneumatic instruments with relevant valves, including solenoid valves, to satisfy demands of the evolving industrial automation sector.

In 1998, SIRAI became part of the US Emerson Electric Co. Group. Following the 2009 merger with ASCO Numatics and Sotrac, Emerson Group companies, a new company was established under the name of ASCO Numatics SIRAI.


ASCO Numatics S.p.a., Sirai Elettromeccanica S.r.l. and Sotrac S.r.l. announced their merger into a single company called ASCO NUMATICS SIRAI S.r.l. in 2010.

How T&D Can Help YouWater

Since 1985 T&D have serviced the UK and world markets with an extensive range of Electrical, Mechanical, Process & Instrumentation Equipment – our Export Department is staffed by a team of professional sales engineers, sourcing specialists, expeditors and customer service advisors.

T&D global project experience has enabled us to build a solid reputation for the reliable supply of brand leaders – we consolidate your supply chain by providing single-source logistics to any international destination.

    • Measurement – Temperature, Humidity, Pressure, CO2

      SIRAI Solenoid Valves - Factory

      SIRAI Solenoid Valves – Factory

See how Thorne & Derrick service and support our key global markets and hazardous area industries in the following SlideShelf of Industry Infographics.

      • Gas Detectors (Industrial), Leak Detection (Refrigerant) & Analyzers
      • Heat Tracing Systems & Trace Heating Cables
      • Heaters – Drum, IBC, Tank, Immersion & Process
      • Solenoid Valves, Gauges, Sensors & Monitors
      • Meters – Flow, Water, Gas, Heat & Energy
      • Surface Heating Elements, Mats & Pads
      • Hazardous Area Power Distribution, Lighting & Enclosures

Integrity, Values & Trust. T&D are a world-class business committed to ensuring the correct installation and application of all products we distribute. Where applicable installer training and support services including site surveys can be made available.