Sil3 Actuator Control Valves Provide Solutions for Safety Instrumented Systems Builders


o Helps process control designers meet IEC 61508 & 61511 safety standards

Grimsby, Ontario, Canada - Midland-ACS announces that a wide range of its actuator control valve products have undergone third-party assessment to the IEC 61508 functional safety standard, and are now certified to support SIL (safety integrity level) 3 capability. Control valves with this high level of safety integrity are increasingly being specified by process industries to protect personnel and plant, by ensuring fail-safe operation of critical functions such as emergency shutdown. By using SIL3 capable stainless steel valves and actuation controls, designers of safety instrumented systems are able to more easily comply with the risk reduction requirements of the IEC 61508 and 61511 technical safety standards.

As part of the process of attaining IEC 61508 certification, Midland-ACS worked closely with the conformity assessment solutions specialist SIRA. "The certification process is all-embracing," says James Kingham of Midland-ACS. "The first part involved analyzing each valve to component level, evaluating the risk, mode and consequences of failure. The second part comprised a comprehensive audit of company processes, including our engineering, production, quality assurance and sales operations. Obtaining SIL3 capability certification for such a broad range of products is a considerable accolade for Midland-ACS, and we are already submitting low service temperature poppet and spool valves, along with further hydraulic products, for assessment."

The first tranche of products to receive SIL3 capability status include direct-acting solenoid and pilot operated poppet valves, pilot operated spool valves, and a number of pilot operated and direct-acting solenoid hydraulic valves for use in ballast control systems. The introduction of such a diverse range of SIL3 capable products provides designers of pneumatic and hydraulic actuation systems with significant configuration flexibility.

All variants of Midland-ACS' 70 Series direct-acting solenoid 3/2 poppet valves are now certified in accordance with IEC 61508 to have SIL3 support capability. Offering a choice of 1/4, 3/8 and 1/2 inch ports, these valves are designed primarily for actuator control using pneumatic or low-pressure hydraulic media. Two types of solenoid are available, certified to protection classes EExd IIC T6 and T4.

A number of 3/2 body ported poppet valves from Midland-ACS' 1750 Series now support SIL3 capability. These compact pilot air operated valves feature large flow paths to minimize pressure drop. Certified models include standard temperature service (-20 to 180 degrees Celsius) valves with Viton seals, spanning port sizes from 1/4 to 1-1/2 inches, as well as 2- and 3-inch port size valves with Nitrile seals.

The standard temperature service versions of pilot operated 3/2 spool valves from Midland-ACS' 1500 and 1600 Series also now support SIL3 capability. These Viton-sealed valves offer a choice of 1/4 and 1/2 inch port sizes.

Many Midland-ACS hydraulic valve products for ballast control systems are also now certified for SIL3 capability. These include the DN5, DN10 and DN15 Series pilot-operated valves, as well as the DN3 Series direct-acting solenoid valves. All these designs feature an integral balanced piloting system that enables the low-powered solenoid to switch the valve at high pressures. The DN5, 10 and 15 Series products have metal-to-metal seats, while the DN3 Series employs a ceramic ball and a stainless steel seat. The SIL3 capable version of the DN3 offers a stay-put manual override facility, and is available certified for protection classes ExD IIC T6 and T5.

All Midland-ACS products certified to SIL3 capability are supplied complete with copies of the Sira certification, which contains all the information that engineers and designers need to calculate the safety integrity level of the complete system, based on its component parts.

Midland-ACS North America, PO Box 422, Ontario L3M 4H8, Canada. t: (905) 309-1834; f: (905) 309-1835.

Background information on Xylem

Midland-ACS is part of the Flow Control business unit of Xylem. Xylem was established in October 2011 as a spinoff from ITT Corporation. It is a leading global water technology company with operations in more than 150 countries, global 2010 revenues of $3.2 billion, and a shared commitment to making a difference in communities around the world. Xylem is comprised of four business units - Water Solutions, Flow Control, Analytics and Residential and Commercial Water. These units are interconnected to one another, anticipating and reflecting the evolving needs and sharing their applications expertise to cover every stage of the water cycle. The name Xylem is derived from classical Greek, and refers to the supporting tissues that help transport water and nutrients from a plant's roots to its leaves. www.xyleminc.com

Sira is a world leader in the conformity assessment solutions field, specialising in explosion safety of equipment used in potentially explosive atmospheres (ATEX & IECEx) and has been examining products and issuing certificates for over 20 years. A large team of experienced ATEX compliance engineers deliver a flexible and commercial approach to approvals, offering a single point contact for all ATEX compliance and hazardous area requirements. In 2009, Sira became a CSA International company and provides certification to North American requirements. info@siracertification.com; tel +44 (0) 1244 670 900.

More from Food Processing & Preparation

All Topics