Building Technologies

Fast response FLT93F flow switch monitors room positive air pressure and exhaust ventilation systems

17 June 2022

Plant engineers and maintenance staff responsible for ensuring the reliable operation of positive air flow pressure and exhaust ventilation systems for clean rooms, labs, analyzer houses or production areas will find the FLT93F flow switch from Fluid Components International (FCI) provides them a highly sensitive and reliable solution to monitor and alarm if their system is degrading, not operating to specifications, or has shut-down.

Positive air flow pressure and exhaust ventilation systems are designed to ensure contaminants are continuously prevented from entering an area or are removed to maintain a safe, healthy closed environment. These systems are found in a wide range of settings, such as clean rooms, research laboratories and production environments, as well as analyzer houses and sheltered areas. Many industries make use of these systems, including the pharmaceutical, biotech and medical industries, as well as chemical plants, refineries and power plants.

These specialized environmental air systems use fans to maintain a higher than ambient air pressureSource: FCISource: FCI environment inside a designated area to ensure clean, contaminate-free air and strong exhaust fans to remove hazardous fumes. With its SIL 2 rating, the highly accurate and dependable FLT93F flow switch is ideal for use when these sensitive application environments are part of a safety instrumented system (SIS) requirement.

The FCI Model FLT93F flow switch is specifically designed for air and gas flow detection. It is both fast responding and capable of detecting even very slight changes in air flow and available in a variety of process connections for ease of installation in most any pipe, vent or duct size. Its universal power supply supports powering by 115 V AC, 230 V AC, or 24 V DC. Trip-point/alarm points are easily user set in the field, at the installation. It comes standard with fail-safe, heavy-duty dual alarm (SPDT) or DPDT relay outputs, rated 6 amps at 115 V AC, 240 V AC or 24 V DC.

The flow sensor element is an all-welded design and constructed of premium 316L stainless steel. It has no moving parts to break or orifices to foul or clog so there is no required routine maintenance needed. The flow switch instrument is available in a choice of rugged, all metal enclosures that are NEMA 4X/IP66 rated for long service life in the most demanding installations and environments. Electronics can be mounted integral with the flow element or remote mounted a distance away from hazardous areas.

For applications in potentially explosive dust or gas environments, the FLT93F is also suitable for installation in Div.1/Zone 1 areas and certified to local standards of FM, FMc, ATEX, IECEx, NEPSI, EAC, Inmetro, UKCA and EQM/ECAS. It also meets the EC directives for EMC and LVD and the flow element complies with Canadian Electrical code requirements of ANSI/ISA 12.27.01-2011 as a single seal device.

To contact the author of this article, email

Powered by CR4, the Engineering Community

Discussion – 0 comments

By posting a comment you confirm that you have read and accept our Posting Rules and Terms of Use.
Engineering Newsletter Signup
Get the Engineering360
Stay up to date on:
Features the top stories, latest news, charts, insights and more on the end-to-end electronics value chain.
Weekly Newsletter
Get news, research, and analysis
on the Electronics industry in your
inbox every week - for FREE
Sign up for our FREE eNewsletter
Find Free Electronics Datasheets